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/ctype.h>
  45 #include <linux/delay.h>
  46 #include <linux/err.h>
  47 #include <linux/gpio.h>
  48 #include <linux/i2c.h>
  49 #include <linux/leds.h>
  50 #include <linux/module.h>
  51 #include <linux/of_device.h>
  52 #include <linux/of.h>
  53 #include <linux/slab.h>
  54 #include <linux/string.h>
  55
  56 #include <dt-bindings/leds/leds-pca955x.h>
  57
  58 /* LED select registers determine the source that drives LED outputs */
  59 #define PCA955X_LS_LED_ON       0x0     /* Output LOW */
  60 #define PCA955X_LS_LED_OFF      0x1     /* Output HI-Z */
  61 #define PCA955X_LS_BLINK0       0x2     /* Blink at PWM0 rate */
  62 #define PCA955X_LS_BLINK1       0x3     /* Blink at PWM1 rate */
  63
  64 enum pca955x_type {
  65         pca9550,
  66         pca9551,
  67         pca9552,
  68         pca9553,
  69 };
  70
  71 struct pca955x_chipdef {
  72         int                     bits;
  73         u8                      slv_addr;       /* 7-bit slave address mask */
  74         int                     slv_addr_shift; /* Number of bits to ignore */
  75 };
  76
  77 static struct pca955x_chipdef pca955x_chipdefs[] = {
  78         [pca9550] = {
  79                 .bits           = 2,
  80                 .slv_addr       = /* 110000x */ 0x60,
  81                 .slv_addr_shift = 1,
  82         },
  83         [pca9551] = {
  84                 .bits           = 8,
  85                 .slv_addr       = /* 1100xxx */ 0x60,
  86                 .slv_addr_shift = 3,
  87         },
  88         [pca9552] = {
  89                 .bits           = 16,
  90                 .slv_addr       = /* 1100xxx */ 0x60,
  91                 .slv_addr_shift = 3,
  92         },
  93         [pca9553] = {
  94                 .bits           = 4,
  95                 .slv_addr       = /* 110001x */ 0x62,
  96                 .slv_addr_shift = 1,
  97         },
  98 };
  99
 100 static const struct i2c_device_id pca955x_id[] = {
 101         { "pca9550", pca9550 },
 102         { "pca9551", pca9551 },
 103         { "pca9552", pca9552 },
 104         { "pca9553", pca9553 },
 105         { }
 106 };
 107 MODULE_DEVICE_TABLE(i2c, pca955x_id);
 108
 109 static const struct acpi_device_id pca955x_acpi_ids[] = {
 110         { "PCA9550",  pca9550 },
 111         { "PCA9551",  pca9551 },
 112         { "PCA9552",  pca9552 },
 113         { "PCA9553",  pca9553 },
 114         { }
 115 };
 116 MODULE_DEVICE_TABLE(acpi, pca955x_acpi_ids);
 117
 118 struct pca955x {
 119         struct mutex lock;
 120         struct pca955x_led *leds;
 121         struct pca955x_chipdef  *chipdef;
 122         struct i2c_client       *client;
 123 #ifdef CONFIG_LEDS_PCA955X_GPIO
 124         struct gpio_chip gpio;
 125 #endif
 126 };
 127
 128 struct pca955x_led {
 129         struct pca955x  *pca955x;
 130         struct led_classdev     led_cdev;
 131         int                     led_num;        /* 0 .. 15 potentially */
 132         char                    name[32];
 133         u32                     type;
 134         const char              *default_trigger;
 135 };
 136
 137 struct pca955x_platform_data {
 138         struct pca955x_led      *leds;
 139         int                     num_leds;
 140 };
 141
 142 /* 8 bits per input register */
 143 static inline int pca95xx_num_input_regs(int bits)
 144 {
 145         return (bits + 7) / 8;
 146 }
 147
 148 /* 4 bits per LED selector register */
 149 static inline int pca95xx_num_led_regs(int bits)
 150 {
 151         return (bits + 3)  / 4;
 152 }
 153
 154 /*
 155  * Return an LED selector register value based on an existing one, with
 156  * the appropriate 2-bit state value set for the given LED number (0-3).
