xref: /linux/drivers/leds/leds-tca6507.c (revision 41e0d49104dbff888ef6446ea46842fde66c0a76)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * leds-tca6507
4  *
5  * The TCA6507 is a programmable LED controller that can drive 7
6  * separate lines either by holding them low, or by pulsing them
7  * with modulated width.
8  * The modulation can be varied in a simple pattern to produce a
9  * blink or double-blink.
10  *
11  * This driver can configure each line either as a 'GPIO' which is
12  * out-only (pull-up resistor required) or as an LED with variable
13  * brightness and hardware-assisted blinking.
14  *
15  * Apart from OFF and ON there are three programmable brightness
16  * levels which can be programmed from 0 to 15 and indicate how many
17  * 500usec intervals in each 8msec that the led is 'on'.  The levels
18  * are named MASTER, BANK0 and BANK1.
19  *
20  * There are two different blink rates that can be programmed, each
21  * with separate time for rise, on, fall, off and second-off.  Thus if
22  * 3 or more different non-trivial rates are required, software must
23  * be used for the extra rates. The two different blink rates must
24  * align with the two levels BANK0 and BANK1.  This driver does not
25  * support double-blink so 'second-off' always matches 'off'.
26  *
27  * Only 16 different times can be programmed in a roughly logarithmic
28  * scale from 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 handled in
33  * software.  This driver allows 12.5% error in matching.
34  *
35  * This driver does not allow rise/fall rates to be set explicitly.
36  * When trying to match a given 'on' or 'off' period, an appropriate
37  * pair of 'change' and 'hold' times are chosen to get a close match.
38  * If the target delay is even, the 'change' number will be the
39  * smaller; if odd, the 'hold' number will be the smaller.
40 
41  * Choosing pairs of delays with 12.5% errors allows us to match
42  * delays in the ranges: 56-72, 112-144, 168-216, 224-27504,
43  * 28560-36720.
44  * 26% of the achievable sums can be matched by multiple pairings.
45  * For example 1536 == 1536+0, 1024+512, or 768+768.
46  * This driver will always choose the pairing with the least
47  * maximum - 768+768 in this case.  Other pairings are not available.
48  *
49  * Access to the 3 levels and 2 blinks are on a first-come,
50  * first-served basis.  Access can be shared by multiple leds if they
51  * have the same level and either same blink rates, or some don't
52  * blink.  When a led changes, it relinquishes access and tries again,
53  * so it might lose access to hardware blink.
54  *
55  * If a blink engine cannot be allocated, software blink is used.  If
56  * the desired brightness cannot be allocated, the closest available
57  * non-zero brightness is used.  As 'full' is always available, the
58  * worst case would be to have two different blink rates at '1', with
59  * Max at '2', then other leds will have to choose between '2' and
60  * '16'.  Hopefully this is not likely.
61  *
62  * Each bank (BANK0 and BANK1) has two usage counts - LEDs using the
63  * brightness and LEDs using the blink.  It can only be reprogrammed
64  * when the appropriate counter is zero.  The MASTER level has a
65  * single usage count.
66  *
67  * Each LED has programmable 'on' and 'off' time as milliseconds.
68  * With each there is a flag saying if it was explicitly requested or
69  * defaulted.  Similarly the banks know if each time was explicit or a
70  * default.  Defaults are permitted to be changed freely - they are
71  * not recognised when matching.
