drivers/leds/leds-pca955x.c

   1 /*
   2  * Copyright 2007-2008 Extreme Engineering Solutions, Inc.
   3  *
   4  * Author: Nate Case <ncase@xes-inc.com>
   5  *
   6  * This file is subject to the terms and conditions of version 2 of
   7  * the GNU General Public License.  See the file COPYING in the main
   8  * directory of this archive for more details.
   9  *
  10  * LED driver for various PCA955x I2C LED drivers
  11  *
  12  * Supported devices:
  13  *
  14  *      Device          Description             7-bit slave address
  15  *      ------          -----------             -------------------
  16  *      PCA9550         2-bit driver            0x60 .. 0x61
  17  *      PCA9551         8-bit driver            0x60 .. 0x67
  18  *      PCA9552         16-bit driver           0x60 .. 0x67
  19  *      PCA9553/01      4-bit driver            0x62
  20  *      PCA9553/02      4-bit driver            0x63
  21  *
  22  * Philips PCA955x LED driver chips follow a register map as shown below:
  23  *
  24  *      Control Register                Description
  25  *      ----------------                -----------
  26  *      0x0                             Input register 0
  27  *                                      ..
  28  *      NUM_INPUT_REGS - 1              Last Input register X
  29  *
  30  *      NUM_INPUT_REGS                  Frequency prescaler 0
  31  *      NUM_INPUT_REGS + 1              PWM register 0
  32  *      NUM_INPUT_REGS + 2              Frequency prescaler 1
  33  *      NUM_INPUT_REGS + 3              PWM register 1
  34  *
  35  *      NUM_INPUT_REGS + 4              LED selector 0
  36  *      NUM_INPUT_REGS + 4
  37  *          + NUM_LED_REGS - 1          Last LED selector
  38  *
  39  *  where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many
  40  *  bits the chip supports.
  41  */
  42
  43 #include <linux/acpi.h>
  44 #include <linux/module.h>
  45 #include <linux/delay.h>
  46 #include <linux/string.h>
  47 #include <linux/ctype.h>
  48 #include <linux/leds.h>
  49 #include <linux/err.h>
  50 #include <linux/i2c.h>
  51 #include <linux/slab.h>
  52
  53 /* LED select registers determine the source that drives LED outputs */
  54 #define PCA955X_LS_LED_ON       0x0     /* Output LOW */
  55 #define PCA955X_LS_LED_OFF      0x1     /* Output HI-Z */
  56 #define PCA955X_LS_BLINK0       0x2     /* Blink at PWM0 rate */
  57 #define PCA955X_LS_BLINK1       0x3     /* Blink at PWM1 rate */
  58
  59 enum pca955x_type {
  60         pca9550,
  61         pca9551,
  62         pca9552,
  63         pca9553,
  64 };
  65
  66 struct pca955x_chipdef {
  67         int                     bits;
  68         u8                      slv_addr;       /* 7-bit slave address mask */
  69         int                     slv_addr_shift; /* Number of bits to ignore */
  70 };
  71
  72 static struct pca955x_chipdef pca955x_chipdefs[] = {
  73         [pca9550] = {
  74                 .bits           = 2,
  75                 .slv_addr       = /* 110000x */ 0x60,
  76                 .slv_addr_shift = 1,
  77         },
  78         [pca9551] = {
  79                 .bits           = 8,
  80                 .slv_addr       = /* 1100xxx */ 0x60,
  81                 .slv_addr_shift = 3,
  82         },
  83         [pca9552] = {
  84                 .bits           = 16,
  85                 .slv_addr       = /* 1100xxx */ 0x60,
  86                 .slv_addr_shift = 3,
  87         },
  88         [pca9553] = {
  89                 .bits           = 4,
  90                 .slv_addr       = /* 110001x */ 0x62,
  91                 .slv_addr_shift = 1,
  92         },
  93 };
  94
  95 static const struct i2c_device_id pca955x_id[] = {
  96         { "pca9550", pca9550 },
  97         { "pca9551", pca9551 },
  98         { "pca9552", pca9552 },
  99         { "pca9553", pca9553 },
 100         { }
 101 };
 102 MODULE_DEVICE_TABLE(i2c, pca955x_id);
 103
 104 static const struct acpi_device_id pca955x_acpi_ids[] = {
 105         { "PCA9550",  pca9550 },
 106         { "PCA9551",  pca9551 },
 107         { "PCA9552",  pca9552 },
 108         { "PCA9553",  pca9553 },
 109         { }
 110 };
 111 MODULE_DEVICE_TABLE(acpi, pca955x_acpi_ids);
 112
 113 struct pca955x {
 114         struct mutex lock;
 115         struct pca955x_led *leds;
 116         struct pca955x_chipdef  *chipdef;
 117         struct i2c_client       *client;
 118 };
 119
 120 struct pca955x_led {
 121         struct pca955x  *pca955x;
 122         struct led_classdev     led_cdev;
 123         int                     led_num;        /* 0 .. 15 potentially */
 124         char                    name[32];
 125 };
 126
 127 /* 8 bits per input register */
 128 static inline int pca95xx_num_input_regs(int bits)
 129 {
 130         return (bits + 7) / 8;
 131 }
 132
 133 /* 4 bits per LED selector register */
 134 static inline int pca95xx_num_led_regs(int bits)
 135 {
 136         return (bits + 3)  / 4;
 137 }
 138
 139 /*
 140  * Return an LED selector register value based on an existing one, with
 141  * the appropriate 2-bit state value set for the given LED number (0-3).
