[ 3.8.y.z extended stable ] Patch "i2c: omap: Clear ARDY bit twice" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    i2c: omap: Clear ARDY bit twice

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.12.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 61afc4ea131bdbded2c42e58cb03a0f138bf687d Mon Sep 17 00:00:00 2001
From: Taras Kondratiuk <taras.kondratiuk at linaro.org>
Date: Mon, 7 Oct 2013 13:41:59 +0300
Subject: i2c: omap: Clear ARDY bit twice

commit 4cdbf7d346e7461c3b93a26707c852e2c9db3753 upstream.

Initially commit cb527ede1bf6ff2008a025606f25344b8ed7b4ac
"i2c-omap: Double clear of ARDY status in IRQ handler"
added a workaround for undocumented errata ProDB0017052.
But then commit 1d7afc95946487945cc7f5019b41255b72224b70
"i2c: omap: ack IRQ in parts" refactored code and missed
one of ARDY clearings. So current code violates errata.
It causes often i2c bus timeouts on my Pandaboard.

This patch adds a second clearing in place.

Signed-off-by: Grygorii Strashko <grygorii.strashko at ti.com>
Signed-off-by: Taras Kondratiuk <taras.kondratiuk at linaro.org>
Signed-off-by: Wolfram Sang <wsa at the-dreams.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/i2c/busses/i2c-omap.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 4cc2f05..6fc54cd 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -941,6 +941,9 @@ omap_i2c_isr_thread(int this_irq, void *dev_id)
 		/*
 		 * ProDB0017052: Clear ARDY bit twice
 		 */
+		if (stat & OMAP_I2C_STAT_ARDY)
+			omap_i2c_ack_stat(dev, OMAP_I2C_STAT_ARDY);
+
 		if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
 					OMAP_I2C_STAT_AL)) {
 			omap_i2c_ack_stat(dev, (OMAP_I2C_STAT_RRDY |
--
1.8.1.2