| // 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"); |