xref: /openbmc/linux/drivers/leds/leds-tca6507.c (revision 8fdff1dc)
1 /*
2  * leds-tca6507
3  *
4  * The TCA6507 is a programmable LED controller that can drive 7
5  * separate lines either by holding them low, or by pulsing them
6  * with modulated width.
7  * The modulation can be varied in a simple pattern to produce a blink or
8  * double-blink.
9  *
10  * This driver can configure each line either as a 'GPIO' which is out-only
11  * (no pull-up) or as an LED with variable brightness and hardware-assisted
12  * blinking.
13  *
14  * Apart from OFF and ON there are three programmable brightness levels which
15  * can be programmed from 0 to 15 and indicate how many 500usec intervals in
16  * each 8msec that the led is 'on'.  The levels are named MASTER, BANK0 and
17  * BANK1.
18  *
19  * There are two different blink rates that can be programmed, each with
20  * separate time for rise, on, fall, off and second-off.  Thus if 3 or more
21  * different non-trivial rates are required, software must be used for the extra
22  * rates. The two different blink rates must align with the two levels BANK0 and
23  * BANK1.
24  * This driver does not support double-blink so 'second-off' always matches
25  * 'off'.
26  *
27  * Only 16 different times can be programmed in a roughly logarithmic scale from
28  * 64ms to 16320ms.  To be precise the possible times are:
29  *    0, 64, 128, 192, 256, 384, 512, 768,
30  *    1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320
31  *
32  * Times that cannot be closely matched with these must be
33  * handled in software.  This driver allows 12.5% error in matching.
34  *
35  * This driver does not allow rise/fall rates to be set explicitly.  When trying
36  * to match a given 'on' or 'off' period, an appropriate pair of 'change' and
37  * 'hold' times are chosen to get a close match.  If the target delay is even,
38  * the 'change' number will be the smaller; if odd, the 'hold' number will be
39  * the smaller.
40 
41  * Choosing pairs of delays with 12.5% errors allows us to match delays in the
42  * ranges: 56-72, 112-144, 168-216, 224-27504, 28560-36720.
43  * 26% of the achievable sums can be matched by multiple pairings. For example
44  * 1536 == 1536+0, 1024+512, or 768+768.  This driver will always choose the
45  * pairing with the least maximum - 768+768 in this case.  Other pairings are
46  * not available.
47  *
48  * Access to the 3 levels and 2 blinks are on a first-come, first-served basis.
49  * Access can be shared by multiple leds if they have the same level and
50  * either same blink rates, or some don't blink.
51  * When a led changes, it relinquishes access and tries again, so it might
52  * lose access to hardware blink.
53  * If a blink engine cannot be allocated, software blink is used.
54  * If the desired brightness cannot be allocated, the closest available non-zero
55  * brightness is used.  As 'full' is always available, the worst case would be
56  * to have two different blink rates at '1', with Max at '2', then other leds
57  * will have to choose between '2' and '16'.  Hopefully this is not likely.
58  *
59  * Each bank (BANK0 and BANK1) has two usage counts - LEDs using the brightness
60  * and LEDs using the blink.  It can only be reprogrammed when the appropriate
61  * counter is zero.  The MASTER level has a single usage count.
62  *
63  * Each Led has programmable 'on' and 'off' time as milliseconds.  With each
64  * there is a flag saying if it was explicitly requested or defaulted.
65  * Similarly the banks know if each time was explicit or a default.  Defaults
66  * are permitted to be changed freely - they are not recognised when matching.
67  *
68  *
69  * An led-tca6507 device must be provided with platform data.  This data
70  * lists for each output: the name, default trigger, and whether the signal
71  * is being used as a GPiO rather than an led.  'struct led_plaform_data'
72  * is used for this.  If 'name' is NULL, the output isn't used.  If 'flags'
73  * is TCA6507_MAKE_CPIO, the output is a GPO.
74  * The "struct led_platform_data" can be embedded in a
75  * "struct tca6507_platform_data" which adds a 'gpio_base' for the GPiOs,
76  * and a 'setup' callback which is called once the GPiOs are available.
