[PATCH 5.15 13/17] usb: ulpi: defer ulpi_register on ulpi_read_id timeout

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Ferry Toth <ftoth@exalondelft.nl>

commit 8a7b31d545d3a15f0e6f5984ae16f0ca4fd76aac upstream.

Since commit 0f0101719138 ("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: ef6a7bcfb01c ("usb: ulpi: Support device discovery via DT")
Cc: stable@vger.kernel.org
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Ferry Toth <ftoth@exalondelft.nl>
Link: https://lore.kernel.org/r/20221205201527.13525-2-ftoth@exalondelft.nl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/common/ulpi.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/common/ulpi.c
+++ b/drivers/usb/common/ulpi.c
@@ -206,7 +206,7 @@ static int ulpi_read_id(struct ulpi *ulp
 	/* 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)