drivers/pwm/pwm-pca9685.c

   1 /*
   2  * Driver for PCA9685 16-channel 12-bit PWM LED controller
   3  *
   4  * Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
   5  * Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
   6  *
   7  * based on the pwm-twl-led.c driver
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License version 2 as published by
  11  * the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16  * more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along with
  19  * this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <linux/acpi.h>
  23 #include <linux/gpio/driver.h>
  24 #include <linux/i2c.h>
  25 #include <linux/module.h>
  26 #include <linux/mutex.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/property.h>
  29 #include <linux/pwm.h>
  30 #include <linux/regmap.h>
  31 #include <linux/slab.h>
  32 #include <linux/delay.h>
  33 #include <linux/pm_runtime.h>
  34
  35 /*
  36  * Because the PCA9685 has only one prescaler per chip, changing the period of
  37  * one channel affects the period of all 16 PWM outputs!
  38  * However, the ratio between each configured duty cycle and the chip-wide
  39  * period remains constant, because the OFF time is set in proportion to the
  40  * counter range.
  41  */
  42
  43 #define PCA9685_MODE1           0x00
  44 #define PCA9685_MODE2           0x01
  45 #define PCA9685_SUBADDR1        0x02
  46 #define PCA9685_SUBADDR2        0x03
  47 #define PCA9685_SUBADDR3        0x04
  48 #define PCA9685_ALLCALLADDR     0x05
  49 #define PCA9685_LEDX_ON_L       0x06
  50 #define PCA9685_LEDX_ON_H       0x07
  51 #define PCA9685_LEDX_OFF_L      0x08
  52 #define PCA9685_LEDX_OFF_H      0x09
  53
  54 #define PCA9685_ALL_LED_ON_L    0xFA
  55 #define PCA9685_ALL_LED_ON_H    0xFB
  56 #define PCA9685_ALL_LED_OFF_L   0xFC
  57 #define PCA9685_ALL_LED_OFF_H   0xFD
  58 #define PCA9685_PRESCALE        0xFE
  59
  60 #define PCA9685_PRESCALE_MIN    0x03    /* => max. frequency of 1526 Hz */
  61 #define PCA9685_PRESCALE_MAX    0xFF    /* => min. frequency of 24 Hz */
  62
  63 #define PCA9685_COUNTER_RANGE   4096
  64 #define PCA9685_DEFAULT_PERIOD  5000000 /* Default period_ns = 1/200 Hz */
  65 #define PCA9685_OSC_CLOCK_MHZ   25      /* Internal oscillator with 25 MHz */
  66
  67 #define PCA9685_NUMREGS         0xFF
  68 #define PCA9685_MAXCHAN         0x10
  69
  70 #define LED_FULL                (1 << 4)
  71 #define MODE1_SLEEP             (1 << 4)
  72 #define MODE2_INVRT             (1 << 4)
  73 #define MODE2_OUTDRV            (1 << 2)
  74
  75 #define LED_N_ON_H(N)   (PCA9685_LEDX_ON_H + (4 * (N)))
  76 #define LED_N_ON_L(N)   (PCA9685_LEDX_ON_L + (4 * (N)))
  77 #define LED_N_OFF_H(N)  (PCA9685_LEDX_OFF_H + (4 * (N)))
  78 #define LED_N_OFF_L(N)  (PCA9685_LEDX_OFF_L + (4 * (N)))
  79
  80 struct pca9685 {
  81         struct pwm_chip chip;
  82         struct regmap *regmap;
  83         int duty_ns;
  84         int period_ns;
  85 #if IS_ENABLED(CONFIG_GPIOLIB)
  86         struct mutex lock;
  87         struct gpio_chip gpio;
  88 #endif
  89 };
  90
  91 static inline struct pca9685 *to_pca(struct pwm_chip *chip)
  92 {
  93         return container_of(chip, struct pca9685, chip);
  94 }
  95
  96 #if IS_ENABLED(CONFIG_GPIOLIB)
  97 static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
  98 {
  99         struct pca9685 *pca = gpiochip_get_data(gpio);
 100         struct pwm_device *pwm;
 101
 102         mutex_lock(&pca->lock);
 103
 104         pwm = &pca->chip.pwms[offset];
 105
 106         if (pwm->flags & (PWMF_REQUESTED | PWMF_EXPORTED)) {
 107                 mutex_unlock(&pca->lock);
 108                 return -EBUSY;
 109         }
 110
 111         pwm_set_chip_data(pwm, (void *)1);
 112
 113         mutex_unlock(&pca->lock);
 114         pm_runtime_get_sync(pca->chip.dev);
 115         return 0;
 116 }
 117
 118 static bool pca9685_pwm_is_gpio(struct pca9685 *pca, struct pwm_device *pwm)
 119 {
 120         bool is_gpio = false;
 121
 122         mutex_lock(&pca->lock);
 123
 124         if (pwm->hwpwm >= PCA9685_MAXCHAN) {
 125                 unsigned int i;
 126
 127                 /*
 128                  * Check if any of the GPIOs are requested and in that case
 129                  * prevent using the "all LEDs" channel.
