1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * HID driver for Google Hammer device.
4 *
5 * Copyright (c) 2017 Google Inc.
6 * Author: Wei-Ning Huang <wnhuang@google.com>
7 */
8
9 /*
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 */
15
16 #include <linux/hid.h>
17 #include <linux/leds.h>
18 #include <linux/module.h>
19
20 #include "hid-ids.h"
21
22 #define MAX_BRIGHTNESS 100
23
24 /* HID usage for keyboard backlight (Alphanumeric display brightness) */
25 #define HID_AD_BRIGHTNESS 0x00140046
26
27 struct hammer_kbd_leds {
28 struct led_classdev cdev;
29 struct hid_device *hdev;
30 u8 buf[2] ____cacheline_aligned;
31 };
32
hammer_kbd_brightness_set_blocking(struct led_classdev * cdev,enum led_brightness br)33 static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
34 enum led_brightness br)
35 {
36 struct hammer_kbd_leds *led = container_of(cdev,
37 struct hammer_kbd_leds,
38 cdev);
39 int ret;
40
41 led->buf[0] = 0;
42 led->buf[1] = br;
43
44 /*
45 * Request USB HID device to be in Full On mode, so that sending
46 * hardware output report and hardware raw request won't fail.
47 */
48 ret = hid_hw_power(led->hdev, PM_HINT_FULLON);
49 if (ret < 0) {
50 hid_err(led->hdev, "failed: device not resumed %d\n", ret);
51 return ret;
52 }
53
54 ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
55 if (ret == -ENOSYS)
56 ret = hid_hw_raw_request(led->hdev, 0, led->buf,
57 sizeof(led->buf),
58 HID_OUTPUT_REPORT,
59 HID_REQ_SET_REPORT);
60 if (ret < 0)
61 hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
62 ret);
63
64 /* Request USB HID device back to Normal Mode. */
65 hid_hw_power(led->hdev, PM_HINT_NORMAL);
66
67 return ret;
68 }
69
hammer_register_leds(struct hid_device * hdev)70 static int hammer_register_leds(struct hid_device *hdev)
71 {
72 struct hammer_kbd_leds *kbd_backlight;
73
74 kbd_backlight = devm_kzalloc(&hdev->dev,
75 sizeof(*kbd_backlight),
76 GFP_KERNEL);
77 if (!kbd_backlight)
78 return -ENOMEM;
79
80 kbd_backlight->hdev = hdev;
81 kbd_backlight->cdev.name = "hammer::kbd_backlight";
82 kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
83 kbd_backlight->cdev.brightness_set_blocking =
84 hammer_kbd_brightness_set_blocking;
85 kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
86
87 /* Set backlight to 0% initially. */
88 hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
89
90 return devm_led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
91 }
92
hammer_input_configured(struct hid_device * hdev,struct hid_input * hi)93 static int hammer_input_configured(struct hid_device *hdev,
94 struct hid_input *hi)
95 {
96 struct list_head *report_list =
97 &hdev->report_enum[HID_OUTPUT_REPORT].report_list;
98 struct hid_report *report;
99
100 if (list_empty(report_list))
101 return 0;
102
103 report = list_first_entry(report_list, struct hid_report, list);
104
105 if (report->maxfield == 1 &&
106 report->field[0]->application == HID_GD_KEYBOARD &&
107 report->field[0]->maxusage == 1 &&
108 report->field[0]->usage[0].hid == HID_AD_BRIGHTNESS) {
109 int err = hammer_register_leds(hdev);
110
111 if (err)
112 hid_warn(hdev,
113 "Failed to register keyboard backlight: %d\n",
114 err);
115 }
116
117 return 0;
118 }
119
120 static const struct hid_device_id hammer_devices[] = {
121 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
122 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_DON) },
123 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
124 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_EEL) },
125 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
126 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
127 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
128 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_JEWEL) },
129 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
130 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MAGNEMITE) },
131 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
132 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MASTERBALL) },
133 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
134 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MOONBALL) },
135 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
136 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
137 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
138 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
139 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
140 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WHISKERS) },
141 { }
142 };
143 MODULE_DEVICE_TABLE(hid, hammer_devices);
144
145 static struct hid_driver hammer_driver = {
146 .name = "hammer",
147 .id_table = hammer_devices,
148 .input_configured = hammer_input_configured,
149 };
150 module_hid_driver(hammer_driver);
151
152 MODULE_LICENSE("GPL");
153