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/ctype.h>
  44 #include <linux/delay.h>
  45 #include <linux/err.h>
  46 #include <linux/gpio.h>
  47 #include <linux/i2c.h>
  48 #include <linux/leds.h>
  49 #include <linux/module.h>
  50 #include <linux/of.h>
  51 #include <linux/property.h>
  52 #include <linux/slab.h>
  53 #include <linux/string.h>
  54
  55 #include <dt-bindings/leds/leds-pca955x.h>
  56
  57 /* LED select registers determine the source that drives LED outputs */
  58 #define PCA955X_LS_LED_ON       0x0     /* Output LOW */
  59 #define PCA955X_LS_LED_OFF      0x1     /* Output HI-Z */
  60 #define PCA955X_LS_BLINK0       0x2     /* Blink at PWM0 rate */
  61 #define PCA955X_LS_BLINK1       0x3     /* Blink at PWM1 rate */
  62
  63 #define PCA955X_GPIO_INPUT      LED_OFF
  64 #define PCA955X_GPIO_HIGH       LED_OFF
  65 #define PCA955X_GPIO_LOW        LED_FULL
  66
  67 enum pca955x_type {
  68         pca9550,
  69         pca9551,
  70         pca9552,
  71         pca9553,
  72 };
  73
  74 struct pca955x_chipdef {
  75         int                     bits;
  76         u8                      slv_addr;       /* 7-bit slave address mask */
  77         int                     slv_addr_shift; /* Number of bits to ignore */
  78 };
  79
  80 static struct pca955x_chipdef pca955x_chipdefs[] = {
  81         [pca9550] = {
  82                 .bits           = 2,
  83                 .slv_addr       = /* 110000x */ 0x60,
  84                 .slv_addr_shift = 1,
  85         },
  86         [pca9551] = {
  87                 .bits           = 8,
  88                 .slv_addr       = /* 1100xxx */ 0x60,
  89                 .slv_addr_shift = 3,
  90         },
  91         [pca9552] = {
  92                 .bits           = 16,
  93                 .slv_addr       = /* 1100xxx */ 0x60,
  94                 .slv_addr_shift = 3,
  95         },
  96         [pca9553] = {
  97                 .bits           = 4,
  98                 .slv_addr       = /* 110001x */ 0x62,
  99                 .slv_addr_shift = 1,
 100         },
 101 };
 102
 103 static const struct i2c_device_id pca955x_id[] = {
 104         { "pca9550", pca9550 },
 105         { "pca9551", pca9551 },
 106         { "pca9552", pca9552 },
 107         { "pca9553", pca9553 },
 108         { }
 109 };
 110 MODULE_DEVICE_TABLE(i2c, pca955x_id);
 111
 112 struct pca955x {
 113         struct mutex lock;
 114         struct pca955x_led *leds;
 115         struct pca955x_chipdef  *chipdef;
 116         struct i2c_client       *client;
 117 #ifdef CONFIG_LEDS_PCA955X_GPIO
 118         struct gpio_chip gpio;
 119 #endif
 120 };
 121
 122 struct pca955x_led {
 123         struct pca955x  *pca955x;
 124         struct led_classdev     led_cdev;
 125         int                     led_num;        /* 0 .. 15 potentially */
 126         char                    name[32];
 127         u32                     type;
 128         const char              *default_trigger;
 129 };
 130
 131 struct pca955x_platform_data {
 132         struct pca955x_led      *leds;
 133         int                     num_leds;
 134 };
 135
 136 /* 8 bits per input register */
 137 static inline int pca95xx_num_input_regs(int bits)
 138 {
 139         return (bits + 7) / 8;
 140 }
 141
 142 /* 4 bits per LED selector register */
 143 static inline int pca95xx_num_led_regs(int bits)
 144 {
 145         return (bits + 3)  / 4;
 146 }
 147
 148 /*
 149  * Return an LED selector register value based on an existing one, with
 150  * the appropriate 2-bit state value set for the given LED number (0-3).
