Re: [PATCH 07/13] scpi: ignore init_versions failure if reported not supported

[Sudeep Holla]

On 23/08/16 09:23, Neil Armstrong wrote:
> On 08/19/2016 06:46 PM, Sudeep Holla wrote:
> > On 18/08/16 11:11, Neil Armstrong wrote:
> > > In Amlogic GXBB Legacy SCPI, the LEGACY_SCPI_CMD_SCPI_CAPABILITIES report
> > > as SCPI_ERR_SUPPORT, so do not fail if this command is not supported.
> > >
> > > Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> > > ---
> > >  drivers/firmware/arm_scpi.c | 12 +++++++-----
> > >  1 file changed, 7 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c
> > > index 3fe39fe..d3be4c5 100644
> > > --- a/drivers/firmware/arm_scpi.c
> > > +++ b/drivers/firmware/arm_scpi.c
> > > @@ -1111,12 +1111,13 @@ err:
> > >          ret = scpi_info->ops->init_versions(scpi_info);
> > >      else
> > >      ret = scpi_init_versions(scpi_info);
> > > -    if (ret) {
> > > +    if (ret && ret != -EOPNOTSUPP) {
> > >          dev_err(dev, "incorrect or no SCP firmware found\n");
> > >          scpi_remove(pdev);
> > >          return ret;
> > >      }
> >
> > Why not deal it in init_versions itself.
> >
> > > +    if (ret != -EOPNOTSUPP) {
> > >      _dev_info(dev, "SCP Protocol %d.%d Firmware %d.%d.%d version\n",
> > >            PROTOCOL_REV_MAJOR(scpi_info->protocol_version),
> > >            PROTOCOL_REV_MINOR(scpi_info->protocol_version),
> >
> > Why not have default value like 0.0 ? Just add a comment. Since get
> > version is exported out, IMO having default value makes more sense. What
> > do you think ?
> >
> > > @@ -1124,15 +1125,16 @@ err:
> > >            FW_REV_MINOR(scpi_info->firmware_version),
> > >            FW_REV_PATCH(scpi_info->firmware_version));
> > >
> > > +        ret = sysfs_create_groups(&dev->kobj, versions_groups);
> > > +        if (ret)
> > > +            dev_err(dev, "unable to create sysfs version group\n");
> > > +    }
> > > +
> >
> > Again this can stay as is if we have default.
>
> Printing version 0.0 firmware 0.0.0 is a nonsense for me...

OK 0.0 was a wrong example. May be 0.1 ?

Since the driver has already exposed, hypothetically user-space can use
that information, so IMO, we need to expose some static version for pre-v1.0

I am surprised that capability is not supported as this was present even
in that legacy SCPI. Do you know what happens if you send that command ?
Have you done some experiments on that ?

--
Regards,
Sudeep