Re: [PATCH 2/2] gpio: Add support for SLG7XL45106 I2C GPO expander

[Sungbo Eo <mans0n@xxxxxxxxxx>]

Hi,

On 2022-06-29 04:21, Andy Shevchenko wrote:
> On Tue, Jun 28, 2022 at 9:13 PM Andy Shevchenko
> <andy.shevchenko@xxxxxxxxx> wrote:
>>
>> On Tue, Jun 28, 2022 at 4:35 PM Shubhrajyoti Datta
>> <shubhrajyoti.datta@xxxxxxxxxx> wrote:
>>>
>>> From: Raviteja Narayanam <raviteja.narayanam@xxxxxxxxxx>
>>>
>>> Dialog semiconductors SLG7XL45106 is an 8-bit I2C GPO expander.
>>> The output port is controlled by a data byte with register
>>> address.
>>
>> 1/ Have you checked if there is a driver that sounds very similar to
>> this already upstream?
> 
> Actually, why can't pca9570 be amended to support this?
> 
>> 2/ Have you tried to use gpio-regmap? Why can it not be used?
> 
> Same Q for PCA9570 driver. (Maybe gpio-regmap wasn't existed that time?)

IIRC regmap could not be used for pca9570 as pca9570 doesn't have a
concept of "address"; it only accepts a data value.[1]
Please let me know if the situation has changed in the meantime.

It seems the slg7xl45106 driver reads/writes a reg at 0xDB so it is not
compatible with pca9570 driver (in the current state), and (I suppose)
it could be converted to use gpio-regmap.

[1]
https://lore.kernel.org/linux-gpio/69f5d1a1970838b8c4bd8d6e8dba6cac@xxxxxxxx/

Thanks,
Sungbo