72  */
73 
74 #include <linux/module.h>
75 #include <linux/slab.h>
76 #include <linux/leds.h>
77 #include <linux/err.h>
78 #include <linux/i2c.h>
79 #include <linux/gpio/driver.h>
80 #include <linux/property.h>
81 #include <linux/workqueue.h>
82 
83 /* LED select registers determine the source that drives LED outputs */
84 #define TCA6507_LS_LED_OFF	0x0	/* Output HI-Z (off) */
85 #define TCA6507_LS_LED_OFF1	0x1	/* Output HI-Z (off) - not used */
86 #define TCA6507_LS_LED_PWM0	0x2	/* Output LOW with Bank0 rate */
87 #define TCA6507_LS_LED_PWM1	0x3	/* Output LOW with Bank1 rate */
88 #define TCA6507_LS_LED_ON	0x4	/* Output LOW (on) */
89 #define TCA6507_LS_LED_MIR	0x5	/* Output LOW with Master Intensity */
90 #define TCA6507_LS_BLINK0	0x6	/* Blink at Bank0 rate */
91 #define TCA6507_LS_BLINK1	0x7	/* Blink at Bank1 rate */
92 
93 struct tca6507_platform_data {
94 	struct led_platform_data leds;
95 #ifdef CONFIG_GPIOLIB
96 	int gpio_base;
97 #endif
98 };
99 
100 #define	TCA6507_MAKE_GPIO 1
101 
102 enum {
103 	BANK0,
104 	BANK1,
105 	MASTER,
106 };
107 static int bank_source[3] = {
108 	TCA6507_LS_LED_PWM0,
109 	TCA6507_LS_LED_PWM1,
110 	TCA6507_LS_LED_MIR,
111 };
112 static int blink_source[2] = {
113 	TCA6507_LS_BLINK0,
114 	TCA6507_LS_BLINK1,
115 };
116 
117 /* PWM registers */
118 #define	TCA6507_REG_CNT			11
119 
120 /*
121  * 0x00, 0x01, 0x02 encode the TCA6507_LS_* values, each output
122  * owns one bit in each register
123  */
124 #define	TCA6507_FADE_ON			0x03
125 #define	TCA6507_FULL_ON			0x04
126 #define	TCA6507_FADE_OFF		0x05
127 #define	TCA6507_FIRST_OFF		0x06
128 #define	TCA6507_SECOND_OFF		0x07
129 #define	TCA6507_MAX_INTENSITY		0x08
130 #define	TCA6507_MASTER_INTENSITY	0x09
131 #define	TCA6507_INITIALIZE		0x0A
132 
133 #define	INIT_CODE			0x8
134 
135 #define TIMECODES 16
136 static int time_codes[TIMECODES] = {
137 	0, 64, 128, 192, 256, 384, 512, 768,
138 	1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320
139 };
140 
141 /* Convert an led.brightness level (0..255) to a TCA6507 level (0..15) */
142 static inline int TO_LEVEL(int brightness)
143 {
144 	return brightness >> 4;
145 }
146 
147 /* ...and convert back */
148 static inline int TO_BRIGHT(int level)
149 {
150 	if (level)
151 		return (level << 4) | 0xf;
152 	return 0;
153 }
154 
155 #define NUM_LEDS 7
156 struct tca6507_chip {
157 	int			reg_set;	/* One bit per register where
158 						 * a '1' means the register
159 						 * should be written */
160 	u8			reg_file[TCA6507_REG_CNT];
161 	/* Bank 2 is Master Intensity and doesn't use times */
162 	struct bank {
163 		int level;
164 		int ontime, offtime;
165 		int on_dflt, off_dflt;
166 		int time_use, level_use;
167 	} bank[3];
168 	struct i2c_client	*client;
169 	struct work_struct	work;
170 	spinlock_t		lock;
171 
172 	struct tca6507_led {
173 		struct tca6507_chip	*chip;
174 		struct led_classdev	led_cdev;
175 		int			num;
176 		int			ontime, offtime;
177 		int			on_dflt, off_dflt;
178 		int			bank;	/* Bank used, or -1 */
179 		int			blink;	/* Set if hardware-blinking */
180 	} leds[NUM_LEDS];
181 #ifdef CONFIG_GPIOLIB
182 	struct gpio_chip		gpio;
183 	int				gpio_map[NUM_LEDS];
184 #endif
185 };
186 
187 static const struct i2c_device_id tca6507_id[] = {
188 	{ "tca6507" },
189 	{ }
190 };
191 MODULE_DEVICE_TABLE(i2c, tca6507_id);
192 
193 static int choose_times(int msec, int *c1p, int *c2p)
194 {
195 	/*
196 	 * Choose two timecodes which add to 'msec' as near as
197 	 * possible.  The first returned is the 'on' or 'off' time.
198 	 * The second is to be used as a 'fade-on' or 'fade-off' time.
