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![Linus Walleij](/assets/img/avatar_default.png)
This driver has a bunch of custom oldstyle GPIO number-passing fields and a custom set-up callback. The good thing is: nothing in the kernel is using it. Convert the driver to use GPIO descriptors with a SPI_MASTER_GPIO_SS flag so that the local CS callback also get invoked as the hardware needs this. New users of this driver can provide GPIO descriptor tables like the other converted drivers. Cc: linux-samsung-soc@vger.kernel.org Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> Cc: Sylwester Nawrocki <snawrocki@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> Link: https://lore.kernel.org/r/20220119000914.192553-1-linus.walleij@linaro.org Signed-off-by: Mark Brown <broonie@kernel.org>
604 lines
14 KiB
C
604 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2006 Ben Dooks
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* Copyright 2006-2009 Simtec Electronics
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* Ben Dooks <ben@simtec.co.uk>
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*/
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/errno.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/slab.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/spi_bitbang.h>
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#include <linux/spi/s3c24xx.h>
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#include <linux/spi/s3c24xx-fiq.h>
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#include <linux/module.h>
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#include <asm/fiq.h>
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#include "spi-s3c24xx-regs.h"
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/**
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* struct s3c24xx_spi_devstate - per device data
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* @hz: Last frequency calculated for @sppre field.
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* @mode: Last mode setting for the @spcon field.
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* @spcon: Value to write to the SPCON register.
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* @sppre: Value to write to the SPPRE register.
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*/
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struct s3c24xx_spi_devstate {
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unsigned int hz;
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unsigned int mode;
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u8 spcon;
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u8 sppre;
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};
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enum spi_fiq_mode {
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FIQ_MODE_NONE = 0,
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FIQ_MODE_TX = 1,
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FIQ_MODE_RX = 2,
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FIQ_MODE_TXRX = 3,
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};
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struct s3c24xx_spi {
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/* bitbang has to be first */
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struct spi_bitbang bitbang;
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struct completion done;
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void __iomem *regs;
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int irq;
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int len;
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int count;
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struct fiq_handler fiq_handler;
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enum spi_fiq_mode fiq_mode;
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unsigned char fiq_inuse;
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unsigned char fiq_claimed;
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/* data buffers */
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const unsigned char *tx;
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unsigned char *rx;
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struct clk *clk;
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struct spi_master *master;
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struct spi_device *curdev;
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struct device *dev;
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struct s3c2410_spi_info *pdata;
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};
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#define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
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#define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
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static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev)
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{
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return spi_master_get_devdata(sdev->master);
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}
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static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
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{
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struct s3c24xx_spi_devstate *cs = spi->controller_state;
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struct s3c24xx_spi *hw = to_hw(spi);
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/* change the chipselect state and the state of the spi engine clock */
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switch (value) {
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case BITBANG_CS_INACTIVE:
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writeb(cs->spcon, hw->regs + S3C2410_SPCON);
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break;
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case BITBANG_CS_ACTIVE:
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writeb(cs->spcon | S3C2410_SPCON_ENSCK,
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hw->regs + S3C2410_SPCON);
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break;
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}
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}
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static int s3c24xx_spi_update_state(struct spi_device *spi,
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struct spi_transfer *t)
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{
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struct s3c24xx_spi *hw = to_hw(spi);
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struct s3c24xx_spi_devstate *cs = spi->controller_state;
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unsigned int hz;
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unsigned int div;
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unsigned long clk;
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hz = t ? t->speed_hz : spi->max_speed_hz;
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if (!hz)
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hz = spi->max_speed_hz;
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if (spi->mode != cs->mode) {
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u8 spcon = SPCON_DEFAULT | S3C2410_SPCON_ENSCK;
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if (spi->mode & SPI_CPHA)
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spcon |= S3C2410_SPCON_CPHA_FMTB;
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if (spi->mode & SPI_CPOL)
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spcon |= S3C2410_SPCON_CPOL_HIGH;
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cs->mode = spi->mode;
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cs->spcon = spcon;
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}
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if (cs->hz != hz) {
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clk = clk_get_rate(hw->clk);
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div = DIV_ROUND_UP(clk, hz * 2) - 1;
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if (div > 255)
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div = 255;
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dev_dbg(&spi->dev, "pre-scaler=%d (wanted %d, got %ld)\n",
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div, hz, clk / (2 * (div + 1)));
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cs->hz = hz;
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cs->sppre = div;
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}
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return 0;
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}
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static int s3c24xx_spi_setupxfer(struct spi_device *spi,
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struct spi_transfer *t)
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{
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struct s3c24xx_spi_devstate *cs = spi->controller_state;
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struct s3c24xx_spi *hw = to_hw(spi);
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int ret;
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ret = s3c24xx_spi_update_state(spi, t);
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if (!ret)
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writeb(cs->sppre, hw->regs + S3C2410_SPPRE);
