xref: /openbmc/linux/drivers/leds/leds-lp5521.c (revision ffbdccdbbaee814963a09d25b1cc598cfe131366)
1 /*
2  * LP5521 LED chip driver.
3  *
4  * Copyright (C) 2010 Nokia Corporation
5  *
6  * Contact: Samu Onkalo <samu.p.onkalo@nokia.com>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * version 2 as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
15  * General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20  * 02110-1301 USA
21  */
22 
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/i2c.h>
26 #include <linux/mutex.h>
27 #include <linux/gpio.h>
28 #include <linux/interrupt.h>
29 #include <linux/delay.h>
30 #include <linux/ctype.h>
31 #include <linux/spinlock.h>
32 #include <linux/wait.h>
33 #include <linux/leds.h>
34 #include <linux/leds-lp5521.h>
35 #include <linux/workqueue.h>
36 #include <linux/slab.h>
37 #include <linux/platform_data/leds-lp55xx.h>
38 
39 #include "leds-lp55xx-common.h"
40 
41 #define LP5521_PROGRAM_LENGTH		32	/* in bytes */
42 
43 #define LP5521_MAX_LEDS			3	/* Maximum number of LEDs */
44 #define LP5521_MAX_ENGINES		3	/* Maximum number of engines */
45 
46 #define LP5521_ENG_MASK_BASE		0x30	/* 00110000 */
47 #define LP5521_ENG_STATUS_MASK		0x07	/* 00000111 */
48 
49 #define LP5521_CMD_LOAD			0x15	/* 00010101 */
50 #define LP5521_CMD_RUN			0x2a	/* 00101010 */
51 #define LP5521_CMD_DIRECT		0x3f	/* 00111111 */
52 #define LP5521_CMD_DISABLED		0x00	/* 00000000 */
53 
54 /* Registers */
55 #define LP5521_REG_ENABLE		0x00
56 #define LP5521_REG_OP_MODE		0x01
57 #define LP5521_REG_R_PWM		0x02
58 #define LP5521_REG_G_PWM		0x03
59 #define LP5521_REG_B_PWM		0x04
60 #define LP5521_REG_R_CURRENT		0x05
61 #define LP5521_REG_G_CURRENT		0x06
62 #define LP5521_REG_B_CURRENT		0x07
63 #define LP5521_REG_CONFIG		0x08
64 #define LP5521_REG_R_CHANNEL_PC		0x09
65 #define LP5521_REG_G_CHANNEL_PC		0x0A
66 #define LP5521_REG_B_CHANNEL_PC		0x0B
67 #define LP5521_REG_STATUS		0x0C
68 #define LP5521_REG_RESET		0x0D
69 #define LP5521_REG_GPO			0x0E
70 #define LP5521_REG_R_PROG_MEM		0x10
71 #define LP5521_REG_G_PROG_MEM		0x30
72 #define LP5521_REG_B_PROG_MEM		0x50
73 
74 #define LP5521_PROG_MEM_BASE		LP5521_REG_R_PROG_MEM
75 #define LP5521_PROG_MEM_SIZE		0x20
76 
77 /* Base register to set LED current */
78 #define LP5521_REG_LED_CURRENT_BASE	LP5521_REG_R_CURRENT
79 
80 /* Base register to set the brightness */
81 #define LP5521_REG_LED_PWM_BASE		LP5521_REG_R_PWM
82 
83 /* Bits in ENABLE register */
84 #define LP5521_MASTER_ENABLE		0x40	/* Chip master enable */
85 #define LP5521_LOGARITHMIC_PWM		0x80	/* Logarithmic PWM adjustment */
86 #define LP5521_EXEC_RUN			0x2A
87 #define LP5521_ENABLE_DEFAULT	\
88 	(LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM)
89 #define LP5521_ENABLE_RUN_PROGRAM	\
90 	(LP5521_ENABLE_DEFAULT | LP5521_EXEC_RUN)
91 
92 /* Status */
93 #define LP5521_EXT_CLK_USED		0x08
94 
95 /* default R channel current register value */
96 #define LP5521_REG_R_CURR_DEFAULT	0xAF
97 
98 /* Pattern Mode */
99 #define PATTERN_OFF	0
100 
101 /* Reset register value */
102 #define LP5521_RESET			0xFF
103 
104 struct lp5521_engine {
105 	int		id;
106 	u8		mode;
107 	u8		prog_page;
108 	u8		engine_mask;
109 };
110 
111 struct lp5521_led {
112 	int			id;
113 	u8			chan_nr;
114 	u8			led_current;
115 	u8			max_current;
116 	struct led_classdev	cdev;
117 	struct work_struct	brightness_work;
118 	u8			brightness;
119 };
120 
121 struct lp5521_chip {
122 	struct lp5521_platform_data *pdata;
123 	struct mutex		lock; /* Serialize control */
124 	struct i2c_client	*client;
125 	struct lp5521_engine	engines[LP5521_MAX_ENGINES];
126 	struct lp5521_led	leds[LP5521_MAX_LEDS];
127 	u8			num_channels;
128 	u8			num_leds;
129 };
130 
