![Wolfram Sang](/assets/img/avatar_default.png)
Use this new function to make code more comprehensible, since we are reinitialzing the completion, not initializing. [akpm@linux-foundation.org: linux-next resyncs] Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13) Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
278 lines
6.9 KiB
C
278 lines
6.9 KiB
C
/*
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* CLPS711X SPI bus driver
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*
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* Copyright (C) 2012 Alexander Shiyan <shc_work@mail.ru>
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/io.h>
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#include <linux/clk.h>
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#include <linux/init.h>
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#include <linux/gpio.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/spi/spi.h>
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#include <linux/platform_data/spi-clps711x.h>
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#include <mach/hardware.h>
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#define DRIVER_NAME "spi-clps711x"
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struct spi_clps711x_data {
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struct completion done;
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struct clk *spi_clk;
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u32 max_speed_hz;
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u8 *tx_buf;
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u8 *rx_buf;
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int count;
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int len;
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int chipselect[0];
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};
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static int spi_clps711x_setup(struct spi_device *spi)
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{
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struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master);
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/* We are expect that SPI-device is not selected */
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gpio_direction_output(hw->chipselect[spi->chip_select],
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!(spi->mode & SPI_CS_HIGH));
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return 0;
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}
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static void spi_clps711x_setup_mode(struct spi_device *spi)
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{
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/* Setup edge for transfer */
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if (spi->mode & SPI_CPHA)
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clps_writew(clps_readw(SYSCON3) | SYSCON3_ADCCKNSEN, SYSCON3);
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else
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clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCKNSEN, SYSCON3);
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}
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static int spi_clps711x_setup_xfer(struct spi_device *spi,
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struct spi_transfer *xfer)
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{
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u32 speed = xfer->speed_hz ? : spi->max_speed_hz;
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u8 bpw = xfer->bits_per_word;
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struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master);
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if (bpw != 8) {
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dev_err(&spi->dev, "Unsupported master bus width %i\n", bpw);
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return -EINVAL;
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}
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/* Setup SPI frequency divider */
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if (!speed || (speed >= hw->max_speed_hz))
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clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
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SYSCON1_ADCKSEL(3), SYSCON1);
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else if (speed >= (hw->max_speed_hz / 2))
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clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
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SYSCON1_ADCKSEL(2), SYSCON1);
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else if (speed >= (hw->max_speed_hz / 8))
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clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
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SYSCON1_ADCKSEL(1), SYSCON1);
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else
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clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
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SYSCON1_ADCKSEL(0), SYSCON1);
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return 0;
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}
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static int spi_clps711x_transfer_one_message(struct spi_master *master,
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struct spi_message *msg)
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{
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struct spi_clps711x_data *hw = spi_master_get_devdata(master);
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struct spi_transfer *xfer;
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int status = 0, cs = hw->chipselect[msg->spi->chip_select];
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u32 data;
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spi_clps711x_setup_mode(msg->spi);
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list_for_each_entry(xfer, &msg->transfers, transfer_list) {
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if (spi_clps711x_setup_xfer(msg->spi, xfer)) {
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status = -EINVAL;
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goto out_xfr;
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}
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gpio_set_value(cs, !!(msg->spi->mode & SPI_CS_HIGH));
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reinit_completion(&hw->done);
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hw->count = 0;
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hw->len = xfer->len;
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hw->tx_buf = (u8 *)xfer->tx_buf;
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hw->rx_buf = (u8 *)xfer->rx_buf;
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/* Initiate transfer */
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data = hw->tx_buf ? hw->tx_buf[hw->count] : 0;
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clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO);
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wait_for_completion(&hw->done);
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if (xfer->delay_usecs)
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udelay(xfer->delay_usecs);
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if (xfer->cs_change ||
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list_is_last(&xfer->transfer_list, &msg->transfers))
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gpio_set_value(cs, !(msg->spi->mode & SPI_CS_HIGH));
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msg->actual_length += xfer->len;
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}
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out_xfr:
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msg->status = status;
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spi_finalize_current_message(master);
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return 0;
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}
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static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
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{
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struct spi_clps711x_data *hw = (struct spi_clps711x_data *)dev_id;
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u32 data;
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/* Handle RX */
