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-rw-r--r--drivers/spi/spi-s3c24xx.c645
1 files changed, 645 insertions, 0 deletions
diff --git a/drivers/spi/spi-s3c24xx.c b/drivers/spi/spi-s3c24xx.c
new file mode 100644
index 000000000..d6f51695c
--- /dev/null
+++ b/drivers/spi/spi-s3c24xx.c
@@ -0,0 +1,645 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2006 Ben Dooks
+ * Copyright 2006-2009 Simtec Electronics
+ * Ben Dooks <ben@simtec.co.uk>
+*/
+
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/spi/s3c24xx.h>
+#include <linux/spi/s3c24xx-fiq.h>
+#include <linux/module.h>
+
+#include <asm/fiq.h>
+
+#include "spi-s3c24xx-regs.h"
+
+/**
+ * struct s3c24xx_spi_devstate - per device data
+ * @hz: Last frequency calculated for @sppre field.
+ * @mode: Last mode setting for the @spcon field.
+ * @spcon: Value to write to the SPCON register.
+ * @sppre: Value to write to the SPPRE register.
+ */
+struct s3c24xx_spi_devstate {
+ unsigned int hz;
+ unsigned int mode;
+ u8 spcon;
+ u8 sppre;
+};
+
+enum spi_fiq_mode {
+ FIQ_MODE_NONE = 0,
+ FIQ_MODE_TX = 1,
+ FIQ_MODE_RX = 2,
+ FIQ_MODE_TXRX = 3,
+};
+
+struct s3c24xx_spi {
+ /* bitbang has to be first */
+ struct spi_bitbang bitbang;
+ struct completion done;
+
+ void __iomem *regs;
+ int irq;
+ int len;
+ int count;
+
+ struct fiq_handler fiq_handler;
+ enum spi_fiq_mode fiq_mode;
+ unsigned char fiq_inuse;
+ unsigned char fiq_claimed;
+
+ void (*set_cs)(struct s3c2410_spi_info *spi,
+ int cs, int pol);
+
+ /* data buffers */
+ const unsigned char *tx;
+ unsigned char *rx;
+
+ struct clk *clk;
+ struct spi_master *master;
+ struct spi_device *curdev;
+ struct device *dev;
+ struct s3c2410_spi_info *pdata;
+};
+
+#define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
+#define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
+
+static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev)
+{
+ return spi_master_get_devdata(sdev->master);
+}
+
+static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info *spi, int cs, int pol)
+{
+ gpio_set_value(spi->pin_cs, pol);
+}
+
+static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
+{
+ struct s3c24xx_spi_devstate *cs = spi->controller_state;
+ struct s3c24xx_spi *hw = to_hw(spi);
+ unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
+
+ /* change the chipselect state and the state of the spi engine clock */
+
+ switch (value) {
+ case BITBANG_CS_INACTIVE:
+ hw->set_cs(hw->pdata, spi->chip_select, cspol^1);
+ writeb(cs->spcon, hw->regs + S3C2410_SPCON);
+ break;
+
+ case BITBANG_CS_ACTIVE:
+ writeb(cs->spcon | S3C2410_SPCON_ENSCK,
+ hw->regs + S3C2410_SPCON);
+ hw->set_cs(hw->pdata, spi->chip_select, cspol);
+ break;
+ }
+}
+
+static int s3c24xx_spi_update_state(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct s3c24xx_spi *hw = to_hw(spi);
+ struct s3c24xx_spi_devstate *cs = spi->controller_state;
+ unsigned int hz;
+ unsigned int div;
+ unsigned long clk;
+
+ hz = t ? t->speed_hz : spi->max_speed_hz;
