On Wed, Feb 09, 2022 at 03:50:13PM +0100, Javier Martinez Canillas wrote:

On 2/9/22 15:22, Mark Brown wrote:

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On Wed, Feb 09, 2022 at 03:17:06PM +0100, Javier Martinez Canillas wrote:

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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.

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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 display controller datasheet and schematics mention VBAT as the power
supply but the documentation says that it's just connected to VCC and the
label in the display says VCC.

But I understand why the Device Tree binding and fbdev driver used VBAT
since that's what the documentation mentions.

What is "the documentation" in this context and how is that distinct
from the datasheet for the display controller?  In general the consumer
driver should be using the name from the datasheet and the regulator
itself should get a regulator-name reflecting the name in the schematic.

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

I'll include a patch for the existing DT binding and mark the vbat-supply
property as required. Probably we won't be able to change the fbdev driver
without causing regressions, and I'm not interested in that driver anyways.

There should be little danger of causing regressions given that a dummy
regualtor will be provided when one is missing.