 151  */
 152 static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
 153 {
 154         return (oldval & (~(0x3 << (led_num << 1)))) |
 155                 ((state & 0x3) << (led_num << 1));
 156 }
 157
 158 /*
 159  * Write to frequency prescaler register, used to program the
 160  * period of the PWM output.  period = (PSCx + 1) / 38
 161  */
 162 static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
 163 {
 164         struct pca955x *pca955x = i2c_get_clientdata(client);
 165         int ret;
 166
 167         ret = i2c_smbus_write_byte_data(client,
 168                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
 169                 val);
 170         if (ret < 0)
 171                 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
 172                         __func__, n, val, ret);
 173         return ret;
 174 }
 175
 176 /*
 177  * Write to PWM register, which determines the duty cycle of the
 178  * output.  LED is OFF when the count is less than the value of this
 179  * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
 180  *
 181  * Duty cycle is (256 - PWMx) / 256
 182  */
 183 static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
 184 {
 185         struct pca955x *pca955x = i2c_get_clientdata(client);
 186         int ret;
 187
 188         ret = i2c_smbus_write_byte_data(client,
 189                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
 190                 val);
 191         if (ret < 0)
 192                 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
 193                         __func__, n, val, ret);
 194         return ret;
 195 }
 196
 197 /*
 198  * Write to LED selector register, which determines the source that
 199  * drives the LED output.
 200  */
 201 static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
 202 {
 203         struct pca955x *pca955x = i2c_get_clientdata(client);
 204         int ret;
 205
 206         ret = i2c_smbus_write_byte_data(client,
 207                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
 208                 val);
 209         if (ret < 0)
 210                 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
 211                         __func__, n, val, ret);
 212         return ret;
 213 }
 214
 215 /*
 216  * Read the LED selector register, which determines the source that
 217  * drives the LED output.
 218  */
 219 static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
 220 {
 221         struct pca955x *pca955x = i2c_get_clientdata(client);
 222         int ret;
 223
 224         ret = i2c_smbus_read_byte_data(client,
 225                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
 226         if (ret < 0) {
 227                 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
 228                         __func__, n, ret);
 229                 return ret;
 230         }
 231         *val = (u8)ret;
 232         return 0;
 233 }
 234
 235 static int pca955x_led_set(struct led_classdev *led_cdev,
 236                             enum led_brightness value)
 237 {
 238         struct pca955x_led *pca955x_led;
 239         struct pca955x *pca955x;
 240         u8 ls;
 241         int chip_ls;    /* which LSx to use (0-3 potentially) */
 242         int ls_led;     /* which set of bits within LSx to use (0-3) */
 243         int ret;
 244
 245         pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
 246         pca955x = pca955x_led->pca955x;
 247
 248         chip_ls = pca955x_led->led_num / 4;
 249         ls_led = pca955x_led->led_num % 4;
 250
 251         mutex_lock(&pca955x->lock);
 252
 253         ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
 254         if (ret)
 255                 goto out;
 256
 257         switch (value) {
 258         case LED_FULL:
 259                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
 260                 break;
 261         case LED_OFF:
 262                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
 263                 break;
 264         case LED_HALF:
 265                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
 266                 break;
 267         default:
 268                 /*
 269                  * Use PWM1 for all other values.  This has the unwanted
 270                  * side effect of making all LEDs on the chip share the
 271                  * same brightness level if set to a value other than
 272                  * OFF, HALF, or FULL.  But, this is probably better than
 273                  * just turning off for all other values.
 274                  */
 275                 ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
 276                 if (ret)
 277                         goto out;
 278                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
 279                 break;
 280         }
 281
 282         ret = pca955x_write_ls(pca955x->client, chip_ls, ls);
 283
 284 out:
 285         mutex_unlock(&pca955x->lock);
 286
 287         return ret;
 288 }
 289
 290 #ifdef CONFIG_LEDS_PCA955X_GPIO
 291 /*
 292  * Read the INPUT register, which contains the state of LEDs.
