Subject: Re: [PATCH 09/15] staging: fbtft: fb_ssd1351.c: Introduce backlight_is_blank()

From: Daniel Thompson <[email-masked]>
Date: Mon, 9 Jan 2023 11:16:22 +0000

On Sun, Jan 08, 2023 at 09:29:43PM +0100, Sam Ravnborg wrote:
> Hi Stephen,
>
> On Sun, Jan 08, 2023 at 08:28:17PM +0100, Stephen Kitt wrote:
> > On Sat, 07 Jan 2023 19:26:23 +0100, Sam Ravnborg via B4 Submission Endpoint
> > <[email-masked]> wrote:
> >
> > > From: Sam Ravnborg <[email-masked]>
> > >
> > > Avoiding direct access to backlight_properties.props.
> > >
> > > Access to the deprecated props.fb_blank replaced by backlight_is_blank().
> > > Access to props.power is dropped - it was only used for debug.
> > >
> > > Signed-off-by: Sam Ravnborg <[email-masked]>
> > > Cc: Stephen Kitt <[email-masked]>
> > > Cc: Greg Kroah-Hartman <[email-masked]>
> > > Cc: Daniel Thompson <[email-masked]>
> > > Cc: Andy Shevchenko <[email-masked]>
> > > Cc: [email-masked]
> > > ---
> > >  drivers/staging/fbtft/fb_ssd1351.c | 9 +++------
> > >  1 file changed, 3 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/staging/fbtft/fb_ssd1351.c
> > > b/drivers/staging/fbtft/fb_ssd1351.c index b8d55aa8c5c7..995fbd2f3dc6 100644
> > > --- a/drivers/staging/fbtft/fb_ssd1351.c
> > > +++ b/drivers/staging/fbtft/fb_ssd1351.c
> > > @@ -190,15 +190,12 @@ static struct fbtft_display display = {
> > >  static int update_onboard_backlight(struct backlight_device *bd)
> > >  {
> > >  	struct fbtft_par *par = bl_get_data(bd);
> > > -	bool on;
> > > +	bool blank = backlight_is_blank(bd);
> > >
> > > -	fbtft_par_dbg(DEBUG_BACKLIGHT, par,
> > > -		      "%s: power=%d, fb_blank=%d\n",
> > > -		      __func__, bd->props.power, bd->props.fb_blank);
> > > +	fbtft_par_dbg(DEBUG_BACKLIGHT, par, "%s: blank=%d\n", __func__,
> > > blank);
> > > -	on = !backlight_is_blank(bd);
> > >  	/* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */
> > > -	write_reg(par, 0xB5, on ? 0x03 : 0x02);
> > > +	write_reg(par, 0xB5, !blank ? 0x03 : 0x02);
> > >
> > >  	return 0;
> > >  }
> > >
> > > --
> > > 2.34.1
> >
> > For debugging purposes here, would there be any point in logging props.state?
> > As in
> >
> >         fbtft_par_dbg(DEBUG_BACKLIGHT, par,
> > -                     "%s: power=%d, fb_blank=%d\n",
> > -                     __func__, bd->props.power, bd->props.fb_blank);
> > +                     "%s: power=%d, state=%u\n",
> > +                     __func__, bd->props.power, bd->props.state);
>
> Thanks for the suggestion - and the reviews!
>
> I was tempted to just remove the debugging.
> If we require debugging, then this could be added in the backlight core,
> thus everyone would benefit from it.

I had the same instinct to remove the debug print here (esp. ones with
__func__ in them) but I think that's probably a much more widely scoped
clean up for fbtft ;-).

On that basis:
Reviewed-by: Daniel Thompson <[email-masked]>

Daniel.