From 033365191136c97f88c81b7bd0011414db28bb4e Mon Sep 17 00:00:00 2001 From: "J.D. Schroeder" Date: Wed, 8 Jul 2015 14:38:12 +0300 Subject: [PATCH] can: c_can: Fix default pinmux glitch at init 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 Signed-off-by: Roger Quadros Reviewed-by: Grygorii Strashko Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 041525d2595c..5d214d135332 100644 --- 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 *dev) { 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 *dev) 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; }