On 15/11/2023 04:57, Chris Packham wrote: > Add bus-reset-gpios and bus-reset-duration-us properties to the binding > description for i2c busses. These can be used to describe hardware where > a common reset GPIO is connected to all downstream devices on and I2C > bus. This reset will be asserted then released before the downstream > devices on the bus are probed. > > Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx> > --- > ... > > Documentation/devicetree/bindings/i2c/i2c.txt | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt > index fc3dd7ec0445..3f95d71b9985 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c.txt > @@ -99,6 +99,14 @@ wants to support one of the below features, it should adapt these bindings. > indicates that the system is accessible via this bus as an endpoint for > MCTP over I2C transport. > > +- bus-reset-gpios: > + GPIO pin providing a common reset for all downstream devices. This GPIO > + will be asserted then released before the downstream devices are probed. I initially reviewed it, but did not think enough about it. After more consideration, I believe this is not a property of the I2C bus controller. This is a property of each device, even if the GPIO is the same. Linux kernel already supports shared GPIO, so you only need enable-ref-counting on it. Putting it into the controller bindings looks like solving OS issue with incorrect hardware description. Best regards, Krzysztof
