[4.2.y-ckt stable] Patch "i2c: rcar: disable runtime PM correctly in slave mode" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

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

    i2c: rcar: disable runtime PM correctly in slave mode

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt2.

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

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 26d2373c6fecf03aee23b2cadf44bf2ec8a5240e Mon Sep 17 00:00:00 2001
From: Wolfram Sang <wsa+renesas at sang-engineering.com>
Date: Wed, 16 Dec 2015 20:05:18 +0100
Subject: i2c: rcar: disable runtime PM correctly in slave mode

commit b4cd08aa1f53c831e67dc5c6bc9f9acff27abcba upstream.

When we also are I2C slave, we need to disable runtime PM because the
address detection mechanism needs to be active all the time. However, we
can reenable runtime PM once the slave instance was unregistered. So,
use pm_runtime_get_sync/put to achieve this, since it has proper
refcounting. pm_runtime_allow/forbid is like a global knob controllable
from userspace which is unsuitable here.

Signed-off-by: Wolfram Sang <wsa+renesas at sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa at the-dreams.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/i2c/busses/i2c-rcar.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index d8b5a8f..3191dd9 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -575,7 +575,7 @@ static int rcar_reg_slave(struct i2c_client *slave)
 	if (slave->flags & I2C_CLIENT_TEN)
 		return -EAFNOSUPPORT;

-	pm_runtime_forbid(rcar_i2c_priv_to_dev(priv));
+	pm_runtime_get_sync(rcar_i2c_priv_to_dev(priv));

 	priv->slave = slave;
 	rcar_i2c_write(priv, ICSAR, slave->addr);
@@ -597,7 +597,7 @@ static int rcar_unreg_slave(struct i2c_client *slave)

 	priv->slave = NULL;

-	pm_runtime_allow(rcar_i2c_priv_to_dev(priv));
+	pm_runtime_put(rcar_i2c_priv_to_dev(priv));

 	return 0;
 }
--
1.9.1