77  *
78  */
79 
80 #include <linux/module.h>
81 #include <linux/slab.h>
82 #include <linux/leds.h>
83 #include <linux/err.h>
84 #include <linux/i2c.h>
85 #include <linux/gpio.h>
86 #include <linux/workqueue.h>
87 #include <linux/leds-tca6507.h>
88 
89 /* LED select registers determine the source that drives LED outputs */
90 #define TCA6507_LS_LED_OFF	0x0	/* Output HI-Z (off) */
91 #define TCA6507_LS_LED_OFF1	0x1	/* Output HI-Z (off) - not used */
92 #define TCA6507_LS_LED_PWM0	0x2	/* Output LOW with Bank0 rate */
93 #define TCA6507_LS_LED_PWM1	0x3	/* Output LOW with Bank1 rate */
94 #define TCA6507_LS_LED_ON	0x4	/* Output LOW (on) */
95 #define TCA6507_LS_LED_MIR	0x5	/* Output LOW with Master Intensity */
96 #define TCA6507_LS_BLINK0	0x6	/* Blink at Bank0 rate */
97 #define TCA6507_LS_BLINK1	0x7	/* Blink at Bank1 rate */
98 
99 enum {
100 	BANK0,
101 	BANK1,
102 	MASTER,
103 };
104 static int bank_source[3] = {
105 	TCA6507_LS_LED_PWM0,
106 	TCA6507_LS_LED_PWM1,
107 	TCA6507_LS_LED_MIR,
108 };
109 static int blink_source[2] = {
110 	TCA6507_LS_BLINK0,
111 	TCA6507_LS_BLINK1,
112 };
113 
114 /* PWM registers */
115 #define	TCA6507_REG_CNT			11
116 
117 /*
118  * 0x00, 0x01, 0x02 encode the TCA6507_LS_* values, each output
119  * owns one bit in each register
120  */
121 #define	TCA6507_FADE_ON			0x03
122 #define	TCA6507_FULL_ON			0x04
123 #define	TCA6507_FADE_OFF		0x05
124 #define	TCA6507_FIRST_OFF		0x06
125 #define	TCA6507_SECOND_OFF		0x07
126 #define	TCA6507_MAX_INTENSITY		0x08
127 #define	TCA6507_MASTER_INTENSITY	0x09
128 #define	TCA6507_INITIALIZE		0x0A
129 
130 #define	INIT_CODE			0x8
131 
132 #define TIMECODES 16
133 static int time_codes[TIMECODES] = {
134 	0, 64, 128, 192, 256, 384, 512, 768,
135 	1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320
136 };
137 
138 /* Convert an led.brightness level (0..255) to a TCA6507 level (0..15) */
139 static inline int TO_LEVEL(int brightness)
140 {
141 	return brightness >> 4;
142 }
143 
144 /* ...and convert back */
145 static inline int TO_BRIGHT(int level)
146 {
147 	if (level)
148 		return (level << 4) | 0xf;
149 	return 0;
150 }
151 
152 #define NUM_LEDS 7
153 struct tca6507_chip {
154 	int			reg_set;	/* One bit per register where
155 						 * a '1' means the register
156 						 * should be written */
157 	u8			reg_file[TCA6507_REG_CNT];
158 	/* Bank 2 is Master Intensity and doesn't use times */
159 	struct bank {
160 		int level;
161 		int ontime, offtime;
162 		int on_dflt, off_dflt;
163 		int time_use, level_use;
164 	} bank[3];
165 	struct i2c_client	*client;
166 	struct work_struct	work;
167 	spinlock_t		lock;
168 
169 	struct tca6507_led {
170 		struct tca6507_chip	*chip;
171 		struct led_classdev	led_cdev;
172 		int			num;
173 		int			ontime, offtime;
174 		int			on_dflt, off_dflt;
175 		int			bank;	/* Bank used, or -1 */
176 		int			blink;	/* Set if hardware-blinking */
177 	} leds[NUM_LEDS];
178 #ifdef CONFIG_GPIOLIB
179 	struct gpio_chip		gpio;
180 	const char			*gpio_name[NUM_LEDS];
181 	int				gpio_map[NUM_LEDS];
182 #endif
183 };
184 
185 static const struct i2c_device_id tca6507_id[] = {
186 	{ "tca6507" },
187 	{ }
188 };
189 MODULE_DEVICE_TABLE(i2c, tca6507_id);
190 
191 static int choose_times(int msec, int *c1p, int *c2p)
192 {
193 	/*
194 	 * Choose two timecodes which add to 'msec' as near as possible.
