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-rw-r--r--drivers/spi/spi-ath79.c44
1 files changed, 43 insertions, 1 deletions
diff --git a/drivers/spi/spi-ath79.c b/drivers/spi/spi-ath79.c
index 9a5d7791c5fb..e02528244451 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);