+
+ if (!hz)
+ hz = spi->max_speed_hz;
+
+ if (spi->mode != cs->mode) {
+ u8 spcon = SPCON_DEFAULT | S3C2410_SPCON_ENSCK;
+
+ if (spi->mode & SPI_CPHA)
+ spcon |= S3C2410_SPCON_CPHA_FMTB;
+
+ if (spi->mode & SPI_CPOL)
+ spcon |= S3C2410_SPCON_CPOL_HIGH;
+
+ cs->mode = spi->mode;
+ cs->spcon = spcon;
+ }
+
+ if (cs->hz != hz) {
+ clk = clk_get_rate(hw->clk);
+ div = DIV_ROUND_UP(clk, hz * 2) - 1;
+
+ if (div > 255)
+ div = 255;
+
+ dev_dbg(&spi->dev, "pre-scaler=%d (wanted %d, got %ld)\n",
+ div, hz, clk / (2 * (div + 1)));
+
+ cs->hz = hz;
+ cs->sppre = div;
+ }
+
+ return 0;
+}
+
+static int s3c24xx_spi_setupxfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct s3c24xx_spi_devstate *cs = spi->controller_state;
+ struct s3c24xx_spi *hw = to_hw(spi);
+ int ret;
+
+ ret = s3c24xx_spi_update_state(spi, t);
+ if (!ret)
+ writeb(cs->sppre, hw->regs + S3C2410_SPPRE);
+
+ return ret;
+}
+
+static int s3c24xx_spi_setup(struct spi_device *spi)
+{
+ struct s3c24xx_spi_devstate *cs = spi->controller_state;
+ struct s3c24xx_spi *hw = to_hw(spi);
+ int ret;
+
+ /* allocate settings on the first call */
+ if (!cs) {
+ cs = devm_kzalloc(&spi->dev,
+ sizeof(struct s3c24xx_spi_devstate),
+ GFP_KERNEL);
+ if (!cs)
+ return -ENOMEM;
+
+ cs->spcon = SPCON_DEFAULT;
+ cs->hz = -1;
+ spi->controller_state = cs;
+ }
+
+ /* initialise the state from the device */
+ ret = s3c24xx_spi_update_state(spi, NULL);
+ if (ret)
+ return ret;
+
+ mutex_lock(&hw->bitbang.lock);
+ if (!hw->bitbang.busy) {
+ hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
+ /* need to ndelay for 0.5 clocktick ? */
+ }
+ mutex_unlock(&hw->bitbang.lock);
+
+ return 0;
+}
+
+static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
+{
+ return hw->tx ? hw->tx[count] : 0;
+}
+
+#ifdef CONFIG_SPI_S3C24XX_FIQ
+/* Support for FIQ based pseudo-DMA to improve the transfer speed.
+ *
+ * This code uses the assembly helper in spi_s3c24xx_spi.S which is
+ * used by the FIQ core to move data between main memory and the peripheral
+ * block. Since this is code running on the processor, there is no problem
+ * with cache coherency of the buffers, so we can use any buffer we like.
+ */
+
+/**
+ * struct spi_fiq_code - FIQ code and header
+ * @length: The length of the code fragment, excluding this header.
+ * @ack_offset: The offset from @data to the word to place the IRQ ACK bit at.
+ * @data: The code itself to install as a FIQ handler.
+ */
+struct spi_fiq_code {
+ u32 length;
+ u32 ack_offset;
+ u8 data[];
+};
+
+/**
+ * s3c24xx_spi_tryfiq - attempt to claim and setup FIQ for transfer
+ * @hw: The hardware state.
+ *
+ * Claim the FIQ handler (only one can be active at any one time) and
+ * then setup the correct transfer code for this transfer.
+ *
+ * This call updates all the necessary state information if successful,
+ * so the caller does not need to do anything more than start the transfer
+ * as normal, since the IRQ will have been re-routed to the FIQ handler.
