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         mutex_unlock(&pca->lock);
 180 }
 181
 182 static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
 183                                           unsigned int offset)
 184 {
 185         /* Always out */
 186         return 0;
 187 }
 188
 189 static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
 190                                             unsigned int offset)
 191 {
 192         return -EINVAL;
 193 }
 194
 195 static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
 196                                              unsigned int offset, int value)
 197 {
 198         pca9685_pwm_gpio_set(gpio, offset, value);
 199
 200         return 0;
 201 }
 202
 203 /*
 204  * The PCA9685 has a bit for turning the PWM output full off or on. Some
 205  * boards like Intel Galileo actually uses these as normal GPIOs so we
 206  * expose a GPIO chip here which can exclusively take over the underlying
 207  * PWM channel.
 208  */
 209 static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 210 {
 211         struct device *dev = pca->chip.dev;
 212
 213         mutex_init(&pca->lock);
 214
 215         pca->gpio.label = dev_name(dev);
 216         pca->gpio.parent = dev;
 217         pca->gpio.request = pca9685_pwm_gpio_request;
 218         pca->gpio.free = pca9685_pwm_gpio_free;
 219         pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
 220         pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
 221         pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
 222         pca->gpio.get = pca9685_pwm_gpio_get;
 223         pca->gpio.set = pca9685_pwm_gpio_set;
 224         pca->gpio.base = -1;
 225         pca->gpio.ngpio = PCA9685_MAXCHAN;
 226         pca->gpio.can_sleep = true;
 227
 228         return devm_gpiochip_add_data(dev, &pca->gpio, pca);
 229 }
 230 #else
 231 static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
 232                                        struct pwm_device *pwm)
 233 {
 234         return false;
 235 }
 236
 237 static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
 238 {
 239         return 0;
 240 }
 241 #endif
 242
 243 static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
 244 {
 245         regmap_update_bits(pca->regmap, PCA9685_MODE1,
 246                            MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
 247         if (!enable) {
 248                 /* Wait 500us for the oscillator to be back up */
 249                 udelay(500);
 250         }
 251 }
 252
 253 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 254                               int duty_ns, int period_ns)
 255 {
 256         struct pca9685 *pca = to_pca(chip);
 257         unsigned long long duty;
 258         unsigned int reg;
 259         int prescale;
 260
 261         if (period_ns != pca->period_ns) {
 262                 prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
 263                                              PCA9685_COUNTER_RANGE * 1000) - 1;
 264
 265                 if (prescale >= PCA9685_PRESCALE_MIN &&
 266                         prescale <= PCA9685_PRESCALE_MAX) {
 267                         /*
 268                          * putting the chip briefly into SLEEP mode
 269                          * at this point won't interfere with the
 270                          * pm_runtime framework, because the pm_runtime
 271                          * state is guaranteed active here.
 272                          */
 273                         /* Put chip into sleep mode */
 274                         pca9685_set_sleep_mode(pca, true);
 275
 276                         /* Change the chip-wide output frequency */
 277                         regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
 278
 279                         /* Wake the chip up */
 280                         pca9685_set_sleep_mode(pca, false);
 281
 282                         pca->period_ns = period_ns;
 283                 } else {
 284                         dev_err(chip->dev,
 285                                 "prescaler not set: period out of bounds!\n");
 286                         return -EINVAL;
 287                 }
 288         }
 289
 290         pca->duty_ns = duty_ns;
 291
 292         if (duty_ns < 1) {
 293                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 294                         reg = PCA9685_ALL_LED_OFF_H;
 295                 else
 296                         reg = LED_N_OFF_H(pwm->hwpwm);
 297
 298                 regmap_write(pca->regmap, reg, LED_FULL);
 299
 300                 return 0;
 301         }
 302
 303         if (duty_ns == period_ns) {
 304                 /* Clear both OFF registers */
 305                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 306                         reg = PCA9685_ALL_LED_OFF_L;
 307                 else
 308                         reg = LED_N_OFF_L(pwm->hwpwm);
 309
 310                 regmap_write(pca->regmap, reg, 0x0);
 311
 312                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 313                         reg = PCA9685_ALL_LED_OFF_H;
 314                 else
 315                         reg = LED_N_OFF_H(pwm->hwpwm);
 316
 317                 regmap_write(pca->regmap, reg, 0x0);
 318
 319                 /* Set the full ON bit */
 320                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 321                         reg = PCA9685_ALL_LED_ON_H;
 322                 else
 323                         reg = LED_N_ON_H(pwm->hwpwm);
 324
 325                 regmap_write(pca->regmap, reg, LED_FULL);
 326
 327                 return 0;
 328         }
 329
 330         duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
 331         duty = DIV_ROUND_UP_ULL(duty, period_ns);
 332
 333         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 334                 reg = PCA9685_ALL_LED_OFF_L;
 335         else
 336                 reg = LED_N_OFF_L(pwm->hwpwm);
 337
 338         regmap_write(pca->regmap, reg, (int)duty & 0xff);
 339
 340         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 341                 reg = PCA9685_ALL_LED_OFF_H;
 342         else
 343                 reg = LED_N_OFF_H(pwm->hwpwm);
 344
 345         regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
 346
 347         /* Clear the full ON bit, otherwise the set OFF time has no effect */
 348         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 349                 reg = PCA9685_ALL_LED_ON_H;
 350         else
 351                 reg = LED_N_ON_H(pwm->hwpwm);
 352
 353         regmap_write(pca->regmap, reg, 0);
 354
 355         return 0;
 356 }
 357
 358 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 359 {
 360         struct pca9685 *pca = to_pca(chip);
 361         unsigned int reg;
 362
 363         /*
 364          * The PWM subsystem does not support a pre-delay.
