![Stefan Agner](/assets/img/avatar_default.png)
Use enum dma_transfer_direction as required by the functions dmaengine_prep_slave_(sg|single)() instead of enum dma_data_direction. This won't change behavior in practice as the enum values are equivalent. This fixes two warnings when building with clang: drivers/spi/spi-atmel.c:771:12: warning: implicit conversion from enumeration type 'enum dma_data_direction' to different enumeration type 'enum dma_transfer_direction' [-Wenum-conversion] DMA_FROM_DEVICE, ^~~~~~~~~~~~~~~ ... Signed-off-by: Stefan Agner <stefan@agner.ch> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
1844 lines
47 KiB
C
1844 lines
47 KiB
C
/*
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* Driver for Atmel AT32 and AT91 SPI Controllers
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*
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* Copyright (C) 2006 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/clk.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/delay.h>
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#include <linux/dma-mapping.h>
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#include <linux/dmaengine.h>
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#include <linux/err.h>
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#include <linux/interrupt.h>
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#include <linux/spi/spi.h>
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#include <linux/slab.h>
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#include <linux/platform_data/dma-atmel.h>
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#include <linux/of.h>
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#include <linux/io.h>
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#include <linux/gpio.h>
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#include <linux/of_gpio.h>
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#include <linux/pinctrl/consumer.h>
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#include <linux/pm_runtime.h>
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/* SPI register offsets */
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#define SPI_CR 0x0000
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#define SPI_MR 0x0004
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#define SPI_RDR 0x0008
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#define SPI_TDR 0x000c
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#define SPI_SR 0x0010
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#define SPI_IER 0x0014
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#define SPI_IDR 0x0018
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#define SPI_IMR 0x001c
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#define SPI_CSR0 0x0030
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#define SPI_CSR1 0x0034
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#define SPI_CSR2 0x0038
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#define SPI_CSR3 0x003c
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#define SPI_FMR 0x0040
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#define SPI_FLR 0x0044
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#define SPI_VERSION 0x00fc
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#define SPI_RPR 0x0100
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#define SPI_RCR 0x0104
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#define SPI_TPR 0x0108
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#define SPI_TCR 0x010c
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#define SPI_RNPR 0x0110
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#define SPI_RNCR 0x0114
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#define SPI_TNPR 0x0118
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#define SPI_TNCR 0x011c
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#define SPI_PTCR 0x0120
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#define SPI_PTSR 0x0124
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/* Bitfields in CR */
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#define SPI_SPIEN_OFFSET 0
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#define SPI_SPIEN_SIZE 1
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#define SPI_SPIDIS_OFFSET 1
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#define SPI_SPIDIS_SIZE 1
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#define SPI_SWRST_OFFSET 7
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#define SPI_SWRST_SIZE 1
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#define SPI_LASTXFER_OFFSET 24
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#define SPI_LASTXFER_SIZE 1
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#define SPI_TXFCLR_OFFSET 16
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#define SPI_TXFCLR_SIZE 1
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#define SPI_RXFCLR_OFFSET 17
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#define SPI_RXFCLR_SIZE 1
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#define SPI_FIFOEN_OFFSET 30
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#define SPI_FIFOEN_SIZE 1
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#define SPI_FIFODIS_OFFSET 31
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#define SPI_FIFODIS_SIZE 1
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/* Bitfields in MR */
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#define SPI_MSTR_OFFSET 0
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#define SPI_MSTR_SIZE 1
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#define SPI_PS_OFFSET 1
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#define SPI_PS_SIZE 1
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#define SPI_PCSDEC_OFFSET 2
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#define SPI_PCSDEC_SIZE 1
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#define SPI_FDIV_OFFSET 3
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#define SPI_FDIV_SIZE 1
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#define SPI_MODFDIS_OFFSET 4
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#define SPI_MODFDIS_SIZE 1
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#define SPI_WDRBT_OFFSET 5
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#define SPI_WDRBT_SIZE 1
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#define SPI_LLB_OFFSET 7
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#define SPI_LLB_SIZE 1
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#define SPI_PCS_OFFSET 16
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#define SPI_PCS_SIZE 4
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#define SPI_DLYBCS_OFFSET 24
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#define SPI_DLYBCS_SIZE 8
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/* Bitfields in RDR */
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#define SPI_RD_OFFSET 0
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#define SPI_RD_SIZE 16
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/* Bitfields in TDR */
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#define SPI_TD_OFFSET 0
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#define SPI_TD_SIZE 16
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/* Bitfields in SR */
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#define SPI_RDRF_OFFSET 0
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#define SPI_RDRF_SIZE 1
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#define SPI_TDRE_OFFSET 1
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#define SPI_TDRE_SIZE 1
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#define SPI_MODF_OFFSET 2
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#define SPI_MODF_SIZE 1
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#define SPI_OVRES_OFFSET 3
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#define SPI_OVRES_SIZE 1
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#define SPI_ENDRX_OFFSET 4
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#define SPI_ENDRX_SIZE 1
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#define SPI_ENDTX_OFFSET 5
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#define SPI_ENDTX_SIZE 1
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#define SPI_RXBUFF_OFFSET 6
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#define SPI_RXBUFF_SIZE 1
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#define SPI_TXBUFE_OFFSET 7
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#define SPI_TXBUFE_SIZE 1
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#define SPI_NSSR_OFFSET 8
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#define SPI_NSSR_SIZE 1
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#define SPI_TXEMPTY_OFFSET 9
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#define SPI_TXEMPTY_SIZE 1
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#define SPI_SPIENS_OFFSET 16
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#define SPI_SPIENS_SIZE 1
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#define SPI_TXFEF_OFFSET 24
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#define SPI_TXFEF_SIZE 1
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#define SPI_TXFFF_OFFSET 25
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#define SPI_TXFFF_SIZE 1
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#define SPI_TXFTHF_OFFSET 26
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#define SPI_TXFTHF_SIZE 1
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#define SPI_RXFEF_OFFSET 27
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#define SPI_RXFEF_SIZE 1
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#define SPI_RXFFF_OFFSET 28
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#define SPI_RXFFF_SIZE 1
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#define SPI_RXFTHF_OFFSET 29
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#define SPI_RXFTHF_SIZE 1
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#define SPI_TXFPTEF_OFFSET 30
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#define SPI_TXFPTEF_SIZE 1
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#define SPI_RXFPTEF_OFFSET 31
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#define SPI_RXFPTEF_SIZE 1
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/* Bitfields in CSR0 */
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#define SPI_CPOL_OFFSET 0
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#define SPI_CPOL_SIZE 1
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#define SPI_NCPHA_OFFSET 1
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#define SPI_NCPHA_SIZE 1
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#define SPI_CSAAT_OFFSET 3
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#define SPI_CSAAT_SIZE 1
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#define SPI_BITS_OFFSET 4
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#define SPI_BITS_SIZE 4
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#define SPI_SCBR_OFFSET 8
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#define SPI_SCBR_SIZE 8
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#define SPI_DLYBS_OFFSET 16
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#define SPI_DLYBS_SIZE 8
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#define SPI_DLYBCT_OFFSET 24
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#define SPI_DLYBCT_SIZE 8
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/* Bitfields in RCR */
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#define SPI_RXCTR_OFFSET 0
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#define SPI_RXCTR_SIZE 16
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/* Bitfields in TCR */
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#define SPI_TXCTR_OFFSET 0
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#define SPI_TXCTR_SIZE 16
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/* Bitfields in RNCR */
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#define SPI_RXNCR_OFFSET 0
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#define SPI_RXNCR_SIZE 16
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/* Bitfields in TNCR */
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#define SPI_TXNCR_OFFSET 0
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#define SPI_TXNCR_SIZE 16
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/* Bitfields in PTCR */
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#define SPI_RXTEN_OFFSET 0
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#define SPI_RXTEN_SIZE 1
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#define SPI_RXTDIS_OFFSET 1
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#define SPI_RXTDIS_SIZE 1
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#define SPI_TXTEN_OFFSET 8
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#define SPI_TXTEN_SIZE 1
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#define SPI_TXTDIS_OFFSET 9
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#define SPI_TXTDIS_SIZE 1
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/* Bitfields in FMR */
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#define SPI_TXRDYM_OFFSET 0
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#define SPI_TXRDYM_SIZE 2
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#define SPI_RXRDYM_OFFSET 4
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#define SPI_RXRDYM_SIZE 2
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#define SPI_TXFTHRES_OFFSET 16
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#define SPI_TXFTHRES_SIZE 6
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#define SPI_RXFTHRES_OFFSET 24
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#define SPI_RXFTHRES_SIZE 6
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/* Bitfields in FLR */
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#define SPI_TXFL_OFFSET 0
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#define SPI_TXFL_SIZE 6
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#define SPI_RXFL_OFFSET 16
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#define SPI_RXFL_SIZE 6
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/* Constants for BITS */
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#define SPI_BITS_8_BPT 0
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#define SPI_BITS_9_BPT 1
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#define SPI_BITS_10_BPT 2
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#define SPI_BITS_11_BPT 3
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#define SPI_BITS_12_BPT 4
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#define SPI_BITS_13_BPT 5
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#define SPI_BITS_14_BPT 6
