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 #include <linux/bitmap.h>
  35
  36 /*
  37  * Because the PCA9685 has only one prescaler per chip, changing the period of
  38  * one channel affects the period of all 16 PWM outputs!
  39  * However, the ratio between each configured duty cycle and the chip-wide
  40  * period remains constant, because the OFF time is set in proportion to the
  41  * counter range.
  42  */
  43
  44 #define PCA9685_MODE1           0x00
  45 #define PCA9685_MODE2           0x01
  46 #define PCA9685_SUBADDR1        0x02
  47 #define PCA9685_SUBADDR2        0x03
  48 #define PCA9685_SUBADDR3        0x04
  49 #define PCA9685_ALLCALLADDR     0x05
  50 #define PCA9685_LEDX_ON_L       0x06
  51 #define PCA9685_LEDX_ON_H       0x07
  52 #define PCA9685_LEDX_OFF_L      0x08
  53 #define PCA9685_LEDX_OFF_H      0x09
  54
  55 #define PCA9685_ALL_LED_ON_L    0xFA
  56 #define PCA9685_ALL_LED_ON_H    0xFB
  57 #define PCA9685_ALL_LED_OFF_L   0xFC
  58 #define PCA9685_ALL_LED_OFF_H   0xFD
  59 #define PCA9685_PRESCALE        0xFE
  60
  61 #define PCA9685_PRESCALE_MIN    0x03    /* => max. frequency of 1526 Hz */
  62 #define PCA9685_PRESCALE_MAX    0xFF    /* => min. frequency of 24 Hz */
  63
  64 #define PCA9685_COUNTER_RANGE   4096
  65 #define PCA9685_DEFAULT_PERIOD  5000000 /* Default period_ns = 1/200 Hz */
  66 #define PCA9685_OSC_CLOCK_MHZ   25      /* Internal oscillator with 25 MHz */
  67
  68 #define PCA9685_NUMREGS         0xFF
  69 #define PCA9685_MAXCHAN         0x10
  70
  71 #define LED_FULL                (1 << 4)
  72 #define MODE1_SLEEP             (1 << 4)
  73 #define MODE2_INVRT             (1 << 4)
  74 #define MODE2_OUTDRV            (1 << 2)
  75
  76 #define LED_N_ON_H(N)   (PCA9685_LEDX_ON_H + (4 * (N)))
  77 #define LED_N_ON_L(N)   (PCA9685_LEDX_ON_L + (4 * (N)))
  78 #define LED_N_OFF_H(N)  (PCA9685_LEDX_OFF_H + (4 * (N)))
  79 #define LED_N_OFF_L(N)  (PCA9685_LEDX_OFF_L + (4 * (N)))
  80
  81 struct pca9685 {
  82         struct pwm_chip chip;
  83         struct regmap *regmap;
  84         int duty_ns;
  85         int period_ns;
  86 #if IS_ENABLED(CONFIG_GPIOLIB)
  87         struct mutex lock;
  88         struct gpio_chip gpio;
  89         DECLARE_BITMAP(pwms_inuse, PCA9685_MAXCHAN + 1);
  90 #endif
  91 };
  92
  93 static inline struct pca9685 *to_pca(struct pwm_chip *chip)
  94 {
  95         return container_of(chip, struct pca9685, chip);
  96 }
  97
  98 #if IS_ENABLED(CONFIG_GPIOLIB)
  99 static bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca, int pwm_idx)
 100 {
 101         bool is_inuse;
 102
 103         mutex_lock(&pca->lock);
 104         if (pwm_idx >= PCA9685_MAXCHAN) {
 105                 /*
 106                  * "all LEDs" channel:
 107                  * pretend already in use if any of the PWMs are requested
 108                  */
 109                 if (!bitmap_empty(pca->pwms_inuse, PCA9685_MAXCHAN)) {
 110                         is_inuse = true;
 111                         goto out;
 112                 }
 113         } else {
 114                 /*
 115                  * regular channel:
 116                  * pretend already in use if the "all LEDs" channel is requested
 117                  */
 118                 if (test_bit(PCA9685_MAXCHAN, pca->pwms_inuse)) {
 119                         is_inuse = true;
 120                         goto out;
 121                 }
 122         }
 123         is_inuse = test_and_set_bit(pwm_idx, pca->pwms_inuse);
 124 out:
 125         mutex_unlock(&pca->lock);
 126         return is_inuse;
 127 }
 128
 129 static void pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
 130 {
 131         mutex_lock(&pca->lock);
 132         clear_bit(pwm_idx, pca->pwms_inuse);
 133         mutex_unlock(&pca->lock);
 134 }
 135
 136 static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
 137 {
 138         struct pca9685 *pca = gpiochip_get_data(gpio);
 139
 140         if (pca9685_pwm_test_and_set_inuse(pca, offset))
 141                 return -EBUSY;
 142         pm_runtime_get_sync(pca->chip.dev);
 143         return 0;
 144 }
 145
 146 static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
 147 {
 148         struct pca9685 *pca = gpiochip_get_data(gpio);
 149         struct pwm_device *pwm = &pca->chip.pwms[offset];
 150         unsigned int value;
 151
 152         regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);
 153
