Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755317AbcC3UFh (ORCPT ); Wed, 30 Mar 2016 16:05:37 -0400 Received: from down.free-electrons.com ([37.187.137.238]:45449 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752608AbcC3UF2 (ORCPT ); Wed, 30 Mar 2016 16:05:28 -0400 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, David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Hartley Sweeten , Ryan Mallon , Alexander Shiyan , Milo Kim , Boris Brezillon Subject: [PATCH v5 25/46] pwm: sti: avoid glitches on already running PWMs Date: Wed, 30 Mar 2016 22:03:48 +0200 Message-Id: <1459368249-13241-26-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> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1491 Lines: 55 The current logic will disable the PWM clk even if a 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 at least one PWM is enabled to avoid any glitches. Signed-off-by: Boris Brezillon --- drivers/pwm/pwm-sti.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c index 0fbca94..bea1d17 100644 --- a/drivers/pwm/pwm-sti.c +++ b/drivers/pwm/pwm-sti.c @@ -343,7 +343,7 @@ static int sti_pwm_probe(struct platform_device *pdev) struct sti_pwm_compat_data *cdata; struct sti_pwm_chip *pc; struct resource *res; - int ret; + int i, ret; pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL); if (!pc) @@ -394,7 +394,7 @@ static int sti_pwm_probe(struct platform_device *pdev) return -EINVAL; } - ret = clk_prepare(pc->clk); + ret = clk_prepare_enable(pc->clk); if (ret) { dev_err(dev, "failed to prepare clock\n"); return ret; @@ -412,6 +412,19 @@ static int sti_pwm_probe(struct platform_device *pdev) return ret; } + /* + * Keep the PWM clk enabled if some PWMs appear to be up and + * running. + */ + for (i = 0; i < pc->chip.npwm; i++) { + struct pwm_state pstate; + + pwm_get_state(&pc->chip.pwms[i], &pstate); + if (pstate.enabled) + clk_enable(pc->clk); + } + clk_disable(pc->clk); + platform_set_drvdata(pdev, pc); return 0; -- 2.5.0