 130                  */
 131                 for (i = 0; i < pca->gpio.ngpio; i++)
 132                         if (gpiochip_is_requested(&pca->gpio, i)) {
 133                                 is_gpio = true;
 134                                 break;
 135                         }
 136         } else if (pwm_get_chip_data(pwm)) {
 137                 is_gpio = true;
 138         }
 139
 140         mutex_unlock(&pca->lock);
 141         return is_gpio;
 142 }
 143
 144 static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
 145 {
 146         struct pca9685 *pca = gpiochip_get_data(gpio);
 147         struct pwm_device *pwm = &pca->chip.pwms[offset];
 148         unsigned int value;
 149
 150         regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);
 151
 152         return value & LED_FULL;
 153 }
 154
 155 static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
 156                                  int value)
 157 {
 158         struct pca9685 *pca = gpiochip_get_data(gpio);
 159         struct pwm_device *pwm = &pca->chip.pwms[offset];
 160         unsigned int on = value ? LED_FULL : 0;
 161
 162         /* Clear both OFF registers */
 163         regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
 164         regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);
 165
 166         /* Set the full ON bit */
 167         regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
 168 }
 169
 170 static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
 171 {
 172         struct pca9685 *pca = gpiochip_get_data(gpio);
 173         struct pwm_device *pwm;
 174
 175         pca9685_pwm_gpio_set(gpio, offset, 0);
 176         pm_runtime_put(pca->chip.dev);
 177         mutex_lock(&pca->lock);
 178         pwm = &pca->chip.pwms[offset];
 179         pwm_set_chip_data(pwm, NULL);
 180         mutex_unlock(&pca->lock);
 181 }
 182
 183 static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
 184                                           unsigned int offset)
 185 {
 186         /* Always out */
 187         return 0;
 188 }
 189
 190 static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
 191                                             unsigned int offset)
 192 {
 193         return -EINVAL;
 194 }
 195
 196 static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
 197                                              unsigned int offset, int value)
 198 {
 199         pca9685_pwm_gpio_set(gpio, offset, value);
 200
 201         return 0;
 202 }
 203
 204 /*
 205  * The PCA9685 has a bit for turning the PWM output full off or on. Some
 206  * boards like Intel Galileo actually uses these as normal GPIOs so we
 207  * expose a GPIO chip here which can exclusively take over the underlying
 208  * PWM channel.
