[PATCH 3/4] arm: sunxi: Add AXP20X_ADC

[Quentin Schulz]

Hi Maxime,

On 24/07/2017 10:18, Maxime Ripard wrote:
> Hi,
> 
> On Sat, Jul 22, 2017 at 10:19:08AM +0800, Chen-Yu Tsai wrote:
>> On Sat, Jul 22, 2017 at 12:20 AM, Maxime Ripard
>> <maxime.ripard at free-electrons.com> wrote:
>>> The APX20X_POWER option, that is a dependency of the USB controllers
>>> depends on IIO and AXP20X_ADC. Add it so that we can get a working USB
>>> back.
>>
>> The statement is only half true. AXP20X_POWER can fall back to reading
>> the ADC registers directly if AXP20X_ADC is not enabled. Is there a plan
>> to remove this feature?
> 
> I never really considered this a feature, but some compatibility for
> older DTs to be honest :)
> 

Have nothing to do with backward compatibility for DT as the DT hasn't
changed. The IIO channels are exposed via an IIO map in the ADC driver
and retrieved from the map in the USB power supply driver. No need for
DT, no changes in DT.

Quentin

>> Also, AXP20X_ADC is only really needed if the hardware is AXP20x, and
>> not the later ones that don't have voltage/current sensing. I would
>> like to change the hard dependency on AXP20X_ADC to the "imply"
>> keyword in Kconfig for the AC and battery power supply drivers.
> 
> I'm not sure. It's also needed when you want to read the battery
> voltage and current, or the AC-IN voltage. And that's a feature found
> on all PMICs.
>> And since the battery and the AC-IN power supplies also have a
> dependency on AXP20X_ADC, I guess we can just add a depnds on. In most
> configuration, it's going to be enabled anyway.
> 
>> That is another discussion though.
> 
> Indeed.
> 
>> So I think the description should be something like
>>
>>     AXP20X_POWER depends on IIO. Even though it does not depend on
>>     AXP20X_ADC, it is the new, preferred way of getting power supply
>>     readings. The other AXP power supply drivers use it as well.
>>
>>     Enable both options.
> 
> That works for me.
> 
> With that comment, do I have your Acked-By?
> 
> Maxime
> 
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

-- 
Quentin Schulz, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 801 bytes
Desc: OpenPGP digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20170724/b1c053d3/attachment.sig>