 142  */
 143 static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
 144 {
 145         return (oldval & (~(0x3 << (led_num << 1)))) |
 146                 ((state & 0x3) << (led_num << 1));
 147 }
 148
 149 /*
 150  * Write to frequency prescaler register, used to program the
 151  * period of the PWM output.  period = (PSCx + 1) / 38
 152  */
 153 static void pca955x_write_psc(struct i2c_client *client, int n, u8 val)
 154 {
 155         struct pca955x *pca955x = i2c_get_clientdata(client);
 156
 157         i2c_smbus_write_byte_data(client,
 158                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
 159                 val);
 160 }
 161
 162 /*
 163  * Write to PWM register, which determines the duty cycle of the
 164  * output.  LED is OFF when the count is less than the value of this
 165  * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
 166  *
 167  * Duty cycle is (256 - PWMx) / 256
 168  */
 169 static void pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
 170 {
 171         struct pca955x *pca955x = i2c_get_clientdata(client);
 172
 173         i2c_smbus_write_byte_data(client,
 174                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
 175                 val);
 176 }
 177
 178 /*
 179  * Write to LED selector register, which determines the source that
 180  * drives the LED output.
 181  */
 182 static void pca955x_write_ls(struct i2c_client *client, int n, u8 val)
 183 {
 184         struct pca955x *pca955x = i2c_get_clientdata(client);
 185
 186         i2c_smbus_write_byte_data(client,
 187                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
 188                 val);
 189 }
 190
 191 /*
 192  * Read the LED selector register, which determines the source that
 193  * drives the LED output.
 194  */
 195 static u8 pca955x_read_ls(struct i2c_client *client, int n)
 196 {
 197         struct pca955x *pca955x = i2c_get_clientdata(client);
 198
 199         return (u8) i2c_smbus_read_byte_data(client,
 200                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
 201 }
 202
 203 static int pca955x_led_set(struct led_classdev *led_cdev,
 204                             enum led_brightness value)
 205 {
 206         struct pca955x_led *pca955x_led;
 207         struct pca955x *pca955x;
 208         u8 ls;
 209         int chip_ls;    /* which LSx to use (0-3 potentially) */
 210         int ls_led;     /* which set of bits within LSx to use (0-3) */
 211
 212         pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
 213         pca955x = pca955x_led->pca955x;
 214
 215         chip_ls = pca955x_led->led_num / 4;
 216         ls_led = pca955x_led->led_num % 4;
 217
 218         mutex_lock(&pca955x->lock);
 219
 220         ls = pca955x_read_ls(pca955x->client, chip_ls);
 221
 222         switch (value) {
 223         case LED_FULL:
 224                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
 225                 break;
 226         case LED_OFF:
 227                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
 228                 break;
 229         case LED_HALF:
 230                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
 231                 break;
 232         default:
 233                 /*
 234                  * Use PWM1 for all other values.  This has the unwanted
 235                  * side effect of making all LEDs on the chip share the
 236                  * same brightness level if set to a value other than
 237                  * OFF, HALF, or FULL.  But, this is probably better than
 238                  * just turning off for all other values.
