imx6: add i2c retry on NAK

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

SVN-Revision: 37935

target/linux/imx6/patches-3.10/0004-i2c-imx-retry-on-NAK.patch

@@ -0,0 +1,40 @@
+From 0d1ee1f265cf9730feb214ddd18bc430c0800e8b Mon Sep 17 00:00:00 2001
+From: Tim Harvey <tharvey@gateworks.com>
+Date: Tue, 10 Sep 2013 21:42:29 +0200
+Subject: [PATCH] i2c: imx: retry on NAK
+
+In case of busy i2c try again to get ACK.
+
+Signed-off-by: Tim Harvey <tharvey@gateworks.com>
+Tested-by: Luka Perkov <luka@openwrt.org>
+---
+ drivers/i2c/busses/i2c-imx.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+--- a/drivers/i2c/busses/i2c-imx.c
++++ b/drivers/i2c/busses/i2c-imx.c
+@@ -62,6 +62,7 @@
+ 
+ /* Default value */
+ #define IMX_I2C_BIT_RATE	100000	/* 100kHz */
++#define IMX_I2C_MAX_RETRIES	3	/* number of retries to attempt */
+ 
+ /* IMX I2C registers */
+ #define IMX_I2C_IADR	0x00	/* i2c slave address */
+@@ -198,7 +199,7 @@ static int i2c_imx_acked(struct imx_i2c_
+ {
+ 	if (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK) {
+ 		dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
+-		return -EIO;  /* No ACK */
++		return -EAGAIN; /* try again */
+ 	}
+ 
+ 	dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
+@@ -533,6 +534,7 @@ static int __init i2c_imx_probe(struct p
+ 	i2c_imx->adapter.dev.parent	= &pdev->dev;
+ 	i2c_imx->adapter.nr 		= pdev->id;
+ 	i2c_imx->adapter.dev.of_node	= pdev->dev.of_node;
++	i2c_imx->adapter.retries	= IMX_I2C_MAX_RETRIES;
+ 	i2c_imx->base			= base;
+ 
+ 	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);