Re: [PATCH v2] HID: google: add google hammer HID driver

[Dmitry Torokhov]

On Thu, Aug 17, 2017 at 1:45 AM, Wei-Ning Huang <wnhuang@xxxxxxxxxxxx> wrote:
> Add Google hammer HID driver. This driver allow us to control hammer
> keyboard backlights and support future features.
>
> Signed-off-by: Wei-Ning Huang <wnhuang@xxxxxxxxxx>

I was helping Wei-Ning internally with this, so

Reviewed-by: Dmitry Torokhov <dtor@xxxxxxxxxx>

You might need to resend to directly to Jiri who is HID maintainer.

> ---
>  drivers/hid/Kconfig             |   6 +++
>  drivers/hid/Makefile            |   1 +
>  drivers/hid/hid-core.c          |   4 ++
>  drivers/hid/hid-google-hammer.c | 108 ++++++++++++++++++++++++++++++++++++++++
>  drivers/hid/hid-ids.h           |   3 ++
>  5 files changed, 122 insertions(+)
>  create mode 100644 drivers/hid/hid-google-hammer.c
>
> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> index 3cd60f460b61..efc71acbcf5b 100644
> --- a/drivers/hid/Kconfig
> +++ b/drivers/hid/Kconfig
> @@ -329,6 +329,12 @@ config HOLTEK_FF
>           Say Y here if you have a Holtek On Line Grip based game controller
>           and want to have force feedback support for it.
>
> +config HID_GOOGLE_HAMMER
> +       tristate "Google Hammer Keyboard"
> +       depends on USB_HID && LEDS_CLASS
> +       ---help---
> +       Say Y here if you have a Google Hammer device.
> +
>  config HID_GT683R
>         tristate "MSI GT68xR LED support"
>         depends on LEDS_CLASS && USB_HID
> diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
> index 8659d7e633a5..b5d3039286e3 100644
> --- a/drivers/hid/Makefile
> +++ b/drivers/hid/Makefile
> @@ -43,6 +43,7 @@ obj-$(CONFIG_HID_ELO)         += hid-elo.o
>  obj-$(CONFIG_HID_EZKEY)                += hid-ezkey.o
>  obj-$(CONFIG_HID_GEMBIRD)      += hid-gembird.o
>  obj-$(CONFIG_HID_GFRM)         += hid-gfrm.o
> +obj-$(CONFIG_HID_GOOGLE_HAMMER)        += hid-google-hammer.o
>  obj-$(CONFIG_HID_GT683R)       += hid-gt683r.o
>  obj-$(CONFIG_HID_GYRATION)     += hid-gyration.o
>  obj-$(CONFIG_HID_HOLTEK)       += hid-holtek-kbd.o
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 9017dcc14502..813e3d86e2d0 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -2049,6 +2049,10 @@ static const struct hid_device_id hid_have_special_driver[] = {
>          { HID_BLUETOOTH_DEVICE(0x58, 0x2000) },
>          { HID_BLUETOOTH_DEVICE(0x471, 0x2210) },
>  #endif
> +#if IS_ENABLED(CONFIG_HID_GOOGLE_HAMMER)
> +       { HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
> +       { HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
> +#endif
>  #if IS_ENABLED(CONFIG_HID_GREENASIA)
>         { HID_USB_DEVICE(USB_VENDOR_ID_GREENASIA, 0x0012) },
>  #endif
> diff --git a/drivers/hid/hid-google-hammer.c b/drivers/hid/hid-google-hammer.c
> new file mode 100644
> index 000000000000..b6955f01c656
> --- /dev/null
> +++ b/drivers/hid/hid-google-hammer.c
> @@ -0,0 +1,108 @@
> +/*
> + *  HID driver for Google Hammer device.
> + *
> + *  Copyright (c) 2017 Google Inc.
> + *  Author: Wei-Ning Huang <wnhuang@xxxxxxxxxx>
> + */
> +
> +/*
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the Free
> + * Software Foundation; either version 2 of the License, or (at your option)
> + * any later version.
> + */
> +
> +#include <linux/hid.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/usb.h>
> +
> +#include "hid-ids.h"
> +
> +#define MAX_BRIGHTNESS 100
> +
> +struct hammer_kbd_leds {
> +       struct led_classdev cdev;
> +       struct hid_device *hdev;
> +       u8 buf[2] ____cacheline_aligned;
> +};
> +
> +static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
> +               enum led_brightness br)
> +{
> +       struct hammer_kbd_leds *led = container_of(cdev,
> +                                                  struct hammer_kbd_leds,
> +                                                  cdev);
> +       int ret;
> +
> +       led->buf[0] = 0;
> +       led->buf[1] = br;
> +
> +       ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
> +       if (ret == -ENOSYS)
> +               ret = hid_hw_raw_request(led->hdev, 0, led->buf,
> +                                        sizeof(led->buf),
> +                                        HID_OUTPUT_REPORT,
> +                                        HID_REQ_SET_REPORT);
> +       if (ret < 0)
> +               hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
> +                       ret);
> +       return ret;
> +}
> +
> +static int hammer_register_leds(struct hid_device *hdev)
> +{
> +       struct hammer_kbd_leds *kbd_backlight;
> +
> +       kbd_backlight = devm_kzalloc(&hdev->dev,
> +                                    sizeof(*kbd_backlight),
> +                                    GFP_KERNEL);
> +       if (!kbd_backlight)
> +               return -ENOMEM;
> +
> +       kbd_backlight->hdev = hdev;
> +       kbd_backlight->cdev.name = "hammer::kbd_backlight";
> +       kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
> +       kbd_backlight->cdev.brightness_set_blocking =
> +               hammer_kbd_brightness_set_blocking;
> +       kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
> +
> +       /* Set backlight to 0% initially. */
> +       hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
> +
> +       return devm_led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
> +}
> +
> +static int hammer_input_configured(struct hid_device *hdev,
> +                                  struct hid_input *hi)
> +{
> +       struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
> +
> +       if (intf->cur_altsetting->desc.bInterfaceProtocol ==
> +           USB_INTERFACE_PROTOCOL_KEYBOARD) {
> +               int err = hammer_register_leds(hdev);
> +
> +               if (err)
> +                       hid_warn(hdev,
> +                                "Failed to register keyboard backlight: %d\n",
> +                                err);
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct hid_device_id hammer_devices[] = {
> +       { HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
> +       { HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
> +       { }
> +};
> +MODULE_DEVICE_TABLE(hid, hammer_devices);
> +
> +static struct hid_driver hammer_driver = {
> +       .name = "hammer",
> +       .id_table = hammer_devices,
> +       .input_configured = hammer_input_configured,
> +};
> +module_hid_driver(hammer_driver);
> +
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
> index c9ba4c6db74c..193959700df8 100644
> --- a/drivers/hid/hid-ids.h
> +++ b/drivers/hid/hid-ids.h
> @@ -434,7 +434,10 @@
>  #define USB_DEVICE_ID_GOODTOUCH_000f   0x000f
>
>  #define USB_VENDOR_ID_GOOGLE           0x18d1
> +#define USB_DEVICE_ID_GOOGLE_QUICKSTEP 0x0477
> +#define USB_DEVICE_ID_GOOGLE_HAMMER    0x5022
>  #define USB_DEVICE_ID_GOOGLE_TOUCH_ROSE        0x5028
> +#define USB_DEVICE_ID_GOOGLE_STAFF     0x502b
>
>  #define USB_VENDOR_ID_GOTOP            0x08f2
>  #define USB_DEVICE_ID_SUPER_Q2         0x007f
> --
> 2.12.2
>