131 static inline void lp5521_wait_enable_done(void)
132 {
133 	/* it takes more 488 us to update ENABLE register */
134 	usleep_range(500, 600);
135 }
136 
137 static inline struct lp5521_led *cdev_to_led(struct led_classdev *cdev)
138 {
139 	return container_of(cdev, struct lp5521_led, cdev);
140 }
141 
142 static inline struct lp5521_chip *engine_to_lp5521(struct lp5521_engine *engine)
143 {
144 	return container_of(engine, struct lp5521_chip,
145 			    engines[engine->id - 1]);
146 }
147 
148 static inline struct lp5521_chip *led_to_lp5521(struct lp5521_led *led)
149 {
150 	return container_of(led, struct lp5521_chip,
151 			    leds[led->id]);
152 }
153 
154 static void lp5521_led_brightness_work(struct work_struct *work);
155 
156 static inline int lp5521_write(struct i2c_client *client, u8 reg, u8 value)
157 {
158 	return i2c_smbus_write_byte_data(client, reg, value);
159 }
160 
161 static int lp5521_read(struct i2c_client *client, u8 reg, u8 *buf)
162 {
163 	s32 ret;
164 
165 	ret = i2c_smbus_read_byte_data(client, reg);
166 	if (ret < 0)
167 		return ret;
168 
169 	*buf = ret;
170 	return 0;
171 }
172 
173 static int lp5521_set_engine_mode(struct lp5521_engine *engine, u8 mode)
174 {
175 	struct lp5521_chip *chip = engine_to_lp5521(engine);
176 	struct i2c_client *client = chip->client;
177 	int ret;
178 	u8 engine_state;
179 
180 	/* Only transition between RUN and DIRECT mode are handled here */
181 	if (mode == LP5521_CMD_LOAD)
182 		return 0;
183 
184 	if (mode == LP5521_CMD_DISABLED)
185 		mode = LP5521_CMD_DIRECT;
186 
187 	ret = lp5521_read(client, LP5521_REG_OP_MODE, &engine_state);
188 	if (ret < 0)
189 		return ret;
190 
191 	/* set mode only for this engine */
192 	engine_state &= ~(engine->engine_mask);
193 	mode &= engine->engine_mask;
194 	engine_state |= mode;
195 	return lp5521_write(client, LP5521_REG_OP_MODE, engine_state);
196 }
197 
198 static int lp5521_load_program(struct lp5521_engine *eng, const u8 *pattern)
199 {
200 	struct lp5521_chip *chip = engine_to_lp5521(eng);
201 	struct i2c_client *client = chip->client;
202 	int ret;
203 	int addr;
204 	u8 mode;
205 
206 	/* move current engine to direct mode and remember the state */
207 	ret = lp5521_set_engine_mode(eng, LP5521_CMD_DIRECT);
208 	if (ret)
209 		return ret;
210 
211 	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
212 	usleep_range(1000, 2000);
213 	ret = lp5521_read(client, LP5521_REG_OP_MODE, &mode);
214 	if (ret)
215 		return ret;
216 
217 	/* For loading, all the engines to load mode */
218 	lp5521_write(client, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);
219 	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
220 	usleep_range(1000, 2000);
221 	lp5521_write(client, LP5521_REG_OP_MODE, LP5521_CMD_LOAD);
222 	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
223 	usleep_range(1000, 2000);
224 
225 	addr = LP5521_PROG_MEM_BASE + eng->prog_page * LP5521_PROG_MEM_SIZE;
226 	i2c_smbus_write_i2c_block_data(client,
227 				addr,
228 				LP5521_PROG_MEM_SIZE,
229 				pattern);
230 
231 	return lp5521_write(client, LP5521_REG_OP_MODE, mode);
232 }
233 
234 static int lp5521_set_led_current(struct lp5521_chip *chip, int led, u8 curr)
235 {
236 	return lp5521_write(chip->client,
237 		    LP5521_REG_LED_CURRENT_BASE + chip->leds[led].chan_nr,
238 		    curr);
239 }
240 
241 static int lp5521_post_init_device(struct lp55xx_chip *chip)
242 {
243 	int ret;
244 	u8 val;
245 
246 	/*
247 	 * Make sure that the chip is reset by reading back the r channel
248 	 * current reg. This is dummy read is required on some platforms -
249 	 * otherwise further access to the R G B channels in the
250 	 * LP5521_REG_ENABLE register will not have any effect - strange!