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return ret;
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}
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static int s3c24xx_spi_setup(struct spi_device *spi)
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{
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struct s3c24xx_spi_devstate *cs = spi->controller_state;
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struct s3c24xx_spi *hw = to_hw(spi);
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int ret;
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/* allocate settings on the first call */
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if (!cs) {
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cs = devm_kzalloc(&spi->dev,
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sizeof(struct s3c24xx_spi_devstate),
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GFP_KERNEL);
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if (!cs)
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return -ENOMEM;
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cs->spcon = SPCON_DEFAULT;
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cs->hz = -1;
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spi->controller_state = cs;
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}
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/* initialise the state from the device */
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ret = s3c24xx_spi_update_state(spi, NULL);
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if (ret)
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return ret;
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mutex_lock(&hw->bitbang.lock);
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if (!hw->bitbang.busy) {
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hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
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/* need to ndelay for 0.5 clocktick ? */
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}
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mutex_unlock(&hw->bitbang.lock);
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return 0;
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}
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static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
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{
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return hw->tx ? hw->tx[count] : 0;
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}
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#ifdef CONFIG_SPI_S3C24XX_FIQ
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/* Support for FIQ based pseudo-DMA to improve the transfer speed.
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*
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* This code uses the assembly helper in spi_s3c24xx_spi.S which is
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* used by the FIQ core to move data between main memory and the peripheral
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* block. Since this is code running on the processor, there is no problem
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* with cache coherency of the buffers, so we can use any buffer we like.
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*/
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/**
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* struct spi_fiq_code - FIQ code and header
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* @length: The length of the code fragment, excluding this header.
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* @ack_offset: The offset from @data to the word to place the IRQ ACK bit at.
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* @data: The code itself to install as a FIQ handler.
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*/
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struct spi_fiq_code {
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u32 length;
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u32 ack_offset;
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u8 data[];
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};
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/**
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* s3c24xx_spi_tryfiq - attempt to claim and setup FIQ for transfer
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* @hw: The hardware state.
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*
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* Claim the FIQ handler (only one can be active at any one time) and
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* then setup the correct transfer code for this transfer.
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*
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* This call updates all the necessary state information if successful,
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* so the caller does not need to do anything more than start the transfer
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* as normal, since the IRQ will have been re-routed to the FIQ handler.
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*/
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static void s3c24xx_spi_tryfiq(struct s3c24xx_spi *hw)
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{
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struct pt_regs regs;
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enum spi_fiq_mode mode;
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struct spi_fiq_code *code;
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u32 *ack_ptr = NULL;
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int ret;
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if (!hw->fiq_claimed) {
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/* try and claim fiq if we haven't got it, and if not
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* then return and simply use another transfer method */
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ret = claim_fiq(&hw->fiq_handler);
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if (ret)
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return;
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}
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if (hw->tx && !hw->rx)
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mode = FIQ_MODE_TX;
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else if (hw->rx && !hw->tx)
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mode = FIQ_MODE_RX;
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else
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mode = FIQ_MODE_TXRX;
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regs.uregs[fiq_rspi] = (long)hw->regs;
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regs.uregs[fiq_rrx] = (long)hw->rx;
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regs.uregs[fiq_rtx] = (long)hw->tx + 1;
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regs.uregs[fiq_rcount] = hw->len - 1;
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set_fiq_regs(®s);
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if (hw->fiq_mode != mode) {
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hw->fiq_mode = mode;
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switch (mode) {
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case FIQ_MODE_TX:
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code = &s3c24xx_spi_fiq_tx;
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break;
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case FIQ_MODE_RX:
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code = &s3c24xx_spi_fiq_rx;
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break;
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case FIQ_MODE_TXRX:
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code = &s3c24xx_spi_fiq_txrx;
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break;
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default:
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code = NULL;
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}
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BUG_ON(!code);
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ack_ptr = (u32 *)&code->data[code->ack_offset];
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set_fiq_handler(&code->data, code->length);
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}
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s3c24xx_set_fiq(hw->irq, ack_ptr, true);
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hw->fiq_mode = mode;
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hw->fiq_inuse = 1;
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}
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/**
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* s3c24xx_spi_fiqop - FIQ core code callback
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* @pw: Data registered with the handler
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* @release: Whether this is a release or a return.
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*
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* Called by the FIQ code when another module wants to use the FIQ, so
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* return whether we are currently using this or not and then update our
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* internal state.
