On 11/13/2014 06:03 PM, Marc Kleine-Budde wrote: > On 11/13/2014 04:23 PM, Roger Quadros wrote: >> DRA7 CAN IP suffers from a problem which causes it to be prevented >> from fully turning OFF (i.e. stuck in transition) if the module was >> disabled while there was traffic on the CAN_RX line. >> >> To work around this issue we select the SLEEP pin state by default >> on probe and use the DEFAULT pin state on CAN up and back to the >> SLEEP pin state on CAN down. >> >> Signed-off-by: Roger Quadros <[email protected]> >> --- >> drivers/net/can/c_can/c_can.c | 37 +++++++++++++++++++++++++++++++++++++ >> drivers/net/can/c_can/c_can.h | 1 + >> 2 files changed, 38 insertions(+) >> >> diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c >> index 8e78bb4..c80cb3d 100644 >> --- a/drivers/net/can/c_can/c_can.c >> +++ b/drivers/net/can/c_can/c_can.c >> @@ -35,6 +35,7 @@ >> #include <linux/list.h> >> #include <linux/io.h> >> #include <linux/pm_runtime.h> >> +#include <linux/pinctrl/consumer.h> >> >> #include <linux/can.h> >> #include <linux/can/dev.h> >> @@ -587,6 +588,21 @@ static int c_can_chip_config(struct net_device *dev) >> return c_can_set_bittiming(dev); >> } >> >> +/* >> + * Selects the pinctrl state specified in the name. >> + */ >> +static void c_can_pinctrl_select_state(struct c_can_priv *priv, >> + const char *name) >> +{ >> + if (!IS_ERR(priv->pinctrl)) { >> + struct pinctrl_state *s; >> + >> + s = pinctrl_lookup_state(priv->pinctrl, name); >> + if (!IS_ERR(s)) >> + pinctrl_select_state(priv->pinctrl, s); >> + } >> +} >> + >> static int c_can_start(struct net_device *dev) >> { >> struct c_can_priv *priv = netdev_priv(dev); >> @@ -603,6 +619,8 @@ static int c_can_start(struct net_device *dev) >> >> priv->can.state = CAN_STATE_ERROR_ACTIVE; >> >> + /* activate pins */ >> + c_can_pinctrl_select_state(priv, PINCTRL_STATE_DEFAULT); >> return 0; >> } >> >> @@ -611,6 +629,9 @@ static void c_can_stop(struct net_device *dev) >> struct c_can_priv *priv = netdev_priv(dev); >> >> c_can_irq_control(priv, false); >> + >> + /* deactivate pins */ >> + c_can_pinctrl_select_state(priv, PINCTRL_STATE_SLEEP); >> priv->can.state = CAN_STATE_STOPPED; >> } >> >> @@ -1244,6 +1265,22 @@ int register_c_can_dev(struct net_device *dev) >> struct c_can_priv *priv = netdev_priv(dev); >> int err; >> >> + priv->pinctrl = devm_pinctrl_get(dev->dev.parent); > > What's dev->dev.parent? > Ah, this is set by SET_NETDEV_DEV(dev, &pdev->dev); Good work! > > I thought we had to set priv->pinctrl in the platform.c. > >> + if (!IS_ERR(priv->pinctrl)) { >> + struct pinctrl_state *s; >> + >> + /* Deactivate pins to prevent DRA7 DCAN IP from being >> + * stuck in transition when module is disabled. >> + * Pins are activated in c_can_start() and deactivated >> + * in c_can_stop() >> + */ >> + s = pinctrl_lookup_state(priv->pinctrl, PINCTRL_STATE_SLEEP); >> + if (!IS_ERR(s)) >> + pinctrl_select_state(priv->pinctrl, s); >> + } else { >> + netdev_dbg(dev, "failed to get pinctrl\n"); >> + } >> + > The above can be replace by this? > > c_can_pinctrl_select_state(priv, PINCTRL_STATE_SLEEP)
Yes, indeed. > > Then we don't have the worrying looking error message if there isn't any > pinctrl, e.g. for the PCI driver with pinctrl enabled in the Kernel. > > I just stumbled over pinctrl_pm_select_sleep_state(), is it possible to > integrate this into runtime pm? > > http://lxr.free-electrons.com/source/drivers/pinctrl/core.c#L1282 I think those functions are there for the same reason but not sure why aren't they used in runtime pm core. Linus W. any hints? cheers, -roger > >> c_can_pm_runtime_enable(priv); >> >> dev->flags |= IFF_ECHO; /* we support local echo */ >> diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h >> index c6715ca..3cedf48 100644 >> --- a/drivers/net/can/c_can/c_can.h >> +++ b/drivers/net/can/c_can/c_can.h >> @@ -210,6 +210,7 @@ struct c_can_priv { >> u32 comm_rcv_high; >> u32 rxmasked; >> u32 dlc[C_CAN_MSG_OBJ_TX_NUM]; >> + struct pinctrl *pinctrl; >> }; >> >> struct net_device *alloc_c_can_dev(void); >> > > Marc > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
