[PATCH v2] video: add ChipWealth CH13726A AMOLED panel driver

[Advait Dhamorikar]

> Hey there! Thanks for your contribution, it is pretty solid but there
> are a few places that can be improved.
Hi Svyatoslav, thanks for your inputs!

> > +config VIDEO_AMOLED_CHIPWEALTH_CH13726A
>
> May you please rename AMOLED > PANEL

Most of the drivers say `CONFIG_VIDEO_LCD_XXXX`
Since this driver is an AMOLED I thought of using that.
There also don't seem to be any existing setups named `CONFG_VIDEO_PANEL_XXX`.
Should I still rename it to VIDEO_PANEL_CHIPWEALTH_CH13726A?

> > +static int ch13726a_dcs_write_buf(struct udevice *dev, const void *data,
> > +                                 size_t len)
> > +{
> > +       struct mipi_dsi_panel_plat *plat = dev_get_plat(dev);
> > +       int ret;
> > +
> > +       ret = mipi_dsi_dcs_write_buffer(plat->device, data, len);
> > +       if (ret < 0)
> > +               log_err("failed to write dcs sequence: %d\n", ret);
> > +
> > +       return ret;
> > +}
> > +
> > +#define dcs_write_seq(dev, cmd, seq...)                                \
> > +({                                                             \
> > +       const u8 d[] = { cmd, seq };                    \
> > +                                                               \
> > +       ch13726a_dcs_write_buf(dev, d, ARRAY_SIZE(d));          \
> > +})
> > +

> You can fold this.

I'll fold this into one single #define altogether.

> > +struct ch13726a_panel_priv {
> > +       struct udevice *reg;
> > +       struct udevice *backlight;
> > +       struct gpio_desc reset;
> > +};
>
> You are lacking supplies here: vdd1v2, vddio, vdd and avdd
>
> U-Boot can handle them so you should include control over them.

My board has the input rails permanently powered, so the current
driver doesn't request any regulators
I'll add support for the vdd, vddio, vdd1v2, and avdd supplies. Should
these be treated as
optional (-ENOENT) and guarded with CONFIG_IS_ENABLED(DM_REGULATOR)?
I couldn't find other panel drivers that consistently follow one approach,
so I'd like to match the preferred U-Boot style.

Best regards,
Advait