139 lines
3.6 KiB
C
139 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* HID driver for Google Hammer device.
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*
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* Copyright (c) 2017 Google Inc.
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* Author: Wei-Ning Huang <wnhuang@google.com>
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*/
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/*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*/
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#include <linux/hid.h>
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#include <linux/leds.h>
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#include <linux/module.h>
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#include "hid-ids.h"
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#define MAX_BRIGHTNESS 100
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/* HID usage for keyboard backlight (Alphanumeric display brightness) */
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#define HID_AD_BRIGHTNESS 0x00140046
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struct hammer_kbd_leds {
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struct led_classdev cdev;
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struct hid_device *hdev;
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u8 buf[2] ____cacheline_aligned;
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};
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static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
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enum led_brightness br)
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{
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struct hammer_kbd_leds *led = container_of(cdev,
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struct hammer_kbd_leds,
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cdev);
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int ret;
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led->buf[0] = 0;
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led->buf[1] = br;
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/*
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* Request USB HID device to be in Full On mode, so that sending
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* hardware output report and hardware raw request won't fail.
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*/
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ret = hid_hw_power(led->hdev, PM_HINT_FULLON);
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if (ret < 0) {
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hid_err(led->hdev, "failed: device not resumed %d\n", ret);
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return ret;
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}
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ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
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if (ret == -ENOSYS)
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ret = hid_hw_raw_request(led->hdev, 0, led->buf,
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sizeof(led->buf),
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HID_OUTPUT_REPORT,
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HID_REQ_SET_REPORT);
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if (ret < 0)
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hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
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ret);
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/* Request USB HID device back to Normal Mode. */
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hid_hw_power(led->hdev, PM_HINT_NORMAL);
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return ret;
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}
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static int hammer_register_leds(struct hid_device *hdev)
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{
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struct hammer_kbd_leds *kbd_backlight;
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kbd_backlight = devm_kzalloc(&hdev->dev,
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sizeof(*kbd_backlight),
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GFP_KERNEL);
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if (!kbd_backlight)
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return -ENOMEM;
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kbd_backlight->hdev = hdev;
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kbd_backlight->cdev.name = "hammer::kbd_backlight";
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kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
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kbd_backlight->cdev.brightness_set_blocking =
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hammer_kbd_brightness_set_blocking;
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kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
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/* Set backlight to 0% initially. */
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hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
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return devm_led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
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}
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static int hammer_input_configured(struct hid_device *hdev,
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struct hid_input *hi)
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{
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struct list_head *report_list =
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&hdev->report_enum[HID_OUTPUT_REPORT].report_list;
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struct hid_report *report;
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if (list_empty(report_list))
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return 0;
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report = list_first_entry(report_list, struct hid_report, list);
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if (report->maxfield == 1 &&
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report->field[0]->application == HID_GD_KEYBOARD &&
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report->field[0]->maxusage == 1 &&
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report->field[0]->usage[0].hid == HID_AD_BRIGHTNESS) {
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int err = hammer_register_leds(hdev);
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if (err)
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hid_warn(hdev,
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"Failed to register keyboard backlight: %d\n",
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err);
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}
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return 0;
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}
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static const struct hid_device_id hammer_devices[] = {
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{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
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USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
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{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
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USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
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{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
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USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
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{ }
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};
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MODULE_DEVICE_TABLE(hid, hammer_devices);
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static struct hid_driver hammer_driver = {
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.name = "hammer",
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.id_table = hammer_devices,
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.input_configured = hammer_input_configured,
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};
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module_hid_driver(hammer_driver);
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MODULE_LICENSE("GPL");
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