On 12/02/2024 12:58, Ralf Schlatterbeck wrote: > On Mon, Feb 12, 2024 at 12:25:48PM +0100, Krzysztof Kozlowski wrote: >> >> Hm, I don't understand how exactly it helps. The GPIO expander has its >> own example and as you pointed below, this is basically the same code, >> except rw and backlight GPIOs. > > The hd44780 is a display that is very often used. > By people (like me some time ago) not familiar with the nice io expander > implementation in Linux. The consequence of that is that you'll find > several out-of-tree implementations for this display with i2c out in the > wild. So my thought of documenting this (again) at that location is to > make it easier for people with a hd44780 with the standard i2c interface > to see how it is done in Linux. GPIO expanders and their usage is nothing specific to this device - other devices also might benefit of them. Or the SoCs which have enough of GPIOs... I really do not understand why do we need expander here and how does it help Anyway, binding examples should not be collection of unrelated solutions, because then we should accept for each device schema several other variations and combinations. Best regards, Krzysztof
