This is a note to let you know that I've just added the patch titled
i2c: tegra: check the clk_prepare_enable() return value
to the 3.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i2c-tegra-check-the-clk_prepare_enable-return-value.patch
and it can be found in the queue-3.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 132c803f7b70b17322579f6f4f3f65cf68e55135 Mon Sep 17 00:00:00 2001
From: Laxman Dewangan <ldewangan@xxxxxxxxxx>
Date: Fri, 15 Mar 2013 05:34:08 +0000
Subject: i2c: tegra: check the clk_prepare_enable() return value
From: Laxman Dewangan <ldewangan@xxxxxxxxxx>
commit 132c803f7b70b17322579f6f4f3f65cf68e55135 upstream.
NVIDIA's Tegra SoC allows read/write of controller register only
if controller clock is enabled. System hangs if read/write happens
to registers without enabling clock.
clk_prepare_enable() can be fail due to unknown reason and hence
adding check for return value of this function. If this function
success then only access register otherwise return to caller with
error.
Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>
Reviewed-by: Stephen Warren <swarren@xxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-tegra.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -392,7 +392,11 @@ static int tegra_i2c_init(struct tegra_i
u32 val;
int err = 0;
- tegra_i2c_clock_enable(i2c_dev);
+ err = tegra_i2c_clock_enable(i2c_dev);
+ if (err < 0) {
+ dev_err(i2c_dev->dev, "Clock enable failed %d\n", err);
+ return err;
+ }
tegra_periph_reset_assert(i2c_dev->div_clk);
udelay(2);
@@ -599,7 +603,12 @@ static int tegra_i2c_xfer(struct i2c_ada
if (i2c_dev->is_suspended)
return -EBUSY;
- tegra_i2c_clock_enable(i2c_dev);
+ ret = tegra_i2c_clock_enable(i2c_dev);
+ if (ret < 0) {
+ dev_err(i2c_dev->dev, "Clock enable failed %d\n", ret);
+ return ret;
+ }
+
for (i = 0; i < num; i++) {
enum msg_end_type end_type = MSG_END_STOP;
if (i < (num - 1)) {
Patches currently in stable-queue which might be from ldewangan@xxxxxxxxxx are
queue-3.8/i2c-tegra-check-the-clk_prepare_enable-return-value.patch
queue-3.8/arm-tegra-fix-register-address-of-slink-controller.patch
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