Re: [PATCH 22/24] usb: dwc3: generic-plat: Add ZTE ZX279128S

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] usb: dwc3: generic driver unconditionally disables suspend clock, breaking wakeup
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commit 6d824e4ed683e8447bfbbcb4a2e9d9fcfd05236b
Author: Navid Ghahremani <ghahramani.navid@gmail.com>

usb: dwc3: generic-plat: Add ZTE ZX279128S

Adds ZTE ZX279128S platform support to the generic DWC3 platform
driver to handle clocks and resets.

[ ... ]

> diff --git a/drivers/usb/dwc3/dwc3-generic-plat.c b/drivers/usb/dwc3/dwc3-generic-plat.c
> index ca69ac0eb07ce..aa838cf0676f2 100644
> --- a/drivers/usb/dwc3/dwc3-generic-plat.c
> +++ b/drivers/usb/dwc3/dwc3-generic-plat.c
> @@ -237,6 +237,7 @@ static const struct of_device_id dwc3_generic_of_match[] = {
>  	{ .compatible = "fsl,ls1028a-dwc3", &fsl_ls1028_dwc3},
>  	{ .compatible = "eswin,eic7700-dwc3", &eic7700_dwc3},
>  	{ .compatible = "starfive,jhb100-dwc3", },
> +	{ .compatible = "zte,zx279128s-dwc3", },

[Severity: Medium]
Will using the generic DWC3 platform driver break USB suspend and wakeup
functionality for this new ZTE platform?

The ZTE device tree defines a suspend clock alongside the regular clocks,
which get acquired in the bulk request during probe.

The generic platform driver sets probe_data.ignore_clocks_and_resets = true
in dwc3_generic_probe():

drivers/usb/dwc3/dwc3-generic-plat.c:dwc3_generic_probe() {
    ...
    probe_data.ignore_clocks_and_resets = true;
    ...
}

This bypasses the DWC3 core's own clock management and suspend clock scaling.
Then, when the system suspends, dwc3_generic_suspend() unconditionally
disables all acquired clocks:

drivers/usb/dwc3/dwc3-generic-plat.c:dwc3_generic_suspend() {
    ...
    clk_bulk_disable_unprepare(dwc3g->num_clocks, dwc3g->clks);
    ...
}

Since the suspend clock is disabled here, won't this power off the suspend
clock during system sleep and prevent wakeup?

>  	{ /* sentinel */ }
>  };
>  MODULE_DEVICE_TABLE(of, dwc3_generic_of_match);

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Sashiko AI review · https://sashiko.dev/#/patchset/20261010130024.177503-1-ghahramani.navid@gmail.com?part=22