 209  */
 210 static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 211 {
 212         struct device *dev = pca->chip.dev;
 213
 214         mutex_init(&pca->lock);
 215
 216         pca->gpio.label = dev_name(dev);
 217         pca->gpio.parent = dev;
 218         pca->gpio.request = pca9685_pwm_gpio_request;
 219         pca->gpio.free = pca9685_pwm_gpio_free;
 220         pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
 221         pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
 222         pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
 223         pca->gpio.get = pca9685_pwm_gpio_get;
 224         pca->gpio.set = pca9685_pwm_gpio_set;
 225         pca->gpio.base = -1;
 226         pca->gpio.ngpio = PCA9685_MAXCHAN;
 227         pca->gpio.can_sleep = true;
 228
 229         return devm_gpiochip_add_data(dev, &pca->gpio, pca);
 230 }
 231 #else
 232 static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
 233                                        struct pwm_device *pwm)
 234 {
 235         return false;
 236 }
 237
 238 static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 239 {
 240         return 0;
 241 }
 242 #endif
 243
 244 static void pca9685_set_sleep_mode(struct pca9685 *pca, int sleep)
 245 {
 246         regmap_update_bits(pca->regmap, PCA9685_MODE1,
 247                            MODE1_SLEEP, sleep ? MODE1_SLEEP : 0);
 248         if (!sleep) {
 249                 /* Wait 500us for the oscillator to be back up */
 250                 udelay(500);
 251         }
 252 }
 253
 254 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 255                               int duty_ns, int period_ns)
 256 {
 257         struct pca9685 *pca = to_pca(chip);
 258         unsigned long long duty;
 259         unsigned int reg;
 260         int prescale;
 261
 262         if (period_ns != pca->period_ns) {
 263                 prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
 264                                              PCA9685_COUNTER_RANGE * 1000) - 1;
 265
 266                 if (prescale >= PCA9685_PRESCALE_MIN &&
 267                         prescale <= PCA9685_PRESCALE_MAX) {
 268                         /*
 269                          * putting the chip briefly into SLEEP mode
 270                          * at this point won't interfere with the
 271                          * pm_runtime framework, because the pm_runtime
 272                          * state is guaranteed active here.
 273                          */
 274                         /* Put chip into sleep mode */
 275                         pca9685_set_sleep_mode(pca, 1);
 276
 277                         /* Change the chip-wide output frequency */
 278                         regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
 279
 280                         /* Wake the chip up */
 281                         pca9685_set_sleep_mode(pca, 0);
 282
 283                         pca->period_ns = period_ns;
 284                 } else {
 285                         dev_err(chip->dev,
 286                                 "prescaler not set: period out of bounds!\n");
 287                         return -EINVAL;
 288                 }
 289         }
 290
 291         pca->duty_ns = duty_ns;
 292
 293         if (duty_ns < 1) {
 294                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 295                         reg = PCA9685_ALL_LED_OFF_H;
 296                 else
 297                         reg = LED_N_OFF_H(pwm->hwpwm);
 298
 299                 regmap_write(pca->regmap, reg, LED_FULL);
 300
 301                 return 0;
 302         }
 303
 304         if (duty_ns == period_ns) {
 305                 /* Clear both OFF registers */
 306                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 307                         reg = PCA9685_ALL_LED_OFF_L;
 308                 else
 309                         reg = LED_N_OFF_L(pwm->hwpwm);
 310
 311                 regmap_write(pca->regmap, reg, 0x0);
 312
 313                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 314                         reg = PCA9685_ALL_LED_OFF_H;
 315                 else
 316                         reg = LED_N_OFF_H(pwm->hwpwm);
 317
 318                 regmap_write(pca->regmap, reg, 0x0);
 319
 320                 /* Set the full ON bit */
 321                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 322                         reg = PCA9685_ALL_LED_ON_H;
 323                 else
 324                         reg = LED_N_ON_H(pwm->hwpwm);
 325
 326                 regmap_write(pca->regmap, reg, LED_FULL);
 327
 328                 return 0;
 329         }
 330
 331         duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
 332         duty = DIV_ROUND_UP_ULL(duty, period_ns);
 333
 334         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 335                 reg = PCA9685_ALL_LED_OFF_L;
 336         else
 337                 reg = LED_N_OFF_L(pwm->hwpwm);
 338
 339         regmap_write(pca->regmap, reg, (int)duty & 0xff);
 340
 341         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 342                 reg = PCA9685_ALL_LED_OFF_H;
 343         else
 344                 reg = LED_N_OFF_H(pwm->hwpwm);
 345
 346         regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
 347
 348         /* Clear the full ON bit, otherwise the set OFF time has no effect */
 349         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 350                 reg = PCA9685_ALL_LED_ON_H;
 351         else
 352                 reg = LED_N_ON_H(pwm->hwpwm);
 353
 354         regmap_write(pca->regmap, reg, 0);
 355
 356         return 0;
 357 }
 358
 359 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 360 {
 361         struct pca9685 *pca = to_pca(chip);
 362         unsigned int reg;
 363
 364         /*
 365          * The PWM subsystem does not support a pre-delay.