199 	 * If 'msec' is even, the first will not be smaller than the
200 	 * second.  If 'msec' is odd, the first will not be larger
201 	 * than the second.
202 	 * If we cannot get a sum within 1/8 of 'msec' fail with
203 	 * -EINVAL, otherwise return the sum that was achieved, plus 1
204 	 * if the first is smaller.
205 	 * If two possibilities are equally good (e.g. 512+0,
206 	 * 256+256), choose the first pair so there is more
207 	 * change-time visible (i.e. it is softer).
208 	 */
209 	int c1, c2;
210 	int tmax = msec * 9 / 8;
211 	int tmin = msec * 7 / 8;
212 	int diff = 65536;
213 
214 	/* We start at '1' to ensure we never even think of choosing a
215 	 * total time of '0'.
216 	 */
217 	for (c1 = 1; c1 < TIMECODES; c1++) {
218 		int t = time_codes[c1];
219 		if (t*2 < tmin)
220 			continue;
221 		if (t > tmax)
222 			break;
223 		for (c2 = 0; c2 <= c1; c2++) {
224 			int tt = t + time_codes[c2];
225 			int d;
226 			if (tt < tmin)
227 				continue;
228 			if (tt > tmax)
229 				break;
230 			/* This works! */
231 			d = abs(msec - tt);
232 			if (d >= diff)
233 				continue;
234 			/* Best yet */
235 			*c1p = c1;
236 			*c2p = c2;
237 			diff = d;
238 			if (d == 0)
239 				return msec;
240 		}
241 	}
242 	if (diff < 65536) {
243 		int actual;
244 		if (msec & 1) {
245 			swap(*c2p, *c1p);
246 		}
247 		actual = time_codes[*c1p] + time_codes[*c2p];
248 		if (*c1p < *c2p)
249 			return actual + 1;
250 		else
251 			return actual;
252 	}
253 	/* No close match */
254 	return -EINVAL;
255 }
256 
257 /*
258  * Update the register file with the appropriate 3-bit state for the
259  * given led.
260  */
261 static void set_select(struct tca6507_chip *tca, int led, int val)
262 {
263 	int mask = (1 << led);
264 	int bit;
265 
266 	for (bit = 0; bit < 3; bit++) {
267 		int n = tca->reg_file[bit] & ~mask;
268 		if (val & (1 << bit))
269 			n |= mask;
270 		if (tca->reg_file[bit] != n) {
271 			tca->reg_file[bit] = n;
272 			tca->reg_set |= (1 << bit);
273 		}
274 	}
275 }
276 
277 /* Update the register file with the appropriate 4-bit code for one
278  * bank or other.  This can be used for timers, for levels, or for
279  * initialization.
280  */
281 static void set_code(struct tca6507_chip *tca, int reg, int bank, int new)
282 {
283 	int mask = 0xF;
284 	int n;
285 	if (bank) {
286 		mask <<= 4;
287 		new <<= 4;
288 	}
289 	n = tca->reg_file[reg] & ~mask;
290 	n |= new;
291 	if (tca->reg_file[reg] != n) {
292 		tca->reg_file[reg] = n;
293 		tca->reg_set |= 1 << reg;
294 	}
295 }
296 
297 /* Update brightness level. */
298 static void set_level(struct tca6507_chip *tca, int bank, int level)
299 {
300 	switch (bank) {
301 	case BANK0:
302 	case BANK1:
303 		set_code(tca, TCA6507_MAX_INTENSITY, bank, level);
304 		break;
305 	case MASTER:
306 		set_code(tca, TCA6507_MASTER_INTENSITY, 0, level);
307 		break;
308 	}
309 	tca->bank[bank].level = level;
310 }
311 
312 /* Record all relevant time codes for a given bank */
313 static void set_times(struct tca6507_chip *tca, int bank)
314 {
315 	int c1, c2;
316 	int result;
317 
318 	result = choose_times(tca->bank[bank].ontime, &c1, &c2);
319 	if (result < 0)
320 		return;
321 	dev_dbg(&tca->client->dev,
322 		"Chose on  times %d(%d) %d(%d) for %dms\n",
323 		c1, time_codes[c1],
324 		c2, time_codes[c2], tca->bank[bank].ontime);
325 	set_code(tca, TCA6507_FADE_ON, bank, c2);
