linux-kernel - [PATCH 5.14 815/849] video: backlight: Drop maximum brightness override for brightness zero

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Date:   Mon, 15 Nov 2021 18:04:58 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Marek Vasut <marex@...x.de>,
        Noralf Trønnes <noralf@...nnes.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Lee Jones <lee.jones@...aro.org>
Subject: [PATCH 5.14 815/849] video: backlight: Drop maximum brightness override for brightness zero

From: Marek Vasut <marex@...x.de>

commit 33a5471f8da976bf271a1ebbd6b9d163cb0cb6aa upstream.

The note in c2adda27d202f ("video: backlight: Add of_find_backlight helper
in backlight.c") says that gpio-backlight uses brightness as power state.
This has been fixed since in ec665b756e6f7 ("backlight: gpio-backlight:
Correct initial power state handling") and other backlight drivers do not
require this workaround. Drop the workaround.

This fixes the case where e.g. pwm-backlight can perfectly well be set to
brightness 0 on boot in DT, which without this patch leads to the display
brightness to be max instead of off.

Fixes: c2adda27d202f ("video: backlight: Add of_find_backlight helper in backlight.c")
Cc: <stable@...r.kernel.org> # 5.4+
Cc: <stable@...r.kernel.org> # 4.19.x: ec665b756e6f7: backlight: gpio-backlight: Correct initial power state handling
Signed-off-by: Marek Vasut <marex@...x.de>
Acked-by: Noralf Trønnes <noralf@...nnes.org>
Reviewed-by: Daniel Thompson <daniel.thompson@...aro.org>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/video/backlight/backlight.c |    6 ------
 1 file changed, 6 deletions(-)

--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -688,12 +688,6 @@ static struct backlight_device *of_find_
 			of_node_put(np);
 			if (!bd)
 				return ERR_PTR(-EPROBE_DEFER);
-			/*
-			 * Note: gpio_backlight uses brightness as
-			 * power state during probe
-			 */
-			if (!bd->props.brightness)
-				bd->props.brightness = bd->props.max_brightness;
 		}
 	}