195 	 * The first returned is the 'on' or 'off' time.  The second is to be
196 	 * used as a 'fade-on' or 'fade-off' time.  If 'msec' is even,
197 	 * the first will not be smaller than the second.  If 'msec' is odd,
198 	 * the first will not be larger than the second.
199 	 * If we cannot get a sum within 1/8 of 'msec' fail with -EINVAL,
200 	 * otherwise return the sum that was achieved, plus 1 if the first is
201 	 * smaller.
202 	 * If two possibilities are equally good (e.g. 512+0, 256+256), choose
203 	 * the first pair so there is more change-time visible (i.e. it is
204 	 * softer).
205 	 */
206 	int c1, c2;
207 	int tmax = msec * 9 / 8;
208 	int tmin = msec * 7 / 8;
209 	int diff = 65536;
210 
211 	/* We start at '1' to ensure we never even think of choosing a
212 	 * total time of '0'.
213 	 */
214 	for (c1 = 1; c1 < TIMECODES; c1++) {
215 		int t = time_codes[c1];
216 		if (t*2 < tmin)
217 			continue;
218 		if (t > tmax)
219 			break;
220 		for (c2 = 0; c2 <= c1; c2++) {
221 			int tt = t + time_codes[c2];
222 			int d;
223 			if (tt < tmin)
224 				continue;
225 			if (tt > tmax)
226 				break;
227 			/* This works! */
228 			d = abs(msec - tt);
229 			if (d >= diff)
230 				continue;
231 			/* Best yet */
232 			*c1p = c1;
233 			*c2p = c2;
234 			diff = d;
235 			if (d == 0)
236 				return msec;
237 		}
238 	}
239 	if (diff < 65536) {
240 		int actual;
241 		if (msec & 1) {
242 			c1 = *c2p;
243 			*c2p = *c1p;
244 			*c1p = c1;
245 		}
246 		actual = time_codes[*c1p] + time_codes[*c2p];
247 		if (*c1p < *c2p)
248 			return actual + 1;
249 		else
250 			return actual;
251 	}
252 	/* No close match */
253 	return -EINVAL;
254 }
255 
256 /*
257  * Update the register file with the appropriate 3-bit state for
258  * the given led.
259  */
260 static void set_select(struct tca6507_chip *tca, int led, int val)
261 {
262 	int mask = (1 << led);
263 	int bit;
264 
265 	for (bit = 0; bit < 3; bit++) {
266 		int n = tca->reg_file[bit] & ~mask;
267 		if (val & (1 << bit))
268 			n |= mask;
269 		if (tca->reg_file[bit] != n) {
270 			tca->reg_file[bit] = n;
271 			tca->reg_set |= (1 << bit);
272 		}
273 	}
274 }
275 
276 /* Update the register file with the appropriate 4-bit code for
277  * one bank or other.  This can be used for timers, for levels, or
278  * for initialisation.