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#define SPI_BITS_15_BPT 7
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#define SPI_BITS_16_BPT 8
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#define SPI_ONE_DATA 0
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#define SPI_TWO_DATA 1
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#define SPI_FOUR_DATA 2
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/* Bit manipulation macros */
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#define SPI_BIT(name) \
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(1 << SPI_##name##_OFFSET)
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#define SPI_BF(name, value) \
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(((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
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#define SPI_BFEXT(name, value) \
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(((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
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#define SPI_BFINS(name, value, old) \
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(((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
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| SPI_BF(name, value))
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/* Register access macros */
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#ifdef CONFIG_AVR32
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#define spi_readl(port, reg) \
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__raw_readl((port)->regs + SPI_##reg)
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#define spi_writel(port, reg, value) \
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__raw_writel((value), (port)->regs + SPI_##reg)
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#define spi_readw(port, reg) \
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__raw_readw((port)->regs + SPI_##reg)
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#define spi_writew(port, reg, value) \
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__raw_writew((value), (port)->regs + SPI_##reg)
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#define spi_readb(port, reg) \
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__raw_readb((port)->regs + SPI_##reg)
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#define spi_writeb(port, reg, value) \
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__raw_writeb((value), (port)->regs + SPI_##reg)
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#else
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#define spi_readl(port, reg) \
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readl_relaxed((port)->regs + SPI_##reg)
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#define spi_writel(port, reg, value) \
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writel_relaxed((value), (port)->regs + SPI_##reg)
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#define spi_readw(port, reg) \
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readw_relaxed((port)->regs + SPI_##reg)
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#define spi_writew(port, reg, value) \
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writew_relaxed((value), (port)->regs + SPI_##reg)
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#define spi_readb(port, reg) \
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readb_relaxed((port)->regs + SPI_##reg)
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#define spi_writeb(port, reg, value) \
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writeb_relaxed((value), (port)->regs + SPI_##reg)
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#endif
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/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
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* cache operations; better heuristics consider wordsize and bitrate.
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*/
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#define DMA_MIN_BYTES 16
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#define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000))
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#define AUTOSUSPEND_TIMEOUT 2000
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struct atmel_spi_caps {
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bool is_spi2;
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bool has_wdrbt;
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bool has_dma_support;
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bool has_pdc_support;
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};
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/*
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* The core SPI transfer engine just talks to a register bank to set up
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* DMA transfers; transfer queue progress is driven by IRQs. The clock
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* framework provides the base clock, subdivided for each spi_device.
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*/
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struct atmel_spi {
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spinlock_t lock;
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unsigned long flags;
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phys_addr_t phybase;
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void __iomem *regs;
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int irq;
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struct clk *clk;
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struct platform_device *pdev;
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unsigned long spi_clk;
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struct spi_transfer *current_transfer;
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int current_remaining_bytes;
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int done_status;
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dma_addr_t dma_addr_rx_bbuf;
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dma_addr_t dma_addr_tx_bbuf;
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void *addr_rx_bbuf;
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void *addr_tx_bbuf;
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struct completion xfer_completion;
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struct atmel_spi_caps caps;
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bool use_dma;
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bool use_pdc;
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bool use_cs_gpios;
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bool keep_cs;
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bool cs_active;
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u32 fifo_size;
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};
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/* Controller-specific per-slave state */
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struct atmel_spi_device {
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unsigned int npcs_pin;
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u32 csr;
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};
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#define SPI_MAX_DMA_XFER 65535 /* true for both PDC and DMA */
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#define INVALID_DMA_ADDRESS 0xffffffff
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/*
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* Version 2 of the SPI controller has
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* - CR.LASTXFER
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* - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
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* - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
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* - SPI_CSRx.CSAAT
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* - SPI_CSRx.SBCR allows faster clocking
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*/
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static bool atmel_spi_is_v2(struct atmel_spi *as)
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{
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return as->caps.is_spi2;
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}
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/*
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* Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
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* they assume that spi slave device state will not change on deselect, so
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* that automagic deselection is OK. ("NPCSx rises if no data is to be
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* transmitted") Not so! Workaround uses nCSx pins as GPIOs; or newer
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* controllers have CSAAT and friends.
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*
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* Since the CSAAT functionality is a bit weird on newer controllers as
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* well, we use GPIO to control nCSx pins on all controllers, updating
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* MR.PCS to avoid confusing the controller. Using GPIOs also lets us
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* support active-high chipselects despite the controller's belief that
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* only active-low devices/systems exists.
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*
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* However, at91rm9200 has a second erratum whereby nCS0 doesn't work
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* right when driven with GPIO. ("Mode Fault does not allow more than one
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* Master on Chip Select 0.") No workaround exists for that ... so for
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* nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
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* and (c) will trigger that first erratum in some cases.
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*/
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static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
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{
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struct atmel_spi_device *asd = spi->controller_state;
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unsigned active = spi->mode & SPI_CS_HIGH;
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u32 mr;
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if (atmel_spi_is_v2(as)) {
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spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
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/* For the low SPI version, there is a issue that PDC transfer
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* on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
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*/
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spi_writel(as, CSR0, asd->csr);
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if (as->caps.has_wdrbt) {
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spi_writel(as, MR,
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SPI_BF(PCS, ~(0x01 << spi->chip_select))
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| SPI_BIT(WDRBT)
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| SPI_BIT(MODFDIS)
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| SPI_BIT(MSTR));
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} else {
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spi_writel(as, MR,
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SPI_BF(PCS, ~(0x01 << spi->chip_select))
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| SPI_BIT(MODFDIS)
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| SPI_BIT(MSTR));
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}
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mr = spi_readl(as, MR);
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if (as->use_cs_gpios)
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gpio_set_value(asd->npcs_pin, active);
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} else {
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u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
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int i;
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u32 csr;
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/* Make sure clock polarity is correct */
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for (i = 0; i < spi->master->num_chipselect; i++) {
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csr = spi_readl(as, CSR0 + 4 * i);
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if ((csr ^ cpol) & SPI_BIT(CPOL))
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spi_writel(as, CSR0 + 4 * i,
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csr ^ SPI_BIT(CPOL));
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}
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mr = spi_readl(as, MR);
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mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
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if (as->use_cs_gpios && spi->chip_select != 0)
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gpio_set_value(asd->npcs_pin, active);
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spi_writel(as, MR, mr);
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}
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dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
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asd->npcs_pin, active ? " (high)" : "",
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mr);
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}
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static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
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{
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struct atmel_spi_device *asd = spi->controller_state;
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unsigned active = spi->mode & SPI_CS_HIGH;
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u32 mr;
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/* only deactivate *this* device; sometimes transfers to
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* another device may be active when this routine is called.