251 	 */
252 	ret = lp55xx_read(chip, LP5521_REG_R_CURRENT, &val);
253 	if (ret) {
254 		dev_err(&chip->cl->dev, "error in resetting chip\n");
255 		return ret;
256 	}
257 	if (val != LP5521_REG_R_CURR_DEFAULT) {
258 		dev_err(&chip->cl->dev,
259 			"unexpected data in register (expected 0x%x got 0x%x)\n",
260 			LP5521_REG_R_CURR_DEFAULT, val);
261 		ret = -EINVAL;
262 		return ret;
263 	}
264 	usleep_range(10000, 20000);
265 
266 	/* Set all PWMs to direct control mode */
267 	ret = lp55xx_write(chip, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);
268 
269 	val = chip->pdata->update_config ?
270 		: (LP5521_PWRSAVE_EN | LP5521_CP_MODE_AUTO | LP5521_R_TO_BATT);
271 	ret = lp55xx_write(chip, LP5521_REG_CONFIG, val);
272 	if (ret)
273 		return ret;
274 
275 	/* Initialize all channels PWM to zero -> leds off */
276 	lp55xx_write(chip, LP5521_REG_R_PWM, 0);
277 	lp55xx_write(chip, LP5521_REG_G_PWM, 0);
278 	lp55xx_write(chip, LP5521_REG_B_PWM, 0);
279 
280 	/* Set engines are set to run state when OP_MODE enables engines */
281 	ret = lp55xx_write(chip, LP5521_REG_ENABLE, LP5521_ENABLE_RUN_PROGRAM);
282 	if (ret)
283 		return ret;
284 
285 	lp5521_wait_enable_done();
286 
287 	return 0;
288 }
289 
290 static int lp5521_run_selftest(struct lp5521_chip *chip, char *buf)
291 {
292 	int ret;
293 	u8 status;
294 
295 	ret = lp5521_read(chip->client, LP5521_REG_STATUS, &status);
296 	if (ret < 0)
297 		return ret;
298 
299 	/* Check that ext clock is really in use if requested */
300 	if (chip->pdata && chip->pdata->clock_mode == LP5521_CLOCK_EXT)
301 		if  ((status & LP5521_EXT_CLK_USED) == 0)
302 			return -EIO;
303 	return 0;
304 }
305 
306 static void lp5521_set_brightness(struct led_classdev *cdev,
307 			     enum led_brightness brightness)
308 {
309 	struct lp5521_led *led = cdev_to_led(cdev);
310 	led->brightness = (u8)brightness;
311 	schedule_work(&led->brightness_work);
312 }
313 
314 static void lp5521_led_brightness_work(struct work_struct *work)
315 {
316 	struct lp5521_led *led = container_of(work,
317 					      struct lp5521_led,
318 					      brightness_work);
319 	struct lp5521_chip *chip = led_to_lp5521(led);
320 	struct i2c_client *client = chip->client;
321 
322 	mutex_lock(&chip->lock);
323 	lp5521_write(client, LP5521_REG_LED_PWM_BASE + led->chan_nr,
324 		led->brightness);
325 	mutex_unlock(&chip->lock);
326 }
327 
328 /* Set engine mode and create appropriate sysfs attributes, if required. */
329 static int lp5521_set_mode(struct lp5521_engine *engine, u8 mode)
330 {
331 	int ret = 0;
332 
333 	/* if in that mode already do nothing, except for run */
334 	if (mode == engine->mode && mode != LP5521_CMD_RUN)
335 		return 0;
336 
337 	if (mode == LP5521_CMD_RUN) {
338 		ret = lp5521_set_engine_mode(engine, LP5521_CMD_RUN);
339 	} else if (mode == LP5521_CMD_LOAD) {
340 		lp5521_set_engine_mode(engine, LP5521_CMD_DISABLED);
341 		lp5521_set_engine_mode(engine, LP5521_CMD_LOAD);
342 	} else if (mode == LP5521_CMD_DISABLED) {
343 		lp5521_set_engine_mode(engine, LP5521_CMD_DISABLED);
344 	}
345 
346 	engine->mode = mode;
347 
348 	return ret;
349 }
350 
351 static int lp5521_do_store_load(struct lp5521_engine *engine,
352 				const char *buf, size_t len)
