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, bool enable) 245 { 246 regmap_update_bits(pca->regmap, PCA9685_MODE1, 247 MODE1_SLEEP, enable ? MODE1_SLEEP : 0); 248 if (!enable) { 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, true); 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, false); 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, true); 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, false); 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"); 595