drivers/pwm/pwm-pca9685.c

   1 /*
   2  * Driver for PCA9685 16-channel 12-bit PWM LED controller
   3  *
   4  * Copyright (C) 2013 Steffen Trumtrar <[email protected]>
   5  * Copyright (C) 2015 Clemens Gruber <[email protected]>
   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/i2c.h>
  24 #include <linux/module.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/property.h>
  27 #include <linux/pwm.h>
  28 #include <linux/regmap.h>
  29 #include <linux/slab.h>
  30 #include <linux/delay.h>
  31
  32 /*
  33  * Because the PCA9685 has only one prescaler per chip, changing the period of
  34  * one channel affects the period of all 16 PWM outputs!
  35  * However, the ratio between each configured duty cycle and the chip-wide
  36  * period remains constant, because the OFF time is set in proportion to the
  37  * counter range.
  38  */
  39
  40 #define PCA9685_MODE1           0x00
  41 #define PCA9685_MODE2           0x01
  42 #define PCA9685_SUBADDR1        0x02
  43 #define PCA9685_SUBADDR2        0x03
  44 #define PCA9685_SUBADDR3        0x04
  45 #define PCA9685_ALLCALLADDR     0x05
  46 #define PCA9685_LEDX_ON_L       0x06
  47 #define PCA9685_LEDX_ON_H       0x07
  48 #define PCA9685_LEDX_OFF_L      0x08
  49 #define PCA9685_LEDX_OFF_H      0x09
  50
  51 #define PCA9685_ALL_LED_ON_L    0xFA
  52 #define PCA9685_ALL_LED_ON_H    0xFB
  53 #define PCA9685_ALL_LED_OFF_L   0xFC
  54 #define PCA9685_ALL_LED_OFF_H   0xFD
  55 #define PCA9685_PRESCALE        0xFE
  56
  57 #define PCA9685_PRESCALE_MIN    0x03    /* => max. frequency of 1526 Hz */
  58 #define PCA9685_PRESCALE_MAX    0xFF    /* => min. frequency of 24 Hz */
  59
  60 #define PCA9685_COUNTER_RANGE   4096
  61 #define PCA9685_DEFAULT_PERIOD  5000000 /* Default period_ns = 1/200 Hz */
  62 #define PCA9685_OSC_CLOCK_MHZ   25      /* Internal oscillator with 25 MHz */
  63
  64 #define PCA9685_NUMREGS         0xFF
  65 #define PCA9685_MAXCHAN         0x10
  66
  67 #define LED_FULL                (1 << 4)
  68 #define MODE1_RESTART           (1 << 7)
  69 #define MODE1_SLEEP             (1 << 4)
  70 #define MODE2_INVRT             (1 << 4)
  71 #define MODE2_OUTDRV            (1 << 2)
  72
  73 #define LED_N_ON_H(N)   (PCA9685_LEDX_ON_H + (4 * (N)))
  74 #define LED_N_ON_L(N)   (PCA9685_LEDX_ON_L + (4 * (N)))
  75 #define LED_N_OFF_H(N)  (PCA9685_LEDX_OFF_H + (4 * (N)))
  76 #define LED_N_OFF_L(N)  (PCA9685_LEDX_OFF_L + (4 * (N)))
  77
  78 struct pca9685 {
  79         struct pwm_chip chip;
  80         struct regmap *regmap;
  81         int active_cnt;
  82         int duty_ns;
  83         int period_ns;
  84 };
  85
  86 static inline struct pca9685 *to_pca(struct pwm_chip *chip)
  87 {
  88         return container_of(chip, struct pca9685, chip);
  89 }
  90
  91 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  92                               int duty_ns, int period_ns)
  93 {
  94         struct pca9685 *pca = to_pca(chip);
  95         unsigned long long duty;
  96         unsigned int reg;
  97         int prescale;
  98
  99         if (period_ns != pca->period_ns) {
 100                 prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
 101                                              PCA9685_COUNTER_RANGE * 1000) - 1;
 102
 103                 if (prescale >= PCA9685_PRESCALE_MIN &&
 104                         prescale <= PCA9685_PRESCALE_MAX) {
 105                         /* Put chip into sleep mode */
 106                         regmap_update_bits(pca->regmap, PCA9685_MODE1,
 107                                            MODE1_SLEEP, MODE1_SLEEP);
 108
 109                         /* Change the chip-wide output frequency */
 110                         regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
 111
 112                         /* Wake the chip up */
 113                         regmap_update_bits(pca->regmap, PCA9685_MODE1,
 114                                            MODE1_SLEEP, 0x0);
 115
 116                         /* Wait 500us for the oscillator to be back up */
 117                         udelay(500);
 118
 119                         pca->period_ns = period_ns;
 120
 121                         /*
 122                          * If the duty cycle did not change, restart PWM with
 123                          * the same duty cycle to period ratio and return.
