From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Thierry Reding <thierry.reding@gmail.com>, linux-pwm@vger.kernel.org
Cc: Mike Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@codeaurora.org>,
linux-clk@vger.kernel.org, Mark Brown <broonie@kernel.org>,
Liam Girdwood <lgirdwood@gmail.com>,
Kamil Debski <k.debski@samsung.com>,
lm-sensors@lm-sensors.org, Jean Delvare <jdelvare@suse.com>,
Guenter Roeck <linux@roeck-us.net>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
linux-input@vger.kernel.org, Bryan Wu <cooloney@gmail.com>,
Richard Purdie <rpurdie@rpsys.net>,
Jacek Anaszewski <j.anaszewski@samsung.com>,
linux-leds@vger.kernel.org,
Maxime Ripard <maxime.ripard@free-electrons.com>,
Chen-Yu Tsai <wens@csie.org>,
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Joachim Eastwood <manabian@gmail.com>,
Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
Heiko Stuebner <heiko@sntech.de>,
linux-rockchip@lists.infradead.org,
Jingoo Han <jingoohan1@gmail.com>,
Lee Jones <lee.jones@linaro.org>,
linux-fbdev@vger.kernel.org,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
Tomi Valkeinen <tomi.valkeinen@ti.com>,
Robert Jarzmik <robert.jarzmik@free.fr>,
Alexandre Belloni <alexandre.belloni@free-electrons.com>,
Kukjin Kim <kgene@kernel.org>,
Krzysztof Kozlowski <k.kozlowski@samsung.com>,
linux-samsung-soc@vger.kernel.org,
intel-gfx@lists.freedesktop.org,
Daniel Vetter <daniel.vetter@intel.com>,
Jani Nikula <jani.nikula@linux.intel.com>,
Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org, David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel@ffwll.ch>,
dri-devel@lists.freedesktop.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Hartley Sweeten <hsweeten@visionengravers.com>,
Ryan Mallon <rmallon@gmail.com>,
Alexander Shiyan <shc_work@mail.ru>, Milo Kim <milo.kim@ti.com>,
Boris Brezillon <boris.brezillon@free-electrons.com>
Subject: [PATCH v5 22/46] pwm: rockchip: avoid glitches on already running PWMs
Date: Wed, 30 Mar 2016 22:03:45 +0200 [thread overview]
Message-ID: <1459368249-13241-23-git-send-email-boris.brezillon@free-electrons.com> (raw)
In-Reply-To: <1459368249-13241-1-git-send-email-boris.brezillon@free-electrons.com>
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 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);
--
2.5.0
next prev parent reply other threads:[~2016-03-30 20:05 UTC|newest]
Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-30 20:03 [PATCH v5 00/46] pwm: add support for atomic update Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 01/46] pwm: rcar: make use of pwm_is_enabled() Boris Brezillon
2016-04-12 11:01 ` Thierry Reding
2016-04-14 11:05 ` Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 02/46] backlight: pwm_bl: remove useless call to pwm_set_period() Boris Brezillon
2016-04-12 11:03 ` Thierry Reding
2016-04-12 14:16 ` Lee Jones
2016-04-12 14:25 ` Thierry Reding
2016-03-30 20:03 ` [PATCH v5 03/46] backlight: lm3630a_bl: stop messing with the pwm->period field Boris Brezillon
2016-04-12 11:08 ` Thierry Reding
2016-04-12 14:16 ` Lee Jones
2016-04-12 14:26 ` Thierry Reding
2016-04-13 8:25 ` Lee Jones
2016-04-13 8:26 ` Lee Jones
2016-03-30 20:03 ` [PATCH v5 04/46] pwm: get rid of pwm->lock Boris Brezillon
2016-04-12 11:22 ` Thierry Reding
2016-04-12 11:32 ` Boris Brezillon
2016-04-12 11:46 ` Thierry Reding
2016-03-30 20:03 ` [PATCH v5 05/46] pwm: introduce the pwm_args concept Boris Brezillon
2016-03-30 21:55 ` Stephen Boyd
2016-03-31 7:09 ` Boris Brezillon
2016-03-31 7:57 ` Boris Brezillon
2016-04-12 11:39 ` Thierry Reding
2016-04-12 12:04 ` Boris Brezillon
2016-04-12 12:20 ` Thierry Reding
2016-04-12 12:55 ` Boris Brezillon
2016-04-12 13:06 ` Boris Brezillon
2016-04-12 13:15 ` Thierry Reding
2016-03-30 20:03 ` [PATCH v5 06/46] pwm: use pwm_get/set_xxx() helpers where appropriate Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 07/46] clk: pwm: use pwm_get_args() " Boris Brezillon
2016-03-30 21:58 ` Stephen Boyd
2016-03-30 20:03 ` [PATCH v5 08/46] hwmon: pwm-fan: " Boris Brezillon
2016-03-30 22:52 ` Guenter Roeck
2016-03-31 7:07 ` Boris Brezillon
2016-04-04 15:20 ` Thierry Reding
2016-04-01 8:29 ` Kamil Debski
2016-03-30 20:03 ` [PATCH v5 09/46] misc: max77693-haptic: " Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 10/46] leds: pwm: " Boris Brezillon
2016-03-31 7:13 ` Jacek Anaszewski
