i.MX8MP power down USB interface from U-Boot

gunnarsson — Thu, 15 Feb 2024 15:36:53 GMT

We would like to be able to put our into suspend from command in u-boot like

void cb_suspend(void)

{

}

int do_suspend(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])

{

do_psci_probe();

disable_interrupts();

/* Put code here to power down devices. */

/* No need to store the states of devices and drivers */

invoke_psci_fn(PSCI_1_0_FN_SYSTEM_, cb_suspend, 0, 0);

return CMD_RET_FAILURE;

}

U_BOOT_CMD(

Suspend, 1 ,0, do_suspend,

“Perform suspend of the device”

“”

);

The code above puts the CPU in suspend but we are not able to shutdown devices, such as the USB interfaces, as described in comments above.

Is it possible to receive a code example that shuts down devices in the correct order? Or is there an application note that describes how the Clock Control Module (CCM), General Power Controller (GPC), System Reset Controller (SRC) is supposed be interfaces. Any such documentation would be greatly appreciated.

We are aware Linux support this functionality but it can unfortunately not be used and extract relevant code from Linux implementation is a bit complicated.

Re: i.MX8MP power down USB interface from U-Boot

AldoG — Mon, 19 Feb 2024 19:12:40 GMT

Hello,

You may refer to the uboot documentation for this:

https://github.com/nxp-imx/uboot-imx/blob/lf_v2022.04/doc/imx/clk/ccf.txt

Also, as I think this some kind of low power application you want to achieve, you may refer to the following AN:

https://www.nxp.com/docs/en/application-note/AN13400.pdf

Best regards/Saludos,
Aldo.

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i.MX8MP power down USB interface from U-Boot

Re: i.MX8MP power down USB interface from U-Boot