 157  */
 158 static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
 159 {
 160         return (oldval & (~(0x3 << (led_num << 1)))) |
 161                 ((state & 0x3) << (led_num << 1));
 162 }
 163
 164 /*
 165  * Write to frequency prescaler register, used to program the
 166  * period of the PWM output.  period = (PSCx + 1) / 38
 167  */
 168 static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
 169 {
 170         struct pca955x *pca955x = i2c_get_clientdata(client);
 171         int ret;
 172
 173         ret = i2c_smbus_write_byte_data(client,
 174                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
 175                 val);
 176         if (ret < 0)
 177                 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
 178                         __func__, n, val, ret);
 179         return ret;
 180 }
 181
 182 /*
 183  * Write to PWM register, which determines the duty cycle of the
 184  * output.  LED is OFF when the count is less than the value of this
 185  * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
 186  *
 187  * Duty cycle is (256 - PWMx) / 256
 188  */
 189 static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
 190 {
 191         struct pca955x *pca955x = i2c_get_clientdata(client);
 192         int ret;
 193
 194         ret = i2c_smbus_write_byte_data(client,
 195                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
 196                 val);
 197         if (ret < 0)
 198                 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
 199                         __func__, n, val, ret);
 200         return ret;
 201 }
 202
 203 /*
 204  * Write to LED selector register, which determines the source that
 205  * drives the LED output.
 206  */
 207 static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
 208 {
 209         struct pca955x *pca955x = i2c_get_clientdata(client);
 210         int ret;
 211
 212         ret = i2c_smbus_write_byte_data(client,
 213                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
 214                 val);
 215         if (ret < 0)
 216                 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
 217                         __func__, n, val, ret);
 218         return ret;
 219 }
 220
 221 /*
 222  * Read the LED selector register, which determines the source that
 223  * drives the LED output.
 224  */
 225 static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
 226 {
 227         struct pca955x *pca955x = i2c_get_clientdata(client);
 228         int ret;
 229
 230         ret = i2c_smbus_read_byte_data(client,
 231                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
 232         if (ret < 0) {
 233                 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
 234                         __func__, n, ret);
 235                 return ret;
 236         }
 237         *val = (u8)ret;
 238         return 0;
 239 }
 240
 241 static int pca955x_led_set(struct led_classdev *led_cdev,
 242                             enum led_brightness value)
 243 {
 244         struct pca955x_led *pca955x_led;
 245         struct pca955x *pca955x;
 246         u8 ls;
 247         int chip_ls;    /* which LSx to use (0-3 potentially) */
 248         int ls_led;     /* which set of bits within LSx to use (0-3) */
 249         int ret;
 250
 251         pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
 252         pca955x = pca955x_led->pca955x;
 253
 254         chip_ls = pca955x_led->led_num / 4;
 255         ls_led = pca955x_led->led_num % 4;
 256
 257         mutex_lock(&pca955x->lock);
 258
 259         ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
 260         if (ret)
 261                 goto out;
 262
 263         switch (value) {
 264         case LED_FULL:
 265                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
 266                 break;
 267         case LED_OFF:
 268                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
 269                 break;
 270         case LED_HALF:
 271                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
 272                 break;
 273         default:
 274                 /*
 275                  * Use PWM1 for all other values.  This has the unwanted
 276                  * side effect of making all LEDs on the chip share the
 277                  * same brightness level if set to a value other than
 278                  * OFF, HALF, or FULL.  But, this is probably better than
 279                  * just turning off for all other values.
 280                  */
 281                 ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
 282                 if (ret)
 283                         goto out;
 284                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
 285                 break;
 286         }
 287
 288         ret = pca955x_write_ls(pca955x->client, chip_ls, ls);
 289
 290 out:
 291         mutex_unlock(&pca955x->lock);
 292
 293         return ret;
 294 }
 295
 296 #ifdef CONFIG_LEDS_PCA955X_GPIO
 297 /*
 298  * Read the INPUT register, which contains the state of LEDs.
 299  */
 300 static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
 301 {
 302         int ret = i2c_smbus_read_byte_data(client, n);
 303
 304         if (ret < 0) {
 305                 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
 306                         __func__, n, ret);
 307                 return ret;
 308         }
 309         *val = (u8)ret;
 310         return 0;
 311
 312 }
 313
 314 static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
 315 {
 316         struct pca955x *pca955x = gpiochip_get_data(gc);
 317         struct pca955x_led *led = &pca955x->leds[offset];
 318
 319         if (led->type == PCA955X_TYPE_GPIO)
