From patchwork Wed Mar 30 20:03:45 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris BREZILLON X-Patchwork-Id: 8706731 Return-Path: X-Original-To: patchwork-dri-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 08784C0553 for ; Thu, 31 Mar 2016 00:52:50 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3522C20376 for ; Thu, 31 Mar 2016 00:52:49 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 6A58120357 for ; Thu, 31 Mar 2016 00:52:48 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 084636E943; Thu, 31 Mar 2016 00:52:45 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail.free-electrons.com (down.free-electrons.com [37.187.137.238]) by gabe.freedesktop.org (Postfix) with ESMTP id E67006E8A9; Wed, 30 Mar 2016 20:05:15 +0000 (UTC) Received: by mail.free-electrons.com (Postfix, from userid 110) id AF91C1854; Wed, 30 Mar 2016 22:05:14 +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=-5.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, 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 54B4417F0; Wed, 30 Mar 2016 22:04:55 +0200 (CEST) From: Boris Brezillon To: Thierry Reding , linux-pwm@vger.kernel.org Subject: [PATCH v5 22/46] pwm: rockchip: avoid glitches on already running PWMs Date: Wed, 30 Mar 2016 22:03:45 +0200 Message-Id: <1459368249-13241-23-git-send-email-boris.brezillon@free-electrons.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1459368249-13241-1-git-send-email-boris.brezillon@free-electrons.com> References: <1459368249-13241-1-git-send-email-boris.brezillon@free-electrons.com> X-Mailman-Approved-At: Thu, 31 Mar 2016 00:47:56 +0000 Cc: Milo Kim , Kamil Debski , linux-doc@vger.kernel.org, Mike Turquette , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com, Alexandre Belloni , Daniel Vetter , Lee Jones , linux-clk@vger.kernel.org, linux-leds@vger.kernel.org, Krzysztof Kozlowski , linux-samsung-soc@vger.kernel.org, Alexander Shiyan , Jonathan Corbet , Robert Jarzmik , lm-sensors@lm-sensors.org, linux-rockchip@lists.infradead.org, Chen-Yu Tsai , Tomi Valkeinen , linux-input@vger.kernel.org, Jean-Christophe Plagniol-Villard , intel-gfx@lists.freedesktop.org, Guenter Roeck , Jean Delvare , Joachim Eastwood , Bryan Wu , Mark Brown , Jacek Anaszewski , linux-arm-kernel@lists.infradead.org, Thomas Petazzoni , Ryan Mallon , Jingoo Han , Dmitry Torokhov , Stephen Boyd , Liam Girdwood , Hartley Sweeten , Richard Purdie , Kukjin Kim , Maxime Ripard X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP The current logic will disable the PWM clk even if the PWM was left enabled by the bootloader (because it's controlling a critical device like a regulator for example). Keep the PWM clk enabled if the PWM is enabled to avoid any glitches. Signed-off-by: Boris Brezillon --- drivers/pwm/pwm-rockchip.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c index 6a1087c..5c7e79c 100644 --- a/drivers/pwm/pwm-rockchip.c +++ b/drivers/pwm/pwm-rockchip.c @@ -302,6 +302,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) { const struct of_device_id *id; struct rockchip_pwm_chip *pc; + struct pwm_state pstate; struct resource *r; int ret; @@ -322,7 +323,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) if (IS_ERR(pc->clk)) return PTR_ERR(pc->clk); - ret = clk_prepare(pc->clk); + ret = clk_prepare_enable(pc->clk); if (ret) return ret; @@ -345,12 +346,33 @@ static int rockchip_pwm_probe(struct platform_device *pdev) dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); } + /* Keep the PWM clk enabled if the PWM appears to be up and running. */ + pwm_get_state(pc->chip.pwms, &pstate); + if (!pstate.enabled) + clk_disable(pc->clk); + return ret; } static int rockchip_pwm_remove(struct platform_device *pdev) { struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev); + struct pwm_state pstate; + + /* + * Disable the PWM clk before unpreparing it if the PWM device is still + * running. This should only happen when the last PWM user left it + * enabled, or when nobody requested a PWM that was previously enabled + * by the bootloader. + * + * FIXME: Maybe the core should disable all PWM devices in + * pwmchip_remove(). In this case we'd only have to call + * clk_unprepare() after pwmchip_remove(). + * + */ + pwm_get_state(pc->chip.pwms, &pstate); + if (pstate.enabled) + clk_disable(pc->clk); clk_unprepare(pc->clk);