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From:   Enric Balletbo i Serra <enric.balletbo@collabora.com>
To:     Lee Jones <lee.jones@linaro.org>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Jingoo Han <jingoohan1@gmail.com>,
        Rob Herring <robh+dt@kernel.org>, Pavel Machek <pavel@ucw.cz>,
        Heiko Stuebner <heiko@sntech.de>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Richard Purdie <rpurdie@rpsys.net>,
        Jacek Anaszewski <jacek.anaszewski@gmail.com>,
        linux-pwm@vger.kernel.org, linux-fbdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, groeck@chromium.org,
        linux-rockchip@lists.infradead.org, linux-leds@vger.kernel.org,
        devicetree@vger.kernel.org, kernel@collabora.com
Subject: [PATCH v6 1/5] pwm-backlight: enable/disable the PWM before/after LCD enable toggle.
Date:   Mon, 26 Mar 2018 11:52:09 +0200
Message-Id: <20180326095213.18362-1-enric.balletbo@collabora.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Before this patch the enable signal was set before the PWM signal and
vice-versa on power off. This sequence is wrong, at least, it is on
the different panels datasheets that I checked, so I inverted the sequence
to follow the specs.

For reference the following panels have the mentioned sequence:
  - N133HSE-EA1 (Innolux)
  - N116BGE (Innolux)
  - N156BGE-L21 (Innolux)
  - B101EAN0 (Auo)
  - B101AW03 (Auo)
  - LTN101NT05 (Samsung)
  - CLAA101WA01A (Chunghwa)

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
---
Changes since v5:
 - Add Acked-by: Thierry Reding <thierry.reding@gmail.com>
Changes since v4:
 - Rebase on top of mainline.
 - Add the acks from Daniel Thompson and Jingoo Han.
Changes since v3:
 - List the part numbers for the panel checked (Daniel Thompson)
Changes since v2:
 - Add this as a separate patch (Thierry Reding)
Changes since v1:
 - None
---
 drivers/video/backlight/pwm_bl.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 1c2289ddd555..698ec68bcdc9 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -54,10 +54,11 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
 	if (err < 0)
 		dev_err(pb->dev, "failed to enable power supply\n");
 
+	pwm_enable(pb->pwm);
+
 	if (pb->enable_gpio)
 		gpiod_set_value_cansleep(pb->enable_gpio, 1);
 
-	pwm_enable(pb->pwm);
 	pb->enabled = true;
 }
 
@@ -66,12 +67,12 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
 	if (!pb->enabled)
 		return;
 
-	pwm_config(pb->pwm, 0, pb->period);
-	pwm_disable(pb->pwm);
-
 	if (pb->enable_gpio)
 		gpiod_set_value_cansleep(pb->enable_gpio, 0);
 
+	pwm_config(pb->pwm, 0, pb->period);
+	pwm_disable(pb->pwm);
+
 	regulator_disable(pb->power_supply);
 	pb->enabled = false;
 }
-- 
2.16.2