 320                 return 0;
 321
 322         return -EBUSY;
 323 }
 324
 325 static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
 326                              int val)
 327 {
 328         struct pca955x *pca955x = gpiochip_get_data(gc);
 329         struct pca955x_led *led = &pca955x->leds[offset];
 330
 331         if (val)
 332                 return pca955x_led_set(&led->led_cdev, LED_FULL);
 333         else
 334                 return pca955x_led_set(&led->led_cdev, LED_OFF);
 335 }
 336
 337 static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
 338                                    int val)
 339 {
 340         pca955x_set_value(gc, offset, val);
 341 }
 342
 343 static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
 344 {
 345         struct pca955x *pca955x = gpiochip_get_data(gc);
 346         struct pca955x_led *led = &pca955x->leds[offset];
 347         u8 reg = 0;
 348
 349         /* There is nothing we can do about errors */
 350         pca955x_read_input(pca955x->client, led->led_num / 8, &reg);
 351
 352         return !!(reg & (1 << (led->led_num % 8)));
 353 }
 354
 355 static int pca955x_gpio_direction_input(struct gpio_chip *gc,
 356                                         unsigned int offset)
 357 {
 358         /* To use as input ensure pin is not driven */
 359         return pca955x_set_value(gc, offset, 0);
 360 }
 361
 362 static int pca955x_gpio_direction_output(struct gpio_chip *gc,
 363                                          unsigned int offset, int val)
 364 {
 365         return pca955x_set_value(gc, offset, val);
 366 }
 367 #endif /* CONFIG_LEDS_PCA955X_GPIO */
 368
 369 #if IS_ENABLED(CONFIG_OF)
 370 static struct pca955x_platform_data *
 371 pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
 372 {
 373         struct device_node *np = client->dev.of_node;
 374         struct device_node *child;
 375         struct pca955x_platform_data *pdata;
 376         int count;
 377
 378         count = of_get_child_count(np);
 379         if (!count || count > chip->bits)
 380                 return ERR_PTR(-ENODEV);
 381
 382         pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
 383         if (!pdata)
 384                 return ERR_PTR(-ENOMEM);
 385
 386         pdata->leds = devm_kzalloc(&client->dev,
 387                                    sizeof(struct pca955x_led) * chip->bits,
 388                                    GFP_KERNEL);
 389         if (!pdata->leds)
 390                 return ERR_PTR(-ENOMEM);
 391
 392         for_each_child_of_node(np, child) {
 393                 const char *name;
 394                 u32 reg;
 395                 int res;
 396
 397                 res = of_property_read_u32(child, "reg", &reg);
 398                 if ((res != 0) || (reg >= chip->bits))
 399                         continue;
 400
 401                 if (of_property_read_string(child, "label", &name))
 402                         name = child->name;
 403
 404                 snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name),
 405                          "%s", name);
 406
 407                 pdata->leds[reg].type = PCA955X_TYPE_LED;
 408                 of_property_read_u32(child, "type", &pdata->leds[reg].type);
 409                 of_property_read_string(child, "linux,default-trigger",
 410                                         &pdata->leds[reg].default_trigger);
 411         }
 412
 413         pdata->num_leds = chip->bits;
 414
 415         return pdata;
 416 }
 417
 418 static const struct of_device_id of_pca955x_match[] = {
 419         { .compatible = "nxp,pca9550", .data = (void *)pca9550 },
 420         { .compatible = "nxp,pca9551", .data = (void *)pca9551 },
 421         { .compatible = "nxp,pca9552", .data = (void *)pca9552 },
 422         { .compatible = "nxp,pca9553", .data = (void *)pca9553 },
 423         {},
 424 };
 425
 426 MODULE_DEVICE_TABLE(of, of_pca955x_match);
 427 #else
 428 static struct pca955x_platform_data *
 429 pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
 430 {
 431         return ERR_PTR(-ENODEV);
 432 }
 433 #endif
 434
 435 static int pca955x_probe(struct i2c_client *client,
 436                                         const struct i2c_device_id *id)
 437 {
 438         struct pca955x *pca955x;
 439         struct pca955x_led *pca955x_led;
 440         struct pca955x_chipdef *chip;
 441         struct i2c_adapter *adapter;
 442         int i, err;
 443         struct pca955x_platform_data *pdata;
 444         int ngpios = 0;
 445
 446         if (id) {
 447                 chip = &pca955x_chipdefs[id->driver_data];
 448         } else {
 449                 const struct acpi_device_id *acpi_id;
 450
 451                 acpi_id = acpi_match_device(pca955x_acpi_ids, &client->dev);
 452                 if (!acpi_id)
 453                         return -ENODEV;
 454                 chip = &pca955x_chipdefs[acpi_id->driver_data];
 455         }
 456         adapter = to_i2c_adapter(client->dev.parent);
 457         pdata = dev_get_platdata(&client->dev);
 458         if (!pdata) {
 459                 pdata = pca955x_pdata_of_init(client, chip);
 460                 if (IS_ERR(pdata))
 461                         return PTR_ERR(pdata);
 462         }
 463
 464         /* Make sure the slave address / chip type combo given is possible */
 465         if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
 466             chip->slv_addr) {
 467                 dev_err(&client->dev, "invalid slave address %02x\n",
 468                                 client->addr);
 469                 return -ENODEV;
 470         }
 471
 472         dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
 473                         "slave address 0x%02x\n",
