Re: [PATCH 2/6] misc: sbrmi: Add platform device add to create platform device

[Gupta, Akshay]

On 7/4/2024 5:20 PM, Greg KH wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> On Thu, Jul 04, 2024 at 11:16:20AM +0000, Akshay Gupta wrote:
> > - AMD provides socket power information from out of band
> >    which can be read by sensors.
> > - platform driver will probe drivers/hwmon/sbrmi as a platform device
> >    and share the sbrmi device data.
> So you are "splitting" a real device into different ones using a
> platform device?  THat's not ok, and an abuse of the platform api.
> Please use the correct one for that instead.

is it ok to call API, devm_hwmon_device_register_with_info() from misc 
driver

which will require to defining the hwmon ops in here.

> > Signed-off-by: Akshay Gupta <akshay.gupta@xxxxxxx>
> > Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@xxxxxxx>
> > ---
> >   drivers/misc/amd-sb/sbrmi-i2c.c | 25 ++++++++++++++++++++++++-
> >   include/misc/amd-sb.h           |  2 ++
> >   2 files changed, 26 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/misc/amd-sb/sbrmi-i2c.c b/drivers/misc/amd-sb/sbrmi-i2c.c
> > index c4903d9e9f0f..b593bbdd78e0 100644
> > --- a/drivers/misc/amd-sb/sbrmi-i2c.c
> > +++ b/drivers/misc/amd-sb/sbrmi-i2c.c
> > @@ -72,7 +72,29 @@ static int sbrmi_i2c_probe(struct i2c_client *client)
> >                return ret;
> >
> >        /* Cache maximum power limit */
> > -     return sbrmi_get_max_pwr_limit(data);
> > +     ret = sbrmi_get_max_pwr_limit(data);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     dev_set_drvdata(dev, (void *)data);
> No need to cast, right?
Yes, will update.
> > +     data->pdev = platform_device_register_data(dev, "sbrmi-hwmon",
> > +                                                PLATFORM_DEVID_NONE,
> Yeah, that's not ok.  Please do this correctly, as this is NOT a
> platform device, but rather a made-up one that you just created out of
> no where.  Instead use the correct apis for that.
>
> > +                                                data,
> > +                                                sizeof(struct sbrmi_data));
> > +     if (IS_ERR(data->pdev)) {
> > +             pr_err("unable to register platform device for sbrmi-hwmon\n");
> > +             return PTR_ERR(data->pdev);
> You don't need to unwind anything else here?
Yes, not required.
> > +     }
> > +     return ret;
> > +}
> > +
> > +static void sbrmi_i2c_remove(struct i2c_client *client)
> > +{
> > +     struct sbrmi_data *data = dev_get_drvdata(&client->dev);
> > +
> > +     if (!data)
> > +             return;
> How can that happen?
Its just a safe check, once we remove platform driver this will not be 
required.
> greg k-h