+*/
+static void s3c24xx_spi_tryfiq(struct s3c24xx_spi *hw)
+{
+ struct pt_regs regs;
+ enum spi_fiq_mode mode;
+ struct spi_fiq_code *code;
+ u32 *ack_ptr = NULL;
+ int ret;
+
+ if (!hw->fiq_claimed) {
+ /* try and claim fiq if we haven't got it, and if not
+ * then return and simply use another transfer method */
+
+ ret = claim_fiq(&hw->fiq_handler);
+ if (ret)
+ return;
+ }
+
+ if (hw->tx && !hw->rx)
+ mode = FIQ_MODE_TX;
+ else if (hw->rx && !hw->tx)
+ mode = FIQ_MODE_RX;
+ else
+ mode = FIQ_MODE_TXRX;
+
+ regs.uregs[fiq_rspi] = (long)hw->regs;
+ regs.uregs[fiq_rrx] = (long)hw->rx;
+ regs.uregs[fiq_rtx] = (long)hw->tx + 1;
+ regs.uregs[fiq_rcount] = hw->len - 1;
+
+ set_fiq_regs(&regs);
+
+ if (hw->fiq_mode != mode) {
+ hw->fiq_mode = mode;
+
+ switch (mode) {
+ case FIQ_MODE_TX:
+ code = &s3c24xx_spi_fiq_tx;
+ break;
+ case FIQ_MODE_RX:
+ code = &s3c24xx_spi_fiq_rx;
+ break;
+ case FIQ_MODE_TXRX:
+ code = &s3c24xx_spi_fiq_txrx;
+ break;
+ default:
+ code = NULL;
+ }
+
+ BUG_ON(!code);
+
+ ack_ptr = (u32 *)&code->data[code->ack_offset];
+ set_fiq_handler(&code->data, code->length);
+ }
+
+ s3c24xx_set_fiq(hw->irq, ack_ptr, true);
+
+ hw->fiq_mode = mode;
+ hw->fiq_inuse = 1;
+}
+
+/**
+ * s3c24xx_spi_fiqop - FIQ core code callback
+ * @pw: Data registered with the handler
+ * @release: Whether this is a release or a return.
+ *
+ * Called by the FIQ code when another module wants to use the FIQ, so
+ * return whether we are currently using this or not and then update our
+ * internal state.
+ */
+static int s3c24xx_spi_fiqop(void *pw, int release)
+{
+ struct s3c24xx_spi *hw = pw;
+ int ret = 0;
+
+ if (release) {
+ if (hw->fiq_inuse)
+ ret = -EBUSY;
+
+ /* note, we do not need to unroute the FIQ, as the FIQ
+ * vector code de-routes it to signal the end of transfer */
+
+ hw->fiq_mode = FIQ_MODE_NONE;
+ hw->fiq_claimed = 0;
+ } else {
+ hw->fiq_claimed = 1;
+ }
+
+ return ret;
+}
+
+/**
+ * s3c24xx_spi_initfiq - setup the information for the FIQ core
+ * @hw: The hardware state.
+ *
+ * Setup the fiq_handler block to pass to the FIQ core.
+ */
+static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *hw)
+{
+ hw->fiq_handler.dev_id = hw;
+ hw->fiq_handler.name = dev_name(hw->dev);
+ hw->fiq_handler.fiq_op = s3c24xx_spi_fiqop;
+}
+
+/**
+ * s3c24xx_spi_usefiq - return if we should be using FIQ.
+ * @hw: The hardware state.
+ *
+ * Return true if the platform data specifies whether this channel is
+ * allowed to use the FIQ.
+ */
+static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *hw)
+{
+ return hw->pdata->use_fiq;
+}
+
+/**
+ * s3c24xx_spi_usingfiq - return if channel is using FIQ
+ * @spi: The hardware state.
+ *
+ * Return whether the channel is currently using the FIQ (separate from
+ * whether the FIQ is claimed).
