drivers/leds/leds-pca955x.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
pca95xx_num_input_regs
pca95xx_num_led_regs
pca955x_ledsel
pca955x_write_psc
pca955x_write_pwm
pca955x_write_ls
pca955x_read_ls
pca955x_led_set
pca955x_read_input
pca955x_gpio_request_pin
pca955x_set_value
pca955x_gpio_set_value
pca955x_gpio_get_value
pca955x_gpio_direction_input
pca955x_gpio_direction_output
pca955x_get_pdata
pca955x_probe
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2007-2008 Extreme Engineering Solutions, Inc.
   4  *
   5  * Author: Nate Case <ncase@xes-inc.com>
   6  *
   7  * LED driver for various PCA955x I2C LED drivers
   8  *
   9  * Supported devices:
  10  *
  11  *      Device          Description             7-bit slave address
  12  *      ------          -----------             -------------------
  13  *      PCA9550         2-bit driver            0x60 .. 0x61
  14  *      PCA9551         8-bit driver            0x60 .. 0x67
  15  *      PCA9552         16-bit driver           0x60 .. 0x67
  16  *      PCA9553/01      4-bit driver            0x62
  17  *      PCA9553/02      4-bit driver            0x63
  18  *
  19  * Philips PCA955x LED driver chips follow a register map as shown below:
  20  *
  21  *      Control Register                Description
  22  *      ----------------                -----------
  23  *      0x0                             Input register 0
  24  *                                      ..
  25  *      NUM_INPUT_REGS - 1              Last Input register X
  26  *
  27  *      NUM_INPUT_REGS                  Frequency prescaler 0
  28  *      NUM_INPUT_REGS + 1              PWM register 0
  29  *      NUM_INPUT_REGS + 2              Frequency prescaler 1
  30  *      NUM_INPUT_REGS + 3              PWM register 1
  31  *
  32  *      NUM_INPUT_REGS + 4              LED selector 0
  33  *      NUM_INPUT_REGS + 4
  34  *          + NUM_LED_REGS - 1          Last LED selector
  35  *
  36  *  where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many
  37  *  bits the chip supports.
  38  */
  39 
  40 #include <linux/ctype.h>
  41 #include <linux/delay.h>
  42 #include <linux/err.h>
  43 #include <linux/gpio.h>
  44 #include <linux/i2c.h>
  45 #include <linux/leds.h>
  46 #include <linux/module.h>
  47 #include <linux/of.h>
  48 #include <linux/property.h>
  49 #include <linux/slab.h>
  50 #include <linux/string.h>
  51 
  52 #include <dt-bindings/leds/leds-pca955x.h>
  53 
  54 /* LED select registers determine the source that drives LED outputs */
  55 #define PCA955X_LS_LED_ON       0x0     /* Output LOW */
  56 #define PCA955X_LS_LED_OFF      0x1     /* Output HI-Z */
  57 #define PCA955X_LS_BLINK0       0x2     /* Blink at PWM0 rate */
  58 #define PCA955X_LS_BLINK1       0x3     /* Blink at PWM1 rate */
  59 
  60 #define PCA955X_GPIO_INPUT      LED_OFF
  61 #define PCA955X_GPIO_HIGH       LED_OFF
  62 #define PCA955X_GPIO_LOW        LED_FULL
  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 struct pca955x {
 110         struct mutex lock;
 111         struct pca955x_led *leds;
 112         struct pca955x_chipdef  *chipdef;
 113         struct i2c_client       *client;
 114 #ifdef CONFIG_LEDS_PCA955X_GPIO
 115         struct gpio_chip gpio;
 116 #endif
 117 };
 118 
 119 struct pca955x_led {
 120         struct pca955x  *pca955x;
 121         struct led_classdev     led_cdev;
 122         int                     led_num;        /* 0 .. 15 potentially */
 123         char                    name[32];
 124         u32                     type;
 125         const char              *default_trigger;
 126 };
 127 
 128 struct pca955x_platform_data {
 129         struct pca955x_led      *leds;
 130         int                     num_leds;
 131 };
 132 
 133 /* 8 bits per input register */
 134 static inline int pca95xx_num_input_regs(int bits)
 135 {
 136         return (bits + 7) / 8;
 137 }
 138 
 139 /* 4 bits per LED selector register */
 140 static inline int pca95xx_num_led_regs(int bits)
 141 {
 142         return (bits + 3)  / 4;
 143 }
 144 
 145 /*
 146  * Return an LED selector register value based on an existing one, with
 147  * the appropriate 2-bit state value set for the given LED number (0-3).