 154         return value & LED_FULL;
 155 }
 156
 157 static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
 158                                  int value)
 159 {
 160         struct pca9685 *pca = gpiochip_get_data(gpio);
 161         struct pwm_device *pwm = &pca->chip.pwms[offset];
 162         unsigned int on = value ? LED_FULL : 0;
 163
 164         /* Clear both OFF registers */
 165         regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
 166         regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);
 167
 168         /* Set the full ON bit */
 169         regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
 170 }
 171
 172 static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
 173 {
 174         struct pca9685 *pca = gpiochip_get_data(gpio);
 175
 176         pca9685_pwm_gpio_set(gpio, offset, 0);
 177         pm_runtime_put(pca->chip.dev);
 178         pca9685_pwm_clear_inuse(pca, offset);
 179 }
 180
 181 static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
 182                                           unsigned int offset)
 183 {
 184         /* Always out */
 185         return 0;
 186 }
 187
 188 static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
 189                                             unsigned int offset)
 190 {
 191         return -EINVAL;
 192 }
 193
 194 static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
 195                                              unsigned int offset, int value)
 196 {
 197         pca9685_pwm_gpio_set(gpio, offset, value);
 198
 199         return 0;
 200 }
 201
 202 /*
 203  * The PCA9685 has a bit for turning the PWM output full off or on. Some
 204  * boards like Intel Galileo actually uses these as normal GPIOs so we
 205  * expose a GPIO chip here which can exclusively take over the underlying
 206  * PWM channel.
 207  */
 208 static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 209 {
 210         struct device *dev = pca->chip.dev;
 211
 212         mutex_init(&pca->lock);
 213
 214         pca->gpio.label = dev_name(dev);
 215         pca->gpio.parent = dev;
 216         pca->gpio.request = pca9685_pwm_gpio_request;
 217         pca->gpio.free = pca9685_pwm_gpio_free;
 218         pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
 219         pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
 220         pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
 221         pca->gpio.get = pca9685_pwm_gpio_get;
 222         pca->gpio.set = pca9685_pwm_gpio_set;
 223         pca->gpio.base = -1;
 224         pca->gpio.ngpio = PCA9685_MAXCHAN;
 225         pca->gpio.can_sleep = true;
 226
 227         return devm_gpiochip_add_data(dev, &pca->gpio, pca);
 228 }
 229 #else
 230 static inline bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca,
 231                                                   int pwm_idx)
 232 {
 233         return false;
 234 }
 235
 236 static inline void
 237 pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
 238 {
 239 }
 240
 241 static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 242 {
 243         return 0;
 244 }
 245 #endif
 246
 247 static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
 248 {
 249         regmap_update_bits(pca->regmap, PCA9685_MODE1,
 250                            MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
 251         if (!enable) {
 252                 /* Wait 500us for the oscillator to be back up */
 253                 udelay(500);
 254         }
 255 }
 256
 257 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 258                               int duty_ns, int period_ns)
 259 {
 260         struct pca9685 *pca = to_pca(chip);
 261         unsigned long long duty;
 262         unsigned int reg;
 263         int prescale;
 264
 265         if (period_ns != pca->period_ns) {
 266                 prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
 267                                              PCA9685_COUNTER_RANGE * 1000) - 1;
 268
 269                 if (prescale >= PCA9685_PRESCALE_MIN &&
 270                         prescale <= PCA9685_PRESCALE_MAX) {
 271                         /*
 272                          * putting the chip briefly into SLEEP mode
 273                          * at this point won't interfere with the
 274                          * pm_runtime framework, because the pm_runtime
 275                          * state is guaranteed active here.