353 {
354 	struct lp5521_chip *chip = engine_to_lp5521(engine);
355 	struct i2c_client *client = chip->client;
356 	int  ret, nrchars, offset = 0, i = 0;
357 	char c[3];
358 	unsigned cmd;
359 	u8 pattern[LP5521_PROGRAM_LENGTH] = {0};
360 
361 	while ((offset < len - 1) && (i < LP5521_PROGRAM_LENGTH)) {
362 		/* separate sscanfs because length is working only for %s */
363 		ret = sscanf(buf + offset, "%2s%n ", c, &nrchars);
364 		if (ret != 2)
365 			goto fail;
366 		ret = sscanf(c, "%2x", &cmd);
367 		if (ret != 1)
368 			goto fail;
369 		pattern[i] = (u8)cmd;
370 
371 		offset += nrchars;
372 		i++;
373 	}
374 
375 	/* Each instruction is 16bit long. Check that length is even */
376 	if (i % 2)
377 		goto fail;
378 
379 	mutex_lock(&chip->lock);
380 	if (engine->mode == LP5521_CMD_LOAD)
381 		ret = lp5521_load_program(engine, pattern);
382 	else
383 		ret = -EINVAL;
384 	mutex_unlock(&chip->lock);
385 
386 	if (ret) {
387 		dev_err(&client->dev, "failed loading pattern\n");
388 		return ret;
389 	}
390 
391 	return len;
392 fail:
393 	dev_err(&client->dev, "wrong pattern format\n");
394 	return -EINVAL;
395 }
396 
397 static ssize_t store_engine_load(struct device *dev,
398 				     struct device_attribute *attr,
399 				     const char *buf, size_t len, int nr)
400 {
401 	struct i2c_client *client = to_i2c_client(dev);
402 	struct lp5521_chip *chip = i2c_get_clientdata(client);
403 	return lp5521_do_store_load(&chip->engines[nr - 1], buf, len);
404 }
405 
406 #define store_load(nr)							\
407 static ssize_t store_engine##nr##_load(struct device *dev,		\
408 				     struct device_attribute *attr,	\
409 				     const char *buf, size_t len)	\
410 {									\
411 	return store_engine_load(dev, attr, buf, len, nr);		\
412 }
413 store_load(1)
414 store_load(2)
415 store_load(3)
416 
417 static ssize_t show_engine_mode(struct device *dev,
418 				struct device_attribute *attr,
419 				char *buf, int nr)
420 {
421 	struct i2c_client *client = to_i2c_client(dev);
422 	struct lp5521_chip *chip = i2c_get_clientdata(client);
423 	switch (chip->engines[nr - 1].mode) {
424 	case LP5521_CMD_RUN:
425 		return sprintf(buf, "run\n");
426 	case LP5521_CMD_LOAD:
427 		return sprintf(buf, "load\n");
428 	case LP5521_CMD_DISABLED:
429 		return sprintf(buf, "disabled\n");
430 	default:
431 		return sprintf(buf, "disabled\n");
432 	}
433 }
434 
435 #define show_mode(nr)							\
436 static ssize_t show_engine##nr##_mode(struct device *dev,		\
437 				    struct device_attribute *attr,	\
438 				    char *buf)				\
439 {									\
440 	return show_engine_mode(dev, attr, buf, nr);			\
441 }
442 show_mode(1)
443 show_mode(2)
444 show_mode(3)
445 
446 static ssize_t store_engine_mode(struct device *dev,
447 				 struct device_attribute *attr,
448 				 const char *buf, size_t len, int nr)
449 {
450 	struct i2c_client *client = to_i2c_client(dev);
451 	struct lp5521_chip *chip = i2c_get_clientdata(client);
452 	struct lp5521_engine *engine = &chip->engines[nr - 1];
453 	mutex_lock(&chip->lock);
454 
455 	if (!strncmp(buf, "run", 3))
456 		lp5521_set_mode(engine, LP5521_CMD_RUN);
457 	else if (!strncmp(buf, "load", 4))
458 		lp5521_set_mode(engine, LP5521_CMD_LOAD);
