[3.11.y.z extended stable] Patch "i2c: mux: gpio: use reg value for i2c_add_mux_adapter" has been added to staging queue

[Luis Henriques]

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

    i2c: mux: gpio: use reg value for i2c_add_mux_adapter

to the linux-3.11.y-queue branch of the 3.11.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-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 0ce28fa04f0a3d7f79b07dce04e9d39117a3aba1 Mon Sep 17 00:00:00 2001
From: Ionut Nicu <ioan.nicu.ext at nsn.com>
Date: Fri, 11 Oct 2013 12:09:57 +0200
Subject: i2c: mux: gpio: use reg value for i2c_add_mux_adapter

commit 8c0ec2500eeb89749341884a972860d7f9e56f9c upstream.

The i2c-mux driver requires that the chan_id parameter
passed to the i2c_add_mux_adapter() function is equal
to the reg value for that adapter:

for_each_child_of_node(mux_dev->of_node, child) {
	ret = of_property_read_u32(child, "reg", &reg);
	if (ret)
		continue;
	if (chan_id == reg) {
		priv->adap.dev.of_node = child;
		break;
	}
}

The i2c-mux-gpio driver uses an internal logical index
for chan_id when calling i2c_add_mux_adapter() instead
of using the reg value.

Because of this, there will problems in selecting the
right adapter when the i2c-mux-gpio's index into
mux->data.values doesn't match the reg value.

An example of such a case:

mux->data.values = { 1, 0 }

For chan_id = 0, i2c-mux will bind the adapter to the
of_node with reg = <0>, but when it will call the
select() callback with chan_id set to 0, the i2c-mux-gpio
will use it as an index into mux->data.values and it will
actually select the bus with reg = <1>.

Signed-off-by: Ionut Nicu <ioan.nicu.ext at nsn.com>
Acked-by: Alexander Sverdlin <alexander.sverdlin at nsn.com>
Signed-off-by: Wolfram Sang <wsa at the-dreams.de>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/i2c/muxes/i2c-mux-gpio.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c
index 5a0ce00..4879796 100644
--- a/drivers/i2c/muxes/i2c-mux-gpio.c
+++ b/drivers/i2c/muxes/i2c-mux-gpio.c
@@ -39,7 +39,7 @@ static int i2c_mux_gpio_select(struct i2c_adapter *adap, void *data, u32 chan)
 {
 	struct gpiomux *mux = data;

-	i2c_mux_gpio_set(mux, mux->data.values[chan]);
+	i2c_mux_gpio_set(mux, chan);

 	return 0;
 }
@@ -223,7 +223,7 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 		unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;

 		mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
-						   i, class,
+						   mux->data.values[i], class,
 						   i2c_mux_gpio_select, deselect);
 		if (!mux->adap[i]) {
 			ret = -ENODEV;
--
1.8.3.2