pwm-pca9685.c 9.8 KB
Newer Older
S
Steffen Trumtrar 已提交
1 2 3 4
/*
 * Driver for PCA9685 16-channel 12-bit PWM LED controller
 *
 * Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
5
 * Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
S
Steffen Trumtrar 已提交
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
 *
 * based on the pwm-twl-led.c driver
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

22
#include <linux/acpi.h>
S
Steffen Trumtrar 已提交
23 24 25
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/platform_device.h>
26
#include <linux/property.h>
S
Steffen Trumtrar 已提交
27 28 29
#include <linux/pwm.h>
#include <linux/regmap.h>
#include <linux/slab.h>
30 31 32 33 34 35 36 37 38
#include <linux/delay.h>

/*
 * Because the PCA9685 has only one prescaler per chip, changing the period of
 * one channel affects the period of all 16 PWM outputs!
 * However, the ratio between each configured duty cycle and the chip-wide
 * period remains constant, because the OFF time is set in proportion to the
 * counter range.
 */
S
Steffen Trumtrar 已提交
39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56

#define PCA9685_MODE1		0x00
#define PCA9685_MODE2		0x01
#define PCA9685_SUBADDR1	0x02
#define PCA9685_SUBADDR2	0x03
#define PCA9685_SUBADDR3	0x04
#define PCA9685_ALLCALLADDR	0x05
#define PCA9685_LEDX_ON_L	0x06
#define PCA9685_LEDX_ON_H	0x07
#define PCA9685_LEDX_OFF_L	0x08
#define PCA9685_LEDX_OFF_H	0x09

#define PCA9685_ALL_LED_ON_L	0xFA
#define PCA9685_ALL_LED_ON_H	0xFB
#define PCA9685_ALL_LED_OFF_L	0xFC
#define PCA9685_ALL_LED_OFF_H	0xFD
#define PCA9685_PRESCALE	0xFE

57 58 59 60 61 62 63
#define PCA9685_PRESCALE_MIN	0x03	/* => max. frequency of 1526 Hz */
#define PCA9685_PRESCALE_MAX	0xFF	/* => min. frequency of 24 Hz */

#define PCA9685_COUNTER_RANGE	4096
#define PCA9685_DEFAULT_PERIOD	5000000	/* Default period_ns = 1/200 Hz */
#define PCA9685_OSC_CLOCK_MHZ	25	/* Internal oscillator with 25 MHz */

S
Steffen Trumtrar 已提交
64 65 66 67
#define PCA9685_NUMREGS		0xFF
#define PCA9685_MAXCHAN		0x10

#define LED_FULL		(1 << 4)
68
#define MODE1_RESTART		(1 << 7)
S
Steffen Trumtrar 已提交
69 70 71 72 73 74 75 76 77 78 79 80 81
#define MODE1_SLEEP		(1 << 4)
#define MODE2_INVRT		(1 << 4)
#define MODE2_OUTDRV		(1 << 2)

#define LED_N_ON_H(N)	(PCA9685_LEDX_ON_H + (4 * (N)))
#define LED_N_ON_L(N)	(PCA9685_LEDX_ON_L + (4 * (N)))
#define LED_N_OFF_H(N)	(PCA9685_LEDX_OFF_H + (4 * (N)))
#define LED_N_OFF_L(N)	(PCA9685_LEDX_OFF_L + (4 * (N)))

struct pca9685 {
	struct pwm_chip chip;
	struct regmap *regmap;
	int active_cnt;
82 83
	int duty_ns;
	int period_ns;
S
Steffen Trumtrar 已提交
84 85 86 87 88 89 90 91 92 93 94 95 96
};

static inline struct pca9685 *to_pca(struct pwm_chip *chip)
{
	return container_of(chip, struct pca9685, chip);
}

static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
			      int duty_ns, int period_ns)
{
	struct pca9685 *pca = to_pca(chip);
	unsigned long long duty;
	unsigned int reg;
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137
	int prescale;

	if (period_ns != pca->period_ns) {
		prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
					     PCA9685_COUNTER_RANGE * 1000) - 1;

		if (prescale >= PCA9685_PRESCALE_MIN &&
			prescale <= PCA9685_PRESCALE_MAX) {
			/* Put chip into sleep mode */
			regmap_update_bits(pca->regmap, PCA9685_MODE1,
					   MODE1_SLEEP, MODE1_SLEEP);