459 	else if (!strncmp(buf, "disabled", 8))
460 		lp5521_set_mode(engine, LP5521_CMD_DISABLED);
461 
462 	mutex_unlock(&chip->lock);
463 	return len;
464 }
465 
466 #define store_mode(nr)							\
467 static ssize_t store_engine##nr##_mode(struct device *dev,		\
468 				     struct device_attribute *attr,	\
469 				     const char *buf, size_t len)	\
470 {									\
471 	return store_engine_mode(dev, attr, buf, len, nr);		\
472 }
473 store_mode(1)
474 store_mode(2)
475 store_mode(3)
476 
477 static ssize_t show_max_current(struct device *dev,
478 			    struct device_attribute *attr,
479 			    char *buf)
480 {
481 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
482 	struct lp5521_led *led = cdev_to_led(led_cdev);
483 
484 	return sprintf(buf, "%d\n", led->max_current);
485 }
486 
487 static ssize_t show_current(struct device *dev,
488 			    struct device_attribute *attr,
489 			    char *buf)
490 {
491 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
492 	struct lp5521_led *led = cdev_to_led(led_cdev);
493 
494 	return sprintf(buf, "%d\n", led->led_current);
495 }
496 
497 static ssize_t store_current(struct device *dev,
498 			     struct device_attribute *attr,
499 			     const char *buf, size_t len)
500 {
501 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
502 	struct lp5521_led *led = cdev_to_led(led_cdev);
503 	struct lp5521_chip *chip = led_to_lp5521(led);
504 	ssize_t ret;
505 	unsigned long curr;
506 
507 	if (kstrtoul(buf, 0, &curr))
508 		return -EINVAL;
509 
510 	if (curr > led->max_current)
511 		return -EINVAL;
512 
513 	mutex_lock(&chip->lock);
514 	ret = lp5521_set_led_current(chip, led->id, curr);
515 	mutex_unlock(&chip->lock);
516 
517 	if (ret < 0)
518 		return ret;
519 
520 	led->led_current = (u8)curr;
521 
522 	return len;
523 }
524 
525 static ssize_t lp5521_selftest(struct device *dev,
526 			       struct device_attribute *attr,
527 			       char *buf)
528 {
529 	struct i2c_client *client = to_i2c_client(dev);
530 	struct lp5521_chip *chip = i2c_get_clientdata(client);
531 	int ret;
532 
533 	mutex_lock(&chip->lock);
534 	ret = lp5521_run_selftest(chip, buf);
535 	mutex_unlock(&chip->lock);
536 	return sprintf(buf, "%s\n", ret ? "FAIL" : "OK");
537 }
538 
539 static void lp5521_clear_program_memory(struct i2c_client *cl)
540 {
541 	int i;
542 	u8 rgb_mem[] = {
543 		LP5521_REG_R_PROG_MEM,
544 		LP5521_REG_G_PROG_MEM,
545 		LP5521_REG_B_PROG_MEM,
546 	};
547 
548 	for (i = 0; i < ARRAY_SIZE(rgb_mem); i++) {
549 		lp5521_write(cl, rgb_mem[i], 0);
550 		lp5521_write(cl, rgb_mem[i] + 1, 0);
551 	}
552 }
553 
554 static void lp5521_write_program_memory(struct i2c_client *cl,
555 				u8 base, u8 *rgb, int size)
556 {
557 	int i;
558 
559 	if (!rgb || size <= 0)
560 		return;
561 
562 	for (i = 0; i < size; i++)
563 		lp5521_write(cl, base + i, *(rgb + i));
564 
565 	lp5521_write(cl, base + i, 0);
566 	lp5521_write(cl, base + i + 1, 0);
567 }
568 
569 static inline struct lp5521_led_pattern *lp5521_get_pattern
570 					(struct lp5521_chip *chip, u8 offset)
571 {
572 	struct lp5521_led_pattern *ptn;
573 	ptn = chip->pdata->patterns + (offset - 1);
574 	return ptn;
575 }
576 
577 static void lp5521_run_led_pattern(int mode, struct lp5521_chip *chip)
