![Ken Wilson](/assets/img/avatar_default.png)
This commit adds support for multiple hardware chip selects to spi-orion. Different SoCs support different number of chip selects (up to 8 on some platforms). The driver allows up to this number, and it is up to the implementer to only use the chip selects that are available. Signed-off-by: Ken Wilson <ken.wilson@opengear.com> Signed-off-by: Mark Brown <broonie@kernel.org>
552 lines
13 KiB
C
552 lines
13 KiB
C
/*
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* Marvell Orion SPI controller driver
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*
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* Author: Shadi Ammouri <shadi@marvell.com>
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* Copyright (C) 2007-2008 Marvell Ltd.
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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/interrupt.h>
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#include <linux/delay.h>
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#include <linux/platform_device.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/spi/spi.h>
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#include <linux/module.h>
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#include <linux/pm_runtime.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/clk.h>
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#include <linux/sizes.h>
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#include <asm/unaligned.h>
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#define DRIVER_NAME "orion_spi"
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/* Runtime PM autosuspend timeout: PM is fairly light on this driver */
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#define SPI_AUTOSUSPEND_TIMEOUT 200
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/* Some SoCs using this driver support up to 8 chip selects.
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* It is up to the implementer to only use the chip selects
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* that are available.
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*/
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#define ORION_NUM_CHIPSELECTS 8
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#define ORION_SPI_WAIT_RDY_MAX_LOOP 2000 /* in usec */
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#define ORION_SPI_IF_CTRL_REG 0x00
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#define ORION_SPI_IF_CONFIG_REG 0x04
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#define ORION_SPI_DATA_OUT_REG 0x08
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#define ORION_SPI_DATA_IN_REG 0x0c
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#define ORION_SPI_INT_CAUSE_REG 0x10
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#define ORION_SPI_MODE_CPOL (1 << 11)
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#define ORION_SPI_MODE_CPHA (1 << 12)
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#define ORION_SPI_IF_8_16_BIT_MODE (1 << 5)
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#define ORION_SPI_CLK_PRESCALE_MASK 0x1F
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#define ARMADA_SPI_CLK_PRESCALE_MASK 0xDF
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#define ORION_SPI_MODE_MASK (ORION_SPI_MODE_CPOL | \
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ORION_SPI_MODE_CPHA)
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#define ORION_SPI_CS_MASK 0x1C
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#define ORION_SPI_CS_SHIFT 2
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#define ORION_SPI_CS(cs) ((cs << ORION_SPI_CS_SHIFT) & \
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ORION_SPI_CS_MASK)
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enum orion_spi_type {
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ORION_SPI,
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ARMADA_SPI,
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};
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struct orion_spi_dev {
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enum orion_spi_type typ;
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unsigned int min_divisor;
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unsigned int max_divisor;
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u32 prescale_mask;
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};
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struct orion_spi {
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struct spi_master *master;
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void __iomem *base;
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struct clk *clk;
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const struct orion_spi_dev *devdata;
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};
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static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
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{
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return orion_spi->base + reg;
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}
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static inline void
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orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
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{
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void __iomem *reg_addr = spi_reg(orion_spi, reg);
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u32 val;
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val = readl(reg_addr);
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val |= mask;
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writel(val, reg_addr);
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}
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static inline void
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orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
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{
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void __iomem *reg_addr = spi_reg(orion_spi, reg);
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u32 val;
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val = readl(reg_addr);
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val &= ~mask;
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writel(val, reg_addr);
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}
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static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
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{
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u32 tclk_hz;
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u32 rate;
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u32 prescale;
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u32 reg;
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struct orion_spi *orion_spi;
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const struct orion_spi_dev *devdata;
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orion_spi = spi_master_get_devdata(spi->master);
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devdata = orion_spi->devdata;
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tclk_hz = clk_get_rate(orion_spi->clk);
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if (devdata->typ == ARMADA_SPI) {
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unsigned int clk, spr, sppr, sppr2, err;
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unsigned int best_spr, best_sppr, best_err;
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best_err = speed;
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best_spr = 0;
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best_sppr = 0;
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/* Iterate over the valid range looking for best fit */
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for (sppr = 0; sppr < 8; sppr++) {
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sppr2 = 0x1 << sppr;
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spr = tclk_hz / sppr2;
