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// 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");
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