Patch "can: c_can: Fix default pinmux glitch at init" has been added to the 4.1-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    can: c_can: Fix default pinmux glitch at init

to the 4.1-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:
     can-c_can-fix-default-pinmux-glitch-at-init.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 033365191136c97f88c81b7bd0011414db28bb4e Mon Sep 17 00:00:00 2001
From: "J.D. Schroeder" <jay.schroeder@garmin.com>
Date: Wed, 8 Jul 2015 14:38:12 +0300
Subject: can: c_can: Fix default pinmux glitch at init

From: "J.D. Schroeder" <jay.schroeder@garmin.com>

commit 033365191136c97f88c81b7bd0011414db28bb4e upstream.

The previous change 3973c526ae9c (net: can: c_can: Disable pins when CAN
interface is down) causes a slight glitch on the pinctrl settings when used.
Since commit ab78029 (drivers/pinctrl: grab default handles from device core),
the device core will automatically set the default pins. This causes the pins
to be momentarily set to the default and then to the sleep state in
register_c_can_dev(). By adding an optional "enable" state, boards can set the
default pin state to be disabled and avoid the glitch when the switch from
default to sleep first occurs. If the "enable" state is not available
c_can_pinctrl_select_state() falls back to using the "default" pinctrl state.

[Roger Q] - Forward port to v4.2 and use pinctrl_get_select().

Signed-off-by: J.D. Schroeder <jay.schroeder@garmin.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/can/c_can/c_can.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -592,6 +592,7 @@ static int c_can_start(struct net_device
 {
 	struct c_can_priv *priv = netdev_priv(dev);
 	int err;
+	struct pinctrl *p;
 
 	/* basic c_can configuration */
 	err = c_can_chip_config(dev);
@@ -604,8 +605,13 @@ static int c_can_start(struct net_device
 
 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
 
-	/* activate pins */
-	pinctrl_pm_select_default_state(dev->dev.parent);
+	/* Attempt to use "active" if available else use "default" */
+	p = pinctrl_get_select(priv->device, "active");
+	if (!IS_ERR(p))
+		pinctrl_put(p);
+	else
+		pinctrl_pm_select_default_state(priv->device);
+
 	return 0;
 }
 


Patches currently in stable-queue which might be from jay.schroeder@garmin.com are

queue-4.1/can-c_can-fix-default-pinmux-glitch-at-init.patch