Re: [linux-sunxi] Re: [PATCH v4 1/6] dt-bindings: update the Allwinner GPADC device tree binding for H3

[icenowy]

å 2017-09-18 16:30ïMaxime Ripard åéï
> On Mon, Sep 18, 2017 at 03:36:43PM +0800, Icenowy Zheng wrote:
> > ä 2017å9æ18æ GMT+08:00 äå3:33:36, Maxime Ripard 
> > <maxime.ripard@xxxxxxxxxxxxxxxxxx> åå:
> > >On Thu, Sep 14, 2017 at 10:52:46PM +0800, Icenowy Zheng wrote:
> > >> Allwinner H3 features a thermal sensor like the one in A33, but has
> > >its
> > >> register re-arranged, the clock divider moved to CCU (originally the
> > >> clock divider is in ADC) and added a pair of bus clock and reset.
> > >>
> > >> Update the binding document to cover H3.
> > >>
> > >> Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
> > >> Reviewed-by: Chen-Yu Tsai <wens@xxxxxxxx>
> > >> ---
> > >> Changes in v4:
> > >> - Add nvmem calibration data (not yet used by the driver)
> > >> Changes in v3:
> > >> - Clock name changes.
> > >> - Example node name changes.
> > >> - Add interupts (not yet used by the driver).
> > >>
> > >>  .../devicetree/bindings/mfd/sun4i-gpadc.txt        | 30
> > >++++++++++++++++++++--
> > >>  1 file changed, 28 insertions(+), 2 deletions(-)
> > >>
> > >> diff --git a/Documentation/devicetree/bindings/mfd/sun4i-gpadc.txt
> > >b/Documentation/devicetree/bindings/mfd/sun4i-gpadc.txt
> > >> index badff3611a98..6c470d584bf9 100644
> > >> --- a/Documentation/devicetree/bindings/mfd/sun4i-gpadc.txt
> > >> +++ b/Documentation/devicetree/bindings/mfd/sun4i-gpadc.txt
> > >> @@ -4,12 +4,26 @@ The Allwinner SoCs all have an ADC that can also
> > >act as a thermal sensor
> > >>  and sometimes as a touchscreen controller.
> > >>
> > >>  Required properties:
> > >> -  - compatible: "allwinner,sun8i-a33-ths",
> > >> +  - compatible: must contain one of the following compatibles:
> > >> +		- "allwinner,sun8i-a33-ths"
> > >> +		- "allwinner,sun8i-h3-ths"
> > >>    - reg: mmio address range of the chip,
> > >>    - #thermal-sensor-cells: shall be 0,
> > >>    - #io-channel-cells: shall be 0,
> > >>
> > >> -Example:
> > >> +Optional properties:
> > >> +  - nvmem-cells: A phandle to the calibration data provided by a
> > >nvmem device.
> > >> +                 If unspecified default values shall be used.
> > >> +  - nvmem-cell-names: Should be "calibration-data"
> > >
> > >I'd prefer to have which sensor it applies to here. It wouldn't change
> > >anything for the H3, but it definitely does for example for the A83t
> > >that has two sensors, one for each cluster, and one for the GPU, each
> > >with calibration data.
> > >
> > >What about cluster0-calibration?

I prefer sensor0-calibration to sensor3-calibration now.
(Theortically the new generation THS can support up to 4 sensors)

> > The calibration data is in fact a 2 word (8 bytes) zone,
> > which is reserved for 4 sensors on all SoCs, even on H3.
> > It's half word per sensor.
> >
> > I prefer to just assume a 2 word cell for every SoC.
>
> You have three different data sources, it should be reprensented as
> such.
>
> Otherwise, the client has to get some knowledge of how the data are
> stored in the provider, which is an abstraction violation.
>
> Maxime
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com