drivers/pwm/pwm-pca9685.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for PCA9685 16-channel 12-bit PWM LED controller
   4  *
   5  * Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
   6  * Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
   7  *
   8  * based on the pwm-twl-led.c driver
   9  */
  10
  11 #include <linux/acpi.h>
  12 #include <linux/gpio/driver.h>
  13 #include <linux/i2c.h>
  14 #include <linux/module.h>
  15 #include <linux/mutex.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/property.h>
  18 #include <linux/pwm.h>
  19 #include <linux/regmap.h>
  20 #include <linux/slab.h>
  21 #include <linux/delay.h>
  22 #include <linux/pm_runtime.h>
  23 #include <linux/bitmap.h>
  24
  25 /*
  26  * Because the PCA9685 has only one prescaler per chip, changing the period of
  27  * one channel affects the period of all 16 PWM outputs!
  28  * However, the ratio between each configured duty cycle and the chip-wide
  29  * period remains constant, because the OFF time is set in proportion to the
  30  * counter range.
  31  */
  32
  33 #define PCA9685_MODE1           0x00
  34 #define PCA9685_MODE2           0x01
  35 #define PCA9685_SUBADDR1        0x02
  36 #define PCA9685_SUBADDR2        0x03
  37 #define PCA9685_SUBADDR3        0x04
  38 #define PCA9685_ALLCALLADDR     0x05
  39 #define PCA9685_LEDX_ON_L       0x06
  40 #define PCA9685_LEDX_ON_H       0x07
  41 #define PCA9685_LEDX_OFF_L      0x08
  42 #define PCA9685_LEDX_OFF_H      0x09
  43
  44 #define PCA9685_ALL_LED_ON_L    0xFA
  45 #define PCA9685_ALL_LED_ON_H    0xFB
  46 #define PCA9685_ALL_LED_OFF_L   0xFC
  47 #define PCA9685_ALL_LED_OFF_H   0xFD
  48 #define PCA9685_PRESCALE        0xFE
  49
  50 #define PCA9685_PRESCALE_MIN    0x03    /* => max. frequency of 1526 Hz */
  51 #define PCA9685_PRESCALE_MAX    0xFF    /* => min. frequency of 24 Hz */
  52
  53 #define PCA9685_COUNTER_RANGE   4096
  54 #define PCA9685_DEFAULT_PERIOD  5000000 /* Default period_ns = 1/200 Hz */
  55 #define PCA9685_OSC_CLOCK_MHZ   25      /* Internal oscillator with 25 MHz */
  56
  57 #define PCA9685_NUMREGS         0xFF
  58 #define PCA9685_MAXCHAN         0x10
  59
  60 #define LED_FULL                (1 << 4)
  61 #define MODE1_SLEEP             (1 << 4)
  62 #define MODE2_INVRT             (1 << 4)
  63 #define MODE2_OUTDRV            (1 << 2)
  64
  65 #define LED_N_ON_H(N)   (PCA9685_LEDX_ON_H + (4 * (N)))
  66 #define LED_N_ON_L(N)   (PCA9685_LEDX_ON_L + (4 * (N)))
  67 #define LED_N_OFF_H(N)  (PCA9685_LEDX_OFF_H + (4 * (N)))
  68 #define LED_N_OFF_L(N)  (PCA9685_LEDX_OFF_L + (4 * (N)))
  69
  70 struct pca9685 {
  71         struct pwm_chip chip;
  72         struct regmap *regmap;
  73         int duty_ns;
  74         int period_ns;
  75 #if IS_ENABLED(CONFIG_GPIOLIB)
  76         struct mutex lock;
  77         struct gpio_chip gpio;
  78         DECLARE_BITMAP(pwms_inuse, PCA9685_MAXCHAN + 1);
  79 #endif
  80 };
  81
  82 static inline struct pca9685 *to_pca(struct pwm_chip *chip)
  83 {
  84         return container_of(chip, struct pca9685, chip);
  85 }
  86
  87 #if IS_ENABLED(CONFIG_GPIOLIB)
  88 static bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca, int pwm_idx)
  89 {
  90         bool is_inuse;
  91
  92         mutex_lock(&pca->lock);
  93         if (pwm_idx >= PCA9685_MAXCHAN) {
  94                 /*
  95                  * "all LEDs" channel:
  96                  * pretend already in use if any of the PWMs are requested