 276                          */
 277                         /* Put chip into sleep mode */
 278                         pca9685_set_sleep_mode(pca, true);
 279
 280                         /* Change the chip-wide output frequency */
 281                         regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
 282
 283                         /* Wake the chip up */
 284                         pca9685_set_sleep_mode(pca, false);
 285
 286                         pca->period_ns = period_ns;
 287                 } else {
 288                         dev_err(chip->dev,
 289                                 "prescaler not set: period out of bounds!\n");
 290                         return -EINVAL;
 291                 }
 292         }
 293
 294         pca->duty_ns = duty_ns;
 295
 296         if (duty_ns < 1) {
 297                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 298                         reg = PCA9685_ALL_LED_OFF_H;
 299                 else
 300                         reg = LED_N_OFF_H(pwm->hwpwm);
 301
 302                 regmap_write(pca->regmap, reg, LED_FULL);
 303
 304                 return 0;
 305         }
 306
 307         if (duty_ns == period_ns) {
 308                 /* Clear both OFF registers */
 309                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 310                         reg = PCA9685_ALL_LED_OFF_L;
 311                 else
 312                         reg = LED_N_OFF_L(pwm->hwpwm);
 313
 314                 regmap_write(pca->regmap, reg, 0x0);
 315
 316                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 317                         reg = PCA9685_ALL_LED_OFF_H;
 318                 else
 319                         reg = LED_N_OFF_H(pwm->hwpwm);
 320
 321                 regmap_write(pca->regmap, reg, 0x0);
 322
 323                 /* Set the full ON bit */
 324                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 325                         reg = PCA9685_ALL_LED_ON_H;
 326                 else
 327                         reg = LED_N_ON_H(pwm->hwpwm);
 328
 329                 regmap_write(pca->regmap, reg, LED_FULL);
 330
 331                 return 0;
 332         }
 333
 334         duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
 335         duty = DIV_ROUND_UP_ULL(duty, period_ns);
 336
 337         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 338                 reg = PCA9685_ALL_LED_OFF_L;
 339         else
 340                 reg = LED_N_OFF_L(pwm->hwpwm);
 341
 342         regmap_write(pca->regmap, reg, (int)duty & 0xff);
 343
 344         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 345                 reg = PCA9685_ALL_LED_OFF_H;
 346         else
 347                 reg = LED_N_OFF_H(pwm->hwpwm);
 348
 349         regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
 350
 351         /* Clear the full ON bit, otherwise the set OFF time has no effect */
 352         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 353                 reg = PCA9685_ALL_LED_ON_H;
 354         else
 355                 reg = LED_N_ON_H(pwm->hwpwm);
 356
 357         regmap_write(pca->regmap, reg, 0);
 358
 359         return 0;
 360 }
 361
 362 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 363 {
 364         struct pca9685 *pca = to_pca(chip);
 365         unsigned int reg;
 366
 367         /*
 368          * The PWM subsystem does not support a pre-delay.