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*/
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mr = spi_readl(as, MR);
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if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
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mr = SPI_BFINS(PCS, 0xf, mr);
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spi_writel(as, MR, mr);
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}
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dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
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asd->npcs_pin, active ? " (low)" : "",
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mr);
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if (!as->use_cs_gpios)
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spi_writel(as, CR, SPI_BIT(LASTXFER));
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else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
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gpio_set_value(asd->npcs_pin, !active);
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}
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static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
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{
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spin_lock_irqsave(&as->lock, as->flags);
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}
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static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock)
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{
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spin_unlock_irqrestore(&as->lock, as->flags);
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}
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static inline bool atmel_spi_is_vmalloc_xfer(struct spi_transfer *xfer)
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{
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return is_vmalloc_addr(xfer->tx_buf) || is_vmalloc_addr(xfer->rx_buf);
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}
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static inline bool atmel_spi_use_dma(struct atmel_spi *as,
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struct spi_transfer *xfer)
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{
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return as->use_dma && xfer->len >= DMA_MIN_BYTES;
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}
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static bool atmel_spi_can_dma(struct spi_master *master,
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struct spi_device *spi,
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struct spi_transfer *xfer)
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{
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struct atmel_spi *as = spi_master_get_devdata(master);
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if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5))
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return atmel_spi_use_dma(as, xfer) &&
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!atmel_spi_is_vmalloc_xfer(xfer);
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else
|
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return atmel_spi_use_dma(as, xfer);
|
|
|
|
}
|
|
|
|
static int atmel_spi_dma_slave_config(struct atmel_spi *as,
|
|
struct dma_slave_config *slave_config,
|
|
u8 bits_per_word)
|
|
{
|
|
struct spi_master *master = platform_get_drvdata(as->pdev);
|
|
int err = 0;
|
|
|
|
if (bits_per_word > 8) {
|
|
slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
|
|
slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
|
|
} else {
|
|
slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
|
|
slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
|
|
}
|
|
|
|
slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
|
|
slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR;
|
|
slave_config->src_maxburst = 1;
|
|
slave_config->dst_maxburst = 1;
|
|
slave_config->device_fc = false;
|
|
|
|
/*
|
|
* This driver uses fixed peripheral select mode (PS bit set to '0' in
|
|
* the Mode Register).
|
|
* So according to the datasheet, when FIFOs are available (and
|
|
* enabled), the Transmit FIFO operates in Multiple Data Mode.
|
|
* In this mode, up to 2 data, not 4, can be written into the Transmit
|
|
* Data Register in a single access.
|
|
* However, the first data has to be written into the lowest 16 bits and
|
|
* the second data into the highest 16 bits of the Transmit
|
|
* Data Register. For 8bit data (the most frequent case), it would
|
|
* require to rework tx_buf so each data would actualy fit 16 bits.
|
|
* So we'd rather write only one data at the time. Hence the transmit
|
|
* path works the same whether FIFOs are available (and enabled) or not.
|
|
*/
|
|
slave_config->direction = DMA_MEM_TO_DEV;
|
|
if (dmaengine_slave_config(master->dma_tx, slave_config)) {
|
|
dev_err(&as->pdev->dev,
|
|
"failed to configure tx dma channel\n");
|
|
err = -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* This driver configures the spi controller for master mode (MSTR bit
|
|
* set to '1' in the Mode Register).
|
|
* So according to the datasheet, when FIFOs are available (and
|
|
* enabled), the Receive FIFO operates in Single Data Mode.
|
|
* So the receive path works the same whether FIFOs are available (and
|
|
* enabled) or not.
|
|
*/
|
|
slave_config->direction = DMA_DEV_TO_MEM;
|
|
if (dmaengine_slave_config(master->dma_rx, slave_config)) {
|
|
dev_err(&as->pdev->dev,
|
|
"failed to configure rx dma channel\n");
|
|
err = -EINVAL;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int atmel_spi_configure_dma(struct spi_master *master,
|
|
struct atmel_spi *as)
|
|
{
|
|
struct dma_slave_config slave_config;
|
|
struct device *dev = &as->pdev->dev;
|
|
int err;
|
|
|
|
dma_cap_mask_t mask;
|
|
dma_cap_zero(mask);
|
|
dma_cap_set(DMA_SLAVE, mask);
|
|
|
|
master->dma_tx = dma_request_slave_channel_reason(dev, "tx");
|
|
if (IS_ERR(master->dma_tx)) {
|
|
err = PTR_ERR(master->dma_tx);
|
|
if (err == -EPROBE_DEFER) {
|
|
dev_warn(dev, "no DMA channel available at the moment\n");
|
|
goto error_clear;
|
|
}
|
|
dev_err(dev,
|
|
"DMA TX channel not available, SPI unable to use DMA\n");
|
|
err = -EBUSY;
|
|
goto error_clear;
|
|
}
|
|
|
|
/*
|
|
* No reason to check EPROBE_DEFER here since we have already requested
|
|
* tx channel. If it fails here, it's for another reason.
|
|
*/
|
|
master->dma_rx = dma_request_slave_channel(dev, "rx");
|
|
|
|
if (!master->dma_rx) {
|
|
dev_err(dev,
|
|
"DMA RX channel not available, SPI unable to use DMA\n");
|
|
err = -EBUSY;
|
|
goto error;
|
|
}
|
|
|
|
err = atmel_spi_dma_slave_config(as, &slave_config, 8);
|
|
if (err)
|
|
goto error;
|
|
|
|
dev_info(&as->pdev->dev,
|
|
"Using %s (tx) and %s (rx) for DMA transfers\n",
|
|
dma_chan_name(master->dma_tx),
|
|
dma_chan_name(master->dma_rx));
|
|
|
|
return 0;
|
|
error:
|
|
if (master->dma_rx)
|
|
dma_release_channel(master->dma_rx);
|
|
if (!IS_ERR(master->dma_tx))
|
|
dma_release_channel(master->dma_tx);
|
|
error_clear:
|
|
master->dma_tx = master->dma_rx = NULL;
|
|
return err;
|
|
}
|
|
|
|
static void atmel_spi_stop_dma(struct spi_master *master)
|
|
{
|
|
if (master->dma_rx)
|
|
dmaengine_terminate_all(master->dma_rx);
|
|
if (master->dma_tx)
|
|
dmaengine_terminate_all(master->dma_tx);
|
|
}
|
|
|
|
static void atmel_spi_release_dma(struct spi_master *master)
|
|
{
|
|
if (master->dma_rx) {
|
|
dma_release_channel(master->dma_rx);
|
|
master->dma_rx = NULL;
|
|
}
|
|
if (master->dma_tx) {
|
|
dma_release_channel(master->dma_tx);
|
|
master->dma_tx = NULL;
|
|
}
|
|
}
|
|
|
|
/* This function is called by the DMA driver from tasklet context */
|
|
static void dma_callback(void *data)
|
|
{
|
|
struct spi_master *master = data;
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
|
|
if (is_vmalloc_addr(as->current_transfer->rx_buf) &&
|
|
IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
|
|
memcpy(as->current_transfer->rx_buf, as->addr_rx_bbuf,
|
|
as->current_transfer->len);
|
|
}
|
|
complete(&as->xfer_completion);
|
|
}
|
|
|
|
/*
|
|
* Next transfer using PIO without FIFO.
|
|
*/
|
|
static void atmel_spi_next_xfer_single(struct spi_master *master,
|
|
struct spi_transfer *xfer)
|
|
{
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
|
|
|
|
dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
|
|
|
|
/* Make sure data is not remaining in RDR */
|
|
spi_readl(as, RDR);
|
|
while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
|
|
spi_readl(as, RDR);
|
|
cpu_relax();
|
|
}
|
|
|
|
if (xfer->bits_per_word > 8)
|
|
spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
|
|
else
|
|
spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
|
|
|
|
dev_dbg(master->dev.parent,
|
|
" start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
|
|
xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
|
|
xfer->bits_per_word);
|
|
|
|
/* Enable relevant interrupts */
|
|
spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES));
|
|
}
|
|
|
|
/*
|
|
* Next transfer using PIO with FIFO.
|
|
*/
|
|
static void atmel_spi_next_xfer_fifo(struct spi_master *master,
|
|
struct spi_transfer *xfer)
|
|
{
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
u32 current_remaining_data, num_data;
|
|
u32 offset = xfer->len - as->current_remaining_bytes;
|
|
const u16 *words = (const u16 *)((u8 *)xfer->tx_buf + offset);
|
|
const u8 *bytes = (const u8 *)((u8 *)xfer->tx_buf + offset);
|
|
u16 td0, td1;
|
|
u32 fifomr;
|
|
|
|
dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_fifo\n");
|
|
|
|
/* Compute the number of data to transfer in the current iteration */
|
|
current_remaining_data = ((xfer->bits_per_word > 8) ?
