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  *
   6  * based on the pwm-twl-led.c driver
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License version 2 as published by
  10  * the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <linux/i2c.h>
  22 #include <linux/module.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/pwm.h>
  25 #include <linux/regmap.h>
  26 #include <linux/slab.h>
  27
  28 #define PCA9685_MODE1           0x00
  29 #define PCA9685_MODE2           0x01
  30 #define PCA9685_SUBADDR1        0x02
  31 #define PCA9685_SUBADDR2        0x03
  32 #define PCA9685_SUBADDR3        0x04
  33 #define PCA9685_ALLCALLADDR     0x05
  34 #define PCA9685_LEDX_ON_L       0x06
  35 #define PCA9685_LEDX_ON_H       0x07
  36 #define PCA9685_LEDX_OFF_L      0x08
  37 #define PCA9685_LEDX_OFF_H      0x09
  38
  39 #define PCA9685_ALL_LED_ON_L    0xFA
  40 #define PCA9685_ALL_LED_ON_H    0xFB
  41 #define PCA9685_ALL_LED_OFF_L   0xFC
  42 #define PCA9685_ALL_LED_OFF_H   0xFD
  43 #define PCA9685_PRESCALE        0xFE
  44
  45 #define PCA9685_NUMREGS         0xFF
  46 #define PCA9685_MAXCHAN         0x10
  47
  48 #define LED_FULL                (1 << 4)
  49 #define MODE1_SLEEP             (1 << 4)
  50 #define MODE2_INVRT             (1 << 4)
  51 #define MODE2_OUTDRV            (1 << 2)
  52
  53 #define LED_N_ON_H(N)   (PCA9685_LEDX_ON_H + (4 * (N)))
  54 #define LED_N_ON_L(N)   (PCA9685_LEDX_ON_L + (4 * (N)))
  55 #define LED_N_OFF_H(N)  (PCA9685_LEDX_OFF_H + (4 * (N)))
  56 #define LED_N_OFF_L(N)  (PCA9685_LEDX_OFF_L + (4 * (N)))
  57
  58 struct pca9685 {
  59         struct pwm_chip chip;
  60         struct regmap *regmap;
  61         int active_cnt;
  62 };
  63
  64 static inline struct pca9685 *to_pca(struct pwm_chip *chip)
  65 {
  66         return container_of(chip, struct pca9685, chip);
  67 }
  68
  69 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  70                               int duty_ns, int period_ns)
  71 {
  72         struct pca9685 *pca = to_pca(chip);
  73         unsigned long long duty;
  74         unsigned int reg;
  75
  76         if (duty_ns < 1) {
  77                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
  78                         reg = PCA9685_ALL_LED_OFF_H;
  79                 else
  80                         reg = LED_N_OFF_H(pwm->hwpwm);
  81
  82                 regmap_write(pca->regmap, reg, LED_FULL);
  83
  84                 return 0;
  85         }
  86
  87         if (duty_ns == period_ns) {
  88                 if (pwm->hwpwm >= PCA9685_MAXCHAN)
  89                         reg = PCA9685_ALL_LED_ON_H;
  90                 else
  91                         reg = LED_N_ON_H(pwm->hwpwm);
  92
  93                 regmap_write(pca->regmap, reg, LED_FULL);
  94
  95                 return 0;
  96         }
  97
  98         duty = 4096 * (unsigned long long)duty_ns;
  99         duty = DIV_ROUND_UP_ULL(duty, period_ns);
 100
 101         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 102                 reg = PCA9685_ALL_LED_OFF_L;
 103         else
 104                 reg = LED_N_OFF_L(pwm->hwpwm);
 105
 106         regmap_write(pca->regmap, reg, (int)duty & 0xff);
 107
 108         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 109                 reg = PCA9685_ALL_LED_OFF_H;
 110         else
 111                 reg = LED_N_OFF_H(pwm->hwpwm);
 112
 113         regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
 114
 115         return 0;
 116 }
 117
 118 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 119 {
 120         struct pca9685 *pca = to_pca(chip);
 121         unsigned int reg;
 122
 123         /*
 124          * The PWM subsystem does not support a pre-delay.
 125          * So, set the ON-timeout to 0
 126          */
 127         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 128                 reg = PCA9685_ALL_LED_ON_L;
 129         else
 130                 reg = LED_N_ON_L(pwm->hwpwm);
 131
 132         regmap_write(pca->regmap, reg, 0);
 133
 134         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 135                 reg = PCA9685_ALL_LED_ON_H;
 136         else
 137                 reg = LED_N_ON_H(pwm->hwpwm);
 138
 139         regmap_write(pca->regmap, reg, 0);
 140
 141         /*
 142          * Clear the full-off bit.
 143          * It has precedence over the others and must be off.