 124                          */
 125                         if (duty_ns == pca->duty_ns) {
 126                                 regmap_update_bits(pca->regmap, PCA9685_MODE1,
 127                                                    MODE1_RESTART, 0x1);
 128                                 return 0;
 129                         }
 130                 } else {
 131                         dev_err(chip->dev,
 132                                 "prescaler not set: period out of bounds!\n");
 133                         return -EINVAL;
 134                 }
 135         }
 136
 137         pca->duty_ns = duty_ns;
 138
 139         if (duty_ns < 1) {
 140                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 141                         reg = PCA9685_ALL_LED_OFF_H;
 142                 else
 143                         reg = LED_N_OFF_H(pwm->hwpwm);
 144
 145                 regmap_write(pca->regmap, reg, LED_FULL);
 146
 147                 return 0;
 148         }
 149
 150         if (duty_ns == period_ns) {
 151                 /* Clear both OFF registers */
 152                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 153                         reg = PCA9685_ALL_LED_OFF_L;
 154                 else
 155                         reg = LED_N_OFF_L(pwm->hwpwm);
 156
 157                 regmap_write(pca->regmap, reg, 0x0);
 158
 159                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 160                         reg = PCA9685_ALL_LED_OFF_H;
 161                 else
 162                         reg = LED_N_OFF_H(pwm->hwpwm);
 163
 164                 regmap_write(pca->regmap, reg, 0x0);
 165
 166                 /* Set the full ON bit */
 167                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
 168                         reg = PCA9685_ALL_LED_ON_H;
 169                 else
 170                         reg = LED_N_ON_H(pwm->hwpwm);
 171
 172                 regmap_write(pca->regmap, reg, LED_FULL);
 173
 174                 return 0;
 175         }
 176
 177         duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
 178         duty = DIV_ROUND_UP_ULL(duty, period_ns);
 179
 180         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 181                 reg = PCA9685_ALL_LED_OFF_L;
 182         else
 183                 reg = LED_N_OFF_L(pwm->hwpwm);
 184
 185         regmap_write(pca->regmap, reg, (int)duty & 0xff);
 186
 187         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 188                 reg = PCA9685_ALL_LED_OFF_H;
 189         else
 190                 reg = LED_N_OFF_H(pwm->hwpwm);
 191
 192         regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
 193
 194         /* Clear the full ON bit, otherwise the set OFF time has no effect */
 195         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 196                 reg = PCA9685_ALL_LED_ON_H;
 197         else
 198                 reg = LED_N_ON_H(pwm->hwpwm);
 199
 200         regmap_write(pca->regmap, reg, 0);
 201
 202         return 0;
 203 }
 204
 205 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 206 {
 207         struct pca9685 *pca = to_pca(chip);
 208         unsigned int reg;
 209
 210         /*
 211          * The PWM subsystem does not support a pre-delay.
 212          * So, set the ON-timeout to 0
 213          */
 214         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 215                 reg = PCA9685_ALL_LED_ON_L;
 216         else
 217                 reg = LED_N_ON_L(pwm->hwpwm);
 218
 219         regmap_write(pca->regmap, reg, 0);
 220
 221         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 222                 reg = PCA9685_ALL_LED_ON_H;
 223         else
 224                 reg = LED_N_ON_H(pwm->hwpwm);
 225
 226         regmap_write(pca->regmap, reg, 0);
 227
 228         /*
 229          * Clear the full-off bit.
 230          * It has precedence over the others and must be off.
