diff options
Diffstat (limited to 'drivers/hid/hid-google-hammer.c')
| -rw-r--r-- | drivers/hid/hid-google-hammer.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/drivers/hid/hid-google-hammer.c b/drivers/hid/hid-google-hammer.c new file mode 100644 index 000000000000..7b8e17b03cb8 --- /dev/null +++ b/drivers/hid/hid-google-hammer.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * HID driver for Google Hammer device. + * + * Copyright (c) 2017 Google Inc. + * Author: Wei-Ning Huang <wnhuang@google.com> + */ + +/* + * 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 "hid-ids.h" + +#define MAX_BRIGHTNESS 100 + +/* HID usage for keyboard backlight (Alphanumeric display brightness) */ +#define HID_AD_BRIGHTNESS 0x00140046 + +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; + + /* + * Request USB HID device to be in Full On mode, so that sending + * hardware output report and hardware raw request won't fail. + */ + ret = hid_hw_power(led->hdev, PM_HINT_FULLON); + if (ret < 0) { + hid_err(led->hdev, "failed: device not resumed %d\n", ret); + return ret; + } + + 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); + + /* Request USB HID device back to Normal Mode. */ + hid_hw_power(led->hdev, PM_HINT_NORMAL); + + 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 list_head *report_list = + &hdev->report_enum[HID_OUTPUT_REPORT].report_list; + struct hid_report *report; + + if (list_empty(report_list)) + return 0; + + report = list_first_entry(report_list, struct hid_report, list); + + if (report->maxfield == 1 && + report->field[0]->application == HID_GD_KEYBOARD && + report->field[0]->maxusage == 1 && + report->field[0]->usage[0].hid == HID_AD_BRIGHTNESS) { + 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_DEVICE(BUS_USB, HID_GROUP_GENERIC, + USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) }, + { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, + USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) }, + { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, + USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) }, + { } +}; +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"); |