Re: Re: [PATCH] backlight: pwm_bl: Fix brightness levels for non-DT case.

[Daniel Thompson]

On 25/08/18 01:04, Robert Jarzmik wrote:
> Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx> writes:
>
> > Commit '88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED
> > linearly to human eye")' allows the possibility to compute a default
> > brightness table when there isn't the brightness-levels property in the
> > DT. Unfortunately the changes made broke the pwm backlight for the
> > non-DT boards.
> >
> > Usually, the non-DT boards don't pass the brightness levels via platform
> > data, instead, they set the max_brightness in their platform data and the
> > driver calculates the level without a table. The ofending patch assumed
> > that when there is no brightness levels table we should create one, but this
> > is clearly wrong for the non-DT case.
> >
> > After this patch the code handles the DT and the non-DT case taking in
> > consideration also if max_brightness is set or not. The default table is
> > only created when neither, brightness-levels and max_brightness, are
> > set.
> >
> > The patch also fixes another issue found by Robert. Before this patch
> > looks like a division by 0 was possible when state.period returned 0 by
> > pwm_get_state(). This is because pwm_get_state() was called before
> > pwm_apply_args() so state.period was not initialized. The patch moves
> > the pwm_apply_args() call before any call to pwm_get_state().
> >
> > Fixes: '88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED linearly to human eye")'
> > Reported-by: Robert Jarzmik <robert.jarzmik@xxxxxxx>
> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> Tested-by: Robert Jarzmik <robert.jarzmik@xxxxxxx>

Acked-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>

(and sorry for the delay)


Daniel.