 369          * So, set the ON-timeout to 0
 370          */
 371         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 372                 reg = PCA9685_ALL_LED_ON_L;
 373         else
 374                 reg = LED_N_ON_L(pwm->hwpwm);
 375
 376         regmap_write(pca->regmap, reg, 0);
 377
 378         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 379                 reg = PCA9685_ALL_LED_ON_H;
 380         else
 381                 reg = LED_N_ON_H(pwm->hwpwm);
 382
 383         regmap_write(pca->regmap, reg, 0);
 384
 385         /*
 386          * Clear the full-off bit.
 387          * It has precedence over the others and must be off.
 388          */
 389         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 390                 reg = PCA9685_ALL_LED_OFF_H;
 391         else
 392                 reg = LED_N_OFF_H(pwm->hwpwm);
 393
 394         regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
 395
 396         return 0;
 397 }
 398
 399 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 400 {
 401         struct pca9685 *pca = to_pca(chip);
 402         unsigned int reg;
 403
 404         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 405                 reg = PCA9685_ALL_LED_OFF_H;
 406         else
 407                 reg = LED_N_OFF_H(pwm->hwpwm);
 408
 409         regmap_write(pca->regmap, reg, LED_FULL);
 410
 411         /* Clear the LED_OFF counter. */
 412         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 413                 reg = PCA9685_ALL_LED_OFF_L;
 414         else
 415                 reg = LED_N_OFF_L(pwm->hwpwm);
 416
 417         regmap_write(pca->regmap, reg, 0x0);
 418 }
 419
 420 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 421 {
 422         struct pca9685 *pca = to_pca(chip);
 423
 424         if (pca9685_pwm_test_and_set_inuse(pca, pwm->hwpwm))
 425                 return -EBUSY;
 426         pm_runtime_get_sync(chip->dev);
 427
 428         return 0;
 429 }
 430
 431 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 432 {
 433         struct pca9685 *pca = to_pca(chip);
 434
 435         pca9685_pwm_disable(chip, pwm);
 436         pm_runtime_put(chip->dev);
 437         pca9685_pwm_clear_inuse(pca, pwm->hwpwm);
 438 }
 439
 440 static const struct pwm_ops pca9685_pwm_ops = {
 441         .enable = pca9685_pwm_enable,
 442         .disable = pca9685_pwm_disable,
 443         .config = pca9685_pwm_config,
 444         .request = pca9685_pwm_request,
 445         .free = pca9685_pwm_free,
 446         .owner = THIS_MODULE,
 447 };
 448
 449 static const struct regmap_config pca9685_regmap_i2c_config = {
 450         .reg_bits = 8,
 451         .val_bits = 8,
 452         .max_register = PCA9685_NUMREGS,
 453         .cache_type = REGCACHE_NONE,
 454 };
 455
 456 static int pca9685_pwm_probe(struct i2c_client *client,
 457                                 const struct i2c_device_id *id)
 458 {
 459         struct pca9685 *pca;
 460         int ret;
 461         int mode2;
 462
 463         pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
 464         if (!pca)
 465                 return -ENOMEM;
 466
 467         pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
 468         if (IS_ERR(pca->regmap)) {
 469                 ret = PTR_ERR(pca->regmap);
 470                 dev_err(&client->dev, "Failed to initialize register map: %d\n",
 471                         ret);
 472                 return ret;
 473         }
 474         pca->duty_ns = 0;
 475         pca->period_ns = PCA9685_DEFAULT_PERIOD;
 476
 477         i2c_set_clientdata(client, pca);
 478
 479         regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
 480
 481         if (device_property_read_bool(&client->dev, "invert"))
 482                 mode2 |= MODE2_INVRT;
 483         else
