From 7fba53402eb0fb4209c74469814c583b6455e096 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Sat, 20 May 2006 15:00:18 -0700 Subject: [PATCH] S3C24XX: hardware SPI driver Hardware based SPI driver for Samsung S3C24XX SoC systems Signed-off-by: Ben Dooks Cc: David Brownell Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/spi/spi_s3c24xx.c | 453 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 453 insertions(+) create mode 100644 drivers/spi/spi_s3c24xx.c (limited to 'drivers/spi/spi_s3c24xx.c') diff --git a/drivers/spi/spi_s3c24xx.c b/drivers/spi/spi_s3c24xx.c new file mode 100644 index 000000000000..9de4b5a04d70 --- /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 + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include +#include +#include + +#include +#include +#include + +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, "); +MODULE_LICENSE("GPL"); -- cgit v1.2.3-59-g8ed1b