Am Freitag, 21. Februar 2025, 11:14:27 MEZ schrieb Quentin Schulz: > From: Quentin Schulz <quentin.schulz@xxxxxxxxx> > > The PCA9670, PCA9671, PCA9672 and PCA9673 all have a RESETN input pin > that is used to reset the I2C GPIO expander. > > One needs to hold this pin low for at least 4us and the reset should be > finished after about 100us according to the datasheet[1]. Once the reset > is done, the "registers and I2C-bus state machine will be held in their > default state until the RESET input is once again HIGH.". > > Because the logic is reset, the latch values eventually provided in the > Device Tree via lines-initial-states property are inapplicable so they > are simply ignored if a reset GPIO is provided. > > [1] https://www.nxp.com/docs/en/data-sheet/PCA9670.pdf 8.5 and fig 22. > > Tested-by: Heiko Stuebner <heiko@xxxxxxxxx> # RK3588 Tiger Haikou Video Demo > Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxx> Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>
