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

Bjorn Andersson
2018-06-22T23:06:49Z

On Wed 20 Jun 04:00 PDT 2018, kgunda@codeaurora.org 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@codeaurora.org>
> > > ---
> > > 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