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