 148  */
 149 static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
 150 {
 151         return (oldval & (~(0x3 << (led_num << 1)))) |
 152                 ((state & 0x3) << (led_num << 1));
 153 }
 154 
 155 /*
 156  * Write to frequency prescaler register, used to program the
 157  * period of the PWM output.  period = (PSCx + 1) / 38
 158  */
 159 static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
 160 {
 161         struct pca955x *pca955x = i2c_get_clientdata(client);
 162         int ret;
 163 
 164         ret = i2c_smbus_write_byte_data(client,
 165                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
 166                 val);
 167         if (ret < 0)
 168                 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
 169                         __func__, n, val, ret);
 170         return ret;
 171 }
 172 
 173 /*
 174  * Write to PWM register, which determines the duty cycle of the
 175  * output.  LED is OFF when the count is less than the value of this
 176  * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
 177  *
 178  * Duty cycle is (256 - PWMx) / 256
 179  */
 180 static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
 181 {
 182         struct pca955x *pca955x = i2c_get_clientdata(client);
 183         int ret;
 184 
 185         ret = i2c_smbus_write_byte_data(client,
 186                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
 187                 val);
 188         if (ret < 0)
 189                 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
 190                         __func__, n, val, ret);
 191         return ret;
 192 }
 193 
 194 /*
 195  * Write to LED selector register, which determines the source that
 196  * drives the LED output.
 197  */
 198 static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
 199 {
 200         struct pca955x *pca955x = i2c_get_clientdata(client);
 201         int ret;
 202 
 203         ret = i2c_smbus_write_byte_data(client,
 204                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
 205                 val);
 206         if (ret < 0)
 207                 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
 208                         __func__, n, val, ret);
 209         return ret;
 210 }
 211 
 212 /*
 213  * Read the LED selector register, which determines the source that
 214  * drives the LED output.
 215  */
 216 static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
 217 {
 218         struct pca955x *pca955x = i2c_get_clientdata(client);
 219         int ret;
 220 
 221         ret = i2c_smbus_read_byte_data(client,
 222                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
 223         if (ret < 0) {
 224                 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
 225                         __func__, n, ret);
 226                 return ret;
 227         }
 228         *val = (u8)ret;
 229         return 0;
 230 }
 231 
 232 static int pca955x_led_set(struct led_classdev *led_cdev,
 233                             enum led_brightness value)
 234 {
 235         struct pca955x_led *pca955x_led;
 236         struct pca955x *pca955x;
 237         u8 ls;
 238         int chip_ls;    /* which LSx to use (0-3 potentially) */
 239         int ls_led;     /* which set of bits within LSx to use (0-3) */
 240         int ret;
 241 
 242         pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
 243         pca955x = pca955x_led->pca955x;
 244 
 245         chip_ls = pca955x_led->led_num / 4;
 246         ls_led = pca955x_led->led_num % 4;
 247 
 248         mutex_lock(&pca955x->lock);
 249 
 250         ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
 251         if (ret)
 252                 goto out;
 253 
 254         switch (value) {
 255         case LED_FULL:
 256                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
 257                 break;
 258         case LED_OFF:
 259                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
 260                 break;
 261         case LED_HALF:
 262                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
 263                 break;
 264         default:
 265                 /*
 266                  * Use PWM1 for all other values.  This has the unwanted
 267                  * side effect of making all LEDs on the chip share the
 268                  * same brightness level if set to a value other than
 269                  * OFF, HALF, or FULL.  But, this is probably better than
 270                  * just turning off for all other values.
