Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933407AbbGHKbr (ORCPT ); Wed, 8 Jul 2015 06:31:47 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:51459 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758104AbbGHKbn (ORCPT ); Wed, 8 Jul 2015 06:31:43 -0400 Message-ID: <559CFBFB.8010400@ti.com> Date: Wed, 8 Jul 2015 13:31:23 +0300 From: Grygorii Strashko User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Roger Quadros , Marc Kleine-Budde , , , Tony Lindgren , 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> In-Reply-To: <559CDBA3.3040405@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: 3770 Lines: 112 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) !? ;) 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 -- 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/