On 07/08/2015 11:13 AM, Roger Quadros wrote:
>
> On 07/07/15 18:49, Grygorii Strashko wrote:
>> On 07/07/2015 05:37 PM, Roger Quadros wrote:
>>> On 07/07/15 17:35, Roger Quadros wrote:
>>>> On 07/07/15 17:33, Marc Kleine-Budde wrote:
>>>>> On 07/07/2015 04:27 PM, Roger Quadros wrote:
>>>>>> From: "J.D. Schroeder" <jay.schroeder@xxxxxxxxxx>
>>>>>>
>>>>>> The previous change 3973c526ae9c (net: can: c_can: Disable pins when
>>>>>> CAN interface
>>>>>> is down) causes a slight glitch on the pinctrl settings when used.
>>>>>> Since
>>>>>> commit ab78029 (drivers/pinctrl: grab default handles from device
>>>>>> core),
>>>>>> the device core will automatically set the default pins. This causes
>>>>>> the pins to be momentarily set to the default and then to the sleep
>>>>>> state in register_c_can_dev(). By adding an optional "enable" state,
>>>>>> boards can set the default pin state to be disabled and avoid the
>>>>>> glitch when the switch from default to sleep first occurs. If the
>>>>>> "enable" state is not available c_can_pinctrl_select_state() falls
>>>>>> back to using the "default" pinctrl state.
>>>>>>
>>>>>> [Roger Q] - Forward port to v4.2
>>>>>>
>>>>>> Signed-off-by: J.D. Schroeder <jay.schroeder@xxxxxxxxxx>
>>>>>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>>>>>> ---
>>>>>> drivers/net/can/c_can/c_can.c | 13 ++++++++++++-
>>>>>> 1 file changed, 12 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/drivers/net/can/c_can/c_can.c
>>>>>> b/drivers/net/can/c_can/c_can.c
>>>>>> index 041525d..66e98e7 100644
>>>>>> --- a/drivers/net/can/c_can/c_can.c
>>>>>> +++ b/drivers/net/can/c_can/c_can.c
>>>>>> @@ -605,7 +605,18 @@ static int c_can_start(struct net_device *dev)
>>>>>> priv->can.state = CAN_STATE_ERROR_ACTIVE;
>>>>>>
>>>>>> /* activate pins */
>>>>>> - pinctrl_pm_select_default_state(dev->dev.parent);
>>>>>> +#ifdef CONFIG_PINCTRL
>>>>>
>>>>> Please remove the ifdef, AFAICS there are static inline noop functions
>>>>> if CONFIG_PINCTRL switched off.
>>>>
>>>> yes, you are right.
>>>
>>> On second thoughts
>>>
>>> device->pins are not defined if CONFIG_PINCTRL is not set.
>>> so we can't remove the #ifdef.
>>
>> May be you can use [devm_]pinctrl_get?
>
> Why should we do that? The device core has already done the
> pinctrl_get() and it is available in device->pins->p.
True. But It seems, you are going to be only one direct user of pin->p in whole
kernel (outside of pictrl core) !? ;)
pinctrl_get() will just return a pointer on pinctrl associated with dev
if called not the first time and increment kbobj use-counter.
Also, there is nice API pinctrl_get_select() and example in kernel 2c7c2c1d.
So, according to the documentation and pinctrl code, below sequence should work:
struct pinctrl *p;
p = pinctrl_get_select(priv->device, "active");
if (!IS_ERR(p))
pinctrl_put(p);
else
pinctrl_pm_select_default_state(priv->device);
>>>>>
>>>>>> + if (priv->device->pins) {
>>>>>> + struct pinctrl_state *s;
>>>>>> +
>>>>>> + /* Attempt to use "active" if available else use
>>>>>> "default" */
>>>>>> + s = pinctrl_lookup_state(priv->device->pins->p, "active");
>>>>>> + if (!IS_ERR(s))
>>>>>> + pinctrl_select_state(priv->device->pins->p, s);
^^ different devices passed here
>>>>>> + else
>>>>>> + pinctrl_pm_select_default_state(dev->dev.parent);
^^ and here ? Is it ok?
>>>>>> + }
>>>>>> +#endif
>>>>>> return 0;
>>>>>> }
>>>>>>
>>
--
regards,
-grygorii
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