Uwe Kleine-König <uwe@xxxxxxxxxxxxxxxxx> (2021-12-31): > The cm4-io board comes with an PCF85063. Add it to the device tree to make > it usable. The i2c0 bus can use two different pinmux settings to use > different pins. To keep the bus appearing on the usual pin pair (gpio0 + > gpio1) use a pinctrl-muxed setting as the vendor dts does. > > Note that if you modified the dts before to add devices to the i2c bus > appearing on pins gpio0 + gpio1 (either directly in the dts or using an > overlay), you have to put these into the i2c@0 node introduced here now. > > Reviewed-by: Maxime Ripard <maxime@xxxxxxxxxx> > Signed-off-by: Uwe Kleine-König <uwe@xxxxxxxxxxxxxxxxx> Tested-by: Cyril Brulebois <cyril@xxxxxxxxxxx> Test hardware: - 1 Compute Module 4 IO Board; - 1 GPIO Extension Board, plugged onto the 40-pin header (mainly used for its labels, to ensure I'm using the correct pins); - 1 Pimoroni 5x5 RGB LED matrix, plugged onto SDA0/SCL0 as exposed by the GPIO Extension Board (plus 3.3V/GND of course); - Debian 11 userspace. With the updated DTB, and provided the right kernel modules have been enabled (CONFIG_RTC_DRV_PCF85063, CONFIG_I2C_MUX_PINCTRL), the RTC comes up automatically; I'm also able to use the relevant library to display a rotating rainbow on the LED matrix while being able to read from / write to the RTC: https://github.com/pimoroni/rgbmatrix5x5-python In passing, I'm seeing the RTC exclusively on (userspace) i2c-2 while I'm seeing the LED matrix on both (userspace) i2c-2 and i2c-3: # i2cdetect -y 2 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- 0c -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 2f 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- # i2cdetect -y 3 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- 74 -- -- -- Tweaking the library to use either of those makes the rotation rainbow display successfully (via python3-smbus): self.i2c = smbus.SMBus(2) self.i2c = smbus.SMBus(3) Cheers, -- Cyril Brulebois -- Debian Consultant @ DEBAMAX -- https://debamax.com/
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