 271                  */
 272                 ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
 273                 if (ret)
 274                         goto out;
 275                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
 276                 break;
 277         }
 278 
 279         ret = pca955x_write_ls(pca955x->client, chip_ls, ls);
 280 
 281 out:
 282         mutex_unlock(&pca955x->lock);
 283 
 284         return ret;
 285 }
 286 
 287 #ifdef CONFIG_LEDS_PCA955X_GPIO
 288 /*
 289  * Read the INPUT register, which contains the state of LEDs.
 290  */
 291 static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
 292 {
 293         int ret = i2c_smbus_read_byte_data(client, n);
 294 
 295         if (ret < 0) {
 296                 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
 297                         __func__, n, ret);
 298                 return ret;
 299         }
 300         *val = (u8)ret;
 301         return 0;
 302 
 303 }
 304 
 305 static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
 306 {
 307         struct pca955x *pca955x = gpiochip_get_data(gc);
 308         struct pca955x_led *led = &pca955x->leds[offset];
 309 
 310         if (led->type == PCA955X_TYPE_GPIO)
 311                 return 0;
 312 
 313         return -EBUSY;
 314 }
 315 
 316 static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
 317                              int val)
 318 {
 319         struct pca955x *pca955x = gpiochip_get_data(gc);
 320         struct pca955x_led *led = &pca955x->leds[offset];
 321 
 322         if (val)
 323                 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);
 324 
 325         return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW);
 326 }
 327 
 328 static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
 329                                    int val)
 330 {
 331         pca955x_set_value(gc, offset, val);
 332 }
 333 
 334 static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
 335 {
 336         struct pca955x *pca955x = gpiochip_get_data(gc);
 337         struct pca955x_led *led = &pca955x->leds[offset];
 338         u8 reg = 0;
 339 
 340         /* There is nothing we can do about errors */
 341         pca955x_read_input(pca955x->client, led->led_num / 8, &reg);
 342 
 343         return !!(reg & (1 << (led->led_num % 8)));
 344 }
 345 
 346 static int pca955x_gpio_direction_input(struct gpio_chip *gc,
 347                                         unsigned int offset)
 348 {
 349         struct pca955x *pca955x = gpiochip_get_data(gc);
 350         struct pca955x_led *led = &pca955x->leds[offset];
 351 
 352         /* To use as input ensure pin is not driven. */
 353         return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
 354 }
 355 
 356 static int pca955x_gpio_direction_output(struct gpio_chip *gc,
 357                                          unsigned int offset, int val)
 358 {
 359         return pca955x_set_value(gc, offset, val);
 360 }
 361 #endif /* CONFIG_LEDS_PCA955X_GPIO */
 362 
 363 static struct pca955x_platform_data *
 364 pca955x_get_pdata(struct i2c_client *client, struct pca955x_chipdef *chip)
 365 {
 366         struct pca955x_platform_data *pdata;
 367         struct fwnode_handle *child;
 368         int count;
 369 
 370         count = device_get_child_node_count(&client->dev);
 371         if (!count || count > chip->bits)
 372                 return ERR_PTR(-ENODEV);
 373 
 374         pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
 375         if (!pdata)
 376                 return ERR_PTR(-ENOMEM);
 377 
 378         pdata->leds = devm_kcalloc(&client->dev,
 379                                    chip->bits, sizeof(struct pca955x_led),
 380                                    GFP_KERNEL);
 381         if (!pdata->leds)
 382                 return ERR_PTR(-ENOMEM);
 383 
 384         device_for_each_child_node(&client->dev, child) {
 385                 const char *name;
 386                 u32 reg;
 387                 int res;
 388 
 389                 res = fwnode_property_read_u32(child, "reg", &reg);
 390                 if ((res != 0) || (reg >= chip->bits))