|
|
((u32)as->current_remaining_bytes >> 1) :
|
|
(u32)as->current_remaining_bytes);
|
|
num_data = min(current_remaining_data, as->fifo_size);
|
|
|
|
/* Flush RX and TX FIFOs */
|
|
spi_writel(as, CR, SPI_BIT(RXFCLR) | SPI_BIT(TXFCLR));
|
|
while (spi_readl(as, FLR))
|
|
cpu_relax();
|
|
|
|
/* Set RX FIFO Threshold to the number of data to transfer */
|
|
fifomr = spi_readl(as, FMR);
|
|
spi_writel(as, FMR, SPI_BFINS(RXFTHRES, num_data, fifomr));
|
|
|
|
/* Clear FIFO flags in the Status Register, especially RXFTHF */
|
|
(void)spi_readl(as, SR);
|
|
|
|
/* Fill TX FIFO */
|
|
while (num_data >= 2) {
|
|
if (xfer->bits_per_word > 8) {
|
|
td0 = *words++;
|
|
td1 = *words++;
|
|
} else {
|
|
td0 = *bytes++;
|
|
td1 = *bytes++;
|
|
}
|
|
|
|
spi_writel(as, TDR, (td1 << 16) | td0);
|
|
num_data -= 2;
|
|
}
|
|
|
|
if (num_data) {
|
|
if (xfer->bits_per_word > 8)
|
|
td0 = *words++;
|
|
else
|
|
td0 = *bytes++;
|
|
|
|
spi_writew(as, TDR, td0);
|
|
num_data--;
|
|
}
|
|
|
|
dev_dbg(master->dev.parent,
|
|
" start fifo xfer %p: len %u tx %p rx %p bitpw %d\n",
|
|
xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
|
|
xfer->bits_per_word);
|
|
|
|
/*
|
|
* Enable RX FIFO Threshold Flag interrupt to be notified about
|
|
* transfer completion.
|
|
*/
|
|
spi_writel(as, IER, SPI_BIT(RXFTHF) | SPI_BIT(OVRES));
|
|
}
|
|
|
|
/*
|
|
* Next transfer using PIO.
|
|
*/
|
|
static void atmel_spi_next_xfer_pio(struct spi_master *master,
|
|
struct spi_transfer *xfer)
|
|
{
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
|
|
if (as->fifo_size)
|
|
atmel_spi_next_xfer_fifo(master, xfer);
|
|
else
|
|
atmel_spi_next_xfer_single(master, xfer);
|
|
}
|
|
|
|
/*
|
|
* Submit next transfer for DMA.
|
|
*/
|
|
static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
|
|
struct spi_transfer *xfer,
|
|
u32 *plen)
|
|
{
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
struct dma_chan *rxchan = master->dma_rx;
|
|
struct dma_chan *txchan = master->dma_tx;
|
|
struct dma_async_tx_descriptor *rxdesc;
|
|
struct dma_async_tx_descriptor *txdesc;
|
|
struct dma_slave_config slave_config;
|
|
dma_cookie_t cookie;
|
|
|
|
dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
|
|
|
|
/* Check that the channels are available */
|
|
if (!rxchan || !txchan)
|
|
return -ENODEV;
|
|
|
|
/* release lock for DMA operations */
|
|
atmel_spi_unlock(as);
|
|
|
|
*plen = xfer->len;
|
|
|
|
if (atmel_spi_dma_slave_config(as, &slave_config,
|
|
xfer->bits_per_word))
|
|
goto err_exit;
|
|
|
|
/* Send both scatterlists */
|
|
if (atmel_spi_is_vmalloc_xfer(xfer) &&
|
|
IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
|
|
rxdesc = dmaengine_prep_slave_single(rxchan,
|
|
as->dma_addr_rx_bbuf,
|
|
xfer->len,
|
|
DMA_DEV_TO_MEM,
|
|
DMA_PREP_INTERRUPT |
|
|
DMA_CTRL_ACK);
|
|
} else {
|
|
rxdesc = dmaengine_prep_slave_sg(rxchan,
|
|
xfer->rx_sg.sgl,
|
|
xfer->rx_sg.nents,
|
|
DMA_DEV_TO_MEM,
|
|
DMA_PREP_INTERRUPT |
|
|
DMA_CTRL_ACK);
|
|
}
|
|
if (!rxdesc)
|
|
goto err_dma;
|
|
|
|
if (atmel_spi_is_vmalloc_xfer(xfer) &&
|
|
IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
|
|
memcpy(as->addr_tx_bbuf, xfer->tx_buf, xfer->len);
|
|
txdesc = dmaengine_prep_slave_single(txchan,
|
|
as->dma_addr_tx_bbuf,
|
|
xfer->len, DMA_MEM_TO_DEV,
|
|
DMA_PREP_INTERRUPT |
|
|
DMA_CTRL_ACK);
|
|
} else {
|
|
txdesc = dmaengine_prep_slave_sg(txchan,
|
|
xfer->tx_sg.sgl,
|
|
xfer->tx_sg.nents,
|
|
DMA_MEM_TO_DEV,
|
|
DMA_PREP_INTERRUPT |
|
|
DMA_CTRL_ACK);
|
|
}
|
|
if (!txdesc)
|
|
goto err_dma;
|
|
|
|
dev_dbg(master->dev.parent,
|
|
" start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
|
|
xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
|
|
xfer->rx_buf, (unsigned long long)xfer->rx_dma);
|
|
|
|
/* Enable relevant interrupts */
|
|
spi_writel(as, IER, SPI_BIT(OVRES));
|
|
|
|
/* Put the callback on the RX transfer only, that should finish last */
|
|
rxdesc->callback = dma_callback;
|
|
rxdesc->callback_param = master;
|
|
|
|
/* Submit and fire RX and TX with TX last so we're ready to read! */
|
|
cookie = rxdesc->tx_submit(rxdesc);
|
|
if (dma_submit_error(cookie))
|
|
goto err_dma;
|
|
cookie = txdesc->tx_submit(txdesc);
|
|
if (dma_submit_error(cookie))
|
|
goto err_dma;
|
|
rxchan->device->device_issue_pending(rxchan);
|
|
txchan->device->device_issue_pending(txchan);
|
|
|
|
/* take back lock */
|
|
atmel_spi_lock(as);
|
|
return 0;
|
|
|
|
err_dma:
|
|
spi_writel(as, IDR, SPI_BIT(OVRES));
|
|
atmel_spi_stop_dma(master);
|
|
err_exit:
|
|
atmel_spi_lock(as);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void atmel_spi_next_xfer_data(struct spi_master *master,
|
|
struct spi_transfer *xfer,
|
|
dma_addr_t *tx_dma,
|
|
dma_addr_t *rx_dma,
|
|
u32 *plen)
|
|
{
|
|
*rx_dma = xfer->rx_dma + xfer->len - *plen;
|
|
*tx_dma = xfer->tx_dma + xfer->len - *plen;
|
|
if (*plen > master->max_dma_len)
|
|
*plen = master->max_dma_len;
|
|
}
|
|
|
|
static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
|
|
struct spi_device *spi,
|
|
struct spi_transfer *xfer)
|
|
{
|
|
u32 scbr, csr;
|
|
unsigned long bus_hz;
|
|
|
|
/* v1 chips start out at half the peripheral bus speed. */
|
|
bus_hz = as->spi_clk;
|
|
if (!atmel_spi_is_v2(as))
|
|
bus_hz /= 2;
|
|
|
|
/*
|
|
* Calculate the lowest divider that satisfies the
|
|
* constraint, assuming div32/fdiv/mbz == 0.
|
|
*/
|
|
scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
|
|
|
|
/*
|
|
* If the resulting divider doesn't fit into the
|
|
* register bitfield, we can't satisfy the constraint.
|
|
*/
|
|
if (scbr >= (1 << SPI_SCBR_SIZE)) {
|
|
dev_err(&spi->dev,
|
|
"setup: %d Hz too slow, scbr %u; min %ld Hz\n",
|
|
xfer->speed_hz, scbr, bus_hz/255);
|
|
return -EINVAL;
|
|
}
|
|
if (scbr == 0) {
|
|
dev_err(&spi->dev,
|
|
"setup: %d Hz too high, scbr %u; max %ld Hz\n",
|
|
xfer->speed_hz, scbr, bus_hz);
|
|
return -EINVAL;
|
|
}
|
|
csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
|
|
csr = SPI_BFINS(SCBR, scbr, csr);
|
|
spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Submit next transfer for PDC.
