2022-11-10 21:26:51

by Ferry Toth

Subject: [PATCH v2 0/2] usb: dwc3: core: defer probe on ulpi_read_id timeout

v2:
- Split into separate commits (Thinh)
- One defer probe on -ETIMEDOUT (Thinh)
- Loose curly brackets (Heikki)

Ferry Toth (2):
usb: ulpi: defer ulpi_register on ulpi_read_id timeout
usb: dwc3: core: defer probe on ulpi_read_id timeout

drivers/usb/common/ulpi.c | 2 +-
drivers/usb/dwc3/core.c | 7 ++++++-
2 files changed, 7 insertions(+), 2 deletions(-)

--
2.34.1

2022-11-10 21:27:49

by Ferry Toth

Subject: [PATCH v2 2/2] usb: dwc3: core: defer probe on ulpi_read_id timeout

Since commit 0f010171
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() masking the timeout on the first
test write. In the past dwc3 probe continued by calling dwc3_core_soft_reset()
followed by dwc3_get_extcon() which happend to return -EPROBE_DEFER.
On deferred probe ulpi_read_id() finally succeeded.

As we now changed ulpi_read_id() to return -ETIMEDOUT in this case, we
need to handle the error by calling dwc3_core_soft_reset() and request
-EPROBE_DEFER. On deferred probe ulpi_read_id() is retried and succeeds.

Signed-off-by: Ferry Toth <[email protected]>
---
drivers/usb/dwc3/core.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 648f1c570021..2779f17bffaf 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1106,8 +1106,13 @@ static int dwc3_core_init(struct dwc3 *dwc)

if (!dwc->ulpi_ready) {
ret = dwc3_core_ulpi_init(dwc);
- if (ret)
+ if (ret) {
+ if (ret == -ETIMEDOUT) {
+ dwc3_core_soft_reset(dwc);
+ ret = -EPROBE_DEFER;
+ }
goto err0;
+ }
dwc->ulpi_ready = true;
}

--
2.34.1