[PATCH] backlight: rave-sp: don't touch initial state and register with correct device

[Daniel Thompson]

On Thu, May 02, 2019 at 02:01:45PM +0200, Lucas Stach wrote:
> Hi Daniel,
> 
> Am Donnerstag, den 02.05.2019, 11:33 +0100 schrieb Daniel Thompson:
> > On 29/04/2019 16:29, Lucas Stach wrote:
> > > This way the backlight can be referenced through its device node and
> > > enabling/disabling can be managed through the panel driver.
> > 
> > Is it possible to implement something similar to 
> > pwm_backlight_initial_power_state() to handle this?
> 
> I'm not aware of any protocol to the RAVE-SP that would allow to read
> back the backlight state. AFAICS the backlight is implemented as a
> unidirectional protocol.

That function does two things... one is read the current power state to
ensure meta-data is correctly up to date which cannot be replicated.
The other is to choose different behaviour depending on whether the
backlight is standalone or has a phandle link to another device.

Does the second part apply to the rave-sp?


Daniel.



> > backlight drivers already suffer from too much diversity so I prefer 
> > things like this to align behaviour with the (fairly heavilyly used) PWM 
> > driver if possible.
> > 
> > 
> > Daniel.
> > 
> > 
> > > > > Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> > > ---
> > >   drivers/video/backlight/rave-sp-backlight.c | 4 +---
> > >   1 file changed, 1 insertion(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/video/backlight/rave-sp-backlight.c b/drivers/video/backlight/rave-sp-backlight.c
> > > index 462f14a1b19d..d296bfcf4396 100644
> > > --- a/drivers/video/backlight/rave-sp-backlight.c
> > > +++ b/drivers/video/backlight/rave-sp-backlight.c
> > > @@ -48,15 +48,13 @@ static int rave_sp_backlight_probe(struct platform_device *pdev)
> > > > >   	struct device *dev = &pdev->dev;
> > > > >   	struct backlight_device *bd;
> > >   
> > > > > -	bd = devm_backlight_device_register(dev, pdev->name, dev->parent,
> > > > > +	bd = devm_backlight_device_register(dev, pdev->name, dev,
> > > > >   					    dev_get_drvdata(dev->parent),
> > > > >   					    &rave_sp_backlight_ops,
> > > > >   					    &rave_sp_backlight_props);
> > > > >   	if (IS_ERR(bd))
> > > > >   		return PTR_ERR(bd);
> > >   
> > > > > -	backlight_update_status(bd);
> > > -
> > > > >   	return 0;
> > >   }
> > >   
> > > 
> > 
> >