 231          */
 232         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 233                 reg = PCA9685_ALL_LED_OFF_H;
 234         else
 235                 reg = LED_N_OFF_H(pwm->hwpwm);
 236
 237         regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
 238
 239         return 0;
 240 }
 241
 242 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 243 {
 244         struct pca9685 *pca = to_pca(chip);
 245         unsigned int reg;
 246
 247         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 248                 reg = PCA9685_ALL_LED_OFF_H;
 249         else
 250                 reg = LED_N_OFF_H(pwm->hwpwm);
 251
 252         regmap_write(pca->regmap, reg, LED_FULL);
 253
 254         /* Clear the LED_OFF counter. */
 255         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 256                 reg = PCA9685_ALL_LED_OFF_L;
 257         else
 258                 reg = LED_N_OFF_L(pwm->hwpwm);
 259
 260         regmap_write(pca->regmap, reg, 0x0);
 261 }
 262
 263 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 264 {
 265         struct pca9685 *pca = to_pca(chip);
 266
 267         if (pca->active_cnt++ == 0)
 268                 return regmap_update_bits(pca->regmap, PCA9685_MODE1,
 269                                           MODE1_SLEEP, 0x0);
 270
 271         return 0;
 272 }
 273
 274 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 275 {
 276         struct pca9685 *pca = to_pca(chip);
 277
 278         if (--pca->active_cnt == 0)
 279                 regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
 280                                    MODE1_SLEEP);
 281 }
 282
 283 static const struct pwm_ops pca9685_pwm_ops = {
 284         .enable = pca9685_pwm_enable,
 285         .disable = pca9685_pwm_disable,
 286         .config = pca9685_pwm_config,
 287         .request = pca9685_pwm_request,
 288         .free = pca9685_pwm_free,
 289         .owner = THIS_MODULE,
 290 };
 291
 292 static const struct regmap_config pca9685_regmap_i2c_config = {
 293         .reg_bits = 8,
 294         .val_bits = 8,
 295         .max_register = PCA9685_NUMREGS,
 296         .cache_type = REGCACHE_NONE,
 297 };
 298
 299 static int pca9685_pwm_probe(struct i2c_client *client,
 300                                 const struct i2c_device_id *id)
 301 {
 302         struct pca9685 *pca;
 303         int ret;
 304         int mode2;
 305
 306         pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
 307         if (!pca)
 308                 return -ENOMEM;
 309
 310         pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
 311         if (IS_ERR(pca->regmap)) {
 312                 ret = PTR_ERR(pca->regmap);
 313                 dev_err(&client->dev, "Failed to initialize register map: %d\n",
 314                         ret);
 315                 return ret;
 316         }
 317         pca->duty_ns = 0;
 318         pca->period_ns = PCA9685_DEFAULT_PERIOD;
 319
 320         i2c_set_clientdata(client, pca);
 321
 322         regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
 323
 324         if (device_property_read_bool(&client->dev, "invert"))
 325                 mode2 |= MODE2_INVRT;
 326         else
 327                 mode2 &= ~MODE2_INVRT;
 328
 329         if (device_property_read_bool(&client->dev, "open-drain"))
 330                 mode2 &= ~MODE2_OUTDRV;
 331         else
 332                 mode2 |= MODE2_OUTDRV;
 333
 334         regmap_write(pca->regmap, PCA9685_MODE2, mode2);
 335
 336         /* clear all "full off" bits */
 337         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
 338         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
 339
 340         pca->chip.ops = &pca9685_pwm_ops;
 341         /* add an extra channel for ALL_LED */
 342         pca->chip.npwm = PCA9685_MAXCHAN + 1;
 343
 344         pca->chip.dev = &client->dev;
 345         pca->chip.base = -1;
 346         pca->chip.can_sleep = true;
 347
 348         return pwmchip_add(&pca->chip);
 349 }
 350
 351 static int pca9685_pwm_remove(struct i2c_client *client)
 352 {
 353         struct pca9685 *pca = i2c_get_clientdata(client);
 354
 355         regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
 356                            MODE1_SLEEP);
 357
 358         return pwmchip_remove(&pca->chip);
 359 }
 360
 361 static const struct i2c_device_id pca9685_id[] = {
 362         { "pca9685", 0 },
 363         { /* sentinel */ },
 364 };
 365 MODULE_DEVICE_TABLE(i2c, pca9685_id);
 366
 367 #ifdef CONFIG_ACPI
 368 static const struct acpi_device_id pca9685_acpi_ids[] = {
 369         { "INT3492", 0 },
 370         { /* sentinel */ },
 371 };
 372 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
 373 #endif
 374
 375 #ifdef CONFIG_OF
 376 static const struct of_device_id pca9685_dt_ids[] = {
 377         { .compatible = "nxp,pca9685-pwm", },
 378         { /* sentinel */ }
 379 };
 380 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
 381 #endif
 382
 383 static struct i2c_driver pca9685_i2c_driver = {
 384         .driver = {
 385                 .name = "pca9685-pwm",
 386                 .acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
 387                 .of_match_table = of_match_ptr(pca9685_dt_ids),
 388         },
 389         .probe = pca9685_pwm_probe,
 390         .remove = pca9685_pwm_remove,
 391         .id_table = pca9685_id,
 392 };
 393
 394 module_i2c_driver(pca9685_i2c_driver);
 395
 396 MODULE_AUTHOR("Steffen Trumtrar <[email protected]>");
 397 MODULE_DESCRIPTION("PWM driver for PCA9685");
 398 MODULE_LICENSE("GPL");