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"); 301