  97                  */
  98                 if (!bitmap_empty(pca->pwms_inuse, PCA9685_MAXCHAN)) {
  99                         is_inuse = true;
 100                         goto out;
 101                 }
 102         } else {
 103                 /*
 104                  * regular channel:
 105                  * pretend already in use if the "all LEDs" channel is requested
 106                  */
 107                 if (test_bit(PCA9685_MAXCHAN, pca->pwms_inuse)) {
 108                         is_inuse = true;
 109                         goto out;
 110                 }
 111         }
 112         is_inuse = test_and_set_bit(pwm_idx, pca->pwms_inuse);
 113 out:
 114         mutex_unlock(&pca->lock);
 115         return is_inuse;
 116 }
 117
 118 static void pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
 119 {
 120         mutex_lock(&pca->lock);
 121         clear_bit(pwm_idx, pca->pwms_inuse);
 122         mutex_unlock(&pca->lock);
 123 }
 124
 125 static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
 126 {
 127         struct pca9685 *pca = gpiochip_get_data(gpio);
 128
 129         if (pca9685_pwm_test_and_set_inuse(pca, offset))
 130                 return -EBUSY;
 131         pm_runtime_get_sync(pca->chip.dev);
 132         return 0;
 133 }
 134
 135 static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
 136 {
 137         struct pca9685 *pca = gpiochip_get_data(gpio);
 138         struct pwm_device *pwm = &pca->chip.pwms[offset];
 139         unsigned int value;
 140
 141         regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);
 142
 143         return value & LED_FULL;
 144 }
 145
 146 static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
 147                                  int value)
 148 {
 149         struct pca9685 *pca = gpiochip_get_data(gpio);
 150         struct pwm_device *pwm = &pca->chip.pwms[offset];
 151         unsigned int on = value ? LED_FULL : 0;
 152
 153         /* Clear both OFF registers */
 154         regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
 155         regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);
 156
 157         /* Set the full ON bit */
 158         regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
 159 }
 160
 161 static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
 162 {
 163         struct pca9685 *pca = gpiochip_get_data(gpio);
 164
 165         pca9685_pwm_gpio_set(gpio, offset, 0);
 166         pm_runtime_put(pca->chip.dev);
 167         pca9685_pwm_clear_inuse(pca, offset);
 168 }
 169
 170 static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
 171                                           unsigned int offset)
 172 {
 173         /* Always out */
 174         return 0;
 175 }
 176
 177 static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
 178                                             unsigned int offset)
 179 {
 180         return -EINVAL;
 181 }
 182
 183 static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
 184                                              unsigned int offset, int value)
 185 {
 186         pca9685_pwm_gpio_set(gpio, offset, value);
 187
 188         return 0;
 189 }
 190
 191 /*
 192  * The PCA9685 has a bit for turning the PWM output full off or on. Some
 193  * boards like Intel Galileo actually uses these as normal GPIOs so we
 194  * expose a GPIO chip here which can exclusively take over the underlying
 195  * PWM channel.
