Re: [PATCH v4 1/3] drm/panel: refactor INNOLUX P079ZCA panel driver

[hl]

Hi Emil,


On Wednesday, March 14, 2018 08:02 PM, Emil Velikov wrote:
> Hi Lin,
>
> On 14 March 2018 at 09:12, Lin Huang <hl@xxxxxxxxxxxxxx> wrote:
> > From: huang lin <hl@xxxxxxxxxxxxxx>
> >
> > Refactor Innolux P079ZCA panel driver, let it support
> > multi panel.
> >
> > Change-Id: If89be5e56dba8cb498e2d50c1bbeb0e8016123a2
> > Signed-off-by: Lin Huang <hl@xxxxxxxxxxxxxx>
> > ---
> > Changes in v2:
> > - Change regulator property name to meet the panel datasheet
> > Changes in v3:
> > - this patch only refactor P079ZCA panel to support multi panel, support P097PFG panel in another patch
> > Changes in v4:
> > - Modify the patch which suggest by Thierry
> Thanks for splitting this up. I think there's another piece that fell
> through the cracks.
> I'm not deeply familiar with the driver, so just sharing some quick notes.
>
>
> >   struct innolux_panel {
> >          struct drm_panel base;
> >          struct mipi_dsi_device *link;
> > +       const struct panel_desc *desc;
> >
> >          struct backlight_device *backlight;
> > -       struct regulator *supply;
> > +       struct regulator *vddi;
> > +       struct regulator *avdd;
> > +       struct regulator *avee;
> These two seem are new addition, as opposed to a dummy refactor.
> Are they optional, does one need them for the existing panel (separate
> patch?) or only for the new one (squash with the new panel code)?
>
>
> >          struct gpio_desc *enable_gpio;
> >
> >          bool prepared;
> > @@ -77,9 +93,9 @@ static int innolux_panel_unprepare(struct drm_panel *panel)
> >          /* T8: 80ms - 1000ms */
> >          msleep(80);
> >
> > -       err = regulator_disable(innolux->supply);
> > -       if (err < 0)
> > -               return err;
> Good call on dropping the early return here.
>
>
> > @@ -207,19 +248,28 @@ static const struct drm_panel_funcs innolux_panel_funcs = {
> > -       innolux->supply = devm_regulator_get(dev, "power");
> > -       if (IS_ERR(innolux->supply))
> > -               return PTR_ERR(innolux->supply);
> > +       innolux = devm_kzalloc(dev, sizeof(*innolux), GFP_KERNEL);
> > +       if (!innolux)
> > +               return -ENOMEM;
> > +
> > +       innolux->desc = desc;
> > +       innolux->vddi = devm_regulator_get(dev, "power");
> > +       innolux->avdd = devm_regulator_get(dev, "avdd");
> > +       innolux->avee = devm_regulator_get(dev, "avee");
> AFAICT devm_regulator_get returns a pointer which is unsuitable to be
> passed into regulator_{enable,disable}.
> Hence, the IS_ERR check should stay. If any of the regulators are
> optional, you want to call regulator_{enable,disable} only as
> applicable.

devm_regulator_get() will use dummy_regulator if there not regulator pass to driver,
so it not affect regulator_{enable, disable}. These three regulator are optional,
the p079zca will use "power" and p097pgf will use "avdd" and "avee",
so i think it better not to check ERR here.

> > @@ -318,5 +377,6 @@ static struct mipi_dsi_driver innolux_panel_driver = {
> >   module_mipi_dsi_driver(innolux_panel_driver);
> >
> >   MODULE_AUTHOR("Chris Zhong <zyw@xxxxxxxxxxxxxx>");
> > +MODULE_AUTHOR("Lin Huang <hl@xxxxxxxxxxxxxx>");
> I don't think refactoring existing code classify as being the module author.
> Then again, I could be wrong.
>
> HTH
> Emil