ar71xx: use backported SPI patches

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

SVN-Revision: 35873

1 files changed, 126 insertions, 0 deletions

diff --git a/target/linux/ar71xx/patches-3.8/001-spi-ath79-add-delay-between-SCK-changes.patch b/target/linux/ar71xx/patches-3.8/001-spi-ath79-add-delay-between-SCK-changes.patch
new file mode 100644
index 0000000000..9a1062287c
--- /dev/null
+++ b/target/linux/ar71xx/patches-3.8/001-spi-ath79-add-delay-between-SCK-changes.patch
@@ -0,0 +1,126 @@
+From 486c150478777ef53cfef6f0d46840b9406b0612 Mon Sep 17 00:00:00 2001
+From: Gabor Juhos <juhosg@openwrt.org>
+Date: Thu, 27 Dec 2012 10:42:24 +0100
+Subject: [PATCH] spi/ath79: add delay between SCK changes
+
+commit 440114fdb13cbc53ea734bcc05b86bcf5b1e430c upstream.
+
+The driver uses the "as fast as it can" approach
+to drive the SCK signal. However this does not
+work with certain low speed SPI chips (e.g. the
+PCF2123 RTC chip).
+
+The patch adds per-bit slowdowns in order to be
+able to use the driver with such chips as well.
+
+Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
+Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
+---
+ drivers/spi/spi-ath79.c |   44 +++++++++++++++++++++++++++++++++++++++++++-
+ 1 file changed, 43 insertions(+), 1 deletion(-)
+
+--- 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_sp
+ 	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 s
+ 
+ 		/* 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 platfo
+ 	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 platfo
+ 		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 platf
+ 	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);