 196  */
 197 static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 198 {
 199         struct device *dev = pca->chip.dev;
 200
 201         mutex_init(&pca->lock);
 202
 203         pca->gpio.label = dev_name(dev);
 204         pca->gpio.parent = dev;
 205         pca->gpio.request = pca9685_pwm_gpio_request;
 206         pca->gpio.free = pca9685_pwm_gpio_free;
 207         pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
 208         pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
 209         pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
 210         pca->gpio.get = pca9685_pwm_gpio_get;
 211         pca->gpio.set = pca9685_pwm_gpio_set;
 212         pca->gpio.base = -1;
 213         pca->gpio.ngpio = PCA9685_MAXCHAN;
 214         pca->gpio.can_sleep = true;
 215
 216         return devm_gpiochip_add_data(dev, &pca->gpio, pca);
 217 }
 218 #else
 219 static inline bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca,
 220                                                   int pwm_idx)
 221 {
 222         return false;
 223 }
 224
 225 static inline void
 226 pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
 227 {
 228 }
 229
 230 static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 231 {
 232         return 0;
 233 }
 234 #endif
 235
 236 static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
 237 {
 238         regmap_update_bits(pca->regmap, PCA9685_MODE1,
 239                            MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
 240         if (!enable) {
 241                 /* Wait 500us for the oscillator to be back up */
 242                 udelay(500);
 243         }
 244 }
 245
 246 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 247                               int duty_ns, int period_ns)
 248 {
 249         struct pca9685 *pca = to_pca(chip);
 250         unsigned long long duty;
 251         unsigned int reg;
 252         int prescale;
 253
 254         if (period_ns != pca->period_ns) {
 255                 prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
 256                                              PCA9685_COUNTER_RANGE * 1000) - 1;
 257
 258                 if (prescale >= PCA9685_PRESCALE_MIN &&
 259                         prescale <= PCA9685_PRESCALE_MAX) {
 260                         /*
 261                          * putting the chip briefly into SLEEP mode
 262                          * at this point won't interfere with the
 263                          * pm_runtime framework, because the pm_runtime
 264                          * state is guaranteed active here.
 265                          */
 266                         /* Put chip into sleep mode */
 267                         pca9685_set_sleep_mode(pca, true);
 268
 269                         /* Change the chip-wide output frequency */
 270                         regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
 271
 272                         /* Wake the chip up */
 273                         pca9685_set_sleep_mode(pca, false);
 274
 275                         pca->period_ns = period_ns;
 276                 } else {
 277                         dev_err(chip->dev,
 278                                 "prescaler not set: period out of bounds!\n");
 279                         return -EINVAL;
 280                 }
 281         }
 282
 283         pca->duty_ns = duty_ns;
 284
 285         if (duty_ns < 1) {
 286                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 287                         reg = PCA9685_ALL_LED_OFF_H;
 288                 else
 289                         reg = LED_N_OFF_H(pwm->hwpwm);
 290
 291                 regmap_write(pca->regmap, reg, LED_FULL);
 292
 293                 return 0;
 294         }
 295
 296         if (duty_ns == period_ns) {
 297                 /* Clear both OFF registers */
 298                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 299                         reg = PCA9685_ALL_LED_OFF_L;
 300                 else
 301                         reg = LED_N_OFF_L(pwm->hwpwm);
 302
 303                 regmap_write(pca->regmap, reg, 0x0);
 304
 305                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 306                         reg = PCA9685_ALL_LED_OFF_H;
 307                 else
 308                         reg = LED_N_OFF_H(pwm->hwpwm);
 309
 310                 regmap_write(pca->regmap, reg, 0x0);
 311
 312                 /* Set the full ON bit */
 313                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 314                         reg = PCA9685_ALL_LED_ON_H;
 315                 else
 316                         reg = LED_N_ON_H(pwm->hwpwm);
 317
 318                 regmap_write(pca->regmap, reg, LED_FULL);
 319
 320                 return 0;
 321         }
 322
 323         duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
 324         duty = DIV_ROUND_UP_ULL(duty, period_ns);
 325
 326         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 327                 reg = PCA9685_ALL_LED_OFF_L;
 328         else
 329                 reg = LED_N_OFF_L(pwm->hwpwm);
 330
 331         regmap_write(pca->regmap, reg, (int)duty & 0xff);
 332
 333         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 334                 reg = PCA9685_ALL_LED_OFF_H;
 335         else
 336                 reg = LED_N_OFF_H(pwm->hwpwm);
 337
 338         regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
 339
 340         /* Clear the full ON bit, otherwise the set OFF time has no effect */
 341         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 342                 reg = PCA9685_ALL_LED_ON_H;
 343         else
 344                 reg = LED_N_ON_H(pwm->hwpwm);
 345
 346         regmap_write(pca->regmap, reg, 0);
 347
 348         return 0;
 349 }
 350
 351 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 352 {
 353         struct pca9685 *pca = to_pca(chip);
 354         unsigned int reg;
 355
 356         /*
 357          * The PWM subsystem does not support a pre-delay.