			/* Change the chip-wide output frequency */
			regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);

			/* Wake the chip up */
			regmap_update_bits(pca->regmap, PCA9685_MODE1,
					   MODE1_SLEEP, 0x0);

			/* Wait 500us for the oscillator to be back up */
			udelay(500);

			pca->period_ns = period_ns;

			/*
			 * If the duty cycle did not change, restart PWM with
			 * the same duty cycle to period ratio and return.
			 */
			if (duty_ns == pca->duty_ns) {
				regmap_update_bits(pca->regmap, PCA9685_MODE1,
						   MODE1_RESTART, 0x1);
				return 0;
			}
		} else {
			dev_err(chip->dev,
				"prescaler not set: period out of bounds!\n");
			return -EINVAL;
		}
	}

	pca->duty_ns = duty_ns;
S
Steffen Trumtrar 已提交
138 139 140 141 142 143 144 145 146 147 148 149 150

	if (duty_ns < 1) {
		if (pwm->hwpwm >= PCA9685_MAXCHAN)
			reg = PCA9685_ALL_LED_OFF_H;
		else
			reg = LED_N_OFF_H(pwm->hwpwm);

		regmap_write(pca->regmap, reg, LED_FULL);

		return 0;
	}

	if (duty_ns == period_ns) {
151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166
		/* Clear both OFF registers */
		if (pwm->hwpwm >= PCA9685_MAXCHAN)
			reg = PCA9685_ALL_LED_OFF_L;
		else
			reg = LED_N_OFF_L(pwm->hwpwm);

		regmap_write(pca->regmap, reg, 0x0);

		if (pwm->hwpwm >= PCA9685_MAXCHAN)
			reg = PCA9685_ALL_LED_OFF_H;
		else
			reg = LED_N_OFF_H(pwm->hwpwm);

		regmap_write(pca->regmap, reg, 0x0);

		/* Set the full ON bit */
S
Steffen Trumtrar 已提交
167 168 169 170 171 172 173 174 175 176
		if (pwm->hwpwm >= PCA9685_MAXCHAN)
			reg = PCA9685_ALL_LED_ON_H;
		else
			reg = LED_N_ON_H(pwm->hwpwm);

		regmap_write(pca->regmap, reg, LED_FULL);

		return 0;
	}

177
	duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
S
Steffen Trumtrar 已提交
178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193
	duty = DIV_ROUND_UP_ULL(duty, period_ns);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_L;
	else
		reg = LED_N_OFF_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, (int)duty & 0xff);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_H;
	else
		reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);

194 195 196 197 198 199 200 201
	/* Clear the full ON bit, otherwise the set OFF time has no effect */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_ON_H;
	else
		reg = LED_N_ON_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0);

S
Steffen Trumtrar 已提交
202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279
	return 0;
}

static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pca9685 *pca = to_pca(chip);
	unsigned int reg;

	/*
	 * The PWM subsystem does not support a pre-delay.
	 * So, set the ON-timeout to 0
	 */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_ON_L;
	else
		reg = LED_N_ON_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_ON_H;
	else
		reg = LED_N_ON_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0);

	/*
	 * Clear the full-off bit.
	 * It has precedence over the others and must be off.
	 */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_H;
	else
		reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);

	return 0;
}

static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pca9685 *pca = to_pca(chip);
	unsigned int reg;

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_H;
	else
		reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, LED_FULL);

