Re: [PATCH 09/13] HID: playstation: add DualSense lightbar support

[Roderick Colenbrander <roderick@gaikai.com>]

Hi Barnabás,

Thanks for your review.

On Sun, Dec 27, 2020 at 6:41 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 0b62bcb28d8a..f8cf82a27d43 100644
> > [...]
> > +/* Create a DualSense/DualShock4 RGB lightbar represented by a multicolor LED. */
> > +static struct led_classdev_mc *ps_lightbar_create(struct ps_device *ps_dev,
> > +     int (*brightness_set)(struct led_classdev *, enum led_brightness))
> > +{
> > +     struct hid_device *hdev = ps_dev->hdev;
> > +     struct led_classdev_mc *lightbar_mc_dev;
> > +     struct mc_subled *mc_led_info;
> > +     struct led_classdev *led_cdev;
> > +     int ret;
> > +
> > +     lightbar_mc_dev = devm_kzalloc(&hdev->dev, sizeof(*lightbar_mc_dev), GFP_KERNEL);
> > +     if (!lightbar_mc_dev)
> > +             return ERR_PTR(-ENOMEM);
> > +
> > +     mc_led_info = devm_kzalloc(&hdev->dev, 3*sizeof(*mc_led_info), GFP_KERNEL);
> > +     if (!mc_led_info)
> > +             return ERR_PTR(-ENOMEM);
> > +
>
> Is there any reason why these are dynamically allocated?

No particular reason. I should probably at least not dynamically
allocate 'mc_dev' and pass it in similar to regular LED registration
(previously I had my regular LEDs dynamically allocated). The
mc_led_info I will probably keep dynamic. It feels a bit nasty to have
the caller be aware of these internal details.

>
>
> > +     mc_led_info[0].color_index = LED_COLOR_ID_RED;
> > +     mc_led_info[0].channel = 0;
> > +     mc_led_info[1].color_index = LED_COLOR_ID_GREEN;
> > +     mc_led_info[1].channel = 1;
> > +     mc_led_info[2].color_index = LED_COLOR_ID_BLUE;
> > +     mc_led_info[2].channel = 2;
> > +
> > +     lightbar_mc_dev->subled_info = mc_led_info;
> > +     lightbar_mc_dev->num_colors = 3;
> > +
> > +     led_cdev = &lightbar_mc_dev->led_cdev;
> > +     led_cdev->name = devm_kasprintf(&hdev->dev, GFP_KERNEL, "playstation::%pMR::rgb",
> > +                     ps_dev->mac_address);
>
> I guess the double colons are used because the MAC address has ':' in it; but
> as far as I know this doesn't follow the naming scheme for LED devices, so I'm
> not sure if this is the best way to go about it.

Actually it was Benjamin who suggested this type of naming. He wasn't
a fan of the previous hid-sony device naming (neither was I). This was
the main idea so far.

>
> > +     led_cdev->brightness = 255;
> > +     led_cdev->max_brightness = 255;
> > +     led_cdev->brightness_set_blocking = brightness_set;
> > +
> > +     ret = devm_led_classdev_multicolor_register(&hdev->dev, lightbar_mc_dev);
> > +     if (ret < 0) {
> > +             hid_err(hdev, "Cannot register multicolor LED device\n");
> > +             return ERR_PTR(ret);
> > +     }
> > +
> > +     return lightbar_mc_dev;
> > +}
> > [...]
> > +static int dualsense_reset_leds(struct dualsense *ds)
> > +{
> > +     struct dualsense_output_report report;
> > +     uint8_t *buf;
> > +
> > +     buf = kzalloc(sizeof(struct dualsense_output_report_bt), GFP_KERNEL);
> > +     if (!buf)
> > +             return -ENOMEM;
> > +
> > +     dualsense_init_output_report(ds, &report, buf);
> > +     /* On Bluetooth the DualSense outputs an animation on the lightbar
> > +      * during startup and maintains a color afterwards. We need to explicitly
> > +      * reconfigure the lightbar before we can do any programming later on.
> > +      * In USB the lightbar is not on by default, but redoing the setup there
> > +      * doesn't hurt.
> > +      */
> > +     report.common->valid_flag2 = DS_OUTPUT_VALID_FLAG2_LIGHTBAR_SETUP_CONTROL_ENABLE;
> > +     report.common->lightbar_setup = 2; /* Fade light out. */
>
> Maybe it'd be better to name that '2'?

Will document this one.

>
>
> > +     dualsense_send_output_report(ds, &report);
> > +
> > +     kfree(buf);
> > +     return 0;
> > +}
> > [...]
>
>
> Regards,
> Barnabás Pőcze

Thanks,
Roderick