Re: [PATCH 13/13] HID: playstation: report DualSense hardware and firmware version.

[Roderick Colenbrander <roderick@gaikai.com>]

Hi Barnabás,

Thanks for you great feedback.

On Sun, Dec 27, 2020 at 9:06 AM Barnabás Pőcze <pobrn@protonmail.com> wrote:
>
> Hi
>
>
> 2020. december 19., szombat 7:23 keltezéssel, Roderick Colenbrander írta:
>
> > diff --git a/drivers/hid/hid-playstation.c b/drivers/hid/hid-playstation.c
> > index a55375ac79a9..2f989da906f3 100644
> > --- a/drivers/hid/hid-playstation.c
> > +++ b/drivers/hid/hid-playstation.c
> > [...]
> > +static ssize_t ps_show_firmware_version(struct device *dev,
> > +                             struct device_attribute
> > +                             *attr, char *buf)
> > +{
> > +     struct hid_device *hdev = to_hid_device(dev);
> > +     struct ps_device *ps_dev = hid_get_drvdata(hdev);
> > +
> > +     return snprintf(buf, PAGE_SIZE, "0x%08x\n", ps_dev->fw_version);
>
> `sysfs_emit()` is preferred over *printf().

Thanks, I wasn't aware of its existence. Looks like it was added
recently, but yeah it is a lot nicer.

>
> > +}
> > +
> > +static DEVICE_ATTR(firmware_version, 0444, ps_show_firmware_version, NULL);
> > +
> > +static ssize_t ps_show_hardware_version(struct device *dev,
> > +                             struct device_attribute
> > +                             *attr, char *buf)
> > +{
> > +     struct hid_device *hdev = to_hid_device(dev);
> > +     struct ps_device *ps_dev = hid_get_drvdata(hdev);
> > +
> > +     return snprintf(buf, PAGE_SIZE, "0x%08x\n", ps_dev->hw_version);
>
> Same here.
>
>
> > +}
> > [...]
> > +static int dualsense_get_firmware_info(struct dualsense *ds)
> > +{
> > +     uint8_t *buf;
> > +     int ret = 0;
>
> Is there any reason it needs to be initialized?
>
>
> > +
> > +     buf = kzalloc(DS_FEATURE_REPORT_FIRMWARE_INFO_SIZE, GFP_KERNEL);
> > +     if (!buf)
> > +             return -ENOMEM;
> > +
> > +     ret = hid_hw_raw_request(ds->base.hdev, DS_FEATURE_REPORT_FIRMWARE_INFO, buf,
> > +                     DS_FEATURE_REPORT_FIRMWARE_INFO_SIZE, HID_FEATURE_REPORT,
> > +                     HID_REQ_GET_REPORT);
> > +     if (ret < 0)
> > +             goto err_free;
> > +
> > +     ds->base.hw_version = get_unaligned_le32(&buf[24]);
> > +     ds->base.fw_version = get_unaligned_le32(&buf[28]);
>
> Shouldn't the size of the reply be checked?

Good point, I added a check and returning -EINVAL now in case of a
size mismatch.

>
> > +
> > +err_free:
> > +     kfree(buf);
> > +     return ret;
> > +}
> > +
> >  static int dualsense_get_mac_address(struct dualsense *ds)
> >  {
> >       uint8_t *buf;
> > @@ -1172,6 +1233,12 @@ static struct ps_device *dualsense_create(struct hid_device *hdev)
> >       }
> >       snprintf(hdev->uniq, sizeof(hdev->uniq), "%pMR", ds->base.mac_address);
> >
> > +     ret = dualsense_get_firmware_info(ds);
> > +     if (ret < 0) {
> > +             hid_err(hdev, "Failed to get firmware info from DualSense\n");
> > +             return ERR_PTR(ret);
> > +     }
> > +
> >       ret = ps_devices_list_add((struct ps_device *)ds);
> >       if (ret < 0)
> >               return ERR_PTR(ret);
> > @@ -1241,6 +1308,12 @@ static struct ps_device *dualsense_create(struct hid_device *hdev)
> >       /* Set player LEDs to our player id. */
> >       dualsense_set_player_leds(ds);
> >
> > +     /* Reporting hardware and firmware is important as there are frequent updates, which
> > +      * can change behavior.
> > +      */
> > +     hid_info(hdev, "Registered DualSense controller hw_version=%x fw_version=%x\n",
> > +                     ds->base.hw_version, ds->base.fw_version);
> > +
> >       return (struct ps_device *)ds;
> >
> >  err:
> > @@ -1295,6 +1368,12 @@ static int ps_probe(struct hid_device *hdev, const struct hid_device_id *id)
> >               goto err_close;
> >       }
> >
> > +     ret = sysfs_create_group(&hdev->dev.kobj, &ps_device_attribute_group);
>
> It's a minor thing, but I think `device_{add,remove}_group()` would be better
> here in the sense that it expresses the fact that the group is added to a device,
> not just any object better.

Agreed, that's nicer I wasn't aware of it. I try to follow what other
hid drivers do and they all used the kobj directly, which honestly
felt nasty. Will change it to this.

>
> > +     if (ret < 0) {
> > +             hid_err(hdev, "Failed to register sysfs nodes.\n");
> > +             goto err_close;
> > +     }
> > +
> >       return ret;
> >
> >  err_close:
> > @@ -1313,6 +1392,8 @@ static void ps_remove(struct hid_device *hdev)
> >
> >       hid_hw_close(hdev);
> >       hid_hw_stop(hdev);
> > +
> > +     sysfs_remove_group(&hdev->dev.kobj, &ps_device_attribute_group);
> >  }
> >
> >  static const struct hid_device_id ps_devices[] = {
> > --
> > 2.26.2
>
>
> Regards,
> Barnabás Pőcze

Thanks,
Roderick