|
|
* lock is held, spi irq is blocked
|
|
*/
|
|
static void atmel_spi_pdc_next_xfer(struct spi_master *master,
|
|
struct spi_message *msg,
|
|
struct spi_transfer *xfer)
|
|
{
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
u32 len;
|
|
dma_addr_t tx_dma, rx_dma;
|
|
|
|
spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
|
|
|
|
len = as->current_remaining_bytes;
|
|
atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
|
|
as->current_remaining_bytes -= len;
|
|
|
|
spi_writel(as, RPR, rx_dma);
|
|
spi_writel(as, TPR, tx_dma);
|
|
|
|
if (msg->spi->bits_per_word > 8)
|
|
len >>= 1;
|
|
spi_writel(as, RCR, len);
|
|
spi_writel(as, TCR, len);
|
|
|
|
dev_dbg(&msg->spi->dev,
|
|
" start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
|
|
xfer, xfer->len, xfer->tx_buf,
|
|
(unsigned long long)xfer->tx_dma, xfer->rx_buf,
|
|
(unsigned long long)xfer->rx_dma);
|
|
|
|
if (as->current_remaining_bytes) {
|
|
len = as->current_remaining_bytes;
|
|
atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
|
|
as->current_remaining_bytes -= len;
|
|
|
|
spi_writel(as, RNPR, rx_dma);
|
|
spi_writel(as, TNPR, tx_dma);
|
|
|
|
if (msg->spi->bits_per_word > 8)
|
|
len >>= 1;
|
|
spi_writel(as, RNCR, len);
|
|
spi_writel(as, TNCR, len);
|
|
|
|
dev_dbg(&msg->spi->dev,
|
|
" next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
|
|
xfer, xfer->len, xfer->tx_buf,
|
|
(unsigned long long)xfer->tx_dma, xfer->rx_buf,
|
|
(unsigned long long)xfer->rx_dma);
|
|
}
|
|
|
|
/* REVISIT: We're waiting for RXBUFF before we start the next
|
|
* transfer because we need to handle some difficult timing
|
|
* issues otherwise. If we wait for TXBUFE in one transfer and
|
|
* then starts waiting for RXBUFF in the next, it's difficult
|
|
* to tell the difference between the RXBUFF interrupt we're
|
|
* actually waiting for and the RXBUFF interrupt of the
|
|
* previous transfer.
|
|
*
|
|
* It should be doable, though. Just not now...
|
|
*/
|
|
spi_writel(as, IER, SPI_BIT(RXBUFF) | SPI_BIT(OVRES));
|
|
spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
|
|
}
|
|
|
|
/*
|
|
* For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
|
|
* - The buffer is either valid for CPU access, else NULL
|
|
* - If the buffer is valid, so is its DMA address
|
|
*
|
|
* This driver manages the dma address unless message->is_dma_mapped.
|
|
*/
|
|
static int
|
|
atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
|
|
{
|
|
struct device *dev = &as->pdev->dev;
|
|
|
|
xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
|
|
if (xfer->tx_buf) {
|
|
/* tx_buf is a const void* where we need a void * for the dma
|
|
* mapping */
|
|
void *nonconst_tx = (void *)xfer->tx_buf;
|
|
|
|
xfer->tx_dma = dma_map_single(dev,
|
|
nonconst_tx, xfer->len,
|
|
DMA_TO_DEVICE);
|
|
if (dma_mapping_error(dev, xfer->tx_dma))
|
|
return -ENOMEM;
|
|
}
|
|
if (xfer->rx_buf) {
|
|
xfer->rx_dma = dma_map_single(dev,
|
|
xfer->rx_buf, xfer->len,
|
|
DMA_FROM_DEVICE);
|
|
if (dma_mapping_error(dev, xfer->rx_dma)) {
|
|
if (xfer->tx_buf)
|
|
dma_unmap_single(dev,
|
|
xfer->tx_dma, xfer->len,
|
|
DMA_TO_DEVICE);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
|
|
struct spi_transfer *xfer)
|
|
{
|
|
if (xfer->tx_dma != INVALID_DMA_ADDRESS)
|
|
dma_unmap_single(master->dev.parent, xfer->tx_dma,
|
|
xfer->len, DMA_TO_DEVICE);
|
|
if (xfer->rx_dma != INVALID_DMA_ADDRESS)
|
|
dma_unmap_single(master->dev.parent, xfer->rx_dma,
|
|
xfer->len, DMA_FROM_DEVICE);
|
|
}
|
|
|
|
static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
|
|
{
|
|
spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
|
|
}
|
|
|
|
static void
|
|
atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer)
|
|
{
|
|
u8 *rxp;
|
|
u16 *rxp16;
|
|
unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
|
|
|
|
if (xfer->bits_per_word > 8) {
|
|
rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
|
|
*rxp16 = spi_readl(as, RDR);
|
|
} else {
|
|
rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
|
|
*rxp = spi_readl(as, RDR);
|
|
}
|
|
if (xfer->bits_per_word > 8) {
|
|
if (as->current_remaining_bytes > 2)
|
|
as->current_remaining_bytes -= 2;
|
|
else
|
|
as->current_remaining_bytes = 0;
|
|
} else {
|
|
as->current_remaining_bytes--;
|
|
}
|
|
}
|
|
|
|
static void
|
|
atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer)
|
|
{
|
|
u32 fifolr = spi_readl(as, FLR);
|
|
u32 num_bytes, num_data = SPI_BFEXT(RXFL, fifolr);
|
|
u32 offset = xfer->len - as->current_remaining_bytes;
|
|
u16 *words = (u16 *)((u8 *)xfer->rx_buf + offset);
|
|
u8 *bytes = (u8 *)((u8 *)xfer->rx_buf + offset);
|
|
u16 rd; /* RD field is the lowest 16 bits of RDR */
|
|
|
|
/* Update the number of remaining bytes to transfer */
|
|
num_bytes = ((xfer->bits_per_word > 8) ?
|
|
(num_data << 1) :
|
|
num_data);
|
|
|
|
if (as->current_remaining_bytes > num_bytes)
|
|
as->current_remaining_bytes -= num_bytes;
|
|
else
|
|
as->current_remaining_bytes = 0;
|
|
|
|
/* Handle odd number of bytes when data are more than 8bit width */
|
|
if (xfer->bits_per_word > 8)
|
|
as->current_remaining_bytes &= ~0x1;
|
|
|
|
/* Read data */
|
|
while (num_data) {
|
|
rd = spi_readl(as, RDR);
|
|
if (xfer->bits_per_word > 8)
|
|
*words++ = rd;
|
|
else
|
|
*bytes++ = rd;
|
|
num_data--;
|
|
}
|
|
}
|
|
|
|
/* Called from IRQ
|
|
*
|
|
* Must update "current_remaining_bytes" to keep track of data
|
|
* to transfer.
|
|
*/
|
|
static void
|
|
atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
|
|
{
|
|
if (as->fifo_size)
|
|
atmel_spi_pump_fifo_data(as, xfer);
|
|
else
|
|
atmel_spi_pump_single_data(as, xfer);
|
|
}
|
|
|
|
/* Interrupt
|
|
*
|
|
* No need for locking in this Interrupt handler: done_status is the
|
|
* only information modified.
|
|
*/
|
|
static irqreturn_t
|
|
atmel_spi_pio_interrupt(int irq, void *dev_id)
|
|
{
|
|
struct spi_master *master = dev_id;
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
u32 status, pending, imr;
|
|
struct spi_transfer *xfer;
|
|
int ret = IRQ_NONE;
|
|
|
|
imr = spi_readl(as, IMR);
|
|
status = spi_readl(as, SR);
|
|
pending = status & imr;
|
|
|
|
if (pending & SPI_BIT(OVRES)) {
|
|
ret = IRQ_HANDLED;
|
|
spi_writel(as, IDR, SPI_BIT(OVRES));
|
|
dev_warn(master->dev.parent, "overrun\n");
|
|
|
|
/*
|
|
* When we get an overrun, we disregard the current
|
|
* transfer. Data will not be copied back from any
|
|
* bounce buffer and msg->actual_len will not be
|
|
* updated with the last xfer.