578 {
579 	struct lp5521_led_pattern *ptn;
580 	struct i2c_client *cl = chip->client;
581 	int num_patterns = chip->pdata->num_patterns;
582 
583 	if (mode > num_patterns || !(chip->pdata->patterns))
584 		return;
585 
586 	if (mode == PATTERN_OFF) {
587 		lp5521_write(cl, LP5521_REG_ENABLE, LP5521_ENABLE_DEFAULT);
588 		usleep_range(1000, 2000);
589 		lp5521_write(cl, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);
590 	} else {
591 		ptn = lp5521_get_pattern(chip, mode);
592 		if (!ptn)
593 			return;
594 
595 		lp5521_write(cl, LP5521_REG_OP_MODE, LP5521_CMD_LOAD);
596 		usleep_range(1000, 2000);
597 
598 		lp5521_clear_program_memory(cl);
599 
600 		lp5521_write_program_memory(cl, LP5521_REG_R_PROG_MEM,
601 					ptn->r, ptn->size_r);
602 		lp5521_write_program_memory(cl, LP5521_REG_G_PROG_MEM,
603 					ptn->g, ptn->size_g);
604 		lp5521_write_program_memory(cl, LP5521_REG_B_PROG_MEM,
605 					ptn->b, ptn->size_b);
606 
607 		lp5521_write(cl, LP5521_REG_OP_MODE, LP5521_CMD_RUN);
608 		usleep_range(1000, 2000);
609 		lp5521_write(cl, LP5521_REG_ENABLE, LP5521_ENABLE_RUN_PROGRAM);
610 	}
611 }
612 
613 static ssize_t store_led_pattern(struct device *dev,
614 				struct device_attribute *attr,
615 				const char *buf, size_t len)
616 {
617 	struct lp5521_chip *chip = i2c_get_clientdata(to_i2c_client(dev));
618 	unsigned long val;
619 	int ret;
620 
621 	ret = kstrtoul(buf, 16, &val);
622 	if (ret)
623 		return ret;
624 
625 	lp5521_run_led_pattern(val, chip);
626 
627 	return len;
628 }
629 
630 /* led class device attributes */
631 static DEVICE_ATTR(led_current, S_IRUGO | S_IWUSR, show_current, store_current);
632 static DEVICE_ATTR(max_current, S_IRUGO , show_max_current, NULL);
633 
634 static struct attribute *lp5521_led_attributes[] = {
635 	&dev_attr_led_current.attr,
636 	&dev_attr_max_current.attr,
637 	NULL,
638 };
639 
640 static struct attribute_group lp5521_led_attribute_group = {
641 	.attrs = lp5521_led_attributes
642 };
643 
644 /* device attributes */
645 static DEVICE_ATTR(engine1_mode, S_IRUGO | S_IWUSR,
646 		   show_engine1_mode, store_engine1_mode);
647 static DEVICE_ATTR(engine2_mode, S_IRUGO | S_IWUSR,
648 		   show_engine2_mode, store_engine2_mode);
649 static DEVICE_ATTR(engine3_mode, S_IRUGO | S_IWUSR,
650 		   show_engine3_mode, store_engine3_mode);
651 static DEVICE_ATTR(engine1_load, S_IWUSR, NULL, store_engine1_load);
652 static DEVICE_ATTR(engine2_load, S_IWUSR, NULL, store_engine2_load);
653 static DEVICE_ATTR(engine3_load, S_IWUSR, NULL, store_engine3_load);
654 static DEVICE_ATTR(selftest, S_IRUGO, lp5521_selftest, NULL);
655 static DEVICE_ATTR(led_pattern, S_IWUSR, NULL, store_led_pattern);
656 
657 static struct attribute *lp5521_attributes[] = {
658 	&dev_attr_engine1_mode.attr,
659 	&dev_attr_engine2_mode.attr,
660 	&dev_attr_engine3_mode.attr,
661 	&dev_attr_selftest.attr,
662 	&dev_attr_engine1_load.attr,
663 	&dev_attr_engine2_load.attr,
664 	&dev_attr_engine3_load.attr,
665 	&dev_attr_led_pattern.attr,
666 	NULL
667 };
668 
669 static const struct attribute_group lp5521_group = {
670 	.attrs = lp5521_attributes,
671 };
672 
673 static int lp5521_register_sysfs(struct i2c_client *client)
674 {
675 	struct device *dev = &client->dev;