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spr = DIV_ROUND_UP(spr, speed);
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if ((spr == 0) || (spr > 15))
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continue;
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clk = tclk_hz / (spr * sppr2);
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err = speed - clk;
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if (err < best_err) {
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best_spr = spr;
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best_sppr = sppr;
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best_err = err;
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}
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}
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if ((best_sppr == 0) && (best_spr == 0))
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return -EINVAL;
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prescale = ((best_sppr & 0x6) << 5) |
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((best_sppr & 0x1) << 4) | best_spr;
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} else {
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/*
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* the supported rates are: 4,6,8...30
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* round up as we look for equal or less speed
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*/
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rate = DIV_ROUND_UP(tclk_hz, speed);
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rate = roundup(rate, 2);
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/* check if requested speed is too small */
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if (rate > 30)
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return -EINVAL;
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if (rate < 4)
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rate = 4;
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/* Convert the rate to SPI clock divisor value. */
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prescale = 0x10 + rate/2;
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}
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reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
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reg = ((reg & ~devdata->prescale_mask) | prescale);
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writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
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return 0;
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}
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static void
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orion_spi_mode_set(struct spi_device *spi)
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{
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u32 reg;
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struct orion_spi *orion_spi;
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orion_spi = spi_master_get_devdata(spi->master);
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reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
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reg &= ~ORION_SPI_MODE_MASK;
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if (spi->mode & SPI_CPOL)
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reg |= ORION_SPI_MODE_CPOL;
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if (spi->mode & SPI_CPHA)
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reg |= ORION_SPI_MODE_CPHA;
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writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
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}
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/*
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* called only when no transfer is active on the bus
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*/
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static int
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orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
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{
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struct orion_spi *orion_spi;
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unsigned int speed = spi->max_speed_hz;
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unsigned int bits_per_word = spi->bits_per_word;
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int rc;
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orion_spi = spi_master_get_devdata(spi->master);
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if ((t != NULL) && t->speed_hz)
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speed = t->speed_hz;
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if ((t != NULL) && t->bits_per_word)
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bits_per_word = t->bits_per_word;
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orion_spi_mode_set(spi);
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rc = orion_spi_baudrate_set(spi, speed);
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if (rc)
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return rc;
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if (bits_per_word == 16)
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orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
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ORION_SPI_IF_8_16_BIT_MODE);
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else
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orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
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ORION_SPI_IF_8_16_BIT_MODE);
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return 0;
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}
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static void orion_spi_set_cs(struct spi_device *spi, bool enable)
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{
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struct orion_spi *orion_spi;
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orion_spi = spi_master_get_devdata(spi->master);
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orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, ORION_SPI_CS_MASK);
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orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG,
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ORION_SPI_CS(spi->chip_select));
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/* Chip select logic is inverted from spi_set_cs */
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if (!enable)
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orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
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else
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orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
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}
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static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
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{
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int i;
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for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
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if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
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return 1;
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udelay(1);
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}
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return -1;
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}
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static inline int
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orion_spi_write_read_8bit(struct spi_device *spi,
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const u8 **tx_buf, u8 **rx_buf)
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{
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void __iomem *tx_reg, *rx_reg, *int_reg;