|
|
*
|
|
* We will also not process any remaning transfers in
|
|
* the message.
|
|
*/
|
|
as->done_status = -EIO;
|
|
smp_wmb();
|
|
|
|
/* Clear any overrun happening while cleaning up */
|
|
spi_readl(as, SR);
|
|
|
|
complete(&as->xfer_completion);
|
|
|
|
} else if (pending & (SPI_BIT(RDRF) | SPI_BIT(RXFTHF))) {
|
|
atmel_spi_lock(as);
|
|
|
|
if (as->current_remaining_bytes) {
|
|
ret = IRQ_HANDLED;
|
|
xfer = as->current_transfer;
|
|
atmel_spi_pump_pio_data(as, xfer);
|
|
if (!as->current_remaining_bytes)
|
|
spi_writel(as, IDR, pending);
|
|
|
|
complete(&as->xfer_completion);
|
|
}
|
|
|
|
atmel_spi_unlock(as);
|
|
} else {
|
|
WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
|
|
ret = IRQ_HANDLED;
|
|
spi_writel(as, IDR, pending);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static irqreturn_t
|
|
atmel_spi_pdc_interrupt(int irq, void *dev_id)
|
|
{
|
|
struct spi_master *master = dev_id;
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
u32 status, pending, imr;
|
|
int ret = IRQ_NONE;
|
|
|
|
imr = spi_readl(as, IMR);
|
|
status = spi_readl(as, SR);
|
|
pending = status & imr;
|
|
|
|
if (pending & SPI_BIT(OVRES)) {
|
|
|
|
ret = IRQ_HANDLED;
|
|
|
|
spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
|
|
| SPI_BIT(OVRES)));
|
|
|
|
/* Clear any overrun happening while cleaning up */
|
|
spi_readl(as, SR);
|
|
|
|
as->done_status = -EIO;
|
|
|
|
complete(&as->xfer_completion);
|
|
|
|
} else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
|
|
ret = IRQ_HANDLED;
|
|
|
|
spi_writel(as, IDR, pending);
|
|
|
|
complete(&as->xfer_completion);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int atmel_spi_setup(struct spi_device *spi)
|
|
{
|
|
struct atmel_spi *as;
|
|
struct atmel_spi_device *asd;
|
|
u32 csr;
|
|
unsigned int bits = spi->bits_per_word;
|
|
unsigned int npcs_pin;
|
|
|
|
as = spi_master_get_devdata(spi->master);
|
|
|
|
/* see notes above re chipselect */
|
|
if (!atmel_spi_is_v2(as)
|
|
&& spi->chip_select == 0
|
|
&& (spi->mode & SPI_CS_HIGH)) {
|
|
dev_dbg(&spi->dev, "setup: can't be active-high\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
csr = SPI_BF(BITS, bits - 8);
|
|
if (spi->mode & SPI_CPOL)
|
|
csr |= SPI_BIT(CPOL);
|
|
if (!(spi->mode & SPI_CPHA))
|
|
csr |= SPI_BIT(NCPHA);
|
|
if (!as->use_cs_gpios)
|
|
csr |= SPI_BIT(CSAAT);
|
|
|
|
/* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
|
|
*
|
|
* DLYBCT would add delays between words, slowing down transfers.
|
|
* It could potentially be useful to cope with DMA bottlenecks, but
|
|
* in those cases it's probably best to just use a lower bitrate.
|
|
*/
|
|
csr |= SPI_BF(DLYBS, 0);
|
|
csr |= SPI_BF(DLYBCT, 0);
|
|
|
|
/* chipselect must have been muxed as GPIO (e.g. in board setup) */
|
|
npcs_pin = (unsigned long)spi->controller_data;
|
|
|
|
if (!as->use_cs_gpios)
|
|
npcs_pin = spi->chip_select;
|
|
else if (gpio_is_valid(spi->cs_gpio))
|
|
npcs_pin = spi->cs_gpio;
|
|
|
|
asd = spi->controller_state;
|
|
if (!asd) {
|
|
asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
|
|
if (!asd)
|
|
return -ENOMEM;
|
|
|
|
if (as->use_cs_gpios)
|
|
gpio_direction_output(npcs_pin,
|
|
!(spi->mode & SPI_CS_HIGH));
|
|
|
|
asd->npcs_pin = npcs_pin;
|
|
spi->controller_state = asd;
|
|
}
|
|
|
|
asd->csr = csr;
|
|
|
|
dev_dbg(&spi->dev,
|
|
"setup: bpw %u mode 0x%x -> csr%d %08x\n",
|
|
bits, spi->mode, spi->chip_select, csr);
|
|
|
|
if (!atmel_spi_is_v2(as))
|
|
spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int atmel_spi_one_transfer(struct spi_master *master,
|
|
struct spi_message *msg,
|
|
struct spi_transfer *xfer)
|
|
{
|
|
struct atmel_spi *as;
|
|
struct spi_device *spi = msg->spi;
|
|
u8 bits;
|
|
u32 len;
|
|
struct atmel_spi_device *asd;
|
|
int timeout;
|
|
int ret;
|
|
unsigned long dma_timeout;
|
|
|
|
as = spi_master_get_devdata(master);
|
|
|
|
if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
|
|
dev_dbg(&spi->dev, "missing rx or tx buf\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
asd = spi->controller_state;
|
|
bits = (asd->csr >> 4) & 0xf;
|
|
if (bits != xfer->bits_per_word - 8) {
|
|
dev_dbg(&spi->dev,
|
|
"you can't yet change bits_per_word in transfers\n");
|
|
return -ENOPROTOOPT;
|
|
}
|
|
|
|
/*
|
|
* DMA map early, for performance (empties dcache ASAP) and
|
|
* better fault reporting.
|
|
*/
|
|
if ((!msg->is_dma_mapped)
|
|
&& as->use_pdc) {
|
|
if (atmel_spi_dma_map_xfer(as, xfer) < 0)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
atmel_spi_set_xfer_speed(as, msg->spi, xfer);
|
|
|
|
as->done_status = 0;
|
|
as->current_transfer = xfer;
|
|
as->current_remaining_bytes = xfer->len;
|
|
while (as->current_remaining_bytes) {
|
|
reinit_completion(&as->xfer_completion);
|
|
|
|
if (as->use_pdc) {
|
|
atmel_spi_pdc_next_xfer(master, msg, xfer);
|
|
} else if (atmel_spi_use_dma(as, xfer)) {
|
|
len = as->current_remaining_bytes;
|
|
ret = atmel_spi_next_xfer_dma_submit(master,
|
|
xfer, &len);
|
|
if (ret) {
|
|
dev_err(&spi->dev,
|
|
"unable to use DMA, fallback to PIO\n");
|
|
atmel_spi_next_xfer_pio(master, xfer);
|
|
} else {
|
|
as->current_remaining_bytes -= len;
|
|
if (as->current_remaining_bytes < 0)
|
|
as->current_remaining_bytes = 0;
|
|
}
|
|
} else {
|
|
atmel_spi_next_xfer_pio(master, xfer);
|
|
}
|
|
|
|
/* interrupts are disabled, so free the lock for schedule */
|
|
atmel_spi_unlock(as);
|
|
dma_timeout = wait_for_completion_timeout(&as->xfer_completion,
|
|
SPI_DMA_TIMEOUT);
|
|
atmel_spi_lock(as);
|
|
if (WARN_ON(dma_timeout == 0)) {
|
|
dev_err(&spi->dev, "spi transfer timeout\n");
|
|
as->done_status = -EIO;
|
|
}
|
|
|
|
if (as->done_status)
|
|
break;
|
|
}
|
|
|
|
if (as->done_status) {
|
|
if (as->use_pdc) {
|
|
dev_warn(master->dev.parent,
|
|
"overrun (%u/%u remaining)\n",
|
|
spi_readl(as, TCR), spi_readl(as, RCR));
|
|
|
|
/*
|
|
* Clean up DMA registers and make sure the data
|
|
* registers are empty.
