From: Brian Norris <briannorris@chromium.org> To: Boris Brezillon <boris.brezillon@free-electrons.com> Cc: Thierry Reding <thierry.reding@gmail.com>, linux-pwm@vger.kernel.org, Mark Brown <broonie@kernel.org>, Liam Girdwood <lgirdwood@gmail.com>, Heiko Stuebner <heiko@sntech.de>, linux-rockchip@lists.infradead.org, Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>, Mark Rutland <mark.rutland@arm.com>, Ian Campbell <ijc+devicetree@hellion.org.uk>, Kumar Gala <galak@codeaurora.org>, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Milo Kim <milo.kim@ti.com>, Doug Anderson <dianders@google.com>, Caesar Wang <wxt@rock-chips.com>, Stephen Barber <smbarber@chromium.org>, Ajit Pal Singh <ajitpal.singh@st.com>, Srinivas Kandagatla <srinivas.kandagatla@gmail.com>, Maxime Coquelin <maxime.coquelin@st.com>, Patrice Chotard <patrice.chotard@st.com>, kernel@stlinux.com Subject: Re: [PATCH 05/14] pwm: rockchip: Avoid glitches on already running PWMs Date: Fri, 3 Jun 2016 13:28:59 -0700 [thread overview] Message-ID: <20160603202859.GD124478@google.com> (raw) In-Reply-To: <1464942192-25967-6-git-send-email-boris.brezillon@free-electrons.com> Hi, Just noticed a few things: On Fri, Jun 03, 2016 at 10:23:03AM +0200, Boris Brezillon wrote: > 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 <boris.brezillon@free-electrons.com> > --- > 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 dfacf7d..798a787 100644 > --- a/drivers/pwm/pwm-rockchip.c > +++ b/drivers/pwm/pwm-rockchip.c > @@ -299,6 +299,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) > { > const struct of_device_id *id; > struct rockchip_pwm_chip *pc; > + struct pwm_state state; > struct resource *r; > int ret; > > @@ -319,7 +320,7 @@ 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; > > @@ -342,12 +343,33 @@ 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, &state); > + if (!state.enabled) Why not just if (!pwm_is_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 state; > + > + /* > + * 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, &state); > + if (state.enabled) Same here. With that: Reviewed-by: Brian Norris <briannorris@chromium.org> And it tests out fine: Tested-by: Brian Norris <briannorris@chromium.org> > + clk_disable(pc->clk); > > clk_unprepare(pc->clk); > > -- > 2.7.4 >
WARNING: multiple messages have this Message-ID (diff)
From: briannorris@chromium.org (Brian Norris) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 05/14] pwm: rockchip: Avoid glitches on already running PWMs Date: Fri, 3 Jun 2016 13:28:59 -0700 [thread overview] Message-ID: <20160603202859.GD124478@google.com> (raw) In-Reply-To: <1464942192-25967-6-git-send-email-boris.brezillon@free-electrons.com> Hi, Just noticed a few things: On Fri, Jun 03, 2016 at 10:23:03AM +0200, Boris Brezillon wrote: > 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 <boris.brezillon@free-electrons.com> > --- > 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 dfacf7d..798a787 100644 > --- a/drivers/pwm/pwm-rockchip.c > +++ b/drivers/pwm/pwm-rockchip.c > @@ -299,6 +299,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) > { > const struct of_device_id *id; > struct rockchip_pwm_chip *pc; > + struct pwm_state state; > struct resource *r; > int ret; > > @@ -319,7 +320,7 @@ 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; > > @@ -342,12 +343,33 @@ 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, &state); > + if (!state.enabled) Why not just if (!pwm_is_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 state; > + > + /* > + * 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, &state); > + if (state.enabled) Same here. With that: Reviewed-by: Brian Norris <briannorris@chromium.org> And it tests out fine: Tested-by: Brian Norris <briannorris@chromium.org> > + clk_disable(pc->clk); > > clk_unprepare(pc->clk); > > -- > 2.7.4 >