326 	set_code(tca, TCA6507_FULL_ON, bank, c1);
327 	tca->bank[bank].ontime = result;
328 
329 	result = choose_times(tca->bank[bank].offtime, &c1, &c2);
330 	dev_dbg(&tca->client->dev,
331 		"Chose off times %d(%d) %d(%d) for %dms\n",
332 		c1, time_codes[c1],
333 		c2, time_codes[c2], tca->bank[bank].offtime);
334 	set_code(tca, TCA6507_FADE_OFF, bank, c2);
335 	set_code(tca, TCA6507_FIRST_OFF, bank, c1);
336 	set_code(tca, TCA6507_SECOND_OFF, bank, c1);
337 	tca->bank[bank].offtime = result;
338 
339 	set_code(tca, TCA6507_INITIALIZE, bank, INIT_CODE);
340 }
341 
342 /* Write all needed register of tca6507 */
343 
344 static void tca6507_work(struct work_struct *work)
345 {
346 	struct tca6507_chip *tca = container_of(work, struct tca6507_chip,
347 						work);
348 	struct i2c_client *cl = tca->client;
349 	int set;
350 	u8 file[TCA6507_REG_CNT];
351 	int r;
352 
353 	spin_lock_irq(&tca->lock);
354 	set = tca->reg_set;
355 	memcpy(file, tca->reg_file, TCA6507_REG_CNT);
356 	tca->reg_set = 0;
357 	spin_unlock_irq(&tca->lock);
358 
359 	for (r = 0; r < TCA6507_REG_CNT; r++)
360 		if (set & (1<<r))
361 			i2c_smbus_write_byte_data(cl, r, file[r]);
362 }
363 
364 static void led_release(struct tca6507_led *led)
365 {
366 	/* If led owns any resource, release it. */
367 	struct tca6507_chip *tca = led->chip;
368 	if (led->bank >= 0) {
369 		struct bank *b = tca->bank + led->bank;
370 		if (led->blink)
371 			b->time_use--;
372 		b->level_use--;
373 	}
374 	led->blink = 0;
375 	led->bank = -1;
376 }
377 
378 static int led_prepare(struct tca6507_led *led)
379 {
380 	/* Assign this led to a bank, configuring that bank if
381 	 * necessary. */
382 	int level = TO_LEVEL(led->led_cdev.brightness);
383 	struct tca6507_chip *tca = led->chip;
384 	int c1, c2;
385 	int i;
386 	struct bank *b;
387 	int need_init = 0;
388 
389 	led->led_cdev.brightness = TO_BRIGHT(level);
390 	if (level == 0) {
391 		set_select(tca, led->num, TCA6507_LS_LED_OFF);
392 		return 0;
393 	}
394 
395 	if (led->ontime == 0 || led->offtime == 0) {
396 		/*
397 		 * Just set the brightness, choosing first usable
398 		 * bank.  If none perfect, choose best.  Count
399 		 * backwards so we check MASTER bank first to avoid
400 		 * wasting a timer.
401 		 */
402 		int best = -1;/* full-on */
403 		int diff = 15-level;
404 
405 		if (level == 15) {
406 			set_select(tca, led->num, TCA6507_LS_LED_ON);
407 			return 0;
408 		}
409 
410 		for (i = MASTER; i >= BANK0; i--) {
411 			int d;
412 			if (tca->bank[i].level == level ||
413 			    tca->bank[i].level_use == 0) {
414 				best = i;
415 				break;
416 			}
417 			d = abs(level - tca->bank[i].level);
418 			if (d < diff) {
419 				diff = d;
420 				best = i;
421 			}
422 		}
423 		if (best == -1) {
424 			/* Best brightness is full-on */
425 			set_select(tca, led->num, TCA6507_LS_LED_ON);
426 			led->led_cdev.brightness = LED_FULL;
427 			return 0;
428 		}
429 
430 		if (!tca->bank[best].level_use)
431 			set_level(tca, best, level);
432 
433 		tca->bank[best].level_use++;
434 		led->bank = best;
435 		set_select(tca, led->num, bank_source[best]);
436 		led->led_cdev.brightness = TO_BRIGHT(tca->bank[best].level);
437 		return 0;
438 	}
439 
440 	/*
441 	 * We have on/off time so we need to try to allocate a timing
442 	 * bank.  First check if times are compatible with hardware
443 	 * and give up if not.