|
|
*/
|
|
spi_writel(as, RNCR, 0);
|
|
spi_writel(as, TNCR, 0);
|
|
spi_writel(as, RCR, 0);
|
|
spi_writel(as, TCR, 0);
|
|
for (timeout = 1000; timeout; timeout--)
|
|
if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
|
|
break;
|
|
if (!timeout)
|
|
dev_warn(master->dev.parent,
|
|
"timeout waiting for TXEMPTY");
|
|
while (spi_readl(as, SR) & SPI_BIT(RDRF))
|
|
spi_readl(as, RDR);
|
|
|
|
/* Clear any overrun happening while cleaning up */
|
|
spi_readl(as, SR);
|
|
|
|
} else if (atmel_spi_use_dma(as, xfer)) {
|
|
atmel_spi_stop_dma(master);
|
|
}
|
|
|
|
if (!msg->is_dma_mapped
|
|
&& as->use_pdc)
|
|
atmel_spi_dma_unmap_xfer(master, xfer);
|
|
|
|
return 0;
|
|
|
|
} else {
|
|
/* only update length if no error */
|
|
msg->actual_length += xfer->len;
|
|
}
|
|
|
|
if (!msg->is_dma_mapped
|
|
&& as->use_pdc)
|
|
atmel_spi_dma_unmap_xfer(master, xfer);
|
|
|
|
if (xfer->delay_usecs)
|
|
udelay(xfer->delay_usecs);
|
|
|
|
if (xfer->cs_change) {
|
|
if (list_is_last(&xfer->transfer_list,
|
|
&msg->transfers)) {
|
|
as->keep_cs = true;
|
|
} else {
|
|
as->cs_active = !as->cs_active;
|
|
if (as->cs_active)
|
|
cs_activate(as, msg->spi);
|
|
else
|
|
cs_deactivate(as, msg->spi);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int atmel_spi_transfer_one_message(struct spi_master *master,
|
|
struct spi_message *msg)
|
|
{
|
|
struct atmel_spi *as;
|
|
struct spi_transfer *xfer;
|
|
struct spi_device *spi = msg->spi;
|
|
int ret = 0;
|
|
|
|
as = spi_master_get_devdata(master);
|
|
|
|
dev_dbg(&spi->dev, "new message %p submitted for %s\n",
|
|
msg, dev_name(&spi->dev));
|
|
|
|
atmel_spi_lock(as);
|
|
cs_activate(as, spi);
|
|
|
|
as->cs_active = true;
|
|
as->keep_cs = false;
|
|
|
|
msg->status = 0;
|
|
msg->actual_length = 0;
|
|
|
|
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
|
|
ret = atmel_spi_one_transfer(master, msg, xfer);
|
|
if (ret)
|
|
goto msg_done;
|
|
}
|
|
|
|
if (as->use_pdc)
|
|
atmel_spi_disable_pdc_transfer(as);
|
|
|
|
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
|
|
dev_dbg(&spi->dev,
|
|
" xfer %p: len %u tx %p/%pad rx %p/%pad\n",
|
|
xfer, xfer->len,
|
|
xfer->tx_buf, &xfer->tx_dma,
|
|
xfer->rx_buf, &xfer->rx_dma);
|
|
}
|
|
|
|
msg_done:
|
|
if (!as->keep_cs)
|
|
cs_deactivate(as, msg->spi);
|
|
|
|
atmel_spi_unlock(as);
|
|
|
|
msg->status = as->done_status;
|
|
spi_finalize_current_message(spi->master);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void atmel_spi_cleanup(struct spi_device *spi)
|
|
{
|
|
struct atmel_spi_device *asd = spi->controller_state;
|
|
|
|
if (!asd)
|
|
return;
|
|
|
|
spi->controller_state = NULL;
|
|
kfree(asd);
|
|
}
|
|
|
|
static inline unsigned int atmel_get_version(struct atmel_spi *as)
|
|
{
|
|
return spi_readl(as, VERSION) & 0x00000fff;
|
|
}
|
|
|
|
static void atmel_get_caps(struct atmel_spi *as)
|
|
{
|
|
unsigned int version;
|
|
|
|
version = atmel_get_version(as);
|
|
|
|
as->caps.is_spi2 = version > 0x121;
|
|
as->caps.has_wdrbt = version >= 0x210;
|
|
as->caps.has_dma_support = version >= 0x212;
|
|
as->caps.has_pdc_support = version < 0x212;
|
|
}
|
|
|
|
/*-------------------------------------------------------------------------*/
|
|
static int atmel_spi_gpio_cs(struct platform_device *pdev)
|
|
{
|
|
struct spi_master *master = platform_get_drvdata(pdev);
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
struct device_node *np = master->dev.of_node;
|
|
int i;
|
|
int ret = 0;
|
|
int nb = 0;
|
|
|
|
if (!as->use_cs_gpios)
|
|
return 0;
|
|
|
|
if (!np)
|
|
return 0;
|
|
|
|
nb = of_gpio_named_count(np, "cs-gpios");
|
|
for (i = 0; i < nb; i++) {
|
|
int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
|
|
"cs-gpios", i);
|
|
|
|
if (cs_gpio == -EPROBE_DEFER)
|
|
return cs_gpio;
|
|
|
|
if (gpio_is_valid(cs_gpio)) {
|
|
ret = devm_gpio_request(&pdev->dev, cs_gpio,
|
|
dev_name(&pdev->dev));
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void atmel_spi_init(struct atmel_spi *as)
|
|
{
|
|
spi_writel(as, CR, SPI_BIT(SWRST));
|
|
spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
|
|
|
|
/* It is recommended to enable FIFOs first thing after reset */
|
|
if (as->fifo_size)
|
|
spi_writel(as, CR, SPI_BIT(FIFOEN));
|
|
|
|
if (as->caps.has_wdrbt) {
|
|
spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
|
|
| SPI_BIT(MSTR));
|
|
} else {
|
|
spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
|
|
}
|
|
|
|
if (as->use_pdc)
|
|
spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
|
|
spi_writel(as, CR, SPI_BIT(SPIEN));
|
|
}
|
|
|
|
static int atmel_spi_probe(struct platform_device *pdev)
|
|
{
|
|
struct resource *regs;
|
|
int irq;
|
|
struct clk *clk;
|
|
int ret;
|
|
struct spi_master *master;
|
|
struct atmel_spi *as;
|
|
|
|
/* Select default pin state */
|
|
pinctrl_pm_select_default_state(&pdev->dev);
|
|
|
|
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
if (!regs)
|
|
return -ENXIO;
|
|
|
|
irq = platform_get_irq(pdev, 0);
|
|
if (irq < 0)
|
|
return irq;
|
|
|
|
clk = devm_clk_get(&pdev->dev, "spi_clk");
|
|
if (IS_ERR(clk))
|
|
return PTR_ERR(clk);
|
|
|
|
/* setup spi core then atmel-specific driver state */
|
|
ret = -ENOMEM;
|
|
master = spi_alloc_master(&pdev->dev, sizeof(*as));
|
|
if (!master)
|
|
goto out_free;
|
|
|
|
/* the spi->mode bits understood by this driver: */
|
|
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
|
|
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
|
|
master->dev.of_node = pdev->dev.of_node;
|
|
master->bus_num = pdev->id;
|
|
master->num_chipselect = master->dev.of_node ? 0 : 4;
|
|
master->setup = atmel_spi_setup;
|
|
master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
|
|
master->transfer_one_message = atmel_spi_transfer_one_message;
|
|
master->cleanup = atmel_spi_cleanup;
|
|
master->auto_runtime_pm = true;
|
|
master->max_dma_len = SPI_MAX_DMA_XFER;
|
|
master->can_dma = atmel_spi_can_dma;
|
|
platform_set_drvdata(pdev, master);
|
|
|
|
as = spi_master_get_devdata(master);
|
|
|
|
spin_lock_init(&as->lock);
|
|
|
|
as->pdev = pdev;
|
|
as->regs = devm_ioremap_resource(&pdev->dev, regs);
|
|
if (IS_ERR(as->regs)) {
|
|
ret = PTR_ERR(as->regs);
|
|
goto out_unmap_regs;
|
|
}
|
|
as->phybase = regs->start;
|
|
as->irq = irq;
|
|
as->clk = clk;
|
|
|
|
init_completion(&as->xfer_completion);
|
|
|
|
atmel_get_caps(as);
|
|
|
|
as->use_cs_gpios = true;
|
|
if (atmel_spi_is_v2(as) &&
|
|
pdev->dev.of_node &&
