Re: [PATCH 2/6] pinctrl: sunxi: Add I/O bias setting for H6 R-PIO

[Samuel Holland <samuel@xxxxxxxxxxxx>]

On 6/27/22 3:34 PM, Jernej Škrabec wrote:
> Dne nedelja, 26. junij 2022 ob 04:11:43 CEST je Samuel Holland napisal(a):
>> H6 requires I/O bias configuration on both of its PIO devices.
>> Previously it was only done for the main PIO.
>>
>> The setting for Port L is at bit 0, so the bank calculation needs to
>> account for the pin base. Otherwise the wrong bit is used.
>>
>> Fixes: cc62383fcebe ("pinctrl: sunxi: Support I/O bias voltage setting on
>> H6") Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
> 
> Reviewed-by: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>
> 
> Did you noticed any improvement with this properly set? In theory, 3.3 V bias 
> should always work, right?

I think it matters for inputs, which may not detect a high level state if the
bias (comparator reference) voltage is too high.

It looks like Orange Pi 3 has a 1.8 V supply for port M. I am not currently set
up to test the behavior with different bias settings, but I may do that if I get
the chance.

Regards,
Samuel