Re: [PATCH v2] backlight: lp855x: use private data for regulator control

[Kim, Milo]

Hi Paul,

On 7/11/2015 12:01 AM, Sean Paul wrote:
> On Fri, Jul 10, 2015 at 4:26 AM, Milo Kim <milo.kim@xxxxxx> wrote:
> > LP855x backlight device can be enabled by external VDD input.
> > The 'supply' data is used for this purpose.
> > It's kind of private data which runs internally, so there is no reason to
> > expose to the platform data.
> >
> > And devm_regulator_get() is moved from _parse_dt() to _probe().
> > Regulator consumer(lp855x) can control regulator not only from DT but also
> > from platform data configuration in a source file such like board-*.c.
> >
> > If 'power' regulator driver is not ready, lp855x should continue to work
> > because the power supply control is optional. So -EPROBE_DEFER return code
> > is removed.
> >
> > v1->v2:
> >    Keeps optional property '<name>-supply' in LP855x DT binding.
> >
> > Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
> > Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
> > Cc: Lee Jones <lee.jones@xxxxxxxxxx>
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Signed-off-by: Milo Kim <milo.kim@xxxxxx>
> > ---
> >   drivers/video/backlight/lp855x_bl.c  | 20 +++++++++-----------
> >   include/linux/platform_data/lp855x.h |  2 --
> >   2 files changed, 9 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
> > index a26d3bb..277d5ca 100644
> > --- a/drivers/video/backlight/lp855x_bl.c
> > +++ b/drivers/video/backlight/lp855x_bl.c
> > @@ -73,6 +73,7 @@ struct lp855x {
> >          struct device *dev;
> >          struct lp855x_platform_data *pdata;
> >          struct pwm_device *pwm;
> > +       struct regulator *supply;       /* regulator for VDD input */
> >   };
> >
> >   static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
> > @@ -384,13 +385,6 @@ static int lp855x_parse_dt(struct lp855x *lp)
> >                  pdata->rom_data = &rom[0];
> >          }
> >
> > -       pdata->supply = devm_regulator_get(dev, "power");
> > -       if (IS_ERR(pdata->supply)) {
> > -               if (PTR_ERR(pdata->supply) == -EPROBE_DEFER)
> > -                       return -EPROBE_DEFER;
> > -               pdata->supply = NULL;
> > -       }
> > -
> >          lp->pdata = pdata;
> >
> >          return 0;
> > @@ -431,8 +425,12 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
> >          else
> >                  lp->mode = REGISTER_BASED;
> >
> > -       if (lp->pdata->supply) {
> > -               ret = regulator_enable(lp->pdata->supply);
> > +       lp->supply = devm_regulator_get(lp->dev, "power");
> > +       if (IS_ERR(lp->supply))
> > +               lp->supply = NULL;
>
>
> Hi Milo,
> You removed the probe deferral handling on the regulator and broke
> probe deferral in cases where the regulator isn't ready.

This power supply is optional. Even if lp855x can not get regulator 
driver, it should work. (And I saw same comment in the DT. The 
'power-supply' property is optional). So -EPORBE_DEFER is not necessary 
in _probe().

Best regards,
Milo
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