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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