 358          * So, set the ON-timeout to 0
 359          */
 360         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 361                 reg = PCA9685_ALL_LED_ON_L;
 362         else
 363                 reg = LED_N_ON_L(pwm->hwpwm);
 364
 365         regmap_write(pca->regmap, reg, 0);
 366
 367         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 368                 reg = PCA9685_ALL_LED_ON_H;
 369         else
 370                 reg = LED_N_ON_H(pwm->hwpwm);
 371
 372         regmap_write(pca->regmap, reg, 0);
 373
 374         /*
 375          * Clear the full-off bit.
 376          * It has precedence over the others and must be off.
 377          */
 378         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 379                 reg = PCA9685_ALL_LED_OFF_H;
 380         else
 381                 reg = LED_N_OFF_H(pwm->hwpwm);
 382
 383         regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
 384
 385         return 0;
 386 }
 387
 388 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 389 {
 390         struct pca9685 *pca = to_pca(chip);
 391         unsigned int reg;
 392
 393         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 394                 reg = PCA9685_ALL_LED_OFF_H;
 395         else
 396                 reg = LED_N_OFF_H(pwm->hwpwm);
 397
 398         regmap_write(pca->regmap, reg, LED_FULL);
 399
 400         /* Clear the LED_OFF counter. */
 401         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 402                 reg = PCA9685_ALL_LED_OFF_L;
 403         else
 404                 reg = LED_N_OFF_L(pwm->hwpwm);
 405
 406         regmap_write(pca->regmap, reg, 0x0);
 407 }
 408
 409 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 410 {
 411         struct pca9685 *pca = to_pca(chip);
 412
 413         if (pca9685_pwm_test_and_set_inuse(pca, pwm->hwpwm))
 414                 return -EBUSY;
 415         pm_runtime_get_sync(chip->dev);
 416
 417         return 0;
 418 }
 419
 420 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 421 {
 422         struct pca9685 *pca = to_pca(chip);
 423
 424         pca9685_pwm_disable(chip, pwm);
 425         pm_runtime_put(chip->dev);
 426         pca9685_pwm_clear_inuse(pca, pwm->hwpwm);
 427 }
 428
 429 static const struct pwm_ops pca9685_pwm_ops = {
 430         .enable = pca9685_pwm_enable,
 431         .disable = pca9685_pwm_disable,
 432         .config = pca9685_pwm_config,
 433         .request = pca9685_pwm_request,
 434         .free = pca9685_pwm_free,
 435         .owner = THIS_MODULE,
 436 };
 437
 438 static const struct regmap_config pca9685_regmap_i2c_config = {
 439         .reg_bits = 8,
 440         .val_bits = 8,
 441         .max_register = PCA9685_NUMREGS,
 442         .cache_type = REGCACHE_NONE,
 443 };
 444
 445 static int pca9685_pwm_probe(struct i2c_client *client,
 446                                 const struct i2c_device_id *id)
 447 {
 448         struct pca9685 *pca;
 449         int ret;
 450         int mode2;
 451
 452         pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
 453         if (!pca)
 454                 return -ENOMEM;
 455
 456         pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
 457         if (IS_ERR(pca->regmap)) {
 458                 ret = PTR_ERR(pca->regmap);
 459                 dev_err(&client->dev, "Failed to initialize register map: %d\n",
 460                         ret);
 461                 return ret;
 462         }
 463         pca->duty_ns = 0;
 464         pca->period_ns = PCA9685_DEFAULT_PERIOD;
 465
 466         i2c_set_clientdata(client, pca);
 467
 468         regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
 469
 470         if (device_property_read_bool(&client->dev, "invert"))
 471                 mode2 |= MODE2_INVRT;
 472         else