676 	return sysfs_create_group(&dev->kobj, &lp5521_group);
677 }
678 
679 static void lp5521_unregister_sysfs(struct i2c_client *client)
680 {
681 	struct lp5521_chip *chip = i2c_get_clientdata(client);
682 	struct device *dev = &client->dev;
683 	int i;
684 
685 	sysfs_remove_group(&dev->kobj, &lp5521_group);
686 
687 	for (i = 0; i < chip->num_leds; i++)
688 		sysfs_remove_group(&chip->leds[i].cdev.dev->kobj,
689 				&lp5521_led_attribute_group);
690 }
691 
692 static void lp5521_deinit_device(struct lp5521_chip *chip);
693 static int lp5521_init_device(struct lp5521_chip *chip)
694 {
695 	struct i2c_client *client = chip->client;
696 	struct lp55xx_chip *temp;
697 	int ret;
698 
699 	ret = lp5521_post_init_device(temp);
700 	if (ret < 0) {
701 		dev_err(&client->dev, "error configuring chip\n");
702 		goto err_config;
703 	}
704 
705 	return 0;
706 
707 err_config:
708 	lp5521_deinit_device(chip);
709 	return ret;
710 }
711 
712 static void lp5521_deinit_device(struct lp5521_chip *chip)
713 {
714 	struct lp5521_platform_data *pdata = chip->pdata;
715 
716 	if (pdata->enable)
717 		pdata->enable(0);
718 	if (pdata->release_resources)
719 		pdata->release_resources();
720 }
721 
722 static int lp5521_init_led(struct lp5521_led *led,
723 				struct i2c_client *client,
724 				int chan, struct lp5521_platform_data *pdata)
725 {
726 	struct device *dev = &client->dev;
727 	char name[32];
728 	int res;
729 
730 	if (chan >= LP5521_MAX_LEDS)
731 		return -EINVAL;
732 
733 	if (pdata->led_config[chan].led_current == 0)
734 		return 0;
735 
736 	led->led_current = pdata->led_config[chan].led_current;
737 	led->max_current = pdata->led_config[chan].max_current;
738 	led->chan_nr = pdata->led_config[chan].chan_nr;
739 
740 	if (led->chan_nr >= LP5521_MAX_LEDS) {
741 		dev_err(dev, "Use channel numbers between 0 and %d\n",
742 			LP5521_MAX_LEDS - 1);
743 		return -EINVAL;
744 	}
745 
746 	led->cdev.brightness_set = lp5521_set_brightness;
747 	if (pdata->led_config[chan].name) {
748 		led->cdev.name = pdata->led_config[chan].name;
749 	} else {
750 		snprintf(name, sizeof(name), "%s:channel%d",
751 			pdata->label ?: client->name, chan);
752 		led->cdev.name = name;
753 	}
754 
755 	res = led_classdev_register(dev, &led->cdev);
756 	if (res < 0) {
757 		dev_err(dev, "couldn't register led on channel %d\n", chan);
758 		return res;
759 	}
760 
761 	res = sysfs_create_group(&led->cdev.dev->kobj,
762 			&lp5521_led_attribute_group);
763 	if (res < 0) {
764 		dev_err(dev, "couldn't register current attribute\n");
765 		led_classdev_unregister(&led->cdev);
766 		return res;
767 	}
768 	return 0;
769 }
770 
771 static int lp5521_register_leds(struct lp5521_chip *chip)
772 {
773 	struct lp5521_platform_data *pdata = chip->pdata;
774 	struct i2c_client *client = chip->client;
775 	int i;
776 	int led;
777 	int ret;
778 
779 	/* Initialize leds */
780 	chip->num_channels = pdata->num_channels;
781 	chip->num_leds = 0;
782 	led = 0;
783 	for (i = 0; i < pdata->num_channels; i++) {
784 		/* Do not initialize channels that are not connected */
785 		if (pdata->led_config[i].led_current == 0)
786 			continue;
787 
788 		ret = lp5521_init_led(&chip->leds[led], client, i, pdata);
