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