I am designing my own carrier for xavier. I have an IO expander (PCA9539) connected to I2C5_CLK/DATA (pin A53/C53). It is the i2c controller - i2c9 (i2c@31e0000). But PCA9539 is not detected. We have the same PCA9539 connected to I2C1_CLK/DATA, this one works.
I checked OEM and pinmux spreadsheet. I2C5_CLK/DATA (pin A53/C53) can be muxed in DP_AUX_CH3_P/N function. But it should be default set to I2C function.
However, I did a test on that pinmux spreadsheet by switch them in DP_AUX_CH3_P/N function and convert it in pinmux .cfg file. I realized that there is NO change in pinmux .cfg file.
I also looked through pinctrl-tegra194.c driver, it seems there is no pinmux function setting for i2c9.
Is I2C5_CLK/DATA, (i2c9 i2c@31e0000) really in I2C mode, and usage?
Also, note that I am using Jetpack-4.4.