279  */
280 static void set_code(struct tca6507_chip *tca, int reg, int bank, int new)
281 {
282 	int mask = 0xF;
283 	int n;
284 	if (bank) {
285 		mask <<= 4;
286 		new <<= 4;
287 	}
288 	n = tca->reg_file[reg] & ~mask;
289 	n |= new;
290 	if (tca->reg_file[reg] != n) {
291 		tca->reg_file[reg] = n;
292 		tca->reg_set |= 1 << reg;
293 	}
294 }
295 
296 /* Update brightness level. */
297 static void set_level(struct tca6507_chip *tca, int bank, int level)
298 {
299 	switch (bank) {
300 	case BANK0:
301 	case BANK1:
302 		set_code(tca, TCA6507_MAX_INTENSITY, bank, level);
303 		break;
304 	case MASTER:
305 		set_code(tca, TCA6507_MASTER_INTENSITY, 0, level);
306 		break;
307 	}
308 	tca->bank[bank].level = level;
309 }
310 
311 /* Record all relevant time code for a given bank */
312 static void set_times(struct tca6507_chip *tca, int bank)
313 {
314 	int c1, c2;
315 	int result;
316 
317 	result = choose_times(tca->bank[bank].ontime, &c1, &c2);
318 	dev_dbg(&tca->client->dev,
319 		"Chose on  times %d(%d) %d(%d) for %dms\n", c1, time_codes[c1],
320 		c2, time_codes[c2], tca->bank[bank].ontime);
321 	set_code(tca, TCA6507_FADE_ON, bank, c2);
322 	set_code(tca, TCA6507_FULL_ON, bank, c1);
323 	tca->bank[bank].ontime = result;
324 
325 	result = choose_times(tca->bank[bank].offtime, &c1, &c2);
326 	dev_dbg(&tca->client->dev,
327 		"Chose off times %d(%d) %d(%d) for %dms\n", c1, time_codes[c1],
328 		c2, time_codes[c2], tca->bank[bank].offtime);
329 	set_code(tca, TCA6507_FADE_OFF, bank, c2);
330 	set_code(tca, TCA6507_FIRST_OFF, bank, c1);
331 	set_code(tca, TCA6507_SECOND_OFF, bank, c1);
332 	tca->bank[bank].offtime = result;
333 
334 	set_code(tca, TCA6507_INITIALIZE, bank, INIT_CODE);
335 }
336 
337 /* Write all needed register of tca6507 */
338 
339 static void tca6507_work(struct work_struct *work)
340 {
341 	struct tca6507_chip *tca = container_of(work, struct tca6507_chip,
342 						work);
343 	struct i2c_client *cl = tca->client;
344 	int set;
345 	u8 file[TCA6507_REG_CNT];
346 	int r;
347 
348 	spin_lock_irq(&tca->lock);
349 	set = tca->reg_set;
350 	memcpy(file, tca->reg_file, TCA6507_REG_CNT);
351 	tca->reg_set = 0;
352 	spin_unlock_irq(&tca->lock);
353 
354 	for (r = 0; r < TCA6507_REG_CNT; r++)
355 		if (set & (1<<r))
356 			i2c_smbus_write_byte_data(cl, r, file[r]);
357 }
358 
359 static void led_release(struct tca6507_led *led)
360 {
361 	/* If led owns any resource, release it. */
362 	struct tca6507_chip *tca = led->chip;
363 	if (led->bank >= 0) {
364 		struct bank *b = tca->bank + led->bank;
365 		if (led->blink)
366 			b->time_use--;
367 		b->level_use--;
368 	}
369 	led->blink = 0;
370 	led->bank = -1;
371 }
372 
373 static int led_prepare(struct tca6507_led *led)
374 {
375 	/* Assign this led to a bank, configuring that bank if necessary. */
376 	int level = TO_LEVEL(led->led_cdev.brightness);
377 	struct tca6507_chip *tca = led->chip;
378 	int c1, c2;
379 	int i;
380 	struct bank *b;
381 	int need_init = 0;
382 
383 	led->led_cdev.brightness = TO_BRIGHT(level);
384 	if (level == 0) {
385 		set_select(tca, led->num, TCA6507_LS_LED_OFF);
386 		return 0;
387 	}
388 
389 	if (led->ontime == 0 || led->offtime == 0) {
390 		/*
391 		 * Just set the brightness, choosing first usable bank.
392 		 * If none perfect, choose best.
393 		 * Count backwards so we check MASTER bank first
394 		 * to avoid wasting a timer.