789 		if (ret) {
790 			dev_err(&client->dev, "error initializing leds\n");
791 			return ret;
792 		}
793 		chip->num_leds++;
794 
795 		chip->leds[led].id = led;
796 		/* Set initial LED current */
797 		lp5521_set_led_current(chip, led,
798 				chip->leds[led].led_current);
799 
800 		INIT_WORK(&(chip->leds[led].brightness_work),
801 			lp5521_led_brightness_work);
802 
803 		led++;
804 	}
805 
806 	return 0;
807 }
808 
809 static void lp5521_unregister_leds(struct lp5521_chip *chip)
810 {
811 	int i;
812 
813 	for (i = 0; i < chip->num_leds; i++) {
814 		led_classdev_unregister(&chip->leds[i].cdev);
815 		cancel_work_sync(&chip->leds[i].brightness_work);
816 	}
817 }
818 
819 /* Chip specific configurations */
820 static struct lp55xx_device_config lp5521_cfg = {
821 	.reset = {
822 		.addr = LP5521_REG_RESET,
823 		.val  = LP5521_RESET,
824 	},
825 	.enable = {
826 		.addr = LP5521_REG_ENABLE,
827 		.val  = LP5521_ENABLE_DEFAULT,
828 	},
829 	.post_init_device   = lp5521_post_init_device,
830 };
831 
832 static int lp5521_probe(struct i2c_client *client,
833 			const struct i2c_device_id *id)
834 {
835 	struct lp5521_chip		*old_chip = NULL;
836 	int ret;
837 	struct lp55xx_chip *chip;
838 	struct lp55xx_led *led;
839 	struct lp55xx_platform_data *pdata = client->dev.platform_data;
840 
841 	if (!pdata) {
842 		dev_err(&client->dev, "no platform data\n");
843 		return -EINVAL;
844 	}
845 
846 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
847 	if (!chip)
848 		return -ENOMEM;
849 
850 	led = devm_kzalloc(&client->dev,
851 			sizeof(*led) * pdata->num_channels, GFP_KERNEL);
852 	if (!led)
853 		return -ENOMEM;
854 
855 	chip->cl = client;
856 	chip->pdata = pdata;
857 	chip->cfg = &lp5521_cfg;
858 
859 	mutex_init(&chip->lock);
860 
861 	i2c_set_clientdata(client, led);
862 
863 	ret = lp5521_init_device(old_chip);
864 	if (ret)
865 		goto err_init;
866 
867 	dev_info(&client->dev, "%s programmable led chip found\n", id->name);
868 
869 	ret = lp5521_register_leds(old_chip);
870 	if (ret)
871 		goto fail2;
872 
873 	ret = lp5521_register_sysfs(client);
874 	if (ret) {
875 		dev_err(&client->dev, "registering sysfs failed\n");
876 		goto fail2;
877 	}
878 	return ret;
879 fail2:
880 	lp5521_unregister_leds(old_chip);
881 	lp5521_deinit_device(old_chip);
882 err_init:
883 	return ret;
884 }
885 
886 static int lp5521_remove(struct i2c_client *client)
887 {
888 	struct lp5521_chip *old_chip = i2c_get_clientdata(client);
889 
890 	lp5521_run_led_pattern(PATTERN_OFF, old_chip);
891 	lp5521_unregister_sysfs(client);
892 
893 	lp5521_unregister_leds(old_chip);
894 
895 	lp5521_deinit_device(old_chip);
896 	return 0;
897 }
898 
899 static const struct i2c_device_id lp5521_id[] = {
900 	{ "lp5521", 0 }, /* Three channel chip */
901 	{ }
902 };
903 MODULE_DEVICE_TABLE(i2c, lp5521_id);
904 
905 static struct i2c_driver lp5521_driver = {
906 	.driver = {
907 		.name	= "lp5521",
908 	},
909 	.probe		= lp5521_probe,
910 	.remove		= lp5521_remove,
911 	.id_table	= lp5521_id,
912 };
913 
914 module_i2c_driver(lp5521_driver);
915 
916 MODULE_AUTHOR("Mathias Nyman, Yuri Zaporozhets, Samu Onkalo");
917 MODULE_DESCRIPTION("LP5521 LED engine");
918 MODULE_LICENSE("GPL v2");
919