	/* Clear the LED_OFF counter. */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_L;
	else
		reg = LED_N_OFF_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0x0);
}

static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pca9685 *pca = to_pca(chip);

	if (pca->active_cnt++ == 0)
		return regmap_update_bits(pca->regmap, PCA9685_MODE1,
					  MODE1_SLEEP, 0x0);

	return 0;
}

static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pca9685 *pca = to_pca(chip);

	if (--pca->active_cnt == 0)
		regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
280
				   MODE1_SLEEP);
S
Steffen Trumtrar 已提交
281 282 283 284 285 286 287 288
}

static const struct pwm_ops pca9685_pwm_ops = {
	.enable = pca9685_pwm_enable,
	.disable = pca9685_pwm_disable,
	.config = pca9685_pwm_config,
	.request = pca9685_pwm_request,
	.free = pca9685_pwm_free,
289
	.owner = THIS_MODULE,
S
Steffen Trumtrar 已提交
290 291
};

292
static const struct regmap_config pca9685_regmap_i2c_config = {
S
Steffen Trumtrar 已提交
293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = PCA9685_NUMREGS,
	.cache_type = REGCACHE_NONE,
};

static int pca9685_pwm_probe(struct i2c_client *client,
				const struct i2c_device_id *id)
{
	struct pca9685 *pca;
	int ret;
	int mode2;

	pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
	if (!pca)
		return -ENOMEM;

	pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
	if (IS_ERR(pca->regmap)) {
		ret = PTR_ERR(pca->regmap);
		dev_err(&client->dev, "Failed to initialize register map: %d\n",
			ret);
		return ret;
	}
317 318
	pca->duty_ns = 0;
	pca->period_ns = PCA9685_DEFAULT_PERIOD;
S
Steffen Trumtrar 已提交
319 320 321 322 323

	i2c_set_clientdata(client, pca);

	regmap_read(pca->regmap, PCA9685_MODE2, &mode2);

324
	if (device_property_read_bool(&client->dev, "invert"))
S
Steffen Trumtrar 已提交
325 326 327 328
		mode2 |= MODE2_INVRT;
	else
		mode2 &= ~MODE2_INVRT;

329
	if (device_property_read_bool(&client->dev, "open-drain"))
S
Steffen Trumtrar 已提交
330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354
		mode2 &= ~MODE2_OUTDRV;
	else
		mode2 |= MODE2_OUTDRV;

	regmap_write(pca->regmap, PCA9685_MODE2, mode2);

	/* clear all "full off" bits */
	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);

	pca->chip.ops = &pca9685_pwm_ops;
	/* add an extra channel for ALL_LED */
	pca->chip.npwm = PCA9685_MAXCHAN + 1;

	pca->chip.dev = &client->dev;
	pca->chip.base = -1;
	pca->chip.can_sleep = true;

	return pwmchip_add(&pca->chip);
}

static int pca9685_pwm_remove(struct i2c_client *client)
{
	struct pca9685 *pca = i2c_get_clientdata(client);

355 356
	regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
			   MODE1_SLEEP);
S
Steffen Trumtrar 已提交
357 358 359 360 361 362 363 364 365 366

	return pwmchip_remove(&pca->chip);
}

static const struct i2c_device_id pca9685_id[] = {
	{ "pca9685", 0 },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(i2c, pca9685_id);

367 368 369 370 371 372 373 374 375
#ifdef CONFIG_ACPI
static const struct acpi_device_id pca9685_acpi_ids[] = {
	{ "INT3492", 0 },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
#endif

#ifdef CONFIG_OF
S
Steffen Trumtrar 已提交
376 377 378 379 380
static const struct of_device_id pca9685_dt_ids[] = {
	{ .compatible = "nxp,pca9685-pwm", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
381
#endif
S
Steffen Trumtrar 已提交
382 383 384 385

static struct i2c_driver pca9685_i2c_driver = {
	.driver = {
		.name = "pca9685-pwm",
386 387
		.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
		.of_match_table = of_match_ptr(pca9685_dt_ids),
S
Steffen Trumtrar 已提交
388 389 390 391 392 393 394 395 396 397 398
	},
	.probe = pca9685_pwm_probe,
	.remove = pca9685_pwm_remove,
	.id_table = pca9685_id,
};

module_i2c_driver(pca9685_i2c_driver);

MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
MODULE_DESCRIPTION("PWM driver for PCA9685");
MODULE_LICENSE("GPL");