Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758586AbbGHKpR (ORCPT ); Wed, 8 Jul 2015 06:45:17 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:38156 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757897AbbGHKpN (ORCPT ); Wed, 8 Jul 2015 06:45:13 -0400 Message-ID: <559CFF25.4090007@ti.com> Date: Wed, 8 Jul 2015 13:44:53 +0300 From: Roger Quadros User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Grygorii Strashko , Marc Kleine-Budde , , , Linus Walleij CC: , , , Subject: Re: [PATCH 1/2] net: can: c_can: Fix default pinmux glitch at init References: <1436279277-3386-1-git-send-email-rogerq@ti.com> <1436279277-3386-2-git-send-email-rogerq@ti.com> <559BE34F.8080508@pengutronix.de> <559BE3BE.2020608@ti.com> <559BE433.9020308@ti.com> <559BF4FD.2080400@ti.com> <559CDBA3.3040405@ti.com> <559CFBFB.8010400@ti.com> In-Reply-To: <559CFBFB.8010400@ti.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4013 Lines: 120 On 08/07/15 13:31, Grygorii Strashko wrote: > 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" >>>>>>> >>>>>>> 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 >>>>>>> Signed-off-by: Roger Quadros >>>>>>> --- >>>>>>> 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) !? ;) good point :). > > 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); This is much neater. I will give that a try. Thanks. cheers, -roger > > > > >>>>>> >>>>>>> + 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; >>>>>>> } >>>>>>> >>> > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/