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 <rogerq@xxxxxx>
> ---
> 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)
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
> 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
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
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