+ */
+static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *spi)
+{
+ return spi->fiq_inuse;
+}
+#else
+
+static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *s) { }
+static inline void s3c24xx_spi_tryfiq(struct s3c24xx_spi *s) { }
+static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *s) { return false; }
+static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *s) { return false; }
+
+#endif /* CONFIG_SPI_S3C24XX_FIQ */
+
+static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct s3c24xx_spi *hw = to_hw(spi);
+
+ hw->tx = t->tx_buf;
+ hw->rx = t->rx_buf;
+ hw->len = t->len;
+ hw->count = 0;
+
+ init_completion(&hw->done);
+
+ hw->fiq_inuse = 0;
+ if (s3c24xx_spi_usefiq(hw) && t->len >= 3)
+ s3c24xx_spi_tryfiq(hw);
+
+ /* send the first byte */
+ writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
+
+ wait_for_completion(&hw->done);
+ return hw->count;
+}
+
+static irqreturn_t s3c24xx_spi_irq(int irq, void *dev)
+{
+ struct s3c24xx_spi *hw = dev;
+ unsigned int spsta = readb(hw->regs + S3C2410_SPSTA);
+ unsigned int count = hw->count;
+
+ if (spsta & S3C2410_SPSTA_DCOL) {
+ dev_dbg(hw->dev, "data-collision\n");
+ complete(&hw->done);
+ goto irq_done;
+ }
+
+ if (!(spsta & S3C2410_SPSTA_READY)) {
+ dev_dbg(hw->dev, "spi not ready for tx?\n");
+ complete(&hw->done);
+ goto irq_done;
+ }
+
+ if (!s3c24xx_spi_usingfiq(hw)) {
+ hw->count++;
+
+ if (hw->rx)
+ hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT);
+
+ count++;
+
+ if (count < hw->len)
+ writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT);
+ else
+ complete(&hw->done);
+ } else {
+ hw->count = hw->len;
+ hw->fiq_inuse = 0;
+
+ if (hw->rx)
+ hw->rx[hw->len-1] = readb(hw->regs + S3C2410_SPRDAT);
+
+ complete(&hw->done);
+ }
+
+ irq_done:
+ return IRQ_HANDLED;
+}
+
+static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw)
+{
+ /* for the moment, permanently enable the clock */
+
+ clk_enable(hw->clk);
+
+ /* program defaults into the registers */
+
+ writeb(0xff, hw->regs + S3C2410_SPPRE);
+ writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN);
+ writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON);
+
+ if (hw->pdata) {
+ if (hw->set_cs == s3c24xx_spi_gpiocs)
+ gpio_direction_output(hw->pdata->pin_cs, 1);
+
+ if (hw->pdata->gpio_setup)
+ hw->pdata->gpio_setup(hw->pdata, 1);
+ }
+}
+
+static int s3c24xx_spi_probe(struct platform_device *pdev)
+{
+ struct s3c2410_spi_info *pdata;
+ struct s3c24xx_spi *hw;
+ struct spi_master *master;
+ int err = 0;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi));
+ if (master == NULL) {
+ dev_err(&pdev->dev, "No memory for spi_master\n");
+ return -ENOMEM;
+ }
+
+ hw = spi_master_get_devdata(master);
+
+ hw->master = master;
+ hw->pdata = pdata = dev_get_platdata(&pdev->dev);
+ hw->dev = &pdev->dev;
+
+ if (pdata == NULL) {
+ dev_err(&pdev->dev, "No platform data supplied\n");
+ err = -ENOENT;
+ goto err_no_pdata;
+ }
+
+ platform_set_drvdata(pdev, hw);
+ init_completion(&hw->done);
+
+ /* initialise fiq handler */
+
+ s3c24xx_spi_initfiq(hw);
+
+ /* setup the master state. */
+
+ /* the spi->mode bits understood by this driver: */
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+
+ master->num_chipselect = hw->pdata->num_cs;
+ master->bus_num = pdata->bus_num;
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+
+ /* setup the state for the bitbang driver */
+
+ hw->bitbang.master = hw->master;
+ hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer;
+ hw->bitbang.chipselect = s3c24xx_spi_chipsel;
+ hw->bitbang.txrx_bufs = s3c24xx_spi_txrx;
+
+ 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;
+ }
+
+ /* setup any gpio we can */
+
+ if (!pdata->set_cs) {
+ if (pdata->pin_cs < 0) {
+ dev_err(&pdev->dev, "No chipselect pin\n");
+ err = -EINVAL;
+ goto err_register;
+ }
+
+ err = devm_gpio_request(&pdev->dev, pdata->pin_cs,
+ dev_name(&pdev->dev));
+ if (err) {
+ dev_err(&pdev->dev, "Failed to get gpio for cs\n");
+ goto err_register;
+ }
+
+ hw->set_cs = s3c24xx_spi_gpiocs;
+ gpio_direction_output(pdata->pin_cs, 1);
+ } else
+ hw->set_cs = pdata->set_cs;
+
+ 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;
+
+ if (hw->pdata && hw->pdata->gpio_setup)
+ hw->pdata->gpio_setup(hw->pdata, 0);
+
+ 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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-29 15:34:55 +0000