| Message ID | 20240220-lm3630a-fixups-v1-3-9ca62f7e4a33@z3ntu.xyz (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | Various fixes for the lm3630a backlight driver | expand |
On Tue, Feb 20, 2024 at 12:11:21AM +0100, Luca Weiss wrote: > As per documentation "drivers are expected to use this function in their > update_status() operation to get the brightness value.". > > With this we can also drop the manual backlight_is_blank() handling > since backlight_get_brightness() is already handling this correctly. > > Signed-off-by: Luca Weiss <luca@z3ntu.xyz> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> However... > --- > /* disable sleep */ > @@ -201,9 +202,9 @@ static int lm3630a_bank_a_update_status(struct backlight_device *bl) > goto out_i2c_err; > usleep_range(1000, 2000); > /* minimum brightness is 0x04 */ > - ret = lm3630a_write(pchip, REG_BRT_A, bl->props.brightness); > + ret = lm3630a_write(pchip, REG_BRT_A, brightness); ... then handling of the minimum brightness looks weird in this driver. The range of the backlight is 0..max_brightness. Sadly the drivers are inconsistant regarding whether zero means off or just minimum, however three certainly isn't supposed to mean off! In other words the offsetting should be handled by driver rather than hoping userspace has some magic LM3630A mode. You didn't introduce this so this patch still has my R-b ... Daniel.
On Dienstag, 20. Februar 2024 15:11:07 CET Daniel Thompson wrote: > On Tue, Feb 20, 2024 at 12:11:21AM +0100, Luca Weiss wrote: > > As per documentation "drivers are expected to use this function in their > > update_status() operation to get the brightness value.". > > > > With this we can also drop the manual backlight_is_blank() handling > > since backlight_get_brightness() is already handling this correctly. > > > > Signed-off-by: Luca Weiss <luca@z3ntu.xyz> > > Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> > > However... > > > --- > > /* disable sleep */ > > @@ -201,9 +202,9 @@ static int lm3630a_bank_a_update_status(struct backlight_device *bl) > > goto out_i2c_err; > > usleep_range(1000, 2000); > > /* minimum brightness is 0x04 */ > > - ret = lm3630a_write(pchip, REG_BRT_A, bl->props.brightness); > > + ret = lm3630a_write(pchip, REG_BRT_A, brightness); > > ... then handling of the minimum brightness looks weird in this driver. > > The range of the backlight is 0..max_brightness. Sadly the drivers > are inconsistant regarding whether zero means off or just minimum, > however three certainly isn't supposed to mean off! In other words the > offsetting should be handled by driver rather than hoping userspace has > some magic LM3630A mode. I could also try and fix that.. 1. Treat 1..4 as 4, so have backlight on at that minimum level? Probably wouldn't be noticable that brightness 1=2=3=4. And the backlight will be on compared to off as it is now. 2. Decrease max_brightness by 4 values, so probably 0..251 and shift the values up in the driver so we get 4..255? Or would you have some other idea here? Regards Luca > > You didn't introduce this so this patch still has my R-b ... > > > Daniel. >
On Tue, Feb 20, 2024 at 05:43:32PM +0100, Luca Weiss wrote: > On Dienstag, 20. Februar 2024 15:11:07 CET Daniel Thompson wrote: > > On Tue, Feb 20, 2024 at 12:11:21AM +0100, Luca Weiss wrote: > > > As per documentation "drivers are expected to use this function in their > > > update_status() operation to get the brightness value.". > > > > > > With this we can also drop the manual backlight_is_blank() handling > > > since backlight_get_brightness() is already handling this correctly. > > > > > > Signed-off-by: Luca Weiss <luca@z3ntu.xyz> > > > > Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> > > > > However... > > > > > --- > > > /* disable sleep */ > > > @@ -201,9 +202,9 @@ static int lm3630a_bank_a_update_status(struct backlight_device *bl) > > > goto out_i2c_err; > > > usleep_range(1000, 2000); > > > /* minimum brightness is 0x04 */ > > > - ret = lm3630a_write(pchip, REG_BRT_A, bl->props.brightness); > > > + ret = lm3630a_write(pchip, REG_BRT_A, brightness); > > > > ... then handling of the minimum brightness looks weird in this driver. > > > > The range of the backlight is 0..max_brightness. Sadly the drivers > > are inconsistant regarding whether zero means off or just minimum, > > however three certainly isn't supposed to mean off! In other words the > > offsetting should be handled by driver rather than hoping userspace has > > some magic LM3630A mode. > > I could also try and fix that.. > > 1. Treat 1..4 as 4, so have backlight on at that minimum level? Probably > wouldn't be noticable that brightness 1=2=3=4. And the backlight will be > on compared to off as it is now. > > 2. Decrease max_brightness by 4 values, so probably 0..251 and shift the > values up in the driver so we get 4..255? > > Or would you have some other idea here? I think #2 is the right option but shouldn't it be decrease max_brightness by 3, yielding 0..252 . Only nitpicking on that because, given how old this driver is I'd like to be conservative. I don't expect there to be userspaces with magic LM3630A modes but there could be some that assume #0 is off! Hence I wanted to make sure we are on the same page. Daniel.
diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c index 26ff4178cc16..e6c0916ec88b 100644 --- a/drivers/video/backlight/lm3630a_bl.c +++ b/drivers/video/backlight/lm3630a_bl.c @@ -189,10 +189,11 @@ static int lm3630a_bank_a_update_status(struct backlight_device *bl) int ret; struct lm3630a_chip *pchip = bl_get_data(bl); enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl; + int brightness = backlight_get_brightness(bl); /* pwm control */ if ((pwm_ctrl & LM3630A_PWM_BANK_A) != 0) - return lm3630a_pwm_ctrl(pchip, bl->props.brightness, + return lm3630a_pwm_ctrl(pchip, brightness, bl->props.max_brightness); /* disable sleep */ @@ -201,9 +202,9 @@ static int lm3630a_bank_a_update_status(struct backlight_device *bl) goto out_i2c_err; usleep_range(1000, 2000); /* minimum brightness is 0x04 */ - ret = lm3630a_write(pchip, REG_BRT_A, bl->props.brightness); + ret = lm3630a_write(pchip, REG_BRT_A, brightness); - if (backlight_is_blank(bl) || (backlight_get_brightness(bl) < 0x4)) + if (brightness < 0x4) /* turn the string off */ ret |= lm3630a_update(pchip, REG_CTRL, LM3630A_LEDA_ENABLE, 0); else @@ -263,10 +264,11 @@ static int lm3630a_bank_b_update_status(struct backlight_device *bl) int ret; struct lm3630a_chip *pchip = bl_get_data(bl); enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl; + int brightness = backlight_get_brightness(bl); /* pwm control */ if ((pwm_ctrl & LM3630A_PWM_BANK_B) != 0) - return lm3630a_pwm_ctrl(pchip, bl->props.brightness, + return lm3630a_pwm_ctrl(pchip, brightness, bl->props.max_brightness); /* disable sleep */ @@ -275,9 +277,9 @@ static int lm3630a_bank_b_update_status(struct backlight_device *bl) goto out_i2c_err; usleep_range(1000, 2000); /* minimum brightness is 0x04 */ - ret = lm3630a_write(pchip, REG_BRT_B, bl->props.brightness); + ret = lm3630a_write(pchip, REG_BRT_B, brightness); - if (backlight_is_blank(bl) || (backlight_get_brightness(bl) < 0x4)) + if (brightness < 0x4) /* turn the string off */ ret |= lm3630a_update(pchip, REG_CTRL, LM3630A_LEDB_ENABLE, 0); else
As per documentation "drivers are expected to use this function in their update_status() operation to get the brightness value.". With this we can also drop the manual backlight_is_blank() handling since backlight_get_brightness() is already handling this correctly. Signed-off-by: Luca Weiss <luca@z3ntu.xyz> --- drivers/video/backlight/lm3630a_bl.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)