usb: ulpi: defer ulpi_register on ulpi_read_id timeout

Since commit 0f01017191 ("usb: dwc3: Don't switch OTG -> peripheral
if extcon is present") Dual Role support on Intel Merrifield platform
broke due to rearranging the call to dwc3_get_extcon().

It appears to be caused by ulpi_read_id() on the first test write failing
with -ETIMEDOUT. Currently ulpi_read_id() expects to discover the phy via
DT when the test write fails and returns 0 in that case, even if DT does not
provide the phy. As a result usb probe completes without phy.

Make ulpi_read_id() return -ETIMEDOUT to its user if the first test write
fails. The user should then handle it appropriately. A follow up patch
will make dwc3_core_init() set -EPROBE_DEFER in this case and bail out.

Fixes: ef6a7bcfb0 ("usb: ulpi: Support device discovery via DT")
Cc: [email protected]
Acked-by: Heikki Krogerus <[email protected]>
Signed-off-by: Ferry Toth <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/usb/common/ulpi.c

@@ -207,7 +207,7 @@ static int ulpi_read_id(struct ulpi *ulpi)
 	/* Test the interface */
 	ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa);
 	if (ret < 0)
-		goto err;
+		return ret;
 
 	ret = ulpi_read(ulpi, ULPI_SCRATCH);
 	if (ret < 0)