 365          * So, set the ON-timeout to 0
 366          */
 367         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 368                 reg = PCA9685_ALL_LED_ON_L;
 369         else
 370                 reg = LED_N_ON_L(pwm->hwpwm);
 371
 372         regmap_write(pca->regmap, reg, 0);
 373
 374         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 375                 reg = PCA9685_ALL_LED_ON_H;
 376         else
 377                 reg = LED_N_ON_H(pwm->hwpwm);
 378
 379         regmap_write(pca->regmap, reg, 0);
 380
 381         /*
 382          * Clear the full-off bit.
 383          * It has precedence over the others and must be off.
 384          */
 385         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 386                 reg = PCA9685_ALL_LED_OFF_H;
 387         else
 388                 reg = LED_N_OFF_H(pwm->hwpwm);
 389
 390         regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
 391
 392         return 0;
 393 }
 394
 395 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 396 {
 397         struct pca9685 *pca = to_pca(chip);
 398         unsigned int reg;
 399
 400         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 401                 reg = PCA9685_ALL_LED_OFF_H;
 402         else
 403                 reg = LED_N_OFF_H(pwm->hwpwm);
 404
 405         regmap_write(pca->regmap, reg, LED_FULL);
 406
 407         /* Clear the LED_OFF counter. */
 408         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 409                 reg = PCA9685_ALL_LED_OFF_L;
 410         else
 411                 reg = LED_N_OFF_L(pwm->hwpwm);
 412
 413         regmap_write(pca->regmap, reg, 0x0);
 414 }
 415
 416 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 417 {
 418         struct pca9685 *pca = to_pca(chip);
 419
 420         if (pca9685_pwm_is_gpio(pca, pwm))
 421                 return -EBUSY;
 422         pm_runtime_get_sync(chip->dev);
 423
 424         return 0;
 425 }
 426
 427 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 428 {
 429         pca9685_pwm_disable(chip, pwm);
 430         pm_runtime_put(chip->dev);
 431 }
 432
 433 static const struct pwm_ops pca9685_pwm_ops = {
 434         .enable = pca9685_pwm_enable,
 435         .disable = pca9685_pwm_disable,
 436         .config = pca9685_pwm_config,
 437         .request = pca9685_pwm_request,
 438         .free = pca9685_pwm_free,
 439         .owner = THIS_MODULE,
 440 };
 441
 442 static const struct regmap_config pca9685_regmap_i2c_config = {
 443         .reg_bits = 8,
 444         .val_bits = 8,
 445         .max_register = PCA9685_NUMREGS,
 446         .cache_type = REGCACHE_NONE,
 447 };
 448
 449 static int pca9685_pwm_probe(struct i2c_client *client,
 450                                 const struct i2c_device_id *id)
 451 {
 452         struct pca9685 *pca;
 453         int ret;
 454         int mode2;
 455
 456         pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
 457         if (!pca)
 458                 return -ENOMEM;
 459
 460         pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
 461         if (IS_ERR(pca->regmap)) {
 462                 ret = PTR_ERR(pca->regmap);
 463                 dev_err(&client->dev, "Failed to initialize register map: %d\n",
 464                         ret);
 465                 return ret;
 466         }
 467         pca->duty_ns = 0;
 468         pca->period_ns = PCA9685_DEFAULT_PERIOD;
 469
 470         i2c_set_clientdata(client, pca);
 471
 472         regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
 473
 474         if (device_property_read_bool(&client->dev, "invert"))
 475                 mode2 |= MODE2_INVRT;
 476         else
 477                 mode2 &= ~MODE2_INVRT;
 478
