Re: AW: [PATCH 1/2] dt-bindings: i2c: Add i2c-shared-gpio

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

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Hi all,

> Thats what I broke my head about the most. From testing and
> my little knowledge I came to the conclusion 
> 
> - two native i2c-gpio based busses can not share the same SCL
> - so mux infrastructure cannot build on top of that
> 
> But maybe some I2C expert can advise.

I am not sure i2c-mux is the right approach here. Because every SDA is
already wired, there is no need to select/deselect something. It is only
that SCL is shared, right?

Now, the GPIO subsystem since recently allows for shared GPIOs[1]. This
sounds like the proper approach to me. Sadly, I can't help much because
I have not used this API so far. So, it seems you rather need a GPIO
expert... CCing Bart.

@Bart: is it possible to share a GPIO so that multiple i2c-gpio
instances can use the same GPIO as SCL? Use case is explained in the
cover letter[2].

Happy hacking,

   Wolfram


[1] https://lwn.net/Articles/1044022/
[2] https://lore.kernel.org/r/20260507181711.2696783-1-markus.stockhausen@gmx.de

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