395 		 */
396 		int best = -1;/* full-on */
397 		int diff = 15-level;
398 
399 		if (level == 15) {
400 			set_select(tca, led->num, TCA6507_LS_LED_ON);
401 			return 0;
402 		}
403 
404 		for (i = MASTER; i >= BANK0; i--) {
405 			int d;
406 			if (tca->bank[i].level == level ||
407 			    tca->bank[i].level_use == 0) {
408 				best = i;
409 				break;
410 			}
411 			d = abs(level - tca->bank[i].level);
412 			if (d < diff) {
413 				diff = d;
414 				best = i;
415 			}
416 		}
417 		if (best == -1) {
418 			/* Best brightness is full-on */
419 			set_select(tca, led->num, TCA6507_LS_LED_ON);
420 			led->led_cdev.brightness = LED_FULL;
421 			return 0;
422 		}
423 
424 		if (!tca->bank[best].level_use)
425 			set_level(tca, best, level);
426 
427 		tca->bank[best].level_use++;
428 		led->bank = best;
429 		set_select(tca, led->num, bank_source[best]);
430 		led->led_cdev.brightness = TO_BRIGHT(tca->bank[best].level);
431 		return 0;
432 	}
433 
434 	/*
435 	 * We have on/off time so we need to try to allocate a timing bank.
436 	 * First check if times are compatible with hardware and give up if
437 	 * not.
438 	 */
439 	if (choose_times(led->ontime, &c1, &c2) < 0)
440 		return -EINVAL;
441 	if (choose_times(led->offtime, &c1, &c2) < 0)
442 		return -EINVAL;
443 
444 	for (i = BANK0; i <= BANK1; i++) {
445 		if (tca->bank[i].level_use == 0)
446 			/* not in use - it is ours! */
447 			break;
448 		if (tca->bank[i].level != level)
449 			/* Incompatible level - skip */
450 			/* FIX: if timer matches we maybe should consider
451 			 * this anyway...
452 			 */
453 			continue;
454 
455 		if (tca->bank[i].time_use == 0)
456 			/* Timer not in use, and level matches - use it */
457 			break;
458 
459 		if (!(tca->bank[i].on_dflt ||
460 		      led->on_dflt ||
461 		      tca->bank[i].ontime == led->ontime))
462 			/* on time is incompatible */
463 			continue;
464 
465 		if (!(tca->bank[i].off_dflt ||
466 		      led->off_dflt ||
467 		      tca->bank[i].offtime == led->offtime))
468 			/* off time is incompatible */
469 			continue;
470 
471 		/* looks like a suitable match */
472 		break;
473 	}
474 
475 	if (i > BANK1)
476 		/* Nothing matches - how sad */
477 		return -EINVAL;
478 
479 	b = &tca->bank[i];
480 	if (b->level_use == 0)
481 		set_level(tca, i, level);
482 	b->level_use++;
483 	led->bank = i;
484 
485 	if (b->on_dflt ||
486 	    !led->on_dflt ||
487 	    b->time_use == 0) {
488 		b->ontime = led->ontime;
489 		b->on_dflt = led->on_dflt;
490 		need_init = 1;
491 	}
492 
493 	if (b->off_dflt ||
494 	    !led->off_dflt ||
495 	    b->time_use == 0) {
496 		b->offtime = led->offtime;
497 		b->off_dflt = led->off_dflt;
498 		need_init = 1;
499 	}
500 
501 	if (need_init)
502 		set_times(tca, i);
503 
504 	led->ontime = b->ontime;
505 	led->offtime = b->offtime;
506 
507 	b->time_use++;
508 	led->blink = 1;
509 	led->led_cdev.brightness = TO_BRIGHT(b->level);
510 	set_select(tca, led->num, blink_source[i]);
511 	return 0;
512 }
513 
514 static int led_assign(struct tca6507_led *led)
515 {
516 	struct tca6507_chip *tca = led->chip;
517 	int err;
518 	unsigned long flags;
519 
520 	spin_lock_irqsave(&tca->lock, flags);
521 	led_release(led);
522 	err = led_prepare(led);
523 	if (err) {
524 		/*
525 		 * Can only fail on timer setup.  In that case we need to
526 		 * re-establish as steady level.