 391                         continue;
 392 
 393                 res = fwnode_property_read_string(child, "label", &name);
 394                 if ((res != 0) && is_of_node(child))
 395                         name = to_of_node(child)->name;
 396 
 397                 snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name),
 398                          "%s", name);
 399 
 400                 pdata->leds[reg].type = PCA955X_TYPE_LED;
 401                 fwnode_property_read_u32(child, "type", &pdata->leds[reg].type);
 402                 fwnode_property_read_string(child, "linux,default-trigger",
 403                                         &pdata->leds[reg].default_trigger);
 404         }
 405 
 406         pdata->num_leds = chip->bits;
 407 
 408         return pdata;
 409 }
 410 
 411 static const struct of_device_id of_pca955x_match[] = {
 412         { .compatible = "nxp,pca9550", .data = (void *)pca9550 },
 413         { .compatible = "nxp,pca9551", .data = (void *)pca9551 },
 414         { .compatible = "nxp,pca9552", .data = (void *)pca9552 },
 415         { .compatible = "nxp,pca9553", .data = (void *)pca9553 },
 416         {},
 417 };
 418 MODULE_DEVICE_TABLE(of, of_pca955x_match);
 419 
 420 static int pca955x_probe(struct i2c_client *client,
 421                                         const struct i2c_device_id *id)
 422 {
 423         struct pca955x *pca955x;
 424         struct pca955x_led *pca955x_led;
 425         struct pca955x_chipdef *chip;
 426         struct i2c_adapter *adapter;
 427         int i, err;
 428         struct pca955x_platform_data *pdata;
 429         int ngpios = 0;
 430 
 431         chip = &pca955x_chipdefs[id->driver_data];
 432         adapter = client->adapter;
 433         pdata = dev_get_platdata(&client->dev);
 434         if (!pdata) {
 435                 pdata = pca955x_get_pdata(client, chip);
 436                 if (IS_ERR(pdata))
 437                         return PTR_ERR(pdata);
 438         }
 439 
 440         /* Make sure the slave address / chip type combo given is possible */
 441         if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
 442             chip->slv_addr) {
 443                 dev_err(&client->dev, "invalid slave address %02x\n",
 444                                 client->addr);
 445                 return -ENODEV;
 446         }
 447 
 448         dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
 449                         "slave address 0x%02x\n",
 450                         client->name, chip->bits, client->addr);
 451 
 452         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 453                 return -EIO;
 454 
 455         if (pdata->num_leds != chip->bits) {
 456                 dev_err(&client->dev,
 457                         "board info claims %d LEDs on a %d-bit chip\n",
 458                         pdata->num_leds, chip->bits);
 459                 return -ENODEV;
 460         }
 461 
 462         pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
 463         if (!pca955x)
 464                 return -ENOMEM;
 465 
 466         pca955x->leds = devm_kcalloc(&client->dev,
 467                         chip->bits, sizeof(*pca955x_led), GFP_KERNEL);
 468         if (!pca955x->leds)
 469                 return -ENOMEM;
 470 
 471         i2c_set_clientdata(client, pca955x);
 472 
 473         mutex_init(&pca955x->lock);
 474         pca955x->client = client;
 475         pca955x->chipdef = chip;
 476 
 477         for (i = 0; i < chip->bits; i++) {
 478                 pca955x_led = &pca955x->leds[i];
 479                 pca955x_led->led_num = i;
 480                 pca955x_led->pca955x = pca955x;
 481                 pca955x_led->type = pdata->leds[i].type;
 482 
 483                 switch (pca955x_led->type) {
 484                 case PCA955X_TYPE_NONE:
 485                         break;
 486                 case PCA955X_TYPE_GPIO:
 487                         ngpios++;
 488                         break;
 489                 case PCA955X_TYPE_LED:
 490                         /*
 491                          * Platform data can specify LED names and