|
|
!of_get_property(pdev->dev.of_node, "cs-gpios", NULL)) {
|
|
as->use_cs_gpios = false;
|
|
master->num_chipselect = 4;
|
|
}
|
|
|
|
ret = atmel_spi_gpio_cs(pdev);
|
|
if (ret)
|
|
goto out_unmap_regs;
|
|
|
|
as->use_dma = false;
|
|
as->use_pdc = false;
|
|
if (as->caps.has_dma_support) {
|
|
ret = atmel_spi_configure_dma(master, as);
|
|
if (ret == 0) {
|
|
as->use_dma = true;
|
|
} else if (ret == -EPROBE_DEFER) {
|
|
return ret;
|
|
}
|
|
} else if (as->caps.has_pdc_support) {
|
|
as->use_pdc = true;
|
|
}
|
|
|
|
if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
|
|
as->addr_rx_bbuf = dma_alloc_coherent(&pdev->dev,
|
|
SPI_MAX_DMA_XFER,
|
|
&as->dma_addr_rx_bbuf,
|
|
GFP_KERNEL | GFP_DMA);
|
|
if (!as->addr_rx_bbuf) {
|
|
as->use_dma = false;
|
|
} else {
|
|
as->addr_tx_bbuf = dma_alloc_coherent(&pdev->dev,
|
|
SPI_MAX_DMA_XFER,
|
|
&as->dma_addr_tx_bbuf,
|
|
GFP_KERNEL | GFP_DMA);
|
|
if (!as->addr_tx_bbuf) {
|
|
as->use_dma = false;
|
|
dma_free_coherent(&pdev->dev, SPI_MAX_DMA_XFER,
|
|
as->addr_rx_bbuf,
|
|
as->dma_addr_rx_bbuf);
|
|
}
|
|
}
|
|
if (!as->use_dma)
|
|
dev_info(master->dev.parent,
|
|
" can not allocate dma coherent memory\n");
|
|
}
|
|
|
|
if (as->caps.has_dma_support && !as->use_dma)
|
|
dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
|
|
|
|
if (as->use_pdc) {
|
|
ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
|
|
0, dev_name(&pdev->dev), master);
|
|
} else {
|
|
ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
|
|
0, dev_name(&pdev->dev), master);
|
|
}
|
|
if (ret)
|
|
goto out_unmap_regs;
|
|
|
|
/* Initialize the hardware */
|
|
ret = clk_prepare_enable(clk);
|
|
if (ret)
|
|
goto out_free_irq;
|
|
|
|
as->spi_clk = clk_get_rate(clk);
|
|
|
|
as->fifo_size = 0;
|
|
if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
|
|
&as->fifo_size)) {
|
|
dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size);
|
|
}
|
|
|
|
atmel_spi_init(as);
|
|
|
|
pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
|
|
pm_runtime_use_autosuspend(&pdev->dev);
|
|
pm_runtime_set_active(&pdev->dev);
|
|
pm_runtime_enable(&pdev->dev);
|
|
|
|
ret = devm_spi_register_master(&pdev->dev, master);
|
|
if (ret)
|
|
goto out_free_dma;
|
|
|
|
/* go! */
|
|
dev_info(&pdev->dev, "Atmel SPI Controller version 0x%x at 0x%08lx (irq %d)\n",
|
|
atmel_get_version(as), (unsigned long)regs->start,
|
|
irq);
|
|
|
|
return 0;
|
|
|
|
out_free_dma:
|
|
pm_runtime_disable(&pdev->dev);
|
|
pm_runtime_set_suspended(&pdev->dev);
|
|
|
|
if (as->use_dma)
|
|
atmel_spi_release_dma(master);
|
|
|
|
spi_writel(as, CR, SPI_BIT(SWRST));
|
|
spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
|
|
clk_disable_unprepare(clk);
|
|
out_free_irq:
|
|
out_unmap_regs:
|
|
out_free:
|
|
spi_master_put(master);
|
|
return ret;
|
|
}
|
|
|
|
static int atmel_spi_remove(struct platform_device *pdev)
|
|
{
|
|
struct spi_master *master = platform_get_drvdata(pdev);
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
|
|
pm_runtime_get_sync(&pdev->dev);
|
|
|
|
/* reset the hardware and block queue progress */
|
|
if (as->use_dma) {
|
|
atmel_spi_stop_dma(master);
|
|
atmel_spi_release_dma(master);
|
|
if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
|
|
dma_free_coherent(&pdev->dev, SPI_MAX_DMA_XFER,
|
|
as->addr_tx_bbuf,
|
|
as->dma_addr_tx_bbuf);
|
|
dma_free_coherent(&pdev->dev, SPI_MAX_DMA_XFER,
|
|
as->addr_rx_bbuf,
|
|
as->dma_addr_rx_bbuf);
|
|
}
|
|
}
|
|
|
|
spin_lock_irq(&as->lock);
|
|
spi_writel(as, CR, SPI_BIT(SWRST));
|
|
spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
|
|
spi_readl(as, SR);
|
|
spin_unlock_irq(&as->lock);
|
|
|
|
clk_disable_unprepare(as->clk);
|
|
|
|
pm_runtime_put_noidle(&pdev->dev);
|
|
pm_runtime_disable(&pdev->dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PM
|
|
static int atmel_spi_runtime_suspend(struct device *dev)
|
|
{
|
|
struct spi_master *master = dev_get_drvdata(dev);
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
|
|
clk_disable_unprepare(as->clk);
|
|
pinctrl_pm_select_sleep_state(dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int atmel_spi_runtime_resume(struct device *dev)
|
|
{
|
|
struct spi_master *master = dev_get_drvdata(dev);
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
|
|
pinctrl_pm_select_default_state(dev);
|
|
|
|
return clk_prepare_enable(as->clk);
|
|
}
|
|
|
|
#ifdef CONFIG_PM_SLEEP
|
|
static int atmel_spi_suspend(struct device *dev)
|
|
{
|
|
struct spi_master *master = dev_get_drvdata(dev);
|
|
int ret;
|
|
|
|
/* Stop the queue running */
|
|
ret = spi_master_suspend(master);
|
|
if (ret) {
|
|
dev_warn(dev, "cannot suspend master\n");
|
|
return ret;
|
|
}
|
|
|
|
if (!pm_runtime_suspended(dev))
|
|
atmel_spi_runtime_suspend(dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int atmel_spi_resume(struct device *dev)
|
|
{
|
|
struct spi_master *master = dev_get_drvdata(dev);
|
|
struct atmel_spi *as = spi_master_get_devdata(master);
|
|
int ret;
|
|
|
|
ret = clk_prepare_enable(as->clk);
|
|
if (ret)
|
|
return ret;
|
|
|
|
atmel_spi_init(as);
|
|
|
|
clk_disable_unprepare(as->clk);
|
|
|
|
if (!pm_runtime_suspended(dev)) {
|
|
ret = atmel_spi_runtime_resume(dev);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
/* Start the queue running */
|
|
ret = spi_master_resume(master);
|
|
if (ret)
|
|
dev_err(dev, "problem starting queue (%d)\n", ret);
|
|
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
static const struct dev_pm_ops atmel_spi_pm_ops = {
|
|
SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
|
|
SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
|
|
atmel_spi_runtime_resume, NULL)
|
|
};
|
|
#define ATMEL_SPI_PM_OPS (&atmel_spi_pm_ops)
|
|
#else
|
|
#define ATMEL_SPI_PM_OPS NULL
|
|
#endif
|
|
|
|
#if defined(CONFIG_OF)
|
|
static const struct of_device_id atmel_spi_dt_ids[] = {
|
|
{ .compatible = "atmel,at91rm9200-spi" },
|
|
{ /* sentinel */ }
|
|
};
|
|
|
|
MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
|
|
#endif
|
|
|
|
static struct platform_driver atmel_spi_driver = {
|
|
.driver = {
|
|
.name = "atmel_spi",
|
|
.pm = ATMEL_SPI_PM_OPS,
|
|
.of_match_table = of_match_ptr(atmel_spi_dt_ids),
|
|
},
|
|
.probe = atmel_spi_probe,
|
|
.remove = atmel_spi_remove,
|
|
};
|
|
module_platform_driver(atmel_spi_driver);
|
|
|
|
MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
|
|
MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:atmel_spi");
|