Re: [PATCH v3 1/2] dt-bindings: display: bridge: add TI TDP158

[Maxime Ripard <mripard@kernel.org>]

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On Thu, Jul 04, 2024 at 07:04:41PM GMT, Marc Gonzalez wrote:
> On 01/07/2024 15:50, Maxime Ripard wrote:
> 
> > The i2c register access (and the whole behaviour of the device) is
> > constrained on the I2C_EN pin status, and you can't read it from the
> > device, so it's also something we need to have in the DT.
> 
> I think the purpose of the I2C_EN pin might have been misunderstood.
> 
> I2C_EN is not meant to be toggled, ever, by anyone from this planet.

Toggled, probably not. Connected to a GPIO and the kernel has to assert
a level at boot, I've seen worse hardware design already.

> I2C_EN is a layout-time setting, decided by a board manufacturer:
> 
> - If the TDP158 is fully configured once-and-for-all at layout-time,
> then no I2C bus is required, and I2C_EN is pulled down forever.
> 
> - If the board manufacturer wants to keep open the possibility
> to adjust some parameters at run-time, then they must connect
> the device to an I2C bus, and I2C_EN is pulled up forever.

How do you express both cases in your current binding?

Maxime

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