Re: [PATCH V3 5/7] backlight: qcom-wled: Add support for WLED4 peripheral

[kgunda]

On 2018-06-23 04:39, Bjorn Andersson wrote:
> On Wed 20 Jun 04:00 PDT 2018, kgunda@xxxxxxxxxxxxxx wrote:
>
> > On 2018-06-20 10:44, Bjorn Andersson wrote:
> > > On Tue 19 Jun 04:13 PDT 2018, Kiran Gunda wrote:
> > >
> > > > WLED4 peripheral is present on some PMICs like pmi8998 and
> > > > pm660l. It has a different register map and configurations
> > > > are also different. Add support for it.
> > > >
> > > > Signed-off-by: Kiran Gunda <kgunda@xxxxxxxxxxxxxx>
> > > > ---
> > > >  drivers/video/backlight/qcom-wled.c | 635
> > > > ++++++++++++++++++++++++++++--------
> > > >  1 file changed, 503 insertions(+), 132 deletions(-)
> > >
> > > Split this further into a patch that does structural preparation of
> > > WLED3 support and then an addition of WLED4, the mixture makes parts of
> > > this patch almost impossible to review. Please find some comments below.
> > >
> > Sure. I will split it in the next series.
>
> Thanks!
>
> > > >
> > > > diff --git a/drivers/video/backlight/qcom-wled.c
> > > > b/drivers/video/backlight/qcom-wled.c
> > > [..]
> > > >
> > > >  /* WLED3 sink registers */
> > > >  #define WLED3_SINK_REG_SYNC				0x47
> > >
> > > Drop the 3 from this if it's common between the two.
> > >
> > > > -#define  WLED3_SINK_REG_SYNC_MASK			0x07
> > > > +#define  WLED3_SINK_REG_SYNC_MASK			GENMASK(2, 0)
> > > > +#define  WLED4_SINK_REG_SYNC_MASK			GENMASK(3, 0)
> > > >  #define  WLED3_SINK_REG_SYNC_LED1			BIT(0)
> > > >  #define  WLED3_SINK_REG_SYNC_LED2			BIT(1)
> > > >  #define  WLED3_SINK_REG_SYNC_LED3			BIT(2)
> > > > +#define  WLED4_SINK_REG_SYNC_LED4			BIT(3)
> > > >  #define  WLED3_SINK_REG_SYNC_ALL			0x07
> > > > +#define  WLED4_SINK_REG_SYNC_ALL			0x0f
> > > >  #define  WLED3_SINK_REG_SYNC_CLEAR			0x00
> > > >
> > > [..]
> > > > +static int wled4_set_brightness(struct wled *wled, u16 brightness)
> > >
> > > Afaict this is identical to wled3_set_brightness() with the exception
> > > that there's a minimum brightness and the base address for the
> > > brightness registers are different.
> > >
> > > I would suggest that you add a min_brightness to wled and that you
> > > figure out a way to carry the brightness base register address; and by
> > > that you squash these two functions.
> > >
> > There are four different parameters. 1) minimum brightness 2) WLED 
> > base
> > addresses
> > 3) Brightness base addresses 4) the brightness sink registers address
> > offsets also
> > different for wled 3 and wled4. (in wled3 0x40, 0x42, 0x44, where as 
> > in
> > wled4 0x57, 0x67, 0x77, 0x87).
>
> Sorry, I must have gotten lost in the defines, I see the difference
> between the two register layouts now. If you retain the old mechanism 
> of
> doing the math openly in the function this would have been obvious.
>
> > Irrelevant to this patch, but wled5 has some more extra registers to
> > set the brightness.  Keeping this in mind, it is better to have
> > separate functions? Otherwise we will have to use the version checks
> > in the wled_set_brightness function, if we have the common function.
>
> Okay, so it sounds reasonable to split this out to some degree.
>
> Regards,
> Bjorn
> --
Thanks for that !
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