diff options
Diffstat (limited to 'drivers/spi/spi-ath79.c')
| -rw-r--r-- | drivers/spi/spi-ath79.c | 115 |
1 files changed, 83 insertions, 32 deletions
diff --git a/drivers/spi/spi-ath79.c b/drivers/spi/spi-ath79.c index 9a5d7791c5fb..e504b7636058 100644 --- a/drivers/spi/spi-ath79.c +++ b/drivers/spi/spi-ath79.c @@ -24,17 +24,24 @@ #include <linux/spi/spi_bitbang.h> #include <linux/bitops.h> #include <linux/gpio.h> +#include <linux/clk.h> +#include <linux/err.h> #include <asm/mach-ath79/ar71xx_regs.h> #include <asm/mach-ath79/ath79_spi_platform.h> #define DRV_NAME "ath79-spi" +#define ATH79_SPI_RRW_DELAY_FACTOR 12000 +#define MHZ (1000 * 1000) + struct ath79_spi { struct spi_bitbang bitbang; u32 ioc_base; u32 reg_ctrl; void __iomem *base; + struct clk *clk; + unsigned rrw_delay; }; static inline u32 ath79_spi_rr(struct ath79_spi *sp, unsigned reg) @@ -52,6 +59,12 @@ static inline struct ath79_spi *ath79_spidev_to_sp(struct spi_device *spi) return spi_master_get_devdata(spi->master); } +static inline void ath79_spi_delay(struct ath79_spi *sp, unsigned nsecs) +{ + if (nsecs > sp->rrw_delay) + ndelay(nsecs - sp->rrw_delay); +} + static void ath79_spi_chipselect(struct spi_device *spi, int is_active) { struct ath79_spi *sp = ath79_spidev_to_sp(spi); @@ -83,15 +96,8 @@ static void ath79_spi_chipselect(struct spi_device *spi, int is_active) } -static int ath79_spi_setup_cs(struct spi_device *spi) +static void ath79_spi_enable(struct ath79_spi *sp) { - struct ath79_spi *sp = ath79_spidev_to_sp(spi); - struct ath79_spi_controller_data *cdata; - - cdata = spi->controller_data; - if (spi->chip_select && !cdata) - return -EINVAL; - /* enable GPIO mode */ ath79_spi_wr(sp, AR71XX_SPI_REG_FS, AR71XX_SPI_FS_GPIO); @@ -101,44 +107,48 @@ static int ath79_spi_setup_cs(struct spi_device *spi) /* TODO: setup speed? */ ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, 0x43); +} - if (spi->chip_select) { - int status = 0; +static void ath79_spi_disable(struct ath79_spi *sp) +{ + /* restore CTRL register */ + ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, sp->reg_ctrl); + /* disable GPIO mode */ + ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0); +} - status = gpio_request(cdata->gpio, dev_name(&spi->dev)); - if (status) - return status; +static int ath79_spi_setup_cs(struct spi_device *spi) +{ + struct ath79_spi_controller_data *cdata; + int status; - status = gpio_direction_output(cdata->gpio, - spi->mode & SPI_CS_HIGH); - if (status) { - gpio_free(cdata->gpio); - return status; - } - } else { + cdata = spi->controller_data; + if (spi->chip_select && !cdata) + return -EINVAL; + + status = 0; + if (spi->chip_select) { + unsigned long flags; + + flags = GPIOF_DIR_OUT; if (spi->mode & SPI_CS_HIGH) - sp->ioc_base |= AR71XX_SPI_IOC_CS0; + flags |= GPIOF_INIT_HIGH; else - sp->ioc_base &= ~AR71XX_SPI_IOC_CS0; - ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base); + flags |= GPIOF_INIT_LOW; + + status = gpio_request_one(cdata->gpio, flags, + dev_name(&spi->dev)); } - return 0; + return status; } static void ath79_spi_cleanup_cs(struct spi_device *spi) { - struct ath79_spi *sp = ath79_spidev_to_sp(spi); - if (spi->chip_select) { struct ath79_spi_controller_data *cdata = spi->controller_data; gpio_free(cdata->gpio); } - - /* restore CTRL register */ - ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, sp->reg_ctrl); - /* disable GPIO mode */ - ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0); } static int ath79_spi_setup(struct spi_device *spi) @@ -184,7 +194,11 @@ static u32 ath79_spi_txrx_mode0(struct spi_device *spi, unsigned nsecs, /* setup MSB (to slave) on trailing edge */ ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out); + ath79_spi_delay(sp, nsecs); ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out | AR71XX_SPI_IOC_CLK); + ath79_spi_delay(sp, nsecs); + if (bits == 1) + ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out); word <<= 1; } @@ -198,6 +212,7 @@ static int ath79_spi_probe(struct platform_device *pdev) struct ath79_spi *sp; struct ath79_spi_platform_data *pdata; struct resource *r; + unsigned long rate; int ret; master = spi_alloc_master(&pdev->dev, sizeof(*sp)); @@ -236,12 +251,39 @@ static int ath79_spi_probe(struct platform_device *pdev) goto err_put_master; } + sp->clk = clk_get(&pdev->dev, "ahb"); + if (IS_ERR(sp->clk)) { + ret = PTR_ERR(sp->clk); + goto err_unmap; + } + + ret = clk_enable(sp->clk); + if (ret) + goto err_clk_put; + + rate = DIV_ROUND_UP(clk_get_rate(sp->clk), MHZ); + if (!rate) { + ret = -EINVAL; + goto err_clk_disable; + } + + sp->rrw_delay = ATH79_SPI_RRW_DELAY_FACTOR / rate; + dev_dbg(&pdev->dev, "register read/write delay is %u nsecs\n", + sp->rrw_delay); + + ath79_spi_enable(sp); ret = spi_bitbang_start(&sp->bitbang); if (ret) - goto err_unmap; + goto err_disable; return 0; +err_disable: + ath79_spi_disable(sp); +err_clk_disable: + clk_disable(sp->clk); +err_clk_put: + clk_put(sp->clk); err_unmap: iounmap(sp->base); err_put_master: @@ -256,6 +298,9 @@ static int ath79_spi_remove(struct platform_device *pdev) struct ath79_spi *sp = platform_get_drvdata(pdev); spi_bitbang_stop(&sp->bitbang); + ath79_spi_disable(sp); + clk_disable(sp->clk); + clk_put(sp->clk); iounmap(sp->base); platform_set_drvdata(pdev, NULL); spi_master_put(sp->bitbang.master); @@ -263,9 +308,15 @@ static int ath79_spi_remove(struct platform_device *pdev) return 0; } +static void ath79_spi_shutdown(struct platform_device *pdev) +{ + ath79_spi_remove(pdev); +} + static struct platform_driver ath79_spi_driver = { .probe = ath79_spi_probe, .remove = ath79_spi_remove, + .shutdown = ath79_spi_shutdown, .driver = { .name = DRV_NAME, .owner = THIS_MODULE, |