527 		 */
528 		led->ontime = 0;
529 		led->offtime = 0;
530 		led_prepare(led);
531 	}
532 	spin_unlock_irqrestore(&tca->lock, flags);
533 
534 	if (tca->reg_set)
535 		schedule_work(&tca->work);
536 	return err;
537 }
538 
539 static void tca6507_brightness_set(struct led_classdev *led_cdev,
540 				   enum led_brightness brightness)
541 {
542 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
543 					       led_cdev);
544 	led->led_cdev.brightness = brightness;
545 	led->ontime = 0;
546 	led->offtime = 0;
547 	led_assign(led);
548 }
549 
550 static int tca6507_blink_set(struct led_classdev *led_cdev,
551 			     unsigned long *delay_on,
552 			     unsigned long *delay_off)
553 {
554 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
555 					       led_cdev);
556 
557 	if (*delay_on == 0)
558 		led->on_dflt = 1;
559 	else if (delay_on != &led_cdev->blink_delay_on)
560 		led->on_dflt = 0;
561 	led->ontime = *delay_on;
562 
563 	if (*delay_off == 0)
564 		led->off_dflt = 1;
565 	else if (delay_off != &led_cdev->blink_delay_off)
566 		led->off_dflt = 0;
567 	led->offtime = *delay_off;
568 
569 	if (led->ontime == 0)
570 		led->ontime = 512;
571 	if (led->offtime == 0)
572 		led->offtime = 512;
573 
574 	if (led->led_cdev.brightness == LED_OFF)
575 		led->led_cdev.brightness = LED_FULL;
576 	if (led_assign(led) < 0) {
577 		led->ontime = 0;
578 		led->offtime = 0;
579 		led->led_cdev.brightness = LED_OFF;
580 		return -EINVAL;
581 	}
582 	*delay_on = led->ontime;
583 	*delay_off = led->offtime;
584 	return 0;
585 }
586 
587 #ifdef CONFIG_GPIOLIB
588 static void tca6507_gpio_set_value(struct gpio_chip *gc,
589 				   unsigned offset, int val)
590 {
591 	struct tca6507_chip *tca = container_of(gc, struct tca6507_chip, gpio);
592 	unsigned long flags;
593 
594 	spin_lock_irqsave(&tca->lock, flags);
595 	/*
596 	 * 'OFF' is floating high, and 'ON' is pulled down, so it has the
597 	 * inverse sense of 'val'.
598 	 */
599 	set_select(tca, tca->gpio_map[offset],
600 		   val ? TCA6507_LS_LED_OFF : TCA6507_LS_LED_ON);
601 	spin_unlock_irqrestore(&tca->lock, flags);
602 	if (tca->reg_set)
603 		schedule_work(&tca->work);
604 }
605 
606 static int tca6507_gpio_direction_output(struct gpio_chip *gc,
607 					  unsigned offset, int val)
608 {
609 	tca6507_gpio_set_value(gc, offset, val);
610 	return 0;
611 }
612 
613 static int tca6507_probe_gpios(struct i2c_client *client,
614 			       struct tca6507_chip *tca,
615 			       struct tca6507_platform_data *pdata)
616 {
617 	int err;
618 	int i = 0;
619 	int gpios = 0;
620 
621 	for (i = 0; i < NUM_LEDS; i++)
622 		if (pdata->leds.leds[i].name && pdata->leds.leds[i].flags) {
623 			/* Configure as a gpio */
624 			tca->gpio_name[gpios] = pdata->leds.leds[i].name;
625 			tca->gpio_map[gpios] = i;
626 			gpios++;
627 		}
628 
629 	if (!gpios)
630 		return 0;
631 
632 	tca->gpio.label = "gpio-tca6507";
633 	tca->gpio.names = tca->gpio_name;
634 	tca->gpio.ngpio = gpios;
635 	tca->gpio.base = pdata->gpio_base;
636 	tca->gpio.owner = THIS_MODULE;
637 	tca->gpio.direction_output = tca6507_gpio_direction_output;
638 	tca->gpio.set = tca6507_gpio_set_value;
639 	tca->gpio.dev = &client->dev;
640 	err = gpiochip_add(&tca->gpio);
641 	if (err) {
642 		tca->gpio.ngpio = 0;
643 		return err;
644 	}
