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

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Date:	Thu, 27 Nov 2014 22:19:32 +0100
From:	Marc Kleine-Budde <mkl@...gutronix.de>
To:	Linus Walleij <linus.walleij@...aro.org>,
	Roger Quadros <rogerq@...com>
CC:	wg@...ndegger.com, Wolfram Sang <wsa@...-dreams.de>,
	Tony Lindgren <tony@...mide.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Mugunthan V N <mugunthanvnm@...com>,
	George Cherian <george.cherian@...com>,
	Felipe Balbi <balbi@...com>, Sekhar Nori <nsekhar@...com>,
	Nishanth Menon <nm@...com>,
	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
	Linux-OMAP <linux-omap@...r.kernel.org>,
	linux-can@...r.kernel.org,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH v7 6/8] net: can: c_can: Disable pins when CAN interface
 is down

On 11/27/2014 02:26 PM, Linus Walleij wrote:
> On Fri, Nov 14, 2014 at 4:40 PM, Roger Quadros <rogerq@...com> 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@...com>
> 
> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>

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.

Thanks,
Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
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