 366          * So, set the ON-timeout to 0
 367          */
 368         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 369                 reg = PCA9685_ALL_LED_ON_L;
 370         else
 371                 reg = LED_N_ON_L(pwm->hwpwm);
 372
 373         regmap_write(pca->regmap, reg, 0);
 374
 375         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 376                 reg = PCA9685_ALL_LED_ON_H;
 377         else
 378                 reg = LED_N_ON_H(pwm->hwpwm);
 379
 380         regmap_write(pca->regmap, reg, 0);
 381
 382         /*
 383          * Clear the full-off bit.
 384          * It has precedence over the others and must be off.
 385          */
 386         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 387                 reg = PCA9685_ALL_LED_OFF_H;
 388         else
 389                 reg = LED_N_OFF_H(pwm->hwpwm);
 390
 391         regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
 392
 393         return 0;
 394 }
 395
 396 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 397 {
 398         struct pca9685 *pca = to_pca(chip);
 399         unsigned int reg;
 400
 401         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 402                 reg = PCA9685_ALL_LED_OFF_H;
 403         else
 404                 reg = LED_N_OFF_H(pwm->hwpwm);
 405
 406         regmap_write(pca->regmap, reg, LED_FULL);
 407
 408         /* Clear the LED_OFF counter. */
 409         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 410                 reg = PCA9685_ALL_LED_OFF_L;
 411         else
 412                 reg = LED_N_OFF_L(pwm->hwpwm);
 413
 414         regmap_write(pca->regmap, reg, 0x0);
 415 }
 416
 417 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 418 {
 419         struct pca9685 *pca = to_pca(chip);
 420
 421         if (pca9685_pwm_is_gpio(pca, pwm))
 422                 return -EBUSY;
 423         pm_runtime_get_sync(chip->dev);
 424
 425         return 0;
 426 }
 427
 428 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 429 {
 430         pca9685_pwm_disable(chip, pwm);
 431         pm_runtime_put(chip->dev);
 432 }
 433
 434 static const struct pwm_ops pca9685_pwm_ops = {
 435         .enable = pca9685_pwm_enable,
 436         .disable = pca9685_pwm_disable,
 437         .config = pca9685_pwm_config,
 438         .request = pca9685_pwm_request,
 439         .free = pca9685_pwm_free,
 440         .owner = THIS_MODULE,
 441 };
 442
 443 static const struct regmap_config pca9685_regmap_i2c_config = {
 444         .reg_bits = 8,
 445         .val_bits = 8,
 446         .max_register = PCA9685_NUMREGS,
 447         .cache_type = REGCACHE_NONE,
 448 };
 449
 450 static int pca9685_pwm_probe(struct i2c_client *client,
 451                                 const struct i2c_device_id *id)
 452 {
 453         struct pca9685 *pca;
 454         int ret;
 455         int mode2;
 456
 457         pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
 458         if (!pca)
 459                 return -ENOMEM;
 460
 461         pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
 462         if (IS_ERR(pca->regmap)) {
 463                 ret = PTR_ERR(pca->regmap);
 464                 dev_err(&client->dev, "Failed to initialize register map: %d\n",
 465                         ret);
 466                 return ret;
 467         }
 468         pca->duty_ns = 0;
 469         pca->period_ns = PCA9685_DEFAULT_PERIOD;
 470
 471         i2c_set_clientdata(client, pca);
 472
 473         regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
 474
 475         if (device_property_read_bool(&client->dev, "invert"))
 476                 mode2 |= MODE2_INVRT;
 477         else
 478                 mode2 &= ~MODE2_INVRT;
 479
