[PATCH] S3C24XX: hardware SPI driver
Hardware based SPI driver for Samsung S3C24XX SoC systems
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/spi/spi_s3c24xx.c b/drivers/spi/spi_s3c24xx.c
new file mode 100644
index 0000000..9de4b5a
--- /dev/null
+++ b/drivers/spi/spi_s3c24xx.c
@@ -0,0 +1,453 @@
+/* linux/drivers/spi/spi_s3c24xx.c
+ *
+ * Copyright (c) 2006 Ben Dooks
+ * Copyright (c) 2006 Simtec Electronics
+ * Ben Dooks <ben@simtec.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+*/
+
+
+//#define DEBUG
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.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/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+
+#include <asm/io.h>
+#include <asm/dma.h>
+#include <asm/hardware.h>
+
+#include <asm/arch/regs-gpio.h>
+#include <asm/arch/regs-spi.h>
+#include <asm/arch/spi.h>
+
+struct s3c24xx_spi {
+ /* bitbang has to be first */
+ struct spi_bitbang bitbang;
+ struct completion done;
+
+ void __iomem *regs;
+ int irq;
+ int len;
+ int count;
+
+ /* data buffers */
+ const unsigned char *tx;
+ unsigned char *rx;
+
+ struct clk *clk;
+ struct resource *ioarea;
+ 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_chipsel(struct spi_device *spi, int value)
+{
+ struct s3c24xx_spi *hw = to_hw(spi);
+ unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
+ unsigned int spcon;
+
+ switch (value) {
+ case BITBANG_CS_INACTIVE:
+ if (hw->pdata->set_cs)
+ hw->pdata->set_cs(hw->pdata, value, cspol);
+ else
+ s3c2410_gpio_setpin(hw->pdata->pin_cs, cspol ^ 1);
+ break;
+
+ case BITBANG_CS_ACTIVE:
+ spcon = readb(hw->regs + S3C2410_SPCON);
+
+ if (spi->mode & SPI_CPHA)
+ spcon |= S3C2410_SPCON_CPHA_FMTB;
+ else
+ spcon &= ~S3C2410_SPCON_CPHA_FMTB;
+
+ if (spi->mode & SPI_CPOL)
+ spcon |= S3C2410_SPCON_CPOL_HIGH;
+ else
+ spcon &= ~S3C2410_SPCON_CPOL_HIGH;
+
+ spcon |= S3C2410_SPCON_ENSCK;
+
+ /* write new configration */
+
+ writeb(spcon, hw->regs + S3C2410_SPCON);
+
+ if (hw->pdata->set_cs)
+ hw->pdata->set_cs(hw->pdata, value, cspol);
+ else
+ s3c2410_gpio_setpin(hw->pdata->pin_cs, cspol);
+
+ break;
+
+ }
+}
+
+static int s3c24xx_spi_setupxfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct s3c24xx_spi *hw = to_hw(spi);
+ unsigned int bpw;
+ unsigned int hz;
+ unsigned int div;
+
+ bpw = t ? t->bits_per_word : spi->bits_per_word;
+ hz = t ? t->speed_hz : spi->max_speed_hz;
+
+ if (bpw != 8) {
+ dev_err(&spi->dev, "invalid bits-per-word (%d)\n", bpw);
+ return -EINVAL;
+ }
+
+ div = clk_get_rate(hw->clk) / hz;
+
+ /* is clk = pclk / (2 * (pre+1)), or is it
+ * clk = (pclk * 2) / ( pre + 1) */
+
+ div = (div / 2) - 1;
+
+ if (div < 0)
+ div = 1;
+
+ if (div > 255)
+ div = 255;
+
+ dev_dbg(&spi->dev, "setting pre-scaler to %d (hz %d)\n", div, hz);
+ writeb(div, hw->regs + S3C2410_SPPRE);
+
+ spin_lock(&hw->bitbang.lock);
+ if (!hw->bitbang.busy) {
+ hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
+ /* need to ndelay for 0.5 clocktick ? */
+ }
+ spin_unlock(&hw->bitbang.lock);
+
+ return 0;
+}
+
+static int s3c24xx_spi_setup(struct spi_device *spi)
+{
+ int ret;
+
+ if (!spi->bits_per_word)
+ spi->bits_per_word = 8;
+
+ if ((spi->mode & SPI_LSB_FIRST) != 0)
+ return -EINVAL;
+
+ ret = s3c24xx_spi_setupxfer(spi, NULL);
+ if (ret < 0) {
+ dev_err(&spi->dev, "setupxfer returned %d\n", ret);
+ return ret;
+ }
+
+ dev_dbg(&spi->dev, "%s: mode %d, %u bpw, %d hz\n",
+ __FUNCTION__, spi->mode, spi->bits_per_word,
+ spi->max_speed_hz);
+
+ return 0;
+}
+
+static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
+{
+ return hw->tx ? hw->tx[count] : 0xff;
+}
+
+static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct s3c24xx_spi *hw = to_hw(spi);
+
+ dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
+ t->tx_buf, t->rx_buf, t->len);
+
+ hw->tx = t->tx_buf;
+ hw->rx = t->rx_buf;
+ hw->len = t->len;
+ hw->count = 0;
+
+ /* 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 pt_regs *regs)
+{
+ 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;
+ }
+
+ 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);
+
+ irq_done:
+ return IRQ_HANDLED;
+}
+
+static int s3c24xx_spi_probe(struct platform_device *pdev)