444 	 */
445 	if (choose_times(led->ontime, &c1, &c2) < 0)
446 		return -EINVAL;
447 	if (choose_times(led->offtime, &c1, &c2) < 0)
448 		return -EINVAL;
449 
450 	for (i = BANK0; i <= BANK1; i++) {
451 		if (tca->bank[i].level_use == 0)
452 			/* not in use - it is ours! */
453 			break;
454 		if (tca->bank[i].level != level)
455 			/* Incompatible level - skip */
456 			/* FIX: if timer matches we maybe should consider
457 			 * this anyway...
458 			 */
459 			continue;
460 
461 		if (tca->bank[i].time_use == 0)
462 			/* Timer not in use, and level matches - use it */
463 			break;
464 
465 		if (!(tca->bank[i].on_dflt ||
466 		      led->on_dflt ||
467 		      tca->bank[i].ontime == led->ontime))
468 			/* on time is incompatible */
469 			continue;
470 
471 		if (!(tca->bank[i].off_dflt ||
472 		      led->off_dflt ||
473 		      tca->bank[i].offtime == led->offtime))
474 			/* off time is incompatible */
475 			continue;
476 
477 		/* looks like a suitable match */
478 		break;
479 	}
480 
481 	if (i > BANK1)
482 		/* Nothing matches - how sad */
483 		return -EINVAL;
484 
485 	b = &tca->bank[i];
486 	if (b->level_use == 0)
487 		set_level(tca, i, level);
488 	b->level_use++;
489 	led->bank = i;
490 
491 	if (b->on_dflt ||
492 	    !led->on_dflt ||
493 	    b->time_use == 0) {
494 		b->ontime = led->ontime;
495 		b->on_dflt = led->on_dflt;
496 		need_init = 1;
497 	}
498 
499 	if (b->off_dflt ||
500 	    !led->off_dflt ||
501 	    b->time_use == 0) {
502 		b->offtime = led->offtime;
503 		b->off_dflt = led->off_dflt;
504 		need_init = 1;
505 	}
506 
507 	if (need_init)
508 		set_times(tca, i);
509 
510 	led->ontime = b->ontime;
511 	led->offtime = b->offtime;
512 
513 	b->time_use++;
514 	led->blink = 1;
515 	led->led_cdev.brightness = TO_BRIGHT(b->level);
516 	set_select(tca, led->num, blink_source[i]);
517 	return 0;
518 }
519 
520 static int led_assign(struct tca6507_led *led)
521 {
522 	struct tca6507_chip *tca = led->chip;
523 	int err;
524 	unsigned long flags;
525 
526 	spin_lock_irqsave(&tca->lock, flags);
527 	led_release(led);
528 	err = led_prepare(led);
529 	if (err) {
530 		/*
531 		 * Can only fail on timer setup.  In that case we need
532 		 * to re-establish as steady level.
