Re: [PATCH v4 06/27] dt-bindings: mfd: add samsung,s2dos05

[Dzmitry Sankouski <dsankouski@gmail.com>]

пн, 16 сент. 2024 г. в 12:14, Krzysztof Kozlowski <krzk@kernel.org>:
>
> On Fri, Sep 13, 2024 at 06:07:49PM +0300, Dzmitry Sankouski wrote:
> > Add samsung,s2dos05 MFD module binding.
> >
> > Signed-off-by: Dzmitry Sankouski <dsankouski@gmail.com>
> >
> > ---
> > Changes in v4:
> > - split long(>80) lines
> > - fix indentation
> > - merge with regulators binding
> > - drop pmic suffix
> > - drop unused labels in example
> > - correct description
> > ---
> >  .../devicetree/bindings/mfd/samsung,s2dos05.yaml   | 99 ++++++++++++++++++++++
> >  MAINTAINERS                                        |  1 +
> >  2 files changed, 100 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/mfd/samsung,s2dos05.yaml b/Documentation/devicetree/bindings/mfd/samsung,s2dos05.yaml
> > new file mode 100644
> > index 000000000000..534434002045
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mfd/samsung,s2dos05.yaml
> > @@ -0,0 +1,99 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/mfd/samsung,s2dos05.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Samsung S2DOS05 Power Management IC
> > +
> > +maintainers:
> > +  - Dzmitry Sankouski <dsankouski@gmail.com>
> > +
> > +description:
> > +  This is a device tree bindings for S2DOS family of Power Management IC (PMIC).
>
> Drop this sentence, not really useful. I know that I put it into other
> Samsung PMIC bindings, but let's don't grow this pattern.
>
> > +
> > +  The S2DOS05 is a companion power management IC for the panel and touchscreen
> > +  in smart phones. Provides voltage regulators and
> > +  ADC for power/current measurements.
> > +
> > +  Regulator section has 4 LDO and 1 BUCK regulators and also
> > +  provides ELVDD, ELVSS, AVDD lines.
>
> What are these? Input supplies?
>

ELVSS and ELVDD are common abbreviations for AMOLED panel backlight supplies,
AVDD for panel electronics. I conclude that s2dos05 ic provides
ELVSS, ELVDD, AVDD from the facts, it can measure its current and power.
Those power lines are controlled by display hardware [1],
i.e. vendor kernel driver has no clue how to control those regulators.

I guess they just combined regular regulator ic with ELVSS, ELVDD, AVDD ic
like [2].

[1]: https://github.com/klabit87/twrp_android_samsung_kernel_sdm845/blob/android-8.0/drivers/gpu/drm/msm/samsung/S6E3HA8_AMB577PX01/dsi_panel_S6E3HA8_AMB577PX01_wqhd_octa_cmd.dtsi#L3508
[2]: https://www.st.com/resource/en/data_brief/stmp30.pdf