From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932331AbcFCI1F (ORCPT ); Fri, 3 Jun 2016 04:27:05 -0400 Received: from down.free-electrons.com ([37.187.137.238]:45912 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752417AbcFCIX1 (ORCPT ); Fri, 3 Jun 2016 04:23:27 -0400 From: Boris Brezillon To: Thierry Reding , linux-pwm@vger.kernel.org, Mark Brown , Liam Girdwood Cc: Heiko Stuebner , linux-rockchip@lists.infradead.org, Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Milo Kim , Doug Anderson , Caesar Wang , Stephen Barber , Brian Norris , Ajit Pal Singh , Srinivas Kandagatla , Maxime Coquelin , Patrice Chotard , kernel@stlinux.com, Boris Brezillon Subject: [PATCH 08/14] pwm: sti: Avoid glitches on already running PWMs Date: Fri, 3 Jun 2016 10:23:06 +0200 Message-Id: <1464942192-25967-9-git-send-email-boris.brezillon@free-electrons.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1464942192-25967-1-git-send-email-boris.brezillon@free-electrons.com> References: <1464942192-25967-1-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 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 6300d3e..8232c5b 100644 --- a/drivers/pwm/pwm-sti.c +++ b/drivers/pwm/pwm-sti.c @@ -340,7 +340,7 @@ 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) @@ -391,7 +391,7 @@ 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; @@ -409,6 +409,19 @@ 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 state; + + pwm_get_state(&pc->chip.pwms[i], &state); + if (state.enabled) + clk_enable(pc->clk); + } + clk_disable(pc->clk); + platform_set_drvdata(pdev, pc); return 0; -- 2.7.4