From patchwork Tue May 17 12:08:03 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Brezillon X-Patchwork-Id: 623028 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3r8GLq5Ysnz9snl for ; Tue, 17 May 2016 22:08:19 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754959AbcEQMII (ORCPT ); Tue, 17 May 2016 08:08:08 -0400 Received: from down.free-electrons.com ([37.187.137.238]:59738 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751721AbcEQMIH convert rfc822-to-8bit (ORCPT ); Tue, 17 May 2016 08:08:07 -0400 Received: by mail.free-electrons.com (Postfix, from userid 110) id 84FBD489; Tue, 17 May 2016 14:08:03 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on mail.free-electrons.com X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,SHORTCIRCUIT, URIBL_BLOCKED shortcircuit=ham autolearn=disabled version=3.4.0 Received: from bbrezillon (LStLambert-657-1-97-87.w90-63.abo.wanadoo.fr [90.63.216.87]) by mail.free-electrons.com (Postfix) with ESMTPSA id 3E84C202; Tue, 17 May 2016 14:08:03 +0200 (CEST) Date: Tue, 17 May 2016 14:08:03 +0200 From: Boris Brezillon To: Thierry Reding Cc: linux-pwm@vger.kernel.org, Nicolas Ferre , Jean-Christophe Plagniol-Villard , Alexandre Belloni , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] pwm: atmel-hlcdc: Fix default PWM polarity Message-ID: <20160517140803.078e3f5e@bbrezillon> In-Reply-To: <20160517110005.GA26166@ulmo.ba.sec> References: <1463476352-7485-1-git-send-email-boris.brezillon@free-electrons.com> <20160517110005.GA26166@ulmo.ba.sec> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org Hi Thierry, On Tue, 17 May 2016 13:00:05 +0200 Thierry Reding wrote: > On Tue, May 17, 2016 at 11:12:32AM +0200, Boris Brezillon wrote: > > The PWM device exposed by the HLCDC IP is configured with an inverted > > polarity by default. Registering the PWM chip with the normal polarity > > was not a problem before commit 42e8992c58d4 ("pwm: Add core > > infrastructure to allow atomic updates") because the ->set_polarity() > > hook was called no matter the current polarity state, but this is no longer > > the case. > > > > Signed-off-by: Boris Brezillon > > Fixes: 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") > > That's not technically correct, because it's the driver that has the > bug. The core change merely exposes it. How about if I sort this into > the pwm-atomic branch and reword the commit message accordingly? That > way things should all stay bisectible. > > Then again, given the breakage caused by the pwm_args patch I suppose > it doesn't matter much because that's part of a stable branch that I > can't rebase. If I understood correctly, you plan to rebase your pwm-atomic branch to insert this commit before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates"). Could you consider taking the following commit (or something similar if you already have a fix) as the first commit of your pwm-atomic branch? Sorry for the mess around the introduction of pwm_args and pwm_state (that's not an excuse, but I've reworked this series so many time that I forgot to check bisectibility on the last versions :-(). --- From ad73fa3a56c7320979425d64ab54c09b9d83d4cf Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Tue, 17 May 2016 13:55:02 +0200 Subject: [PATCH] pwm: Fix pwm_apply_args() call sites pwm_apply_args() is supposed to initialize a PWM device according to the arguments provided by the DT or the PWM lookup, but this function was called inside pwm_device_request(), which in turn was called before the core had a chance to initialize the pwm->args fields. Fix that by calling pwm_apply_args directly in pwm_get() and of_pwm_get() after initializing pwm->args field. This commit also fixes an invalid pointer dereference introduced by commit e39c0df1be5a ("pwm: Introduce the pwm_args concept"). Signed-off-by: Boris Brezillon Fixes: e39c0df1be5a ("pwm: Introduce the pwm_args concept") --- drivers/pwm/core.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 680fbc7..22cf395 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -128,13 +128,6 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) set_bit(PWMF_REQUESTED, &pwm->flags); pwm->label = label; - /* - * FIXME: This should be removed once all PWM users properly make use - * of struct pwm_args to initialize the PWM device. As long as this is - * here, the PWM state and hardware state can get out of sync. - */ - pwm_apply_args(pwm); - return 0; } @@ -627,6 +620,13 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id) pwm->label = con_id; + /* + * FIXME: This should be removed once all PWM users properly make use + * of struct pwm_args to initialize the PWM device. As long as this is + * here, the PWM state and hardware state can get out of sync. + */ + pwm_apply_args(pwm); + put: of_node_put(args.np); @@ -754,13 +754,20 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) if (!chip) goto out; - pwm->args.period = chosen->period; - pwm->args.polarity = chosen->polarity; - pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id); if (IS_ERR(pwm)) goto out; + pwm->args.period = chosen->period; + pwm->args.polarity = chosen->polarity; + + /* + * FIXME: This should be removed once all PWM users properly make use + * of struct pwm_args to initialize the PWM device. As long as this is + * here, the PWM state and hardware state can get out of sync. + */ + pwm_apply_args(pwm); + out: mutex_unlock(&pwm_lookup_lock); return pwm;