next prev parent reply other threads:[~2016-06-03 20:29 UTC|newest] Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-06-03 8:22 [PATCH 00/14] regulator: pwm: various improvements Boris Brezillon 2016-06-03 8:22 ` Boris Brezillon 2016-06-03 8:22 ` Boris Brezillon 2016-06-03 8:22 ` [PATCH 01/14] pwm: Add new helpers to create/manipulate PWM states Boris Brezillon 2016-06-03 8:22 ` Boris Brezillon 2016-06-03 8:23 ` [PATCH 02/14] regulator: pwm: Drop unneeded pwm_enable() call Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 11:08 ` Applied "regulator: pwm: Drop unneeded pwm_enable() call" to the regulator tree Mark Brown 2016-06-03 11:08 ` Mark Brown 2016-06-03 11:08 ` Mark Brown 2016-06-03 11:08 ` Mark Brown 2016-06-03 8:23 ` [PATCH 03/14] pwm: rockchip: Fix period and duty_cycle approximation Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 20:03 ` Brian Norris 2016-06-03 20:03 ` Brian Norris 2016-06-04 6:19 ` Boris Brezillon 2016-06-04 6:19 ` Boris Brezillon 2016-06-07 17:25 ` Brian Norris 2016-06-07 17:25 ` Brian Norris 2016-06-03 8:23 ` [PATCH 04/14] pwm: rockchip: Add support for hardware readout Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 20:07 ` Brian Norris 2016-06-03 20:07 ` Brian Norris 2016-06-03 20:20 ` Brian Norris 2016-06-03 20:20 ` Brian Norris 2016-06-04 6:24 ` Boris Brezillon 2016-06-04 6:24 ` Boris Brezillon 2016-06-07 17:26 ` Brian Norris 2016-06-07 17:26 ` Brian Norris 2016-06-03 8:23 ` [PATCH 05/14] pwm: rockchip: Avoid glitches on already running PWMs Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 20:28 ` Brian Norris [this message] 2016-06-03 20:28 ` Brian Norris 2016-06-04 6:26 ` Boris Brezillon 2016-06-04 6:26 ` Boris Brezillon 2016-06-03 8:23 ` [PATCH 06/14] pwm: rockchip: Add support for atomic update Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 20:37 ` Brian Norris 2016-06-03 20:37 ` Brian Norris 2016-06-03 20:37 ` Brian Norris 2016-06-03 8:23 ` [PATCH 07/14] pwm: sti: Add support for hardware readout Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` [PATCH 08/14] pwm: sti: Avoid glitches on already running PWMs Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 20:38 ` Brian Norris 2016-06-03 20:38 ` Brian Norris 2016-06-03 20:38 ` Brian Norris 2016-06-03 8:23 ` [PATCH 09/14] regulator: pwm: Adjust PWM config at probe time Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 20:41 ` Brian Norris 2016-06-03 20:41 ` Brian Norris 2016-06-03 8:23 ` [PATCH 10/14] regulator: pwm: Switch to the atomic PWM API Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 20:50 ` Brian Norris 2016-06-03 20:50 ` Brian Norris 2016-06-03 20:50 ` Brian Norris 2016-06-04 6:28 ` Boris Brezillon 2016-06-04 6:28 ` Boris Brezillon 2016-06-06 6:14 ` Laxman Dewangan 2016-06-06 6:14 ` Laxman Dewangan 2016-06-06 6:14 ` Laxman Dewangan 2016-06-03 8:23 ` [PATCH 11/14] regulator: pwm: properly initialize the ->state field Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 20:51 ` Brian Norris 2016-06-03 20:51 ` Brian Norris 2016-06-03 8:23 ` [PATCH 12/14] regulator: pwm: Retrieve correct voltage Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 20:55 ` Brian Norris 2016-06-03 20:55 ` Brian Norris 2016-06-03 8:23 ` [PATCH 13/14] regulator: pwm: Support extra continuous mode cases Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 21:03 ` Brian Norris 2016-06-03 21:03 ` Brian Norris 2016-06-04 6:30 ` Boris Brezillon 2016-06-04 6:30 ` Boris Brezillon 2016-06-03 8:23 ` [PATCH 14/14] regulator: pwm: Document pwm-dutycycle-unit and pwm-dutycycle-range Boris Brezillon 2016-06-03 8:23 ` Boris Brezillon 2016-06-03 21:04 ` Brian Norris 2016-06-03 21:04 ` Brian Norris 2016-06-03 21:04 ` Brian Norris 2016-06-06 14:09 ` Rob Herring 2016-06-06 14:09 ` Rob Herring
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