Hi,
I have been updating my Intel Baytrail tablet from 4.14 to 4.19 and
noticed that the tusb1210 PHY driver now fails to probe on 4.19.x and
4.20-rc4:
tusb1210: probe of dwc3.0.auto.ulpi failed with error -16 (EBUSY)
The commit that broke this is 211f658b7b40 ("usb: dwc3: pci: Use devm
functions to get the phy GPIOs") because it now claims the phy GPIOs
permanently so the PHY driver (here: tusb1210) cannot get them.
Gadget mode still works with this error and even completely without the
tusb1210 driver, but I have been using the PHY driver additionally
because it has the advantage that it will also power off the PHY during
suspend. (Plus I have some custom hacky code for charger detection in
it at the moment, but I did not have it applied for testing this
problem..)
The comment that still exists above the changed code also mentions why
the GPIO descriptors were put immediately after use:
/*
* These GPIOs will turn on the USB2 PHY. Note that we have to
* put the gpio descriptors again here because the phy driver
* might want to grab them, too.
*/
Reverting the commit makes everything work again for me. Does this
change fix a problem on another device or was it mostly just cleanup?
I wanted to suggest that turning on the PHY may not actually be
necessary in dwc3-pci since the tusb1210 driver has the same code in its
probe() method. However, when I tested it it did not work at all because
the tusb1210 driver is not even loaded if the PHY is not turned on
before dwc3 is loaded...
(The ULPI vendor/product ID is wrong with the PHY turned off)
Additional note: The probe error above happens only if:
- The tablet has a TUSB1210/TUSB1211 external PHY (not sure if this is
the case for all Baytrail tablets..)
- CONFIG_USB_DWC3_ULPI and CONFIG_PHY_TUSB1210 are enabled
- GPIOs are defined in the ACPI DSDT table (Unlike the ACPI GPIOs, the
fallback GPIO mappings are not inherited to the ULPI device..)
I am also open for any other suggestions. :)
Thanks,
Stephan
