From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: [PATCH v3 08/14] pwm: sti: Avoid glitches on already running PWMs Date: Tue, 14 Jun 2016 11:13:16 +0200 Message-ID: <1465895602-31008-9-git-send-email-boris.brezillon@free-electrons.com> References: <1465895602-31008-1-git-send-email-boris.brezillon@free-electrons.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1465895602-31008-1-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+glpar-linux-rockchip=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Thierry Reding , linux-pwm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mark Brown , Liam Girdwood Cc: Mark Rutland , Milo Kim , Heiko Stuebner , Patrice Chotard , Laxman Dewangan , kernel-F5mvAk5X5gdBDgjK7y7TUQ@public.gmane.org, Boris Brezillon , Brian Norris , Stephen Barber , linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Caesar Wang , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Pawel Moll , Ian Campbell , Doug Anderson , Rob Herring , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Maxime Coquelin , Srinivas Kandagatla , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Kumar Gala , Ajit Pal Singh List-Id: devicetree@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 | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c index 6300d3e..5bda51d 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 +409,16 @@ 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++) { + if (pwm_is_enabled(&pc->chip.pwms[i])) + clk_enable(pc->clk); + } + clk_disable(pc->clk); + platform_set_drvdata(pdev, pc); return 0; -- 2.7.4