Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays

[Javier Martinez Canillas <javierm@redhat.com>]

On 6/13/22 17:35, andriy.shevchenko@linux.intel.com wrote:
> On Mon, Jun 13, 2022 at 11:39:30AM +0000, Dominik Kierner wrote:
>> On 5/25/2022 21:46, Javier Martinez Canillas wrote:
> 
> ...
> 
>>> Thanks, I looked at the code briefly and think that there are things there that we
>>> could use. I.e the 3-wire SPI support that's in panel-solomon-ssd130x-spi-3wire.c.
>>
>> When writing my driver code, I wasn't even considering using regmaps,
>> like You did in Your I2C-Code. If that's applicable for 3-wire-SPI,
>> it would likely be the better, more generic option. Your SPI-code
>> reuses these parts to some extent. For that case,
>> ssd130x_spi_regmap_config.reg_bits would need be changed to 1,
>> as the "register address" has a length of 1 bit and we are sending
>> 9 bits over the line and not 16.
>> Since we still have 2 bytes of host memory,
>> it should still be compatible with the 4-wire write, right?
>> Or would 3-wire SPI require a second regmap?
> 
> I believe the cleanest solution is to have different regmap configurations.
> 

I agree with this.

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat