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.
> + 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.
> +
> /* 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
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
Attachment:
signature.asc
Description: OpenPGP digital signature
