drivers/leds/leds-pca9685.c

   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
  42 static const struct i2c_device_id pca9685_id[] = {
  43         { "pca9685", 0 },
  44         { }
  45 };
  46 MODULE_DEVICE_TABLE(i2c, pca9685_id);
  47
  48 struct 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
  57 static 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
  68 static 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
  74 static 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
 100 static 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
 110 static 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
 178 exit:
 179         while (i--) {
 180                 led_classdev_unregister(&pca9685[i].led_cdev);
 181                 cancel_work_sync(&pca9685[i].work);
 182         }
 183         return err;
 184 }
 185
 186 static 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
 199 static 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
 209 module_i2c_driver(pca9685_driver);
 210
 211 MODULE_AUTHOR("Maximilian Güntner <maximilian.guentner@gmail.com>");
 212 MODULE_DESCRIPTION("PCA9685 LED Driver");
 213 MODULE_LICENSE("GPL v2");