From: Linus Walleij <linus.walleij@linaro.org>
To: Lee Jones <lee.jones@linaro.org>,
Daniel Thompson <daniel.thompson@linaro.org>,
Jingoo Han <jingoohan1@gmail.com>,
dri-devel@lists.freedesktop.org
Subject: [PATCH] backlight: ktd253: Bring up in a known state
Date: Tue, 26 Jan 2021 22:32:00 +0100 [thread overview]
Message-ID: <20210126213200.14366-1-linus.walleij@linaro.org> (raw)
The KTD253 backlight might already be on when the driver
is probed: then we don't really know what the current
ratio is and all light intensity settings will be off
relative to what it was at boot.
To fix this, bring up the backlight OFF then move it to
the default backlight from there so we know the state.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/video/backlight/ktd253-backlight.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/video/backlight/ktd253-backlight.c b/drivers/video/backlight/ktd253-backlight.c
index e3fee3f1f582..d7b287cffd5c 100644
--- a/drivers/video/backlight/ktd253-backlight.c
+++ b/drivers/video/backlight/ktd253-backlight.c
@@ -137,15 +137,7 @@ static int ktd253_backlight_probe(struct platform_device *pdev)
brightness = max_brightness;
}
- if (brightness)
- /* This will be the default ratio when the KTD253 is enabled */
- ktd253->ratio = KTD253_MAX_RATIO;
- else
- ktd253->ratio = 0;
-
- ktd253->gpiod = devm_gpiod_get(dev, "enable",
- brightness ? GPIOD_OUT_HIGH :
- GPIOD_OUT_LOW);
+ ktd253->gpiod = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
if (IS_ERR(ktd253->gpiod)) {
ret = PTR_ERR(ktd253->gpiod);
if (ret != -EPROBE_DEFER)
@@ -153,6 +145,8 @@ static int ktd253_backlight_probe(struct platform_device *pdev)
return ret;
}
gpiod_set_consumer_name(ktd253->gpiod, dev_name(dev));
+ /* Bring backlight to a known off state */
+ msleep(KTD253_T_OFF_MS);
bl = devm_backlight_device_register(dev, dev_name(dev), dev, ktd253,
&ktd253_backlight_ops, NULL);
--
2.29.2
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next reply other threads:[~2021-01-26 21:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-26 21:32 Linus Walleij [this message]
2021-02-05 17:27 ` [PATCH] backlight: ktd253: Bring up in a known state Daniel Thompson
2021-02-09 10:10 ` Linus Walleij
2021-02-09 14:10 ` Lee Jones
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