 144          */
 145         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 146                 reg = PCA9685_ALL_LED_OFF_H;
 147         else
 148                 reg = LED_N_OFF_H(pwm->hwpwm);
 149
 150         regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
 151
 152         return 0;
 153 }
 154
 155 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 156 {
 157         struct pca9685 *pca = to_pca(chip);
 158         unsigned int reg;
 159
 160         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 161                 reg = PCA9685_ALL_LED_OFF_H;
 162         else
 163                 reg = LED_N_OFF_H(pwm->hwpwm);
 164
 165         regmap_write(pca->regmap, reg, LED_FULL);
 166
 167         /* Clear the LED_OFF counter. */
 168         if (pwm->hwpwm >= PCA9685_MAXCHAN)
 169                 reg = PCA9685_ALL_LED_OFF_L;
 170         else
 171                 reg = LED_N_OFF_L(pwm->hwpwm);
 172
 173         regmap_write(pca->regmap, reg, 0x0);
 174 }
 175
 176 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 177 {
 178         struct pca9685 *pca = to_pca(chip);
 179
 180         if (pca->active_cnt++ == 0)
 181                 return regmap_update_bits(pca->regmap, PCA9685_MODE1,
 182                                           MODE1_SLEEP, 0x0);
 183
 184         return 0;
 185 }
 186
 187 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 188 {
 189         struct pca9685 *pca = to_pca(chip);
 190
 191         if (--pca->active_cnt == 0)
 192                 regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
 193                                    MODE1_SLEEP);
 194 }
 195
 196 static const struct pwm_ops pca9685_pwm_ops = {
 197         .enable = pca9685_pwm_enable,
 198         .disable = pca9685_pwm_disable,
 199         .config = pca9685_pwm_config,
 200         .request = pca9685_pwm_request,
 201         .free = pca9685_pwm_free,
 202         .owner = THIS_MODULE,
 203 };
 204
 205 static struct regmap_config pca9685_regmap_i2c_config = {
 206         .reg_bits = 8,
 207         .val_bits = 8,
 208         .max_register = PCA9685_NUMREGS,
 209         .cache_type = REGCACHE_NONE,
 210 };
 211
 212 static int pca9685_pwm_probe(struct i2c_client *client,
 213                                 const struct i2c_device_id *id)
 214 {
 215         struct device_node *np = client->dev.of_node;
 216         struct pca9685 *pca;
 217         int ret;
 218         int mode2;
 219
 220         pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
 221         if (!pca)
 222                 return -ENOMEM;
 223
 224         pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
 225         if (IS_ERR(pca->regmap)) {
 226                 ret = PTR_ERR(pca->regmap);
 227                 dev_err(&client->dev, "Failed to initialize register map: %d\n",
 228                         ret);
 229                 return ret;
 230         }
 231
 232         i2c_set_clientdata(client, pca);
 233
 234         regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
 235
 236         if (of_property_read_bool(np, "invert"))
 237                 mode2 |= MODE2_INVRT;
 238         else
 239                 mode2 &= ~MODE2_INVRT;
 240
 241         if (of_property_read_bool(np, "open-drain"))
 242                 mode2 &= ~MODE2_OUTDRV;
 243         else
 244                 mode2 |= MODE2_OUTDRV;
 245
 246         regmap_write(pca->regmap, PCA9685_MODE2, mode2);
 247
 248         /* clear all "full off" bits */
 249         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
 250         regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
 251
 252         pca->chip.ops = &pca9685_pwm_ops;
 253         /* add an extra channel for ALL_LED */
 254         pca->chip.npwm = PCA9685_MAXCHAN + 1;
 255
 256         pca->chip.dev = &client->dev;
 257         pca->chip.base = -1;
 258         pca->chip.can_sleep = true;
 259
 260         return pwmchip_add(&pca->chip);
 261 }
 262
 263 static int pca9685_pwm_remove(struct i2c_client *client)
 264 {
 265         struct pca9685 *pca = i2c_get_clientdata(client);
 266
 267         regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
 268                            MODE1_SLEEP);
 269
 270         return pwmchip_remove(&pca->chip);
 271 }
 272
 273 static const struct i2c_device_id pca9685_id[] = {
 274         { "pca9685", 0 },
 275         { /* sentinel */ },
 276 };
 277 MODULE_DEVICE_TABLE(i2c, pca9685_id);
 278
 279 static const struct of_device_id pca9685_dt_ids[] = {
 280         { .compatible = "nxp,pca9685-pwm", },
 281         { /* sentinel */ }
 282 };
 283 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
 284
 285 static struct i2c_driver pca9685_i2c_driver = {
 286         .driver = {
 287                 .name = "pca9685-pwm",
 288                 .owner = THIS_MODULE,
 289                 .of_match_table = pca9685_dt_ids,
 290         },
 291         .probe = pca9685_pwm_probe,
 292         .remove = pca9685_pwm_remove,
 293         .id_table = pca9685_id,
 294 };
 295
 296 module_i2c_driver(pca9685_i2c_driver);
 297
 298 MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
 299 MODULE_DESCRIPTION("PWM driver for PCA9685");
 300 MODULE_LICENSE("GPL");