diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-ath79.c | 44 |
1 files changed, 43 insertions, 1 deletions
diff --git a/drivers/spi/spi-ath79.c b/drivers/spi/spi-ath79.c index 9a5d779..e025282 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); @@ -184,7 +197,9 @@ 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); word <<= 1; } @@ -198,6 +213,7 @@ 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 +252,36 @@ 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); + ret = spi_bitbang_start(&sp->bitbang); if (ret) - goto err_unmap; + goto err_clk_disable; return 0; +err_clk_disable: + clk_disable(sp->clk); +err_clk_put: + clk_put(sp->clk); err_unmap: iounmap(sp->base); err_put_master: @@ -256,6 +296,8 @@ static int ath79_spi_remove(struct platform_device *pdev) struct ath79_spi *sp = platform_get_drvdata(pdev); spi_bitbang_stop(&sp->bitbang); + clk_disable(sp->clk); + clk_put(sp->clk); iounmap(sp->base); platform_set_drvdata(pdev, NULL); spi_master_put(sp->bitbang.master); |