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*/
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static int s3c24xx_spi_fiqop(void *pw, int release)
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{
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struct s3c24xx_spi *hw = pw;
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int ret = 0;
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if (release) {
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if (hw->fiq_inuse)
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ret = -EBUSY;
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/* note, we do not need to unroute the FIQ, as the FIQ
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* vector code de-routes it to signal the end of transfer */
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hw->fiq_mode = FIQ_MODE_NONE;
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hw->fiq_claimed = 0;
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} else {
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hw->fiq_claimed = 1;
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}
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return ret;
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}
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/**
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* s3c24xx_spi_initfiq - setup the information for the FIQ core
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* @hw: The hardware state.
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*
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* Setup the fiq_handler block to pass to the FIQ core.
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*/
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static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *hw)
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{
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hw->fiq_handler.dev_id = hw;
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hw->fiq_handler.name = dev_name(hw->dev);
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hw->fiq_handler.fiq_op = s3c24xx_spi_fiqop;
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}
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/**
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* s3c24xx_spi_usefiq - return if we should be using FIQ.
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* @hw: The hardware state.
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*
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* Return true if the platform data specifies whether this channel is
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* allowed to use the FIQ.
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*/
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static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *hw)
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{
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return hw->pdata->use_fiq;
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}
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/**
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* s3c24xx_spi_usingfiq - return if channel is using FIQ
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* @spi: The hardware state.
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*
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* Return whether the channel is currently using the FIQ (separate from
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* whether the FIQ is claimed).
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*/
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static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *spi)
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{
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return spi->fiq_inuse;
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}
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#else
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static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *s) { }
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static inline void s3c24xx_spi_tryfiq(struct s3c24xx_spi *s) { }
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static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *s) { return false; }
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static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *s) { return false; }
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#endif /* CONFIG_SPI_S3C24XX_FIQ */
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static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
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{
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struct s3c24xx_spi *hw = to_hw(spi);
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hw->tx = t->tx_buf;
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hw->rx = t->rx_buf;
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hw->len = t->len;
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hw->count = 0;
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init_completion(&hw->done);
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hw->fiq_inuse = 0;
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if (s3c24xx_spi_usefiq(hw) && t->len >= 3)
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s3c24xx_spi_tryfiq(hw);
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/* send the first byte */
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writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
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wait_for_completion(&hw->done);
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return hw->count;
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}
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static irqreturn_t s3c24xx_spi_irq(int irq, void *dev)
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{
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struct s3c24xx_spi *hw = dev;
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unsigned int spsta = readb(hw->regs + S3C2410_SPSTA);
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unsigned int count = hw->count;
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if (spsta & S3C2410_SPSTA_DCOL) {
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dev_dbg(hw->dev, "data-collision\n");
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complete(&hw->done);
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goto irq_done;
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}
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if (!(spsta & S3C2410_SPSTA_READY)) {
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dev_dbg(hw->dev, "spi not ready for tx?\n");
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complete(&hw->done);
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goto irq_done;
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}
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if (!s3c24xx_spi_usingfiq(hw)) {
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hw->count++;
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if (hw->rx)
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hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT);
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count++;
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if (count < hw->len)
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writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT);
