Subject: Re: [PATCH v7 6/8] net: can: c_can: Disable pins when CAN interface is down

From: Roger Quadros <[email-masked]>
Date: Fri, 28 Nov 2014 11:22:12 +0200

On 27/11/14 23:19, Marc Kleine-Budde wrote:
> On 11/27/2014 02:26 PM, Linus Walleij wrote:
>> On Fri, Nov 14, 2014 at 4:40 PM, Roger Quadros <[email-masked]> 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-masked]>
>>
>> Reviewed-by: Linus Walleij <[email-masked]>
> 
> Thanks, however the patch is already upstream.
> 
>>
>> I see you figured it out all by yourselves :D
>>
>> (Sorry for being absent.)
>>
>>> +#include <linux/pinctrl/consumer.h>
>>> +       pinctrl_pm_select_default_state(dev->dev.parent);
>>> +       pinctrl_pm_select_sleep_state(dev->dev.parent);
>>> +       pinctrl_pm_select_sleep_state(dev->dev.parent);
>>
>> NB: in drivers/base/pinctrl.c:
>>
>> #ifdef CONFIG_PM
>>         /*
>>          * If power management is enabled, we also look for the optional
>>          * sleep and idle pin states, with semantics as defined in
>>          * <linux/pinctrl/pinctrl-state.h>
>>          */
>>         dev->pins->sleep_state = pinctrl_lookup_state(dev->pins->p,
>>                                         PINCTRL_STATE_SLEEP);
>>
>> So if these states are necessary for the driver to work, put
>> depends on PM or select PM in the Kconfig.
> 
> Roger, you can prepare a patch, if needed.

As pinctrl sleep is an optional driver feature we don't need to do any changes.
For the DRA7 specific case, the platform configs ensure that PM is enabled.

cheers,
-roger