From 0520e6a5d0030f0cc153d070e424dc4f4f69e47a Mon Sep 17 00:00:00 2001
From: Stefan Schantl <stefan.schantl@ipfire.org>
Date: Thu, 19 Dec 2013 21:26:15 +0100
Subject: [PATCH] Kernel: In case of busy i2c try again to get ACK on imx
 platforms.

---
 lfs/linux                                     |  2 +
 .../imx/0001-i2c-imx-retry-on-NAK.patch       | 38 +++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 src/patches/kernel/wandboard/imx/0001-i2c-imx-retry-on-NAK.patch

diff --git a/lfs/linux b/lfs/linux
index b787aac47..182143cdc 100644
--- a/lfs/linux
+++ b/lfs/linux
@@ -171,6 +171,8 @@ ifeq "$(KCFG)" "-multi"
 	cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/kernel/wandboard/dts/0002-ARM-dts-imx6qdl-wandboard-add-gpio-lines-to-wandboar.patch
 	cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/kernel/wandboard/dts/0003-ARM-dts-imx6qdl-wandboard-Add-support-for-i2c1.patch
 
+	cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/kernel/wandboard/imx/0001-i2c-imx-retry-on-NAK.patch
+
 	# Patchset for Compulab Utilite.
 	cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/kernel/utilite/linux-3.10-compulab-utilite-support.patch
 endif
diff --git a/src/patches/kernel/wandboard/imx/0001-i2c-imx-retry-on-NAK.patch b/src/patches/kernel/wandboard/imx/0001-i2c-imx-retry-on-NAK.patch
new file mode 100644
index 000000000..e876c6ed4
--- /dev/null
+++ b/src/patches/kernel/wandboard/imx/0001-i2c-imx-retry-on-NAK.patch
@@ -0,0 +1,38 @@
+From: Tim Harvey <tharvey@gateworks.com>
+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);
-- 
2.39.2