tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright 2013 Maximilian Güntner <maximilian.guentner@gmail.com>
3 *
4 * This file is subject to the terms and conditions of version 2 of
5 * the GNU General Public License. See the file COPYING in the main
6 * directory of this archive for more details.
7 *
8 * Based on leds-pca963x.c driver by
9 * Peter Meerwald <p.meerwald@bct-electronic.com>
10 *
11 * Driver for the NXP PCA9685 12-Bit PWM LED driver chip.
12 *
13 */
14
15#include <linux/ctype.h>
16#include <linux/delay.h>
17#include <linux/err.h>
18#include <linux/i2c.h>
19#include <linux/leds.h>
20#include <linux/module.h>
21#include <linux/slab.h>
22#include <linux/string.h>
23#include <linux/workqueue.h>
24
25#include <linux/platform_data/leds-pca9685.h>
26
27/* Register Addresses */
28#define PCA9685_MODE1 0x00
29#define PCA9685_MODE2 0x01
30#define PCA9685_LED0_ON_L 0x06
31#define PCA9685_ALL_LED_ON_L 0xFA
32
33/* MODE1 Register */
34#define PCA9685_ALLCALL 0x00
35#define PCA9685_SLEEP 0x04
36#define PCA9685_AI 0x05
37
38/* MODE2 Register */
39#define PCA9685_INVRT 0x04
40#define PCA9685_OUTDRV 0x02
41
42static const struct i2c_device_id pca9685_id[] = {
43 { "pca9685", 0 },
44 { }
45};
46MODULE_DEVICE_TABLE(i2c, pca9685_id);
47
48struct pca9685_led {
49 struct i2c_client *client;
50 struct work_struct work;
51 u16 brightness;
52 struct led_classdev led_cdev;
53 int led_num; /* 0-15 */
54 char name[32];
55};
56
57static void pca9685_write_msg(struct i2c_client *client, u8 *buf, u8 len)
58{
59 struct i2c_msg msg = {
60 .addr = client->addr,
61 .flags = 0x00,
62 .len = len,
63 .buf = buf
64 };
65 i2c_transfer(client->adapter, &msg, 1);
66}
67
68static void pca9685_all_off(struct i2c_client *client)
69{
70 u8 i2c_buffer[5] = {PCA9685_ALL_LED_ON_L, 0x00, 0x00, 0x00, 0x10};
71 pca9685_write_msg(client, i2c_buffer, 5);
72}
73
74static void pca9685_led_work(struct work_struct *work)
75{
76 struct pca9685_led *pca9685;
77 u8 i2c_buffer[5];
78
79 pca9685 = container_of(work, struct pca9685_led, work);
80 i2c_buffer[0] = PCA9685_LED0_ON_L + 4 * pca9685->led_num;
81 /*
82 * 4095 is the maximum brightness, so we set the ON time to 0x1000
83 * which disables the PWM generator for that LED
84 */
85 if (pca9685->brightness == 4095)
86 *((__le16 *)(i2c_buffer+1)) = cpu_to_le16(0x1000);
87 else
88 *((__le16 *)(i2c_buffer+1)) = 0x0000;
89
90 if (pca9685->brightness == 0)
91 *((__le16 *)(i2c_buffer+3)) = cpu_to_le16(0x1000);
92 else if (pca9685->brightness == 4095)
93 *((__le16 *)(i2c_buffer+3)) = 0x0000;
94 else
95 *((__le16 *)(i2c_buffer+3)) = cpu_to_le16(pca9685->brightness);
96
97 pca9685_write_msg(pca9685->client, i2c_buffer, 5);
98}
99
100static void pca9685_led_set(struct led_classdev *led_cdev,
101 enum led_brightness value)
102{
103 struct pca9685_led *pca9685;
104 pca9685 = container_of(led_cdev, struct pca9685_led, led_cdev);
105 pca9685->brightness = value;
106
107 schedule_work(&pca9685->work);
108}
109
