usb: dwc2: fix hang during suspend if set as peripheral

dwc2 on most platforms needs phy controller, clock and power supply.
All of them must be enabled/activated to properly operate. If dwc2
is configured as peripheral mode, then all the above three hardware
resources are disabled at the end of the probe:

	/* Gadget code manages lowlevel hw on its own */
	if (hsotg->dr_mode == USB_DR_MODE_PERIPHERAL)
		dwc2_lowlevel_hw_disable(hsotg);

But the dwc2_suspend() tries to read the dwc2's reg to check whether
is_device_mode or not, this would result in hang during suspend if dwc2
is configured as peripheral mode.

Fix this hang by bypassing suspend/resume if lowlevel hw isn't
enabled.

Fixes: 09a75e857790 ("usb: dwc2: refactor common low-level hw code to platform.c")
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://patch.msgid.link/20251104002503.17158-3-jszhang@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index b07bdf16326a40b82efd812ec084983ce30c2afd..ef0d7307703473ee0d17085fdfe361898c8aedcd 100644 (file)
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -649,9 +649,13 @@ error:
 static int __maybe_unused dwc2_suspend(struct device *dev)
 {
        struct dwc2_hsotg *dwc2 = dev_get_drvdata(dev);
-       bool is_device_mode = dwc2_is_device_mode(dwc2);
+       bool is_device_mode;
        int ret = 0;
 
+       if (!dwc2->ll_hw_enabled)
+               return 0;
+
+       is_device_mode = dwc2_is_device_mode(dwc2);
        if (is_device_mode)
                dwc2_hsotg_suspend(dwc2);
 
@@ -728,6 +732,9 @@ static int __maybe_unused dwc2_resume(struct device *dev)
        struct dwc2_hsotg *dwc2 = dev_get_drvdata(dev);
        int ret = 0;
 
+       if (!dwc2->ll_hw_enabled)
+               return 0;
+
        if (dwc2->phy_off_for_suspend && dwc2->ll_hw_enabled) {
                ret = __dwc2_lowlevel_hw_enable(dwc2);
                if (ret)