 479         if (device_property_read_bool(&client->dev, "open-drain"))
 480                 mode2 &= ~MODE2_OUTDRV;
 481         else
 482                 mode2 |= MODE2_OUTDRV;
 483
 484         regmap_write(pca->regmap, PCA9685_MODE2, mode2);
 485
 486         /* clear all "full off" bits */
 487         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
 488         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
 489
 490         pca->chip.ops = &pca9685_pwm_ops;
 491         /* add an extra channel for ALL_LED */
 492         pca->chip.npwm = PCA9685_MAXCHAN + 1;
 493
 494         pca->chip.dev = &client->dev;
 495         pca->chip.base = -1;
 496
 497         ret = pwmchip_add(&pca->chip);
 498         if (ret < 0)
 499                 return ret;
 500
 501         ret = pca9685_pwm_gpio_probe(pca);
 502         if (ret < 0) {
 503                 pwmchip_remove(&pca->chip);
 504                 return ret;
 505         }
 506
 507         /* the chip comes out of power-up in the active state */
 508         pm_runtime_set_active(&client->dev);
 509         /*
 510          * enable will put the chip into suspend, which is what we
 511          * want as all outputs are disabled at this point
 512          */
 513         pm_runtime_enable(&client->dev);
 514
 515         return 0;
 516 }
 517
 518 static int pca9685_pwm_remove(struct i2c_client *client)
 519 {
 520         struct pca9685 *pca = i2c_get_clientdata(client);
 521         int ret;
 522
 523         ret = pwmchip_remove(&pca->chip);
 524         if (ret)
 525                 return ret;
 526         pm_runtime_disable(&client->dev);
 527         return 0;
 528 }
 529
 530 #ifdef CONFIG_PM
 531 static int pca9685_pwm_runtime_suspend(struct device *dev)
 532 {
 533         struct i2c_client *client = to_i2c_client(dev);
 534         struct pca9685 *pca = i2c_get_clientdata(client);
 535
 536         pca9685_set_sleep_mode(pca, true);
 537         return 0;
 538 }
 539
 540 static int pca9685_pwm_runtime_resume(struct device *dev)
 541 {
 542         struct i2c_client *client = to_i2c_client(dev);
 543         struct pca9685 *pca = i2c_get_clientdata(client);
 544
 545         pca9685_set_sleep_mode(pca, false);
 546         return 0;
 547 }
 548 #endif
 549
 550 static const struct i2c_device_id pca9685_id[] = {
 551         { "pca9685", 0 },
 552         { /* sentinel */ },
 553 };
 554 MODULE_DEVICE_TABLE(i2c, pca9685_id);
 555
 556 #ifdef CONFIG_ACPI
 557 static const struct acpi_device_id pca9685_acpi_ids[] = {
 558         { "INT3492", 0 },
 559         { /* sentinel */ },
 560 };
 561 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
 562 #endif
 563
 564 #ifdef CONFIG_OF
 565 static const struct of_device_id pca9685_dt_ids[] = {
 566         { .compatible = "nxp,pca9685-pwm", },
 567         { /* sentinel */ }
 568 };
 569 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
 570 #endif
 571
 572 static const struct dev_pm_ops pca9685_pwm_pm = {
 573         SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
 574                            pca9685_pwm_runtime_resume, NULL)
 575 };
 576
 577 static struct i2c_driver pca9685_i2c_driver = {
 578         .driver = {
 579                 .name = "pca9685-pwm",
 580                 .acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
 581                 .of_match_table = of_match_ptr(pca9685_dt_ids),
 582                 .pm = &pca9685_pwm_pm,
 583         },
 584         .probe = pca9685_pwm_probe,
 585         .remove = pca9685_pwm_remove,
 586         .id_table = pca9685_id,
 587 };
 588
 589 module_i2c_driver(pca9685_i2c_driver);
 590
 591 MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
 592 MODULE_DESCRIPTION("PWM driver for PCA9685");
 593 MODULE_LICENSE("GPL");