On 11/13/2014 02:56 PM, Marc Kleine-Budde wrote: > On 11/12/2014 03:16 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 <rogerq@xxxxxx> >> --- >> drivers/net/can/c_can/c_can.c | 21 +++++++++++++++++++++ >> drivers/net/can/c_can/c_can.h | 1 + >> drivers/net/can/c_can/c_can_platform.c | 20 ++++++++++++++++++++ >> 3 files changed, 42 insertions(+) >> >> diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c >> index 8e78bb4..a950eea 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)) { > > What happens if priv->pinctrl is NULL? This is probably the case with > the c_can_pci driver. There will be a NULL pointer dereference error. :( > >> + 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; >> } >> >> 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); >> diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c >> index b838c6b..71b9063 100644 >> --- a/drivers/net/can/c_can/c_can_platform.c >> +++ b/drivers/net/can/c_can/c_can_platform.c >> @@ -34,6 +34,7 @@ >> #include <linux/of_device.h> >> #include <linux/mfd/syscon.h> >> #include <linux/regmap.h> >> +#include <linux/pinctrl/consumer.h> >> >> #include <linux/can/dev.h> >> >> @@ -230,6 +231,7 @@ static int c_can_plat_probe(struct platform_device *pdev) >> struct clk *clk; >> const struct c_can_driver_data *drvdata; >> struct device_node *np = pdev->dev.of_node; >> + struct pinctrl *pinctrl; >> >> match = of_match_device(c_can_of_table, &pdev->dev); >> if (match) { >> @@ -241,6 +243,23 @@ static int c_can_plat_probe(struct platform_device *pdev) >> return -ENODEV; >> } >> >> + pinctrl = devm_pinctrl_get(&pdev->dev); >> + if (!IS_ERR(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(pinctrl, PINCTRL_STATE_SLEEP); >> + if (!IS_ERR(s)) >> + pinctrl_select_state(pinctrl, s); >> + } else { >> + dev_warn(&pdev->dev, >> + "failed to get pinctrl\n"); >> + } > > Can you move the initial setting into c_can.c, register_c_can_dev() > should be a good candidate. OK. This should also address the NULL pointer issue you pointed out earlier with c_can_pci. cheers, -roger > >> + >> /* get the appropriate clk */ >> clk = devm_clk_get(&pdev->dev, NULL); >> if (IS_ERR(clk)) { >> @@ -270,6 +289,7 @@ static int c_can_plat_probe(struct platform_device *pdev) >> } >> >> priv = netdev_priv(dev); >> + priv->pinctrl = pinctrl; >> >> switch (drvdata->id) { >> case BOSCH_C_CAN: >> > > Marc > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html