Re: [PATCH v3 2/8] backlight: expose the current brightness in the new kernel API

[Mario Limonciello <mario.limonciello@amd.com>]

On 5/4/26 08:55, Louis Chauvet wrote:
> [You don't often get email from louis.chauvet@bootlin.com. Learn why 
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> 
> On 4/25/26 00:09, Mario Limonciello wrote:
>> From: Marta Lofstedt <marta.lofstedt@intel.com>
>>
>> Current brightness needs to be queried from drivers.
>>
>> Signed-off-by: Marta Lofstedt <marta.lofstedt@intel.com>
>> v3:
>>   * Rebase
>>   * Add description
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
>> ---
>>   drivers/video/backlight/backlight.c | 6 ++++++
>>   include/linux/backlight.h           | 1 +
>>   2 files changed, 7 insertions(+)
>>
>> diff --git a/drivers/video/backlight/backlight.c b/drivers/video/ 
>> backlight/backlight.c
>> index c3673bee6d9cf..9bbfc16cf2d74 100644
>> --- a/drivers/video/backlight/backlight.c
>> +++ b/drivers/video/backlight/backlight.c
>> @@ -206,6 +206,12 @@ int backlight_device_set_brightness(struct 
>> backlight_device *bd,
>>   }
>>   EXPORT_SYMBOL(backlight_device_set_brightness);
>>
>> +int backlight_device_get_brightness(struct backlight_device *bd)
>> +{
>> +     return bd->props.brightness;
> 
> Hello,
> 
> The function backlight_get_brightness already exists and is already
> public, maybe you can use the existing function?
> 

Thanks for the suggestion.  I'll have a try with this.

> 
>> +}
>> +EXPORT_SYMBOL(backlight_device_get_brightness);
>> +
>>   static ssize_t brightness_store(struct device *dev,
>>               struct device_attribute *attr, const char *buf, size_t 
>> count)
>>   {
>> diff --git a/include/linux/backlight.h b/include/linux/backlight.h
>> index 7e4fee65fddd9..851570b39d041 100644
>> --- a/include/linux/backlight.h
>> +++ b/include/linux/backlight.h
>> @@ -412,6 +412,7 @@ struct backlight_device 
>> *backlight_device_get_by_name(const char *name);
>>   struct backlight_device *backlight_device_get_by_type(enum 
>> backlight_type type);
>>   int backlight_device_set_brightness(struct backlight_device *bd,
>>                                   unsigned long brightness);
>> +extern int backlight_device_get_brightness(struct backlight_device *bd);
>>
>>   #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>   void backlight_notify_blank(struct backlight_device *bd,
>