 239                  */
 240                 pca955x_write_pwm(pca955x->client, 1,
 241                                 255 - value);
 242                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
 243                 break;
 244         }
 245
 246         pca955x_write_ls(pca955x->client, chip_ls, ls);
 247
 248         mutex_unlock(&pca955x->lock);
 249
 250         return 0;
 251 }
 252
 253 static int pca955x_probe(struct i2c_client *client,
 254                                         const struct i2c_device_id *id)
 255 {
 256         struct pca955x *pca955x;
 257         struct pca955x_led *pca955x_led;
 258         struct pca955x_chipdef *chip;
 259         struct i2c_adapter *adapter;
 260         struct led_platform_data *pdata;
 261         int i, err;
 262
 263         if (id) {
 264                 chip = &pca955x_chipdefs[id->driver_data];
 265         } else {
 266                 const struct acpi_device_id *acpi_id;
 267
 268                 acpi_id = acpi_match_device(pca955x_acpi_ids, &client->dev);
 269                 if (!acpi_id)
 270                         return -ENODEV;
 271                 chip = &pca955x_chipdefs[acpi_id->driver_data];
 272         }
 273         adapter = to_i2c_adapter(client->dev.parent);
 274         pdata = dev_get_platdata(&client->dev);
 275
 276         /* Make sure the slave address / chip type combo given is possible */
 277         if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
 278             chip->slv_addr) {
 279                 dev_err(&client->dev, "invalid slave address %02x\n",
 280                                 client->addr);
 281                 return -ENODEV;
 282         }
 283
 284         dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
 285                         "slave address 0x%02x\n",
 286                         client->name, chip->bits, client->addr);
 287
 288         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 289                 return -EIO;
 290
 291         if (pdata) {
 292                 if (pdata->num_leds != chip->bits) {
 293                         dev_err(&client->dev, "board info claims %d LEDs"
 294                                         " on a %d-bit chip\n",
 295                                         pdata->num_leds, chip->bits);
 296                         return -ENODEV;
 297                 }
 298         }
 299
 300         pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
 301         if (!pca955x)
 302                 return -ENOMEM;
 303
 304         pca955x->leds = devm_kzalloc(&client->dev,
 305                         sizeof(*pca955x_led) * chip->bits, GFP_KERNEL);
 306         if (!pca955x->leds)
 307                 return -ENOMEM;
 308
 309         i2c_set_clientdata(client, pca955x);
 310
 311         mutex_init(&pca955x->lock);
 312         pca955x->client = client;
 313         pca955x->chipdef = chip;
 314
 315         for (i = 0; i < chip->bits; i++) {
 316                 pca955x_led = &pca955x->leds[i];
 317                 pca955x_led->led_num = i;
 318                 pca955x_led->pca955x = pca955x;
 319
 320                 /* Platform data can specify LED names and default triggers */
 321                 if (pdata) {
 322                         if (pdata->leds[i].name)
 323                                 snprintf(pca955x_led->name,
 324                                         sizeof(pca955x_led->name), "pca955x:%s",
 325                                         pdata->leds[i].name);
 326                         if (pdata->leds[i].default_trigger)
 327                                 pca955x_led->led_cdev.default_trigger =
 328                                         pdata->leds[i].default_trigger;
 329                 } else {
 330                         snprintf(pca955x_led->name, sizeof(pca955x_led->name),
 331                                  "pca955x:%d", i);
 332                 }
 333
 334                 pca955x_led->led_cdev.name = pca955x_led->name;
 335                 pca955x_led->led_cdev.brightness_set_blocking = pca955x_led_set;
 336
 337                 err = led_classdev_register(&client->dev,
 338                                         &pca955x_led->led_cdev);
 339                 if (err < 0)
 340                         goto exit;
 341         }
 342
 343         /* Turn off LEDs */
 344         for (i = 0; i < pca95xx_num_led_regs(chip->bits); i++)
 345                 pca955x_write_ls(client, i, 0x55);
 346
 347         /* PWM0 is used for half brightness or 50% duty cycle */
 348         pca955x_write_pwm(client, 0, 255-LED_HALF);
 349
 350         /* PWM1 is used for variable brightness, default to OFF */
 351         pca955x_write_pwm(client, 1, 0);
 352
 353         /* Set to fast frequency so we do not see flashing */
 354         pca955x_write_psc(client, 0, 0);
 355         pca955x_write_psc(client, 1, 0);
 356
 357         return 0;
 358
 359 exit:
 360         while (i--)
 361                 led_classdev_unregister(&pca955x->leds[i].led_cdev);
 362
 363         return err;
 364 }
 365
 366 static int pca955x_remove(struct i2c_client *client)
 367 {
 368         struct pca955x *pca955x = i2c_get_clientdata(client);
 369         int i;
 370
 371         for (i = 0; i < pca955x->chipdef->bits; i++)
 372                 led_classdev_unregister(&pca955x->leds[i].led_cdev);
 373
 374         return 0;
 375 }
 376
 377 static struct i2c_driver pca955x_driver = {
 378         .driver = {
 379                 .name   = "leds-pca955x",
 380                 .acpi_match_table = ACPI_PTR(pca955x_acpi_ids),
 381         },
 382         .probe  = pca955x_probe,
 383         .remove = pca955x_remove,
 384         .id_table = pca955x_id,
 385 };
 386
 387 module_i2c_driver(pca955x_driver);
 388
 389 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
 390 MODULE_DESCRIPTION("PCA955x LED driver");
 391 MODULE_LICENSE("GPL v2");