 492                          * default triggers
 493                          */
 494                         if (pdata->leds[i].name[0] == '\0')
 495                                 snprintf(pdata->leds[i].name,
 496                                         sizeof(pdata->leds[i].name), "%d", i);
 497 
 498                         snprintf(pca955x_led->name,
 499                                 sizeof(pca955x_led->name), "pca955x:%s",
 500                                 pdata->leds[i].name);
 501 
 502                         if (pdata->leds[i].default_trigger)
 503                                 pca955x_led->led_cdev.default_trigger =
 504                                         pdata->leds[i].default_trigger;
 505 
 506                         pca955x_led->led_cdev.name = pca955x_led->name;
 507                         pca955x_led->led_cdev.brightness_set_blocking =
 508                                 pca955x_led_set;
 509 
 510                         err = devm_led_classdev_register(&client->dev,
 511                                                         &pca955x_led->led_cdev);
 512                         if (err)
 513                                 return err;
 514 
 515                         /* Turn off LED */
 516                         err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
 517                         if (err)
 518                                 return err;
 519                 }
 520         }
 521 
 522         /* PWM0 is used for half brightness or 50% duty cycle */
 523         err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
 524         if (err)
 525                 return err;
 526 
 527         /* PWM1 is used for variable brightness, default to OFF */
 528         err = pca955x_write_pwm(client, 1, 0);
 529         if (err)
 530                 return err;
 531 
 532         /* Set to fast frequency so we do not see flashing */
 533         err = pca955x_write_psc(client, 0, 0);
 534         if (err)
 535                 return err;
 536         err = pca955x_write_psc(client, 1, 0);
 537         if (err)
 538                 return err;
 539 
 540 #ifdef CONFIG_LEDS_PCA955X_GPIO
 541         if (ngpios) {
 542                 pca955x->gpio.label = "gpio-pca955x";
 543                 pca955x->gpio.direction_input = pca955x_gpio_direction_input;
 544                 pca955x->gpio.direction_output = pca955x_gpio_direction_output;
 545                 pca955x->gpio.set = pca955x_gpio_set_value;
 546                 pca955x->gpio.get = pca955x_gpio_get_value;
 547                 pca955x->gpio.request = pca955x_gpio_request_pin;
 548                 pca955x->gpio.can_sleep = 1;
 549                 pca955x->gpio.base = -1;
 550                 pca955x->gpio.ngpio = ngpios;
 551                 pca955x->gpio.parent = &client->dev;
 552                 pca955x->gpio.owner = THIS_MODULE;
 553 
 554                 err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
 555                                              pca955x);
 556                 if (err) {
 557                         /* Use data->gpio.dev as a flag for freeing gpiochip */
 558                         pca955x->gpio.parent = NULL;
 559                         dev_warn(&client->dev, "could not add gpiochip\n");
 560                         return err;
 561                 }
 562                 dev_info(&client->dev, "gpios %i...%i\n",
 563                          pca955x->gpio.base, pca955x->gpio.base +
 564                          pca955x->gpio.ngpio - 1);
 565         }
 566 #endif
 567 
 568         return 0;
 569 }
 570 
 571 static struct i2c_driver pca955x_driver = {
 572         .driver = {
 573                 .name   = "leds-pca955x",
 574                 .of_match_table = of_pca955x_match,
 575         },
 576         .probe  = pca955x_probe,
 577         .id_table = pca955x_id,
 578 };
 579 
 580 module_i2c_driver(pca955x_driver);
 581 
 582 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
 583 MODULE_DESCRIPTION("PCA955x LED driver");
 584 MODULE_LICENSE("GPL v2");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/leds/leds-pca955x.c

DEFINITIONS
