Root/drivers/leds/leds-pca9633.c

1/*
2 * Copyright 2011 bct electronic GmbH
3 *
4 * Author: Peter Meerwald <p.meerwald@bct-electronic.com>
5 *
6 * Based on leds-pca955x.c
7 *
8 * This file is subject to the terms and conditions of version 2 of
9 * the GNU General Public License. See the file COPYING in the main
10 * directory of this archive for more details.
11 *
12 * LED driver for the PCA9633 I2C LED driver (7-bit slave address 0x62)
13 *
14 */
15
16#include <linux/module.h>
17#include <linux/delay.h>
18#include <linux/string.h>
19#include <linux/ctype.h>
20#include <linux/leds.h>
21#include <linux/err.h>
22#include <linux/i2c.h>
23#include <linux/workqueue.h>
24#include <linux/slab.h>
25#include <linux/platform_data/leds-pca9633.h>
26
27/* LED select registers determine the source that drives LED outputs */
28#define PCA9633_LED_OFF 0x0 /* LED driver off */
29#define PCA9633_LED_ON 0x1 /* LED driver on */
30#define PCA9633_LED_PWM 0x2 /* Controlled through PWM */
31#define PCA9633_LED_GRP_PWM 0x3 /* Controlled through PWM/GRPPWM */
32
33#define PCA9633_MODE1 0x00
34#define PCA9633_MODE2 0x01
35#define PCA9633_PWM_BASE 0x02
36#define PCA9633_LEDOUT 0x08
37
38static const struct i2c_device_id pca9633_id[] = {
39    { "pca9633", 0 },
40    { }
41};
42MODULE_DEVICE_TABLE(i2c, pca9633_id);
43
44struct pca9633_led {
45    struct i2c_client *client;
46    struct work_struct work;
47    enum led_brightness brightness;
48    struct led_classdev led_cdev;
49    int led_num; /* 0 .. 3 potentially */
50    char name[32];
51};
52
53static void pca9633_led_work(struct work_struct *work)
54{
55    struct pca9633_led *pca9633 = container_of(work,
56        struct pca9633_led, work);
57    u8 ledout = i2c_smbus_read_byte_data(pca9633->client, PCA9633_LEDOUT);
58    int shift = 2 * pca9633->led_num;
59    u8 mask = 0x3 << shift;
60
61    switch (pca9633->brightness) {
62    case LED_FULL:
63        i2c_smbus_write_byte_data(pca9633->client, PCA9633_LEDOUT,
64            (ledout & ~mask) | (PCA9633_LED_ON << shift));
65        break;
66    case LED_OFF:
67        i2c_smbus_write_byte_data(pca9633->client, PCA9633_LEDOUT,
68            ledout & ~mask);
69        break;
70    default:
71        i2c_smbus_write_byte_data(pca9633->client,
72            PCA9633_PWM_BASE + pca9633->led_num,
73            pca9633->brightness);
74        i2c_smbus_write_byte_data(pca9633->client, PCA9633_LEDOUT,
75            (ledout & ~mask) | (PCA9633_LED_PWM << shift));
76        break;
77    }
78}
79
80static void pca9633_led_set(struct led_classdev *led_cdev,
81    enum led_brightness value)
82{
83    struct pca9633_led *pca9633;
84
85    pca9633 = container_of(led_cdev, struct pca9633_led, led_cdev);
86
87    pca9633->brightness = value;
88
89    /*
90     * Must use workqueue for the actual I/O since I2C operations
91     * can sleep.
92     */
93    schedule_work(&pca9633->work);
94}
95
96static int pca9633_probe(struct i2c_client *client,
97                    const struct i2c_device_id *id)
98{
99    struct pca9633_led *pca9633;
100    struct pca9633_platform_data *pdata;
101    int i, err;
102
103    pdata = client->dev.platform_data;
104
105    if (pdata) {
106        if (pdata->leds.num_leds <= 0 || pdata->leds.num_leds > 4) {
107            dev_err(&client->dev, "board info must claim at most 4 LEDs");
108            return -EINVAL;
109        }
110    }
111
112    pca9633 = devm_kzalloc(&client->dev, 4 * sizeof(*pca9633), GFP_KERNEL);
113    if (!pca9633)
114        return -ENOMEM;
115
116    i2c_set_clientdata(client, pca9633);
117
118    for (i = 0; i < 4; i++) {
119        pca9633[i].client = client;
120        pca9633[i].led_num = i;
121
122        /* Platform data can specify LED names and default triggers */
123        if (pdata && i < pdata->leds.num_leds) {
124            if (pdata->leds.leds[i].name)
125                snprintf(pca9633[i].name,
126                     sizeof(pca9633[i].name), "pca9633:%s",
127                     pdata->leds.leds[i].name);
128            if (pdata->leds.leds[i].default_trigger)
129                pca9633[i].led_cdev.default_trigger =
130                    pdata->leds.leds[i].default_trigger;
131        } else {
132            snprintf(pca9633[i].name, sizeof(pca9633[i].name),
133                 "pca9633:%d", i);
134        }
135
136        pca9633[i].led_cdev.name = pca9633[i].name;
137        pca9633[i].led_cdev.brightness_set = pca9633_led_set;
138
139        INIT_WORK(&pca9633[i].work, pca9633_led_work);
140
141        err = led_classdev_register(&client->dev, &pca9633[i].led_cdev);
142        if (err < 0)
143            goto exit;
144    }
145
146    /* Disable LED all-call address and set normal mode */
147    i2c_smbus_write_byte_data(client, PCA9633_MODE1, 0x00);
148
149    /* Configure output: open-drain or totem pole (push-pull) */
150    if (pdata && pdata->outdrv == PCA9633_OPEN_DRAIN)
151        i2c_smbus_write_byte_data(client, PCA9633_MODE2, 0x01);
152
153    /* Turn off LEDs */
154    i2c_smbus_write_byte_data(client, PCA9633_LEDOUT, 0x00);
155
156    return 0;
157
158exit:
159    while (i--) {
160        led_classdev_unregister(&pca9633[i].led_cdev);
161        cancel_work_sync(&pca9633[i].work);
162    }
163
164    return err;
165}
166
167static int pca9633_remove(struct i2c_client *client)
168{
169    struct pca9633_led *pca9633 = i2c_get_clientdata(client);
170    int i;
171
172    for (i = 0; i < 4; i++) {
173        led_classdev_unregister(&pca9633[i].led_cdev);
174        cancel_work_sync(&pca9633[i].work);
175    }
176
177    return 0;
178}
179
180static struct i2c_driver pca9633_driver = {
181    .driver = {
182        .name = "leds-pca9633",
183        .owner = THIS_MODULE,
184    },
185    .probe = pca9633_probe,
186    .remove = pca9633_remove,
187    .id_table = pca9633_id,
188};
189
190module_i2c_driver(pca9633_driver);
191
192MODULE_AUTHOR("Peter Meerwald <p.meerwald@bct-electronic.com>");
193MODULE_DESCRIPTION("PCA9633 LED driver");
194MODULE_LICENSE("GPL v2");
195

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