 473                 mode2 &= ~MODE2_INVRT;
 474
 475         if (device_property_read_bool(&client->dev, "open-drain"))
 476                 mode2 &= ~MODE2_OUTDRV;
 477         else
 478                 mode2 |= MODE2_OUTDRV;
 479
 480         regmap_write(pca->regmap, PCA9685_MODE2, mode2);
 481
 482         /* clear all "full off" bits */
 483         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
 484         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
 485
 486         pca->chip.ops = &pca9685_pwm_ops;
 487         /* add an extra channel for ALL_LED */
 488         pca->chip.npwm = PCA9685_MAXCHAN + 1;
 489
 490         pca->chip.dev = &client->dev;
 491         pca->chip.base = -1;
 492
 493         ret = pwmchip_add(&pca->chip);
 494         if (ret < 0)
 495                 return ret;
 496
 497         ret = pca9685_pwm_gpio_probe(pca);
 498         if (ret < 0) {
 499                 pwmchip_remove(&pca->chip);
 500                 return ret;
 501         }
 502
 503         /* the chip comes out of power-up in the active state */
 504         pm_runtime_set_active(&client->dev);
 505         /*
 506          * enable will put the chip into suspend, which is what we
 507          * want as all outputs are disabled at this point
 508          */
 509         pm_runtime_enable(&client->dev);
 510
 511         return 0;
 512 }
 513
 514 static int pca9685_pwm_remove(struct i2c_client *client)
 515 {
 516         struct pca9685 *pca = i2c_get_clientdata(client);
 517         int ret;
 518
 519         ret = pwmchip_remove(&pca->chip);
 520         if (ret)
 521                 return ret;
 522         pm_runtime_disable(&client->dev);
 523         return 0;
 524 }
 525
 526 #ifdef CONFIG_PM
 527 static int pca9685_pwm_runtime_suspend(struct device *dev)
 528 {
 529         struct i2c_client *client = to_i2c_client(dev);
 530         struct pca9685 *pca = i2c_get_clientdata(client);
 531
 532         pca9685_set_sleep_mode(pca, true);
 533         return 0;
 534 }
 535
 536 static int pca9685_pwm_runtime_resume(struct device *dev)
 537 {
 538         struct i2c_client *client = to_i2c_client(dev);
 539         struct pca9685 *pca = i2c_get_clientdata(client);
 540
 541         pca9685_set_sleep_mode(pca, false);
 542         return 0;
 543 }
 544 #endif
 545
 546 static const struct i2c_device_id pca9685_id[] = {
 547         { "pca9685", 0 },
 548         { /* sentinel */ },
 549 };
 550 MODULE_DEVICE_TABLE(i2c, pca9685_id);
 551
 552 #ifdef CONFIG_ACPI
 553 static const struct acpi_device_id pca9685_acpi_ids[] = {
 554         { "INT3492", 0 },
 555         { /* sentinel */ },
 556 };
 557 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
 558 #endif
 559
 560 #ifdef CONFIG_OF
 561 static const struct of_device_id pca9685_dt_ids[] = {
 562         { .compatible = "nxp,pca9685-pwm", },
 563         { /* sentinel */ }
 564 };
 565 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
 566 #endif
 567
 568 static const struct dev_pm_ops pca9685_pwm_pm = {
 569         SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
 570                            pca9685_pwm_runtime_resume, NULL)
 571 };
 572
 573 static struct i2c_driver pca9685_i2c_driver = {
 574         .driver = {
 575                 .name = "pca9685-pwm",
 576                 .acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
 577                 .of_match_table = of_match_ptr(pca9685_dt_ids),
 578                 .pm = &pca9685_pwm_pm,
 579         },
 580         .probe = pca9685_pwm_probe,
 581         .remove = pca9685_pwm_remove,
 582         .id_table = pca9685_id,
 583 };
 584
 585 module_i2c_driver(pca9685_i2c_driver);
 586
 587 MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
 588 MODULE_DESCRIPTION("PWM driver for PCA9685");
 589 MODULE_LICENSE("GPL");