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struct orion_spi *orion_spi;
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orion_spi = spi_master_get_devdata(spi->master);
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tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
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rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
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int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
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/* clear the interrupt cause register */
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writel(0x0, int_reg);
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if (tx_buf && *tx_buf)
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writel(*(*tx_buf)++, tx_reg);
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else
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writel(0, tx_reg);
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if (orion_spi_wait_till_ready(orion_spi) < 0) {
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dev_err(&spi->dev, "TXS timed out\n");
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return -1;
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}
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if (rx_buf && *rx_buf)
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*(*rx_buf)++ = readl(rx_reg);
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return 1;
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}
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static inline int
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orion_spi_write_read_16bit(struct spi_device *spi,
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const u16 **tx_buf, u16 **rx_buf)
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{
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void __iomem *tx_reg, *rx_reg, *int_reg;
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struct orion_spi *orion_spi;
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orion_spi = spi_master_get_devdata(spi->master);
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tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
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rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
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int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
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/* clear the interrupt cause register */
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writel(0x0, int_reg);
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if (tx_buf && *tx_buf)
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writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
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else
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writel(0, tx_reg);
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if (orion_spi_wait_till_ready(orion_spi) < 0) {
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dev_err(&spi->dev, "TXS timed out\n");
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return -1;
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}
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if (rx_buf && *rx_buf)
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put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);
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return 1;
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}
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static unsigned int
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orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
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{
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unsigned int count;
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int word_len;
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word_len = spi->bits_per_word;
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count = xfer->len;
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if (word_len == 8) {
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const u8 *tx = xfer->tx_buf;
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u8 *rx = xfer->rx_buf;
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do {
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if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
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goto out;
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count--;
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} while (count);
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} else if (word_len == 16) {
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const u16 *tx = xfer->tx_buf;
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u16 *rx = xfer->rx_buf;
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do {
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if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
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goto out;
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count -= 2;
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} while (count);
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}
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out:
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return xfer->len - count;
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}
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static int orion_spi_transfer_one(struct spi_master *master,
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struct spi_device *spi,
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struct spi_transfer *t)
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{
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int status = 0;
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status = orion_spi_setup_transfer(spi, t);
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if (status < 0)
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return status;
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if (t->len)
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orion_spi_write_read(spi, t);
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return status;
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}
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static int orion_spi_setup(struct spi_device *spi)
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{
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return orion_spi_setup_transfer(spi, NULL);
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}
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static int orion_spi_reset(struct orion_spi *orion_spi)
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{
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/* Verify that the CS is deasserted */
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orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
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return 0;
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}
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static const struct orion_spi_dev orion_spi_dev_data = {
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.typ = ORION_SPI,
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.min_divisor = 4,
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.max_divisor = 30,
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.prescale_mask = ORION_SPI_CLK_PRESCALE_MASK,
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};
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static const struct orion_spi_dev armada_spi_dev_data = {
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.typ = ARMADA_SPI,
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.min_divisor = 1,
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.max_divisor = 1920,
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.prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
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};
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static const struct of_device_id orion_spi_of_match_table[] = {
