From patchwork Thu Apr 14 19:17:40 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris BREZILLON X-Patchwork-Id: 8841811 Return-Path: X-Original-To: patchwork-linux-samsung-soc@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 633629F54F for ; Thu, 14 Apr 2016 19:21:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 787D72012D for ; Thu, 14 Apr 2016 19:21:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7141F202DD for ; Thu, 14 Apr 2016 19:21:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753272AbcDNTVi (ORCPT ); Thu, 14 Apr 2016 15:21:38 -0400 Received: from down.free-electrons.com ([37.187.137.238]:34039 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752143AbcDNTSy (ORCPT ); Thu, 14 Apr 2016 15:18:54 -0400 Received: by mail.free-electrons.com (Postfix, from userid 110) id E430E20D1; Thu, 14 Apr 2016 21:18:51 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from localhost.localdomain (LFbn-1-2159-240.w90-76.abo.wanadoo.fr [90.76.216.240]) by mail.free-electrons.com (Postfix) with ESMTPSA id 219241BE5; Thu, 14 Apr 2016 21:18:32 +0200 (CEST) From: Boris Brezillon To: Thierry Reding , linux-pwm@vger.kernel.org Cc: Mike Turquette , Stephen Boyd , linux-clk@vger.kernel.org, Mark Brown , Liam Girdwood , Kamil Debski , lm-sensors@lm-sensors.org, Jean Delvare , Guenter Roeck , Dmitry Torokhov , linux-input@vger.kernel.org, Bryan Wu , Richard Purdie , Jacek Anaszewski , linux-leds@vger.kernel.org, Maxime Ripard , Chen-Yu Tsai , linux-sunxi@googlegroups.com, Joachim Eastwood , Thomas Petazzoni , Heiko Stuebner , linux-rockchip@lists.infradead.org, Jingoo Han , Lee Jones , linux-fbdev@vger.kernel.org, Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Robert Jarzmik , Alexandre Belloni , Kukjin Kim , Krzysztof Kozlowski , linux-samsung-soc@vger.kernel.org, intel-gfx@lists.freedesktop.org, Daniel Vetter , Jani Nikula , Jonathan Corbet , linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Hartley Sweeten , Ryan Mallon , Alexander Shiyan , Milo Kim , Doug Anderson , Caesar Wang , Stephen Barber , Boris Brezillon Subject: [PATCH v5 20/24] pwm: add the PWM initial state retrieval infra Date: Thu, 14 Apr 2016 21:17:40 +0200 Message-Id: <1460661464-11216-21-git-send-email-boris.brezillon@free-electrons.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1460661464-11216-1-git-send-email-boris.brezillon@free-electrons.com> References: <1460661464-11216-1-git-send-email-boris.brezillon@free-electrons.com> Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add a ->get_state() function to the pwm_ops struct to let PWM drivers initialize the PWM state attached to a PWM device. Signed-off-by: Boris Brezillon --- drivers/pwm/core.c | 3 +++ include/linux/pwm.h | 28 ++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index c2759bc..0e7f687 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -270,6 +270,9 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip, pwm->hwpwm = i; pwm->state.polarity = polarity; + if (chip->ops->get_state) + chip->ops->get_state(chip, pwm, &pwm->state); + radix_tree_insert(&pwm_tree, pwm->pwm, pwm); } diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 7bfeacf..73ca679 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -205,6 +205,29 @@ static inline void pwm_get_args(const struct pwm_device *pwm, static inline void pwm_apply_args(struct pwm_device *pwm) { + /* + * PWM users calling pwm_apply_args() expect to have a fresh config + * where the polarity and period are set according to pwm_args info. + * The problem is, polarity can only be changed when the PWM is + * disabled. + * + * PWM drivers supporting hardware readout may declare the PWM device + * as enabled, and prevent polarity setting, which changes from the + * existing behavior, where all PWM devices are declared as disabled + * at startup (even if they are actually enabled), thus authorizing + * polarity setting. + * + * Instead of setting ->enabled to false, we call pwm_disable() + * before pwm_set_polarity() to ensure that everything is configured + * as expected, and the PWM is really disabled when the user request + * it. + * + * Note that PWM users requiring a smooth handover between the + * bootloader and the kernel (like critical regulators controlled by + * PWM devices) will have to switch to the atomic API and avoid calling + * pwm_apply_args(). + */ + pwm_disable(pwm); pwm_set_polarity(pwm, pwm->args.polarity); } @@ -216,6 +239,9 @@ static inline void pwm_apply_args(struct pwm_device *pwm) * @set_polarity: configure the polarity of this PWM * @enable: enable PWM output toggling * @disable: disable PWM output toggling + * @get_state: get the current PWM state. This function is only + * called once per PWM device when the PWM chip is + * registered. * @dbg_show: optional routine to show contents in debugfs * @owner: helps prevent removal of modules exporting active PWMs */ @@ -228,6 +254,8 @@ struct pwm_ops { enum pwm_polarity polarity); int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm); void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm); + void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state); #ifdef CONFIG_DEBUG_FS void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s); #endif