 480         if (device_property_read_bool(&client->dev, "open-drain"))
 481                 mode2 &= ~MODE2_OUTDRV;
 482         else
 483                 mode2 |= MODE2_OUTDRV;
 484
 485         regmap_write(pca->regmap, PCA9685_MODE2, mode2);
 486
 487         /* clear all "full off" bits */
 488         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
 489         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
 490
 491         pca->chip.ops = &pca9685_pwm_ops;
 492         /* add an extra channel for ALL_LED */
 493         pca->chip.npwm = PCA9685_MAXCHAN + 1;
 494
 495         pca->chip.dev = &client->dev;
 496         pca->chip.base = -1;
 497
 498         ret = pwmchip_add(&pca->chip);
 499         if (ret < 0)
 500                 return ret;
 501
 502         ret = pca9685_pwm_gpio_probe(pca);
 503         if (ret < 0) {
 504                 pwmchip_remove(&pca->chip);
 505                 return ret;
 506         }
 507
 508         /* the chip comes out of power-up in the active state */
 509         pm_runtime_set_active(&client->dev);
 510         /*
 511          * enable will put the chip into suspend, which is what we
 512          * want as all outputs are disabled at this point
 513          */
 514         pm_runtime_enable(&client->dev);
 515
 516         return 0;
 517 }
 518
 519 static int pca9685_pwm_remove(struct i2c_client *client)
 520 {
 521         struct pca9685 *pca = i2c_get_clientdata(client);
 522         int ret;
 523
 524         ret = pwmchip_remove(&pca->chip);
 525         if (ret)
 526                 return ret;
 527         pm_runtime_disable(&client->dev);
 528         return 0;
 529 }
 530
 531 #ifdef CONFIG_PM
 532 static int pca9685_pwm_runtime_suspend(struct device *dev)
 533 {
 534         struct i2c_client *client = to_i2c_client(dev);
 535         struct pca9685 *pca = i2c_get_clientdata(client);
 536
 537         pca9685_set_sleep_mode(pca, 1);
 538         return 0;
 539 }
 540
 541 static int pca9685_pwm_runtime_resume(struct device *dev)
 542 {
 543         struct i2c_client *client = to_i2c_client(dev);
 544         struct pca9685 *pca = i2c_get_clientdata(client);
 545
 546         pca9685_set_sleep_mode(pca, 0);
 547         return 0;
 548 }
 549 #endif
 550
 551 static const struct i2c_device_id pca9685_id[] = {
 552         { "pca9685", 0 },
 553         { /* sentinel */ },
 554 };
 555 MODULE_DEVICE_TABLE(i2c, pca9685_id);
 556
 557 #ifdef CONFIG_ACPI
 558 static const struct acpi_device_id pca9685_acpi_ids[] = {
 559         { "INT3492", 0 },
 560         { /* sentinel */ },
 561 };
 562 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
 563 #endif
 564
 565 #ifdef CONFIG_OF
 566 static const struct of_device_id pca9685_dt_ids[] = {
 567         { .compatible = "nxp,pca9685-pwm", },
 568         { /* sentinel */ }
 569 };
 570 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
 571 #endif
 572
 573 static const struct dev_pm_ops pca9685_pwm_pm = {
 574         SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
 575                            pca9685_pwm_runtime_resume, NULL)
 576 };
 577
 578 static struct i2c_driver pca9685_i2c_driver = {
 579         .driver = {
 580                 .name = "pca9685-pwm",
 581                 .acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
 582                 .of_match_table = of_match_ptr(pca9685_dt_ids),
 583                 .pm = &pca9685_pwm_pm,
 584         },
 585         .probe = pca9685_pwm_probe,
 586         .remove = pca9685_pwm_remove,
 587         .id_table = pca9685_id,
 588 };
 589
 590 module_i2c_driver(pca9685_i2c_driver);
 591
 592 MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
 593 MODULE_DESCRIPTION("PWM driver for PCA9685");
 594 MODULE_LICENSE("GPL");