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

Message ID 20221110211132.297512-1-ftoth@exalondelft.nl
Headers show
Series usb: dwc3: core: defer probe on ulpi_read_id timeout | expand

Message

Ferry Toth Nov. 10, 2022, 9:11 p.m. UTC 
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(-)

Comments

Ferry Toth Nov. 11, 2022, 2:04 p.m. UTC | #1 
+ Stephen Boyd

On 10-11-2022 22:11, Ferry Toth wrote:
> 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() 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.
> 
> Signed-off-by: Ferry Toth <ftoth@exalondelft.nl>
> ---
>   drivers/usb/common/ulpi.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
> index d7c8461976ce..60e8174686a1 100644
> --- 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)

Would this affect others phys (like qcom HSIC)? I'm not sure if failing 
the test write is a normal behavior.
Stephen Boyd Dec. 12, 2022, 9:51 p.m. UTC | #2 
Quoting Ferry Toth (2022-11-11 06:04:16)
> + Stephen Boyd
> 
> On 10-11-2022 22:11, Ferry Toth wrote:
> > 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() 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.
> > 
> > Signed-off-by: Ferry Toth <ftoth@exalondelft.nl>
> > ---
> >   drivers/usb/common/ulpi.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
> > index d7c8461976ce..60e8174686a1 100644
> > --- 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)
> 
> Would this affect others phys (like qcom HSIC)? I'm not sure if failing 
> the test write is a normal behavior.

I don't think failing a test write is normal behavior. I don't have this
hardware on hand anymore though, so I can't help test it. Looks OK to me
though:

Reviewed-by: Stephen Boyd <sboyd@kernel.org>