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else
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complete(&hw->done);
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} else {
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hw->count = hw->len;
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hw->fiq_inuse = 0;
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if (hw->rx)
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hw->rx[hw->len-1] = readb(hw->regs + S3C2410_SPRDAT);
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complete(&hw->done);
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}
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irq_done:
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return IRQ_HANDLED;
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}
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static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw)
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{
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/* for the moment, permanently enable the clock */
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clk_enable(hw->clk);
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/* program defaults into the registers */
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writeb(0xff, hw->regs + S3C2410_SPPRE);
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writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN);
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writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON);
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}
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static int s3c24xx_spi_probe(struct platform_device *pdev)
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{
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struct s3c2410_spi_info *pdata;
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struct s3c24xx_spi *hw;
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struct spi_master *master;
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int err = 0;
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master = spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi));
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if (master == NULL) {
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dev_err(&pdev->dev, "No memory for spi_master\n");
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return -ENOMEM;
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}
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hw = spi_master_get_devdata(master);
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hw->master = master;
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hw->pdata = pdata = dev_get_platdata(&pdev->dev);
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hw->dev = &pdev->dev;
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if (pdata == NULL) {
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dev_err(&pdev->dev, "No platform data supplied\n");
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err = -ENOENT;
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goto err_no_pdata;
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}
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platform_set_drvdata(pdev, hw);
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init_completion(&hw->done);
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/* initialise fiq handler */
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s3c24xx_spi_initfiq(hw);
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/* setup the master state. */
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/* the spi->mode bits understood by this driver: */
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master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
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master->num_chipselect = hw->pdata->num_cs;
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master->bus_num = pdata->bus_num;
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master->bits_per_word_mask = SPI_BPW_MASK(8);
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/* we need to call the local chipselect callback */
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master->flags = SPI_MASTER_GPIO_SS;
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master->use_gpio_descriptors = true;
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/* setup the state for the bitbang driver */
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hw->bitbang.master = hw->master;
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hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer;
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hw->bitbang.chipselect = s3c24xx_spi_chipsel;
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hw->bitbang.txrx_bufs = s3c24xx_spi_txrx;
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|
|
hw->master->setup = s3c24xx_spi_setup;
|
|
|
|
dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang);
|
|
|
|
/* find and map our resources */
|
|
hw->regs = devm_platform_ioremap_resource(pdev, 0);
|
|
if (IS_ERR(hw->regs)) {
|
|
err = PTR_ERR(hw->regs);
|
|
goto err_no_pdata;
|
|
}
|
|
|
|
hw->irq = platform_get_irq(pdev, 0);
|
|
if (hw->irq < 0) {
|
|
err = -ENOENT;
|
|
goto err_no_pdata;
|
|
}
|
|
|
|
err = devm_request_irq(&pdev->dev, hw->irq, s3c24xx_spi_irq, 0,
|
|
pdev->name, hw);
|
|
if (err) {
|
|
dev_err(&pdev->dev, "Cannot claim IRQ\n");
|
|
goto err_no_pdata;
|
|
}
|
|
|
|
hw->clk = devm_clk_get(&pdev->dev, "spi");
|
|
if (IS_ERR(hw->clk)) {
|
|
dev_err(&pdev->dev, "No clock for device\n");
|
|
err = PTR_ERR(hw->clk);
|
|
goto err_no_pdata;
|
|
}
|
|
|
|
s3c24xx_spi_initialsetup(hw);
|
|
|
|
/* register our spi controller */
|
|
|
|
err = spi_bitbang_start(&hw->bitbang);
|
|
if (err) {
|
|
dev_err(&pdev->dev, "Failed to register SPI master\n");
|
|
goto err_register;
|
|
}
|
|
|
|
return 0;
|
|
|
|
err_register:
|
|
clk_disable(hw->clk);
|
|
|
|
err_no_pdata:
|
|
spi_master_put(hw->master);
|
|
return err;
|
|
}
|
|
|
|
static int s3c24xx_spi_remove(struct platform_device *dev)
|
|
{
|
|
struct s3c24xx_spi *hw = platform_get_drvdata(dev);
|
|
|
|
spi_bitbang_stop(&hw->bitbang);
|
|
clk_disable(hw->clk);
|
|
spi_master_put(hw->master);
|
|
return 0;
|
|
}
|
|
|
|
|
|
#ifdef CONFIG_PM
|
|
|
|
static int s3c24xx_spi_suspend(struct device *dev)
|
|
{
|
|
struct s3c24xx_spi *hw = dev_get_drvdata(dev);
|
|
int ret;
|
|
|
|
ret = spi_master_suspend(hw->master);
|
|
if (ret)
|
|
return ret;
|
|
|
|
clk_disable(hw->clk);
|
|
return 0;
|
|
}
|
|
|
|
static int s3c24xx_spi_resume(struct device *dev)
|
|
{
|
|
struct s3c24xx_spi *hw = dev_get_drvdata(dev);
|
|
|
|
s3c24xx_spi_initialsetup(hw);
|
|
return spi_master_resume(hw->master);
|
|
}
|
|
|
|
static const struct dev_pm_ops s3c24xx_spi_pmops = {
|
|
.suspend = s3c24xx_spi_suspend,
|
|
.resume = s3c24xx_spi_resume,
|
|
};
|
|
|
|
#define S3C24XX_SPI_PMOPS &s3c24xx_spi_pmops
|
|
#else
|
|
#define S3C24XX_SPI_PMOPS NULL
|
|
#endif /* CONFIG_PM */
|
|
|
|
MODULE_ALIAS("platform:s3c2410-spi");
|
|
static struct platform_driver s3c24xx_spi_driver = {
|
|
.probe = s3c24xx_spi_probe,
|
|
.remove = s3c24xx_spi_remove,
|
|
.driver = {
|
|
.name = "s3c2410-spi",
|
|
.pm = S3C24XX_SPI_PMOPS,
|
|
},
|
|
};
|
|
module_platform_driver(s3c24xx_spi_driver);
|
|
|
|
MODULE_DESCRIPTION("S3C24XX SPI Driver");
|
|
MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
|
|
MODULE_LICENSE("GPL");
|