533 		 */
534 		led->ontime = 0;
535 		led->offtime = 0;
536 		led_prepare(led);
537 	}
538 	spin_unlock_irqrestore(&tca->lock, flags);
539 
540 	if (tca->reg_set)
541 		schedule_work(&tca->work);
542 	return err;
543 }
544 
545 static void tca6507_brightness_set(struct led_classdev *led_cdev,
546 				   enum led_brightness brightness)
547 {
548 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
549 					       led_cdev);
550 	led->led_cdev.brightness = brightness;
551 	led->ontime = 0;
552 	led->offtime = 0;
553 	led_assign(led);
554 }
555 
556 static int tca6507_blink_set(struct led_classdev *led_cdev,
557 			     unsigned long *delay_on,
558 			     unsigned long *delay_off)
559 {
560 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
561 					       led_cdev);
562 
563 	if (*delay_on == 0)
564 		led->on_dflt = 1;
565 	else if (delay_on != &led_cdev->blink_delay_on)
566 		led->on_dflt = 0;
567 	led->ontime = *delay_on;
568 
569 	if (*delay_off == 0)
570 		led->off_dflt = 1;
571 	else if (delay_off != &led_cdev->blink_delay_off)
572 		led->off_dflt = 0;
573 	led->offtime = *delay_off;
574 
575 	if (led->ontime == 0)
576 		led->ontime = 512;
577 	if (led->offtime == 0)
578 		led->offtime = 512;
579 
580 	if (led->led_cdev.brightness == LED_OFF)
581 		led->led_cdev.brightness = LED_FULL;
582 	if (led_assign(led) < 0) {
583 		led->ontime = 0;
584 		led->offtime = 0;
585 		led->led_cdev.brightness = LED_OFF;
586 		return -EINVAL;
587 	}
588 	*delay_on = led->ontime;
589 	*delay_off = led->offtime;
590 	return 0;
591 }
592 
593 #ifdef CONFIG_GPIOLIB
594 static void tca6507_gpio_set_value(struct gpio_chip *gc,
595 				   unsigned offset, int val)
596 {
597 	struct tca6507_chip *tca = gpiochip_get_data(gc);
598 	unsigned long flags;
599 
600 	spin_lock_irqsave(&tca->lock, flags);
601 	/*
602 	 * 'OFF' is floating high, and 'ON' is pulled down, so it has
603 	 * the inverse sense of 'val'.
604 	 */
605 	set_select(tca, tca->gpio_map[offset],
606 		   val ? TCA6507_LS_LED_OFF : TCA6507_LS_LED_ON);
607 	spin_unlock_irqrestore(&tca->lock, flags);
608 	if (tca->reg_set)
609 		schedule_work(&tca->work);
610 }
611 
612 static int tca6507_gpio_direction_output(struct gpio_chip *gc,
613 					  unsigned offset, int val)
614 {
615 	tca6507_gpio_set_value(gc, offset, val);
616 	return 0;
617 }
618 
619 static int tca6507_probe_gpios(struct device *dev,
620 			       struct tca6507_chip *tca,
621 			       struct tca6507_platform_data *pdata)
622 {
623 	int err;
624 	int i = 0;
625 	int gpios = 0;
626 
627 	for (i = 0; i < NUM_LEDS; i++)
628 		if (pdata->leds.leds[i].name && pdata->leds.leds[i].flags) {
629 			/* Configure as a gpio */
630 			tca->gpio_map[gpios] = i;
631 			gpios++;
632 		}
633 
634 	if (!gpios)
635 		return 0;
636 
637 	tca->gpio.label = "gpio-tca6507";
638 	tca->gpio.ngpio = gpios;
639 	tca->gpio.base = pdata->gpio_base;
640 	tca->gpio.owner = THIS_MODULE;
641 	tca->gpio.direction_output = tca6507_gpio_direction_output;
642 	tca->gpio.set = tca6507_gpio_set_value;
643 	tca->gpio.parent = dev;
644 	err = gpiochip_add_data(&tca->gpio, tca);
645 	if (err) {
646 		tca->gpio.ngpio = 0;
647 		return err;
648 	}
649 	return 0;
650 }
651 
652 static void tca6507_remove_gpio(struct tca6507_chip *tca)
653 {
654 	if (tca->gpio.ngpio)
655 		gpiochip_remove(&tca->gpio);
656 }
657 #else /* CONFIG_GPIOLIB */
658 static int tca6507_probe_gpios(struct device *dev,
659 			       struct tca6507_chip *tca,
660 			       struct tca6507_platform_data *pdata)