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{ .compatible = "marvell,orion-spi", .data = &orion_spi_dev_data, },
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{ .compatible = "marvell,armada-370-spi", .data = &armada_spi_dev_data, },
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{}
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};
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MODULE_DEVICE_TABLE(of, orion_spi_of_match_table);
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static int orion_spi_probe(struct platform_device *pdev)
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{
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const struct of_device_id *of_id;
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const struct orion_spi_dev *devdata;
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struct spi_master *master;
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struct orion_spi *spi;
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struct resource *r;
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unsigned long tclk_hz;
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int status = 0;
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master = spi_alloc_master(&pdev->dev, sizeof(*spi));
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if (master == NULL) {
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dev_dbg(&pdev->dev, "master allocation failed\n");
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return -ENOMEM;
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}
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if (pdev->id != -1)
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master->bus_num = pdev->id;
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if (pdev->dev.of_node) {
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u32 cell_index;
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if (!of_property_read_u32(pdev->dev.of_node, "cell-index",
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&cell_index))
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master->bus_num = cell_index;
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}
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/* we support only mode 0, and no options */
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master->mode_bits = SPI_CPHA | SPI_CPOL;
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master->set_cs = orion_spi_set_cs;
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master->transfer_one = orion_spi_transfer_one;
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master->num_chipselect = ORION_NUM_CHIPSELECTS;
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master->setup = orion_spi_setup;
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master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
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master->auto_runtime_pm = true;
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platform_set_drvdata(pdev, master);
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spi = spi_master_get_devdata(master);
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spi->master = master;
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of_id = of_match_device(orion_spi_of_match_table, &pdev->dev);
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devdata = (of_id) ? of_id->data : &orion_spi_dev_data;
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spi->devdata = devdata;
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spi->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(spi->clk)) {
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status = PTR_ERR(spi->clk);
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goto out;
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}
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status = clk_prepare_enable(spi->clk);
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if (status)
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goto out;
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tclk_hz = clk_get_rate(spi->clk);
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master->max_speed_hz = DIV_ROUND_UP(tclk_hz, devdata->min_divisor);
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master->min_speed_hz = DIV_ROUND_UP(tclk_hz, devdata->max_divisor);
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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spi->base = devm_ioremap_resource(&pdev->dev, r);
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if (IS_ERR(spi->base)) {
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status = PTR_ERR(spi->base);
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goto out_rel_clk;
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}
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pm_runtime_set_active(&pdev->dev);
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pm_runtime_use_autosuspend(&pdev->dev);
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pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
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pm_runtime_enable(&pdev->dev);
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status = orion_spi_reset(spi);
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if (status < 0)
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goto out_rel_pm;
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pm_runtime_mark_last_busy(&pdev->dev);
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pm_runtime_put_autosuspend(&pdev->dev);
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master->dev.of_node = pdev->dev.of_node;
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status = spi_register_master(master);
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if (status < 0)
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goto out_rel_pm;
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return status;
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out_rel_pm:
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pm_runtime_disable(&pdev->dev);
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out_rel_clk:
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clk_disable_unprepare(spi->clk);
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out:
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spi_master_put(master);
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return status;
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}
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static int orion_spi_remove(struct platform_device *pdev)
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{
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struct spi_master *master = platform_get_drvdata(pdev);
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struct orion_spi *spi = spi_master_get_devdata(master);
|
|
|
|
pm_runtime_get_sync(&pdev->dev);
|
|
clk_disable_unprepare(spi->clk);
|
|
|
|
spi_unregister_master(master);
|
|
pm_runtime_disable(&pdev->dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
MODULE_ALIAS("platform:" DRIVER_NAME);
|
|
|
|
#ifdef CONFIG_PM
|
|
static int orion_spi_runtime_suspend(struct device *dev)
|
|
{
|
|
struct spi_master *master = dev_get_drvdata(dev);
|
|
struct orion_spi *spi = spi_master_get_devdata(master);
|
|
|
|
clk_disable_unprepare(spi->clk);
|
|
return 0;
|
|
}
|
|
|
|
static int orion_spi_runtime_resume(struct device *dev)
|
|
{
|
|
struct spi_master *master = dev_get_drvdata(dev);
|
|
struct orion_spi *spi = spi_master_get_devdata(master);
|
|
|
|
return clk_prepare_enable(spi->clk);
|
|
}
|
|
#endif
|
|
|
|
static const struct dev_pm_ops orion_spi_pm_ops = {
|
|
SET_RUNTIME_PM_OPS(orion_spi_runtime_suspend,
|
|
orion_spi_runtime_resume,
|
|
NULL)
|
|
};
|
|
|
|
static struct platform_driver orion_spi_driver = {
|
|
.driver = {
|
|
.name = DRIVER_NAME,
|
|
.pm = &orion_spi_pm_ops,
|
|
.of_match_table = of_match_ptr(orion_spi_of_match_table),
|
|
},
|
|
.probe = orion_spi_probe,
|
|
.remove = orion_spi_remove,
|
|
};
|
|
|
|
module_platform_driver(orion_spi_driver);
|
|
|
|
MODULE_DESCRIPTION("Orion SPI driver");
|
|
MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
|
|
MODULE_LICENSE("GPL");
|