 293  */
 294 static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
 295 {
 296         int ret = i2c_smbus_read_byte_data(client, n);
 297
 298         if (ret < 0) {
 299                 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
 300                         __func__, n, ret);
 301                 return ret;
 302         }
 303         *val = (u8)ret;
 304         return 0;
 305
 306 }
 307
 308 static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
 309 {
 310         struct pca955x *pca955x = gpiochip_get_data(gc);
 311         struct pca955x_led *led = &pca955x->leds[offset];
 312
 313         if (led->type == PCA955X_TYPE_GPIO)
 314                 return 0;
 315
 316         return -EBUSY;
 317 }
 318
 319 static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
 320                              int val)
 321 {
 322         struct pca955x *pca955x = gpiochip_get_data(gc);
 323         struct pca955x_led *led = &pca955x->leds[offset];
 324
 325         if (val)
 326                 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);
 327
 328         return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW);
 329 }
 330
 331 static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
 332                                    int val)
 333 {
 334         pca955x_set_value(gc, offset, val);
 335 }
 336
 337 static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
 338 {
 339         struct pca955x *pca955x = gpiochip_get_data(gc);
 340         struct pca955x_led *led = &pca955x->leds[offset];
 341         u8 reg = 0;
 342
 343         /* There is nothing we can do about errors */
 344         pca955x_read_input(pca955x->client, led->led_num / 8, &reg);
 345
 346         return !!(reg & (1 << (led->led_num % 8)));
 347 }
 348
 349 static int pca955x_gpio_direction_input(struct gpio_chip *gc,
 350                                         unsigned int offset)
 351 {
 352         struct pca955x *pca955x = gpiochip_get_data(gc);
 353         struct pca955x_led *led = &pca955x->leds[offset];
 354
 355         /* To use as input ensure pin is not driven. */
 356         return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
 357 }
 358
 359 static int pca955x_gpio_direction_output(struct gpio_chip *gc,
 360                                          unsigned int offset, int val)
 361 {
 362         return pca955x_set_value(gc, offset, val);
 363 }
 364 #endif /* CONFIG_LEDS_PCA955X_GPIO */
 365
 366 static struct pca955x_platform_data *
 367 pca955x_get_pdata(struct i2c_client *client, struct pca955x_chipdef *chip)
 368 {
 369         struct pca955x_platform_data *pdata;
 370         struct fwnode_handle *child;
 371         int count;
 372
 373         count = device_get_child_node_count(&client->dev);
 374         if (!count || count > chip->bits)
 375                 return ERR_PTR(-ENODEV);
 376
 377         pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
 378         if (!pdata)
 379                 return ERR_PTR(-ENOMEM);
 380
 381         pdata->leds = devm_kcalloc(&client->dev,
 382                                    chip->bits, sizeof(struct pca955x_led),
 383                                    GFP_KERNEL);
 384         if (!pdata->leds)
 385                 return ERR_PTR(-ENOMEM);
 386
 387         device_for_each_child_node(&client->dev, child) {
 388                 const char *name;
 389                 u32 reg;
 390                 int res;
 391
 392                 res = fwnode_property_read_u32(child, "reg", &reg);
 393                 if ((res != 0) || (reg >= chip->bits))
 394                         continue;
 395
 396                 res = fwnode_property_read_string(child, "label", &name);
 397                 if ((res != 0) && is_of_node(child))
 398                         name = to_of_node(child)->name;
 399
 400                 snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name),
 401                          "%s", name);
 402
 403                 pdata->leds[reg].type = PCA955X_TYPE_LED;
 404                 fwnode_property_read_u32(child, "type", &pdata->leds[reg].type);
 405                 fwnode_property_read_string(child, "linux,default-trigger",
 406                                         &pdata->leds[reg].default_trigger);
 407         }
 408
 409         pdata->num_leds = chip->bits;
 410
 411         return pdata;
 412 }
 413
 414 static const struct of_device_id of_pca955x_match[] = {
 415         { .compatible = "nxp,pca9550", .data = (void *)pca9550 },
 416         { .compatible = "nxp,pca9551", .data = (void *)pca9551 },
 417         { .compatible = "nxp,pca9552", .data = (void *)pca9552 },
 418         { .compatible = "nxp,pca9553", .data = (void *)pca9553 },
 419         {},
 420 };
 421 MODULE_DEVICE_TABLE(of, of_pca955x_match);
 422
 423 static int pca955x_probe(struct i2c_client *client,
 424                                         const struct i2c_device_id *id)
 425 {
 426         struct pca955x *pca955x;
 427         struct pca955x_led *pca955x_led;
 428         struct pca955x_chipdef *chip;
 429         struct i2c_adapter *adapter;
 430         int i, err;
 431         struct pca955x_platform_data *pdata;
 432         int ngpios = 0;
 433
 434         chip = &pca955x_chipdefs[id->driver_data];
 435         adapter = to_i2c_adapter(client->dev.parent);
 436         pdata = dev_get_platdata(&client->dev);
 437         if (!pdata) {
 438                 pdata = pca955x_get_pdata(client, chip);
 439                 if (IS_ERR(pdata))
 440                         return PTR_ERR(pdata);
 441         }
 442
 443         /* Make sure the slave address / chip type combo given is possible */
 444         if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
 445             chip->slv_addr) {
 446                 dev_err(&client->dev, "invalid slave address %02x\n",
 447                                 client->addr);