 474                         client->name, chip->bits, client->addr);
 475
 476         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 477                 return -EIO;
 478
 479         if (pdata->num_leds != chip->bits) {
 480                 dev_err(&client->dev,
 481                         "board info claims %d LEDs on a %d-bit chip\n",
 482                         pdata->num_leds, chip->bits);
 483                 return -ENODEV;
 484         }
 485
 486         pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
 487         if (!pca955x)
 488                 return -ENOMEM;
 489
 490         pca955x->leds = devm_kzalloc(&client->dev,
 491                         sizeof(*pca955x_led) * chip->bits, GFP_KERNEL);
 492         if (!pca955x->leds)
 493                 return -ENOMEM;
 494
 495         i2c_set_clientdata(client, pca955x);
 496
 497         mutex_init(&pca955x->lock);
 498         pca955x->client = client;
 499         pca955x->chipdef = chip;
 500
 501         for (i = 0; i < chip->bits; i++) {
 502                 pca955x_led = &pca955x->leds[i];
 503                 pca955x_led->led_num = i;
 504                 pca955x_led->pca955x = pca955x;
 505                 pca955x_led->type = pdata->leds[i].type;
 506
 507                 switch (pca955x_led->type) {
 508                 case PCA955X_TYPE_NONE:
 509                         break;
 510                 case PCA955X_TYPE_GPIO:
 511                         ngpios++;
 512                         break;
 513                 case PCA955X_TYPE_LED:
 514                         /*
 515                          * Platform data can specify LED names and
 516                          * default triggers
 517                          */
 518                         if (pdata->leds[i].name[0] == '\0')
 519                                 snprintf(pdata->leds[i].name,
 520                                         sizeof(pdata->leds[i].name), "%d", i);
 521
 522                         snprintf(pca955x_led->name,
 523                                 sizeof(pca955x_led->name), "pca955x:%s",
 524                                 pdata->leds[i].name);
 525
 526                         if (pdata->leds[i].default_trigger)
 527                                 pca955x_led->led_cdev.default_trigger =
 528                                         pdata->leds[i].default_trigger;
 529
 530                         pca955x_led->led_cdev.name = pca955x_led->name;
 531                         pca955x_led->led_cdev.brightness_set_blocking =
 532                                 pca955x_led_set;
 533
 534                         err = devm_led_classdev_register(&client->dev,
 535                                                         &pca955x_led->led_cdev);
 536                         if (err)
 537                                 return err;
 538
 539                         /* Turn off LED */
 540                         err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
 541                         if (err)
 542                                 return err;
 543                 }
 544         }
 545
 546         /* PWM0 is used for half brightness or 50% duty cycle */
 547         err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
 548         if (err)
 549                 return err;
 550
 551         /* PWM1 is used for variable brightness, default to OFF */
 552         err = pca955x_write_pwm(client, 1, 0);
 553         if (err)
 554                 return err;
 555
 556         /* Set to fast frequency so we do not see flashing */
 557         err = pca955x_write_psc(client, 0, 0);
 558         if (err)
 559                 return err;
 560         err = pca955x_write_psc(client, 1, 0);
 561         if (err)
 562                 return err;
 563
 564 #ifdef CONFIG_LEDS_PCA955X_GPIO
 565         if (ngpios) {
 566                 pca955x->gpio.label = "gpio-pca955x";
 567                 pca955x->gpio.direction_input = pca955x_gpio_direction_input;
 568                 pca955x->gpio.direction_output = pca955x_gpio_direction_output;
 569                 pca955x->gpio.set = pca955x_gpio_set_value;
 570                 pca955x->gpio.get = pca955x_gpio_get_value;
 571                 pca955x->gpio.request = pca955x_gpio_request_pin;
 572                 pca955x->gpio.can_sleep = 1;
 573                 pca955x->gpio.base = -1;
 574                 pca955x->gpio.ngpio = ngpios;
 575                 pca955x->gpio.parent = &client->dev;
 576                 pca955x->gpio.owner = THIS_MODULE;
 577
 578                 err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
 579                                              pca955x);
 580                 if (err) {
 581                         /* Use data->gpio.dev as a flag for freeing gpiochip */
 582                         pca955x->gpio.parent = NULL;
 583                         dev_warn(&client->dev, "could not add gpiochip\n");
 584                         return err;
 585                 }
 586                 dev_info(&client->dev, "gpios %i...%i\n",
 587                          pca955x->gpio.base, pca955x->gpio.base +
 588                          pca955x->gpio.ngpio - 1);
 589         }
 590 #endif
 591
 592         return 0;
 593 }
 594
 595 static struct i2c_driver pca955x_driver = {
 596         .driver = {
 597                 .name   = "leds-pca955x",
 598                 .acpi_match_table = ACPI_PTR(pca955x_acpi_ids),
 599                 .of_match_table = of_match_ptr(of_pca955x_match),
 600         },
 601         .probe  = pca955x_probe,
 602         .id_table = pca955x_id,
 603 };
 604
 605 module_i2c_driver(pca955x_driver);
 606
 607 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
 608 MODULE_DESCRIPTION("PCA955x LED driver");
 609 MODULE_LICENSE("GPL v2");