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video: backlight: Drop maximum brightness override for brightness zero

PATCH RESEND In review Marek Vasut 2 participants 2 messages Sep 21, 2021 – Sep 22, 2021

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PATCH RESEND v2 1/1 video: backlight: Drop maximum brightness override for brightness zero

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 <[email protected]> # 5.4+
Cc <[email protected]> # 4.19.x: ec665b756e6f7: backlight: gpio-backlight: Correct initial power state handling
Cc Daniel Thompson <[email protected]>
Cc Lee Jones <[email protected]>
Cc Meghana Madhyastha <[email protected]>
Cc Noralf Trønnes <[email protected]>
Cc Sean Paul <[email protected]>
Cc Thierry Reding <[email protected]>

---
V2: Add AB/RB, CC stable

---
 drivers/video/backlight/backlight.c | 6 ------
 1 file changed, 6 deletions(-)
drivers/video/backlight/backlight.c +0 -6
index 537fe1b376ad7..fc990e576340b 100644
@@ -688,12 +688,6 @@ static struct backlight_device *of_find_backlight(struct device *dev)
 			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;
 		}
 	}
 
Signature · 1 line
2.33.0
#1 lore raw
Quoted 22 lines · Marek Vasut

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 <[email protected]> # 5.4+
Cc <[email protected]> # 4.19.x: ec665b756e6f7: backlight: gpio-backlight: Correct initial power state handling
Cc Daniel Thompson <[email protected]>
Cc Lee Jones <[email protected]>
Cc Meghana Madhyastha <[email protected]>
Cc Noralf Trønnes <[email protected]>
Cc Sean Paul <[email protected]>
Cc Thierry Reding <[email protected]>
Quoted 5 lines

---
V2: Add AB/RB, CC stable

---
 drivers/video/backlight/backlight.c | 6 ------
 1 file changed, 6 deletions(-)

Applied with some changes to the sign-off block, thanks.

Quoted 17 lines
drivers/video/backlight/backlight.c +0 -6
index 537fe1b376ad7..fc990e576340b 100644
@@ -688,12 +688,6 @@ static struct backlight_device *of_find_backlight(struct device *dev)
 			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;
 		}
 	}
 
Signature · 4 lines
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
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