I2C2 doesn't work

[alexeykuzmin]

Hello,

I have trouble to enable I2C2 to work on the iMX6 Sabre EVB under Linux and communicate with touch controller. I can’t see any SDA/SCL signals activity from iMX6 on oscilloscope. Communication is doing by i2c_transfer() function.

Already tried change status from “disabled”  for i2c2 node into device tree  (with no effect).

Is I2C number 2 is turned on by defaults?

HW: MCIMX6QP-SDB + MIPI DSI panel

SW: Yocto and Linux kernel v4.9

UPDATE:

Also found some unknown definitions in device tree for I2C2 pinmux.

It’s only I2C2 specific. I2C1 and I2C3 haven’t this group. I can’t explain what It does mean.

pinctrl-1 = <&pinctrl_i2c2_gpio>;

pinctrl_i2c2_gpio: i2c2_gpio_grp {

fsl,pins = <

MX6QDL_PAD_KEY_COL3__GPIO4_IO12><------>0x1b0b0

MX6QDL_PAD_KEY_ROW3__GPIO4_IO13><------>0x1b0b0

>;

};

How to explain?

[igorpadykov]

Hi Alexey

seems "pinctrl_i2c2_gpio: i2c2_gpio_grp " are used for emulation,

really they are configured as gpios. For comparison true i2c settings

have sion pad bit30 set

pinctrl_i2c3: i2c3grp {
            fsl,pins = <
                MX6QDL_PAD_GPIO_3__I2C3_SCL        0x4001b8b1

may be useful to check linux/Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt

Best regards
igor
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