645 	if (pdata->setup)
646 		pdata->setup(tca->gpio.base, tca->gpio.ngpio);
647 	return 0;
648 }
649 
650 static void tca6507_remove_gpio(struct tca6507_chip *tca)
651 {
652 	if (tca->gpio.ngpio) {
653 		int err = gpiochip_remove(&tca->gpio);
654 		dev_err(&tca->client->dev, "%s failed, %d\n",
655 			"gpiochip_remove()", err);
656 	}
657 }
658 #else /* CONFIG_GPIOLIB */
659 static int tca6507_probe_gpios(struct i2c_client *client,
660 			       struct tca6507_chip *tca,
661 			       struct tca6507_platform_data *pdata)
662 {
663 	return 0;
664 }
665 static void tca6507_remove_gpio(struct tca6507_chip *tca)
666 {
667 }
668 #endif /* CONFIG_GPIOLIB */
669 
670 static int tca6507_probe(struct i2c_client *client,
671 				   const struct i2c_device_id *id)
672 {
673 	struct tca6507_chip *tca;
674 	struct i2c_adapter *adapter;
675 	struct tca6507_platform_data *pdata;
676 	int err;
677 	int i = 0;
678 
679 	adapter = to_i2c_adapter(client->dev.parent);
680 	pdata = client->dev.platform_data;
681 
682 	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
683 		return -EIO;
684 
685 	if (!pdata || pdata->leds.num_leds != NUM_LEDS) {
686 		dev_err(&client->dev, "Need %d entries in platform-data list\n",
687 			NUM_LEDS);
688 		return -ENODEV;
689 	}
690 	tca = devm_kzalloc(&client->dev, sizeof(*tca), GFP_KERNEL);
691 	if (!tca)
692 		return -ENOMEM;
693 
694 	tca->client = client;
695 	INIT_WORK(&tca->work, tca6507_work);
696 	spin_lock_init(&tca->lock);
697 	i2c_set_clientdata(client, tca);
698 
699 	for (i = 0; i < NUM_LEDS; i++) {
700 		struct tca6507_led *l = tca->leds + i;
701 
702 		l->chip = tca;
703 		l->num = i;
704 		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {
705 			l->led_cdev.name = pdata->leds.leds[i].name;
706 			l->led_cdev.default_trigger
707 				= pdata->leds.leds[i].default_trigger;
708 			l->led_cdev.brightness_set = tca6507_brightness_set;
709 			l->led_cdev.blink_set = tca6507_blink_set;
710 			l->bank = -1;
711 			err = led_classdev_register(&client->dev,
712 						    &l->led_cdev);
713 			if (err < 0)
714 				goto exit;
715 		}
716 	}
717 	err = tca6507_probe_gpios(client, tca, pdata);
718 	if (err)
719 		goto exit;
720 	/* set all registers to known state - zero */
721 	tca->reg_set = 0x7f;
722 	schedule_work(&tca->work);
723 
724 	return 0;
725 exit:
726 	while (i--) {
727 		if (tca->leds[i].led_cdev.name)
728 			led_classdev_unregister(&tca->leds[i].led_cdev);
729 	}
730 	return err;
731 }
732 
733 static int tca6507_remove(struct i2c_client *client)
734 {
735 	int i;
736 	struct tca6507_chip *tca = i2c_get_clientdata(client);
737 	struct tca6507_led *tca_leds = tca->leds;
738 
739 	for (i = 0; i < NUM_LEDS; i++) {
740 		if (tca_leds[i].led_cdev.name)
741 			led_classdev_unregister(&tca_leds[i].led_cdev);
742 	}
743 	tca6507_remove_gpio(tca);
744 	cancel_work_sync(&tca->work);
745 
746 	return 0;
747 }
748 
749 static struct i2c_driver tca6507_driver = {
750 	.driver   = {
751 		.name    = "leds-tca6507",
752 		.owner   = THIS_MODULE,
753 	},
754 	.probe    = tca6507_probe,
755 	.remove   = tca6507_remove,
756 	.id_table = tca6507_id,
757 };
758 
759 module_i2c_driver(tca6507_driver);
760 
761 MODULE_AUTHOR("NeilBrown <neilb@suse.de>");
762 MODULE_DESCRIPTION("TCA6507 LED/GPO driver");
763 MODULE_LICENSE("GPL v2");
764