+{
+ struct s3c24xx_spi *hw;
+ struct spi_master *master;
+ struct spi_board_info *bi;
+ struct resource *res;
+ int err = 0;
+ int i;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi));
+ if (master == NULL) {
+ dev_err(&pdev->dev, "No memory for spi_master\n");
+ err = -ENOMEM;
+ goto err_nomem;
+ }
+
+ hw = spi_master_get_devdata(master);
+ memset(hw, 0, sizeof(struct s3c24xx_spi));
+
+ hw->master = spi_master_get(master);
+ hw->pdata = pdev->dev.platform_data;
+ hw->dev = &pdev->dev;
+
+ if (hw->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);
+
+ /* 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->bitbang.master->setup = s3c24xx_spi_setup;
+
+ dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang);
+
+ /* find and map our resources */
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (res == NULL) {
+ dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
+ err = -ENOENT;
+ goto err_no_iores;
+ }
+
+ hw->ioarea = request_mem_region(res->start, (res->end - res->start)+1,
+ pdev->name);
+
+ if (hw->ioarea == NULL) {
+ dev_err(&pdev->dev, "Cannot reserve region\n");
+ err = -ENXIO;
+ goto err_no_iores;
+ }
+
+ hw->regs = ioremap(res->start, (res->end - res->start)+1);
+ if (hw->regs == NULL) {
+ dev_err(&pdev->dev, "Cannot map IO\n");
+ err = -ENXIO;
+ goto err_no_iomap;
+ }
+
+ hw->irq = platform_get_irq(pdev, 0);
+ if (hw->irq < 0) {
+ dev_err(&pdev->dev, "No IRQ specified\n");
+ err = -ENOENT;
+ goto err_no_irq;
+ }
+
+ err = request_irq(hw->irq, s3c24xx_spi_irq, 0, pdev->name, hw);
+ if (err) {
+ dev_err(&pdev->dev, "Cannot claim IRQ\n");
+ goto err_no_irq;
+ }
+
+ hw->clk = 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_clk;
+ }
+
+ /* 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);
+
+ /* setup any gpio we can */
+
+ if (!hw->pdata->set_cs) {
+ s3c2410_gpio_setpin(hw->pdata->pin_cs, 1);
+ s3c2410_gpio_cfgpin(hw->pdata->pin_cs, S3C2410_GPIO_OUTPUT);
+ }
+
+ /* 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;
+ }
+
+ dev_dbg(hw->dev, "shutdown=%d\n", hw->bitbang.shutdown);
+
+ /* register all the devices associated */
+
+ bi = &hw->pdata->board_info[0];
+ for (i = 0; i < hw->pdata->board_size; i++, bi++) {
+ dev_info(hw->dev, "registering %s\n", bi->modalias);
+
+ bi->controller_data = hw;
+ spi_new_device(master, bi);
+ }
+
+ return 0;
+
+ err_register:
+ clk_disable(hw->clk);
+ clk_put(hw->clk);
+
+ err_no_clk:
+ free_irq(hw->irq, hw);
+
+ err_no_irq:
+ iounmap(hw->regs);
+
+ err_no_iomap:
+ release_resource(hw->ioarea);
+ kfree(hw->ioarea);
+
+ err_no_iores:
+ err_no_pdata:
+ spi_master_put(hw->master);;
+
+ err_nomem:
+ return err;
+}
+
+static int s3c24xx_spi_remove(struct platform_device *dev)
+{
+ struct s3c24xx_spi *hw = platform_get_drvdata(dev);
+
+ platform_set_drvdata(dev, NULL);
+
+ spi_unregister_master(hw->master);
+
+ clk_disable(hw->clk);
+ clk_put(hw->clk);
+
+ free_irq(hw->irq, hw);
+ iounmap(hw->regs);
+
+ release_resource(hw->ioarea);
+ kfree(hw->ioarea);
+
+ spi_master_put(hw->master);
+ return 0;
+}
+
+
+#ifdef CONFIG_PM
+
+static int s3c24xx_spi_suspend(struct platform_device *pdev, pm_message_t msg)
+{
+ struct s3c24xx_spi *hw = platform_get_drvdata(dev);
+
+ clk_disable(hw->clk);
+ return 0;
+}
+
+static int s3c24xx_spi_resume(struct platform_device *pdev)
+{
+ struct s3c24xx_spi *hw = platform_get_drvdata(dev);
+
+ clk_enable(hw->clk);
+ return 0;
+}
+
+#else
+#define s3c24xx_spi_suspend NULL
+#define s3c24xx_spi_resume NULL
+#endif
+
+static struct platform_driver s3c24xx_spidrv = {
+ .probe = s3c24xx_spi_probe,
+ .remove = s3c24xx_spi_remove,
+ .suspend = s3c24xx_spi_suspend,
+ .resume = s3c24xx_spi_resume,
+ .driver = {
+ .name = "s3c2410-spi",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init s3c24xx_spi_init(void)
+{
+ return platform_driver_register(&s3c24xx_spidrv);
+}
+
+static void __exit s3c24xx_spi_exit(void)
+{
+ platform_driver_unregister(&s3c24xx_spidrv);
+}
+
+module_init(s3c24xx_spi_init);
+module_exit(s3c24xx_spi_exit);
+
+MODULE_DESCRIPTION("S3C24XX SPI Driver");
+MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
+MODULE_LICENSE("GPL");