hid-thingm.c revision aee114fd3c94f1be0f95af84d6ed25cd47702c41 
1/*
2 * ThingM blink(1) USB RGB LED driver
3 *
4 * Copyright 2013 Savoir-faire Linux Inc.
5 *	Vivien Didelot <vivien.didelot@savoirfairelinux.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation, version 2.
10 */
11
12#include <linux/hid.h>
13#include <linux/leds.h>
14#include <linux/module.h>
15
16#include "hid-ids.h"
17
18#define BLINK1_CMD_SIZE		9
19
20#define blink1_rgb_to_r(rgb)	((rgb & 0xFF0000) >> 16)
21#define blink1_rgb_to_g(rgb)	((rgb & 0x00FF00) >> 8)
22#define blink1_rgb_to_b(rgb)	((rgb & 0x0000FF) >> 0)
23
24/**
25 * struct blink1_data - blink(1) device specific data
26 * @hdev:		HID device.
27 * @led_cdev:		LED class instance.
28 * @rgb:		8-bit per channel RGB notation.
29 * @brightness:		brightness coefficient.
30 */
31struct blink1_data {
32	struct hid_device *hdev;
33	struct led_classdev led_cdev;
34	u32 rgb;
35	u8 brightness;
36};
37
38static int blink1_send_command(struct blink1_data *data,
39		u8 buf[BLINK1_CMD_SIZE])
40{
41	int ret;
42
43	hid_dbg(data->hdev, "command: %d%c%.2x%.2x%.2x%.2x%.2x%.2x%.2x\n",
44			buf[0], buf[1], buf[2], buf[3], buf[4],
45			buf[5], buf[6], buf[7], buf[8]);
46
47	ret = hid_hw_raw_request(data->hdev, buf[0], buf, BLINK1_CMD_SIZE,
48				 HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
49
50	return ret < 0 ? ret : 0;
51}
52
53static int blink1_update_color(struct blink1_data *data)
54{
55	u8 buf[BLINK1_CMD_SIZE] = { 1, 'n', 0, 0, 0, 0, 0, 0, 0 };
56
57	if (data->brightness) {
58		unsigned int coef = DIV_ROUND_CLOSEST(255, data->brightness);
59
60		buf[2] = DIV_ROUND_CLOSEST(blink1_rgb_to_r(data->rgb), coef);
61		buf[3] = DIV_ROUND_CLOSEST(blink1_rgb_to_g(data->rgb), coef);
62		buf[4] = DIV_ROUND_CLOSEST(blink1_rgb_to_b(data->rgb), coef);
63	}
64
65	return blink1_send_command(data, buf);
66}
67
68static void blink1_led_set(struct led_classdev *led_cdev,
69		enum led_brightness brightness)
70{
71	struct blink1_data *data = dev_get_drvdata(led_cdev->dev->parent);
72
73	data->brightness = brightness;
74	if (blink1_update_color(data))
75		hid_err(data->hdev, "failed to update color\n");
76}
77
78static enum led_brightness blink1_led_get(struct led_classdev *led_cdev)
79{
80	struct blink1_data *data = dev_get_drvdata(led_cdev->dev->parent);
81
82	return data->brightness;
83}
84
85static ssize_t blink1_show_rgb(struct device *dev,
86		struct device_attribute *attr, char *buf)
87{
88	struct blink1_data *data = dev_get_drvdata(dev->parent);
89
90	return sprintf(buf, "%.6X\n", data->rgb);
91}
92
93static ssize_t blink1_store_rgb(struct device *dev,
94		struct device_attribute *attr, const char *buf, size_t count)
95{
96	struct blink1_data *data = dev_get_drvdata(dev->parent);
97	long unsigned int rgb;
98	int ret;
99
100	ret = kstrtoul(buf, 16, &rgb);
101	if (ret)
102		return ret;
103
104	/* RGB triplet notation is 24-bit hexadecimal */
105	if (rgb > 0xFFFFFF)
106		return -EINVAL;
107
108	data->rgb = rgb;
109	ret = blink1_update_color(data);
110
111	return ret ? ret : count;
112}
113
114static DEVICE_ATTR(rgb, S_IRUGO | S_IWUSR, blink1_show_rgb, blink1_store_rgb);
115
116static const struct attribute_group blink1_sysfs_group = {
117	.attrs = (struct attribute *[]) {
118		&dev_attr_rgb.attr,
119		NULL
120	},
121};
122
123static int thingm_probe(struct hid_device *hdev, const struct hid_device_id *id)
124{
125	struct blink1_data *data;
126	struct led_classdev *led;
127	char led_name[13];
128	int ret;
129
130	data = devm_kzalloc(&hdev->dev, sizeof(struct blink1_data), GFP_KERNEL);
131	if (!data)
132		return -ENOMEM;
133
134	hid_set_drvdata(hdev, data);
135	data->hdev = hdev;
136	data->rgb = 0xFFFFFF; /* set a default white color */
137
138	ret = hid_parse(hdev);
139	if (ret)
140		goto error;
141
142	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
143	if (ret)
144		goto error;
145
146	/* blink(1) serial numbers range is 0x1A001000 to 0x1A002FFF */
147	led = &data->led_cdev;
148	snprintf(led_name, sizeof(led_name), "blink1::%s", hdev->uniq + 4);
149	led->name = led_name;
150	led->brightness_set = blink1_led_set;
151	led->brightness_get = blink1_led_get;
152	ret = led_classdev_register(&hdev->dev, led);
153	if (ret)
154		goto stop;
155
156	ret = sysfs_create_group(&led->dev->kobj, &blink1_sysfs_group);
157	if (ret)
158		goto remove_led;
159
160	return 0;
161
162remove_led:
163	led_classdev_unregister(led);
164stop:
165	hid_hw_stop(hdev);
166error:
167	return ret;
168}
169
170static void thingm_remove(struct hid_device *hdev)
171{
172	struct blink1_data *data = hid_get_drvdata(hdev);
173	struct led_classdev *led = &data->led_cdev;
174
175	sysfs_remove_group(&led->dev->kobj, &blink1_sysfs_group);
176	led_classdev_unregister(led);
177	hid_hw_stop(hdev);
178}
179
180static const struct hid_device_id thingm_table[] = {
181	{ HID_USB_DEVICE(USB_VENDOR_ID_THINGM, USB_DEVICE_ID_BLINK1) },
182	{ }
183};
184MODULE_DEVICE_TABLE(hid, thingm_table);
185
186static struct hid_driver thingm_driver = {
187	.name = "thingm",
188	.probe = thingm_probe,
189	.remove = thingm_remove,
190	.id_table = thingm_table,
191};
192
193module_hid_driver(thingm_driver);
194
195MODULE_LICENSE("GPL");
196MODULE_AUTHOR("Vivien Didelot <vivien.didelot@savoirfairelinux.com>");
197MODULE_DESCRIPTION("ThingM blink(1) USB RGB LED driver");
198