Re: [PATCH v3 3/7] drm: Add driver for Solomon SSD130X OLED displays

[Mark Brown <broonie@kernel.org>]

[-- Attachment #1: Type: text/plain, Size: 1181 bytes --]

On Wed, Feb 09, 2022 at 03:17:06PM +0100, Javier Martinez Canillas wrote:
> On 2/9/22 14:43, Mark Brown wrote:

> > Unless the device supports power being physically omitted regulator
> > usage should not be optional, it's just more code and a recipie for poor
> > error handling.

> The device has a VCC pin but in most cases this is just connected to a
> power provided by the board in its pinout header. For example, I've it
> connected to a rpi4 3.3v pin.

That sounds like a very common configuration.

> I guess in that case what we should do then is to just have a regulator
> fixed as the vbat-supply in the Device Tree, that's regulator-always-on.

Generally I'd suggest labelling things with whatever the supply is
called in the board's schematics/documentation, that tends to make
things clearer and easier to follow.

> The old ssd1307fb fbdev driver also had this as optional and I wanted to
> keep the new driver as backward compatible. But I understand now that is
> not describing the hardware properly by making this regulator optional.

It is depressingly common to see broken code here, unfortunately
graphics drivers seem like one of the most common offendors.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]