Re: [PATCH v2 05/11] Documentation: DT: bindings: mfd: add A33 GPADC binding

[Quentin Schulz <quentin.schulz@free-electrons.com>]

Hi Icenowy,

On 10/03/2017 20:25, Icenowy Zheng wrote:
> 
> 
> 10.03.2017, 18:56, "Quentin Schulz" <quentin.schulz@free-electrons.com>:
>> This patch adds documentation for the A33 GPADC binding.
>>
>> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
>> ---
>>
>> added in v2
>>
>>  .../devicetree/bindings/mfd/sun4i-gpadc.txt | 59 ++++++++++++++++++++++
>>  1 file changed, 59 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/mfd/sun4i-gpadc.txt
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/sun4i-gpadc.txt b/Documentation/devicetree/bindings/mfd/sun4i-gpadc.txt
>> new file mode 100644
>> index 0000000..17242c8
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mfd/sun4i-gpadc.txt
>> @@ -0,0 +1,59 @@
>> +Allwinner SoCs' GPADC Device Tree bindings
>> +------------------------------------------
>> +The Allwinner SoCs all have an ADC that can also act as a thermal sensor
>> +and sometimes as a touchscreen controller.
>> +
>> +Required properties:
>> + - compatible: "sun8i-a33-gpadc-iio",
>> + - reg: mmio address range of the chip,
>> + - #thermal-sensor-cells: shall be 0,
>> + - #io-channel-cells: shall be 0,
>> +
>> +Example:
>> + rtp: rtp@01c25000 {
> 
> I think we'd better call it ths.
> 

To match the datasheet, I agree.

> And can you make thermal-sensor-cells become 1?
> 
> Maxime Ripard wants to base H3/H5/A64 thermal driver on this patchset, and
> for H5/A64 there's 2/3 thermal sensors.
> 

Yes, that'll require a specific DT node for those thermal sensors. Then
since we would update the possible compatibles in the documentation
anyway, that would be a good idea to update to say that
thermal-sensor-cells could be different from 0 too.

That was my mindset to set thermal-sensor-cells to 0, since we only
support SoC which has only one thermal sensor at the moment.

> Thus for A33/H3 we will have thermal-sensor-cells to 1, but only have
> <&ths 0>.
> 

That's non-sense. There is one thermal sensor for the A33,
thermal-sensor-cells has to be 0.

I don't mind to remove the requirement for thermal-sensor-cells to be 0
but I won't put a requirement for it to be 1 as it isn't true.

Thanks,
Quentin
>> + compatible = "allwinner,sun8i-a33-gpadc-iio";
>> + reg = <0x01c25000 0x100>;
>> + #thermal-sensor-cells = <0>;
>> + #io-channel-cells = <0>;
>> + };
>> +
>> +sun4i, sun5i and sun6i SoCs are also supported via the older binding:
>> +
>> +sun4i resistive touchscreen controller
>> +--------------------------------------
>> +
>> +Required properties:
>> + - compatible: "allwinner,sun4i-a10-ts", "allwinner,sun5i-a13-ts" or
>> + "allwinner,sun6i-a31-ts"
>> + - reg: mmio address range of the chip
>> + - interrupts: interrupt to which the chip is connected
>> + - #thermal-sensor-cells: shall be 0
>> +
>> +Optional properties:
>> + - allwinner,ts-attached : boolean indicating that an actual touchscreen
>> + is attached to the controller
>> + - allwinner,tp-sensitive-adjust : integer (4 bits)
>> + adjust sensitivity of pen down detection
>> + between 0 (least sensitive) and 15
>> + (defaults to 15)
>> + - allwinner,filter-type : integer (2 bits)
>> + select median and averaging filter
>> + samples used for median / averaging filter
>> + 0: 4/2
>> + 1: 5/3
>> + 2: 8/4
>> + 3: 16/8
>> + (defaults to 1)
>> +
>> +Example:
>> +
>> + rtp: rtp@01c25000 {
>> + compatible = "allwinner,sun4i-a10-ts";
>> + reg = <0x01c25000 0x100>;
>> + interrupts = <29>;
>> + allwinner,ts-attached;
>> + #thermal-sensor-cells = <0>;
>> + /* sensitive/noisy touch panel */
>> + allwinner,tp-sensitive-adjust = <0>;
>> + allwinner,filter-type = <3>;
>> + };
>> --
>> 2.9.3
>>
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> 
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-- 
Quentin Schulz, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com