 448                 return -ENODEV;
 449         }
 450
 451         dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
 452                         "slave address 0x%02x\n",
 453                         client->name, chip->bits, client->addr);
 454
 455         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 456                 return -EIO;
 457
 458         if (pdata->num_leds != chip->bits) {
 459                 dev_err(&client->dev,
 460                         "board info claims %d LEDs on a %d-bit chip\n",
 461                         pdata->num_leds, chip->bits);
 462                 return -ENODEV;
 463         }
 464
 465         pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
 466         if (!pca955x)
 467                 return -ENOMEM;
 468
 469         pca955x->leds = devm_kcalloc(&client->dev,
 470                         chip->bits, sizeof(*pca955x_led), GFP_KERNEL);
 471         if (!pca955x->leds)
 472                 return -ENOMEM;
 473
 474         i2c_set_clientdata(client, pca955x);
 475
 476         mutex_init(&pca955x->lock);
 477         pca955x->client = client;
 478         pca955x->chipdef = chip;
 479
 480         for (i = 0; i < chip->bits; i++) {
 481                 pca955x_led = &pca955x->leds[i];
 482                 pca955x_led->led_num = i;
 483                 pca955x_led->pca955x = pca955x;
 484                 pca955x_led->type = pdata->leds[i].type;
 485
 486                 switch (pca955x_led->type) {
 487                 case PCA955X_TYPE_NONE:
 488                         break;
 489                 case PCA955X_TYPE_GPIO:
 490                         ngpios++;
 491                         break;
 492                 case PCA955X_TYPE_LED:
 493                         /*
 494                          * Platform data can specify LED names and
 495                          * default triggers
 496                          */
 497                         if (pdata->leds[i].name[0] == '\0')
 498                                 snprintf(pdata->leds[i].name,
 499                                         sizeof(pdata->leds[i].name), "%d", i);
 500
 501                         snprintf(pca955x_led->name,
 502                                 sizeof(pca955x_led->name), "pca955x:%s",
 503                                 pdata->leds[i].name);
 504
 505                         if (pdata->leds[i].default_trigger)
 506                                 pca955x_led->led_cdev.default_trigger =
 507                                         pdata->leds[i].default_trigger;
 508
 509                         pca955x_led->led_cdev.name = pca955x_led->name;
 510                         pca955x_led->led_cdev.brightness_set_blocking =
 511                                 pca955x_led_set;
 512
 513                         err = devm_led_classdev_register(&client->dev,
 514                                                         &pca955x_led->led_cdev);
 515                         if (err)
 516                                 return err;
 517
 518                         /* Turn off LED */
 519                         err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
 520                         if (err)
 521                                 return err;
 522                 }
 523         }
 524
 525         /* PWM0 is used for half brightness or 50% duty cycle */
 526         err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
 527         if (err)
 528                 return err;
 529
 530         /* PWM1 is used for variable brightness, default to OFF */
 531         err = pca955x_write_pwm(client, 1, 0);
 532         if (err)
 533                 return err;
 534
 535         /* Set to fast frequency so we do not see flashing */
 536         err = pca955x_write_psc(client, 0, 0);
 537         if (err)
 538                 return err;
 539         err = pca955x_write_psc(client, 1, 0);
 540         if (err)
 541                 return err;
 542
 543 #ifdef CONFIG_LEDS_PCA955X_GPIO
 544         if (ngpios) {
 545                 pca955x->gpio.label = "gpio-pca955x";
 546                 pca955x->gpio.direction_input = pca955x_gpio_direction_input;
 547                 pca955x->gpio.direction_output = pca955x_gpio_direction_output;
 548                 pca955x->gpio.set = pca955x_gpio_set_value;
 549                 pca955x->gpio.get = pca955x_gpio_get_value;
 550                 pca955x->gpio.request = pca955x_gpio_request_pin;
 551                 pca955x->gpio.can_sleep = 1;
 552                 pca955x->gpio.base = -1;
 553                 pca955x->gpio.ngpio = ngpios;
 554                 pca955x->gpio.parent = &client->dev;
 555                 pca955x->gpio.owner = THIS_MODULE;
 556
 557                 err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
 558                                              pca955x);
 559                 if (err) {
 560                         /* Use data->gpio.dev as a flag for freeing gpiochip */
 561                         pca955x->gpio.parent = NULL;
 562                         dev_warn(&client->dev, "could not add gpiochip\n");
 563                         return err;
 564                 }
 565                 dev_info(&client->dev, "gpios %i...%i\n",
 566                          pca955x->gpio.base, pca955x->gpio.base +
 567                          pca955x->gpio.ngpio - 1);
 568         }
 569 #endif
 570
 571         return 0;
 572 }
 573
 574 static struct i2c_driver pca955x_driver = {
 575         .driver = {
 576                 .name   = "leds-pca955x",
 577                 .of_match_table = of_pca955x_match,
 578         },
 579         .probe  = pca955x_probe,
 580         .id_table = pca955x_id,
 581 };
 582
 583 module_i2c_driver(pca955x_driver);
 584
 585 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
 586 MODULE_DESCRIPTION("PCA955x LED driver");
 587 MODULE_LICENSE("GPL v2");