110static int pca9685_probe(struct i2c_client *client,
111 const struct i2c_device_id *id)
112{
113 struct pca9685_led *pca9685;
114 struct pca9685_platform_data *pdata;
115 int err;
116 u8 i;
117
118 pdata = dev_get_platdata(&client->dev);
119 if (pdata) {
120 if (pdata->leds.num_leds < 1 || pdata->leds.num_leds > 15) {
121 dev_err(&client->dev, "board info must claim 1-16 LEDs");
122 return -EINVAL;
123 }
124 }
125
126 pca9685 = devm_kzalloc(&client->dev, 16 * sizeof(*pca9685), GFP_KERNEL);
127 if (!pca9685)
128 return -ENOMEM;
129
130 i2c_set_clientdata(client, pca9685);
131 pca9685_all_off(client);
132
133 for (i = 0; i < 16; i++) {
134 pca9685[i].client = client;
135 pca9685[i].led_num = i;
136 pca9685[i].name[0] = '\0';
137 if (pdata && i < pdata->leds.num_leds) {
138 if (pdata->leds.leds[i].name)
139 strncpy(pca9685[i].name,
140 pdata->leds.leds[i].name,
141 sizeof(pca9685[i].name)-1);
142 if (pdata->leds.leds[i].default_trigger)
143 pca9685[i].led_cdev.default_trigger =
144 pdata->leds.leds[i].default_trigger;
145 }
146 if (strlen(pca9685[i].name) == 0) {
147 /*
148 * Write adapter and address to the name as well.
149 * Otherwise multiple chips attached to one host would
150 * not work.
151 */
152 snprintf(pca9685[i].name, sizeof(pca9685[i].name),
153 "pca9685:%d:x%.2x:%d",
154 client->adapter->nr, client->addr, i);
155 }
156 pca9685[i].led_cdev.name = pca9685[i].name;
157 pca9685[i].led_cdev.max_brightness = 0xfff;
158 pca9685[i].led_cdev.brightness_set = pca9685_led_set;
159
160 INIT_WORK(&pca9685[i].work, pca9685_led_work);
161 err = led_classdev_register(&client->dev, &pca9685[i].led_cdev);
162 if (err < 0)
163 goto exit;
164 }
165
166 if (pdata)
167 i2c_smbus_write_byte_data(client, PCA9685_MODE2,
168 pdata->outdrv << PCA9685_OUTDRV |
169 pdata->inverted << PCA9685_INVRT);
170 else
171 i2c_smbus_write_byte_data(client, PCA9685_MODE2,
172 PCA9685_TOTEM_POLE << PCA9685_OUTDRV);
173 /* Enable Auto-Increment, enable oscillator, ALLCALL/SUBADDR disabled */
174 i2c_smbus_write_byte_data(client, PCA9685_MODE1, BIT(PCA9685_AI));
175
176 return 0;
177
178exit:
179 while (i--) {
180 led_classdev_unregister(&pca9685[i].led_cdev);
181 cancel_work_sync(&pca9685[i].work);
182 }
183 return err;
184}
185
186static int pca9685_remove(struct i2c_client *client)
187{
188 struct pca9685_led *pca9685 = i2c_get_clientdata(client);
189 u8 i;
190
191 for (i = 0; i < 16; i++) {
192 led_classdev_unregister(&pca9685[i].led_cdev);
193 cancel_work_sync(&pca9685[i].work);
194 }
195 pca9685_all_off(client);
196 return 0;
197}
198
199static struct i2c_driver pca9685_driver = {
200 .driver = {
201 .name = "leds-pca9685",
202 .owner = THIS_MODULE,
203 },
204 .probe = pca9685_probe,
205 .remove = pca9685_remove,
206 .id_table = pca9685_id,
207};
208
209module_i2c_driver(pca9685_driver);
210
211MODULE_AUTHOR("Maximilian Güntner <maximilian.guentner@gmail.com>");
212MODULE_DESCRIPTION("PCA9685 LED Driver");
213MODULE_LICENSE("GPL v2");