diff mbox series

backlight: led_bl: fix initial power state

Message ID 20230705142447.15546-1-mans@mansr.com (mailing list archive)
State Handled Elsewhere
Headers show
Series backlight: led_bl: fix initial power state | expand

Commit Message

Måns Rullgård July 5, 2023, 2:24 p.m. UTC
The condition for the initial power state based on the default
brightness value is reversed.  Fix it.

Furthermore, use the actual state of the LEDs rather than the default
brightness specified in the devicetree as the latter should not cause
the backlight to be automatically turned on.

If the backlight device is not linked to any display, set the initial
power to on unconditionally.

Fixes: ae232e45acf9 ("backlight: add led-backlight driver")
Signed-off-by: Mans Rullgard <mans@mansr.com>
---
Changes in v3:
- Add comment

Changes in v2:
- Use the reported LED state to set initial power state
- Always power on if no phandle in DT
---
 drivers/video/backlight/led_bl.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

Comments

Daniel Thompson July 5, 2023, 2:33 p.m. UTC | #1
On Wed, Jul 05, 2023 at 03:24:14PM +0100, Mans Rullgard wrote:
> The condition for the initial power state based on the default
> brightness value is reversed.  Fix it.
>
> Furthermore, use the actual state of the LEDs rather than the default
> brightness specified in the devicetree as the latter should not cause
> the backlight to be automatically turned on.
>
> If the backlight device is not linked to any display, set the initial
> power to on unconditionally.
>
> Fixes: ae232e45acf9 ("backlight: add led-backlight driver")
> Signed-off-by: Mans Rullgard <mans@mansr.com>
> ---
> Changes in v3:
> - Add comment

This mismatches the subject line ;-) but I can live with that if Lee
and Jingoo can!

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>


Daniel.
Måns Rullgård July 5, 2023, 2:36 p.m. UTC | #2
Daniel Thompson <daniel.thompson@linaro.org> writes:

> On Wed, Jul 05, 2023 at 03:24:14PM +0100, Mans Rullgard wrote:
>> The condition for the initial power state based on the default
>> brightness value is reversed.  Fix it.
>>
>> Furthermore, use the actual state of the LEDs rather than the default
>> brightness specified in the devicetree as the latter should not cause
>> the backlight to be automatically turned on.
>>
>> If the backlight device is not linked to any display, set the initial
>> power to on unconditionally.
>>
>> Fixes: ae232e45acf9 ("backlight: add led-backlight driver")
>> Signed-off-by: Mans Rullgard <mans@mansr.com>
>> ---
>> Changes in v3:
>> - Add comment
>
> This mismatches the subject line ;-) but I can live with that if Lee
> and Jingoo can!

Does it not fix it?  If you think the subject is misleading, feel free
to change it.
Daniel Thompson July 5, 2023, 2:44 p.m. UTC | #3
On Wed, Jul 05, 2023 at 03:36:46PM +0100, Måns Rullgård wrote:
> Daniel Thompson <daniel.thompson@linaro.org> writes:
>
> > On Wed, Jul 05, 2023 at 03:24:14PM +0100, Mans Rullgard wrote:
> >> The condition for the initial power state based on the default
> >> brightness value is reversed.  Fix it.
> >>
> >> Furthermore, use the actual state of the LEDs rather than the default
> >> brightness specified in the devicetree as the latter should not cause
> >> the backlight to be automatically turned on.
> >>
> >> If the backlight device is not linked to any display, set the initial
> >> power to on unconditionally.
> >>
> >> Fixes: ae232e45acf9 ("backlight: add led-backlight driver")
> >> Signed-off-by: Mans Rullgard <mans@mansr.com>
> >> ---
> >> Changes in v3:
> >> - Add comment
> >
> > This mismatches the subject line ;-) but I can live with that if Lee
> > and Jingoo can!
>
> Does it not fix it?  If you think the subject is misleading, feel free
> to change it.

The bit that goes into version control is fine!

However without '[PATCH v3]' on the subject line for the initial patch
there is a risk this thread will get overlooked and not queued[1].


Daniel.


[1] Just to be clear, Lee J. typically hoovers up the backlight patches
    and sends the PR. I only queue backlight patches myself as holiday
    cover...
Måns Rullgård July 5, 2023, 2:51 p.m. UTC | #4
Daniel Thompson <daniel.thompson@linaro.org> writes:

> On Wed, Jul 05, 2023 at 03:36:46PM +0100, Måns Rullgård wrote:
>> Daniel Thompson <daniel.thompson@linaro.org> writes:
>>
>> > On Wed, Jul 05, 2023 at 03:24:14PM +0100, Mans Rullgard wrote:
>> >> The condition for the initial power state based on the default
>> >> brightness value is reversed.  Fix it.
>> >>
>> >> Furthermore, use the actual state of the LEDs rather than the default
>> >> brightness specified in the devicetree as the latter should not cause
>> >> the backlight to be automatically turned on.
>> >>
>> >> If the backlight device is not linked to any display, set the initial
>> >> power to on unconditionally.
>> >>
>> >> Fixes: ae232e45acf9 ("backlight: add led-backlight driver")
>> >> Signed-off-by: Mans Rullgard <mans@mansr.com>
>> >> ---
>> >> Changes in v3:
>> >> - Add comment
>> >
>> > This mismatches the subject line ;-) but I can live with that if Lee
>> > and Jingoo can!
>>
>> Does it not fix it?  If you think the subject is misleading, feel free
>> to change it.
>
> The bit that goes into version control is fine!
>
> However without '[PATCH v3]' on the subject line for the initial patch
> there is a risk this thread will get overlooked and not queued[1].

Oh, I see now I forgot to add the v3 tag.  Sorry about that.
diff mbox series

Patch

diff --git a/drivers/video/backlight/led_bl.c b/drivers/video/backlight/led_bl.c
index 3259292fda76..c94843c00a30 100644
--- a/drivers/video/backlight/led_bl.c
+++ b/drivers/video/backlight/led_bl.c
@@ -176,6 +176,7 @@  static int led_bl_probe(struct platform_device *pdev)
 {
 	struct backlight_properties props;
 	struct led_bl_data *priv;
+	int init_brightness;
 	int ret, i;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
@@ -190,6 +191,8 @@  static int led_bl_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	init_brightness = priv->default_brightness;
+
 	ret = led_bl_parse_levels(&pdev->dev, priv);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Failed to parse DT data\n");
@@ -200,8 +203,11 @@  static int led_bl_probe(struct platform_device *pdev)
 	props.type = BACKLIGHT_RAW;
 	props.max_brightness = priv->max_brightness;
 	props.brightness = priv->default_brightness;
-	props.power = (priv->default_brightness > 0) ? FB_BLANK_POWERDOWN :
-		      FB_BLANK_UNBLANK;
+
+	/* Set power on if LEDs already on or not linked to a display. */
+	props.power = (init_brightness || !pdev->dev.of_node->phandle) ?
+		FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN;
+
 	priv->bl_dev = backlight_device_register(dev_name(&pdev->dev),
 			&pdev->dev, priv, &led_bl_ops, &props);
 	if (IS_ERR(priv->bl_dev)) {