2016-03-30 20:03 ` [PATCH v5 11/46] regulator: " Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 12/46] fbdev: ssd1307fb: " Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 13/46] backlight: pwm_bl: " Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 14/46] pwm: keep PWM state in sync with hardware state Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 15/46] pwm: introduce the pwm_state concept Boris Brezillon
2016-04-12 11:49 ` Thierry Reding
2016-04-12 12:17 ` Boris Brezillon
2016-04-12 12:21 ` Thierry Reding
2016-04-12 12:45 ` Boris Brezillon
2016-04-12 13:11 ` Thierry Reding
2016-04-12 13:26 ` Boris Brezillon
2016-04-12 14:05 ` Thierry Reding
2016-04-12 14:13 ` Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 16/46] pwm: move the enabled/disabled info into pwm_state Boris Brezillon
2016-04-12 11:51 ` Thierry Reding
2016-03-30 20:03 ` [PATCH v5 17/46] pwm: add the PWM initial state retrieval infra Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 18/46] pwm: add the core infrastructure to allow atomic update Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 19/46] pwm: switch to the atomic API Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 20/46] pwm: add information about polarity, duty cycle and period to debugfs Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 21/46] pwm: rockchip: add initial state retrieval Boris Brezillon
2016-03-30 20:03 ` Boris Brezillon [this message]
2016-03-30 20:03 ` [PATCH v5 23/46] pwm: rockchip: add support for atomic update Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 24/46] pwm: sti: add support for initial state retrieval Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 25/46] pwm: sti: avoid glitches on already running PWMs Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 26/46] pwm: sun4i: implement hardware readout Boris Brezillon
2016-03-31 8:00 ` Alexandre Belloni
2016-03-30 20:03 ` [PATCH v5 27/46] regulator: pwm: adjust PWM config at probe time Boris Brezillon
2016-03-30 21:22 ` Mark Brown
2016-03-30 20:03 ` [PATCH v5 28/46] regulator: pwm: swith to the atomic PWM API Boris Brezillon
2016-03-30 21:23 ` Mark Brown
2016-03-30 20:03 ` [PATCH v5 29/46] regulator: pwm: properly initialize the ->state field Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 30/46] regulator: pwm: retrieve correct voltage Boris Brezillon
2016-03-30 21:24 ` Mark Brown
2016-04-07 21:54 ` Boris Brezillon
2016-04-12 4:42 ` Mark Brown
2016-04-12 8:37 ` Boris Brezillon
2016-04-12 10:09 ` Mark Brown
2016-04-12 10:31 ` Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 31/46] pwm: update documentation Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 32/46] pwm: deprecate pwm_config(), pwm_enable() and pwm_disable() Boris Brezillon
2016-03-31 17:38 ` Dmitry Torokhov
2016-03-31 18:54 ` Boris Brezillon
2016-04-04 15:22 ` Thierry Reding
2016-03-30 20:03 ` [PATCH v5 33/46] pwm: replace pwm_disable() by pwm_apply_state() Boris Brezillon
2016-03-30 20:03 ` [PATCH v5 34/46] clk: pwm: switch to the atomic API Boris Brezillon
2016-03-30 22:01 ` Stephen Boyd
2016-03-31 6:57 ` Boris Brezillon
2016-04-04 15:30 ` Thierry Reding
2016-03-30 20:03 ` [PATCH v5 35/46] hwmon: pwm-fan: " Boris Brezillon
2016-04-01 8:29 ` Kamil Debski
2016-03-30 20:03 ` [PATCH v5 36/46] input: misc: max77693: " Boris Brezillon
2016-03-31 17:48 ` Dmitry Torokhov
2016-03-31 18:57 ` Boris Brezillon
2016-04-04 15:34 ` Thierry Reding
2016-03-30 20:04 ` [PATCH v5 37/46] input: misc: max8997: switch to the atomic PWM API Boris Brezillon
2016-03-30 20:04 ` [PATCH v5 38/46] input: misc: pwm-beeper: " Boris Brezillon
2016-03-30 20:04 ` [PATCH v5 39/46] leds: pwm: " Boris Brezillon
2016-03-30 20:04 ` [PATCH v5 40/46] backlight: lm3630a: " Boris Brezillon
2016-03-30 20:04 ` [PATCH v5 41/46] backlight: lp855x: " Boris Brezillon
2016-03-30 20:04 ` [PATCH v5 42/46] backlight: lp8788: " Boris Brezillon
2016-03-30 20:04 ` [PATCH v5 43/46] backlight: pwm_bl: " Boris Brezillon
2016-03-30 20:04 ` [PATCH v5 44/46] video: ssd1307fb: " Boris Brezillon
2016-03-30 20:04 ` [PATCH v5 45/46] drm: i915: " Boris Brezillon
2016-03-30 20:04 ` [PATCH v5 46/46] ARM: s3c24xx: rx1950: " Boris Brezillon
2016-03-30 20:18 ` [PATCH v5 00/46] pwm: add support for atomic update Boris Brezillon
2016-04-11 22:42 ` Boris Brezillon
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