usb: ulpi: defer ulpi_register on ulpi_read_id timeout

[ Upstream commit 8a7b31d545d3a15f0e6f5984ae16f0ca4fd76aac ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
index d7c8461..60e8174 100644 (file)
--- a/drivers/usb/common/ulpi.c
+++ b/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)