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data = clps_readb(SYNCIO);
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if (hw->rx_buf)
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hw->rx_buf[hw->count] = (u8)data;
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hw->count++;
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/* Handle TX */
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if (hw->count < hw->len) {
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data = hw->tx_buf ? hw->tx_buf[hw->count] : 0;
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clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO);
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} else
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complete(&hw->done);
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return IRQ_HANDLED;
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}
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static int spi_clps711x_probe(struct platform_device *pdev)
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{
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int i, ret;
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struct spi_master *master;
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struct spi_clps711x_data *hw;
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struct spi_clps711x_pdata *pdata = dev_get_platdata(&pdev->dev);
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if (!pdata) {
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dev_err(&pdev->dev, "No platform data supplied\n");
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return -EINVAL;
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}
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if (pdata->num_chipselect < 1) {
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dev_err(&pdev->dev, "At least one CS must be defined\n");
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return -EINVAL;
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}
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master = spi_alloc_master(&pdev->dev,
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sizeof(struct spi_clps711x_data) +
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sizeof(int) * pdata->num_chipselect);
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if (!master) {
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dev_err(&pdev->dev, "SPI allocating memory error\n");
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return -ENOMEM;
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}
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master->bus_num = pdev->id;
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master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
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master->bits_per_word_mask = SPI_BPW_MASK(8);
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master->num_chipselect = pdata->num_chipselect;
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master->setup = spi_clps711x_setup;
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master->transfer_one_message = spi_clps711x_transfer_one_message;
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hw = spi_master_get_devdata(master);
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for (i = 0; i < master->num_chipselect; i++) {
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hw->chipselect[i] = pdata->chipselect[i];
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if (!gpio_is_valid(hw->chipselect[i])) {
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dev_err(&pdev->dev, "Invalid CS GPIO %i\n", i);
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ret = -EINVAL;
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goto err_out;
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}
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if (gpio_request(hw->chipselect[i], DRIVER_NAME)) {
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dev_err(&pdev->dev, "Can't get CS GPIO %i\n", i);
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ret = -EINVAL;
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goto err_out;
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}
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}
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hw->spi_clk = devm_clk_get(&pdev->dev, "spi");
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if (IS_ERR(hw->spi_clk)) {
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dev_err(&pdev->dev, "Can't get clocks\n");
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ret = PTR_ERR(hw->spi_clk);
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goto err_out;
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}
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hw->max_speed_hz = clk_get_rate(hw->spi_clk);
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init_completion(&hw->done);
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platform_set_drvdata(pdev, master);
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/* Disable extended mode due hardware problems */
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clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCON, SYSCON3);
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/* Clear possible pending interrupt */
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clps_readl(SYNCIO);
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ret = devm_request_irq(&pdev->dev, IRQ_SSEOTI, spi_clps711x_isr, 0,
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dev_name(&pdev->dev), hw);
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if (ret) {
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dev_err(&pdev->dev, "Can't request IRQ\n");
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goto err_out;
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}
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ret = devm_spi_register_master(&pdev->dev, master);
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if (!ret) {
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dev_info(&pdev->dev,
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"SPI bus driver initialized. Master clock %u Hz\n",
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hw->max_speed_hz);
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return 0;
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}
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dev_err(&pdev->dev, "Failed to register master\n");
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err_out:
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while (--i >= 0)
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if (gpio_is_valid(hw->chipselect[i]))
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gpio_free(hw->chipselect[i]);
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spi_master_put(master);
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return ret;
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}
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static int spi_clps711x_remove(struct platform_device *pdev)
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{
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int i;
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struct spi_master *master = platform_get_drvdata(pdev);
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struct spi_clps711x_data *hw = spi_master_get_devdata(master);
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for (i = 0; i < master->num_chipselect; i++)
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if (gpio_is_valid(hw->chipselect[i]))
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gpio_free(hw->chipselect[i]);
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return 0;
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}
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static struct platform_driver clps711x_spi_driver = {
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.driver = {
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.name = DRIVER_NAME,
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.owner = THIS_MODULE,
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},
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.probe = spi_clps711x_probe,
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.remove = spi_clps711x_remove,
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};
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module_platform_driver(clps711x_spi_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
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MODULE_DESCRIPTION("CLPS711X SPI bus driver");
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