Detect iMX8QM USB overcurrent

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Detect iMX8QM USB overcurrent

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fmonte
Contributor IV

Hello,
there are two signals, CONN_USB_OTGx_OC, that can be obtained by muxing two pads:

SC_P_USB_SS3_TC2_CONN_USB_OTG1_OC
SC_P_USB_SS3_TC3_CONN_USB_OTG2_OC

Is it possible to get the USB overcurrent status from Linux? How?

The Reference Manual does not talk about those signals. I have tried to dump all USB-related memory mapped registers in both level conditions (CONN_USB_OTGx_OC high and low). However, all the differences are on undocumented registers (eg. 0x5B1000B0).

(In our design those pads are connected to the fault output pin of a DCDC step-down converter).

Thank you
Francesco

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jamesbone
NXP TechSupport
NXP TechSupport

Hello you can do it by enabling and detecting the overcurrent interrupt and clear the PP bit in the PORTSC1 register.

Please find more information here:

- dtb/pad settings: pads-imx8qm.h\pinctrl\dt-bindings\include - linux-imx - i.MX Linux kernel .

- 8QM RM - pad/mux control for USB_SS3_TCX (starting with section 9.2.5.1.166)

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