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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
77struct pca9685 {
78 struct pwm_chip chip;
79 struct regmap *regmap;
80 int active_cnt;
81 int duty_ns;
82 int period_ns;
83};
84
85static inline struct pca9685 *to_pca(struct pwm_chip *chip)
86{
87 return container_of(chip, struct pca9685, chip);
88}
89
90static 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
194static 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
231static 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
252static 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
263static 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
272static 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
281static 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
288static 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
340static 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
350static const struct i2c_device_id pca9685_id[] = {
351 { "pca9685", 0 },
352 { /* sentinel */ },
353};
354MODULE_DEVICE_TABLE(i2c, pca9685_id);
355
356#ifdef CONFIG_ACPI
357static const struct acpi_device_id pca9685_acpi_ids[] = {
358 { "INT3492", 0 },
359 { /* sentinel */ },
360};
361MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
362#endif
363
364#ifdef CONFIG_OF
365static const struct of_device_id pca9685_dt_ids[] = {
366 { .compatible = "nxp,pca9685-pwm", },
367 { /* sentinel */ }
368};
369MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
370#endif
371
372static 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
383module_i2c_driver(pca9685_i2c_driver);
384
385MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
386MODULE_DESCRIPTION("PWM driver for PCA9685");
387MODULE_LICENSE("GPL");