 484                 mode2 &= ~MODE2_INVRT;
 485
 486         if (device_property_read_bool(&client->dev, "open-drain"))
 487                 mode2 &= ~MODE2_OUTDRV;
 488         else
 489                 mode2 |= MODE2_OUTDRV;
 490
 491         regmap_write(pca->regmap, PCA9685_MODE2, mode2);
 492
 493         /* clear all "full off" bits */
 494         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
 495         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
 496
 497         pca->chip.ops = &pca9685_pwm_ops;
 498         /* add an extra channel for ALL_LED */
 499         pca->chip.npwm = PCA9685_MAXCHAN + 1;
 500
 501         pca->chip.dev = &client->dev;
 502         pca->chip.base = -1;
 503
 504         ret = pwmchip_add(&pca->chip);
 505         if (ret < 0)
 506                 return ret;
 507
 508         ret = pca9685_pwm_gpio_probe(pca);
 509         if (ret < 0) {
 510                 pwmchip_remove(&pca->chip);
 511                 return ret;
 512         }
 513
 514         /* the chip comes out of power-up in the active state */
 515         pm_runtime_set_active(&client->dev);
 516         /*
 517          * enable will put the chip into suspend, which is what we
 518          * want as all outputs are disabled at this point
 519          */
 520         pm_runtime_enable(&client->dev);
 521
 522         return 0;
 523 }
 524
 525 static int pca9685_pwm_remove(struct i2c_client *client)
 526 {
 527         struct pca9685 *pca = i2c_get_clientdata(client);
 528         int ret;
 529
 530         ret = pwmchip_remove(&pca->chip);
 531         if (ret)
 532                 return ret;
 533         pm_runtime_disable(&client->dev);
 534         return 0;
 535 }
 536
 537 #ifdef CONFIG_PM
 538 static int pca9685_pwm_runtime_suspend(struct device *dev)
 539 {
 540         struct i2c_client *client = to_i2c_client(dev);
 541         struct pca9685 *pca = i2c_get_clientdata(client);
 542
 543         pca9685_set_sleep_mode(pca, true);
 544         return 0;
 545 }
 546
 547 static int pca9685_pwm_runtime_resume(struct device *dev)
 548 {
 549         struct i2c_client *client = to_i2c_client(dev);
 550         struct pca9685 *pca = i2c_get_clientdata(client);
 551
 552         pca9685_set_sleep_mode(pca, false);
 553         return 0;
 554 }
 555 #endif
 556
 557 static const struct i2c_device_id pca9685_id[] = {
 558         { "pca9685", 0 },
 559         { /* sentinel */ },
 560 };
 561 MODULE_DEVICE_TABLE(i2c, pca9685_id);
 562
 563 #ifdef CONFIG_ACPI
 564 static const struct acpi_device_id pca9685_acpi_ids[] = {
 565         { "INT3492", 0 },
 566         { /* sentinel */ },
 567 };
 568 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
 569 #endif
 570
 571 #ifdef CONFIG_OF
 572 static const struct of_device_id pca9685_dt_ids[] = {
 573         { .compatible = "nxp,pca9685-pwm", },
 574         { /* sentinel */ }
 575 };
 576 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
 577 #endif
 578
 579 static const struct dev_pm_ops pca9685_pwm_pm = {
 580         SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
 581                            pca9685_pwm_runtime_resume, NULL)
 582 };
 583
 584 static struct i2c_driver pca9685_i2c_driver = {
 585         .driver = {
 586                 .name = "pca9685-pwm",
 587                 .acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
 588                 .of_match_table = of_match_ptr(pca9685_dt_ids),
 589                 .pm = &pca9685_pwm_pm,
 590         },
 591         .probe = pca9685_pwm_probe,
 592         .remove = pca9685_pwm_remove,
 593         .id_table = pca9685_id,
 594 };
 595
 596 module_i2c_driver(pca9685_i2c_driver);
 597
 598 MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
 599 MODULE_DESCRIPTION("PWM driver for PCA9685");
 600 MODULE_LICENSE("GPL");