661 {
662 	return 0;
663 }
664 static void tca6507_remove_gpio(struct tca6507_chip *tca)
665 {
666 }
667 #endif /* CONFIG_GPIOLIB */
668 
669 static struct tca6507_platform_data *
670 tca6507_led_dt_init(struct device *dev)
671 {
672 	struct tca6507_platform_data *pdata;
673 	struct fwnode_handle *child;
674 	struct led_info *tca_leds;
675 	int count;
676 
677 	count = device_get_child_node_count(dev);
678 	if (!count || count > NUM_LEDS)
679 		return ERR_PTR(-ENODEV);
680 
681 	tca_leds = devm_kcalloc(dev, NUM_LEDS, sizeof(struct led_info),
682 				GFP_KERNEL);
683 	if (!tca_leds)
684 		return ERR_PTR(-ENOMEM);
685 
686 	device_for_each_child_node(dev, child) {
687 		struct led_info led;
688 		u32 reg;
689 		int ret;
690 
691 		if (fwnode_property_read_string(child, "label", &led.name))
692 			led.name = fwnode_get_name(child);
693 
694 		fwnode_property_read_string(child, "linux,default-trigger",
695 					    &led.default_trigger);
696 
697 		led.flags = 0;
698 		if (fwnode_property_match_string(child, "compatible",
699 						 "gpio") >= 0)
700 			led.flags |= TCA6507_MAKE_GPIO;
701 
702 		ret = fwnode_property_read_u32(child, "reg", &reg);
703 		if (ret || reg >= NUM_LEDS) {
704 			fwnode_handle_put(child);
705 			return ERR_PTR(ret ? : -EINVAL);
706 		}
707 
708 		tca_leds[reg] = led;
709 	}
710 
711 	pdata = devm_kzalloc(dev, sizeof(struct tca6507_platform_data),
712 			     GFP_KERNEL);
713 	if (!pdata)
714 		return ERR_PTR(-ENOMEM);
715 
716 	pdata->leds.leds = tca_leds;
717 	pdata->leds.num_leds = NUM_LEDS;
718 #ifdef CONFIG_GPIOLIB
719 	pdata->gpio_base = -1;
720 #endif
721 
722 	return pdata;
723 }
724 
725 static const struct of_device_id __maybe_unused of_tca6507_leds_match[] = {
726 	{ .compatible = "ti,tca6507", },
727 	{},
728 };
729 MODULE_DEVICE_TABLE(of, of_tca6507_leds_match);
730 
731 static int tca6507_probe(struct i2c_client *client,
732 		const struct i2c_device_id *id)
733 {
734 	struct device *dev = &client->dev;
735 	struct i2c_adapter *adapter;
736 	struct tca6507_chip *tca;
737 	struct tca6507_platform_data *pdata;
738 	int err;
739 	int i = 0;
740 
741 	adapter = client->adapter;
742 
743 	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
744 		return -EIO;
745 
746 	pdata = tca6507_led_dt_init(dev);
747 	if (IS_ERR(pdata)) {
748 		dev_err(dev, "Need %d entries in platform-data list\n", NUM_LEDS);
749 		return PTR_ERR(pdata);
750 	}
751 	tca = devm_kzalloc(dev, sizeof(*tca), GFP_KERNEL);
752 	if (!tca)
753 		return -ENOMEM;
754 
755 	tca->client = client;
756 	INIT_WORK(&tca->work, tca6507_work);
757 	spin_lock_init(&tca->lock);
758 	i2c_set_clientdata(client, tca);
759 
760 	for (i = 0; i < NUM_LEDS; i++) {
761 		struct tca6507_led *l = tca->leds + i;
762 
763 		l->chip = tca;
764 		l->num = i;
765 		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {
766 			l->led_cdev.name = pdata->leds.leds[i].name;
767 			l->led_cdev.default_trigger
768 				= pdata->leds.leds[i].default_trigger;
769 			l->led_cdev.brightness_set = tca6507_brightness_set;
770 			l->led_cdev.blink_set = tca6507_blink_set;
771 			l->bank = -1;
772 			err = led_classdev_register(dev, &l->led_cdev);
773 			if (err < 0)
774 				goto exit;
775 		}
776 	}
777 	err = tca6507_probe_gpios(dev, tca, pdata);
778 	if (err)
779 		goto exit;
780 	/* set all registers to known state - zero */
781 	tca->reg_set = 0x7f;
782 	schedule_work(&tca->work);
783 
784 	return 0;
785 exit:
786 	while (i--) {
787 		if (tca->leds[i].led_cdev.name)
788 			led_classdev_unregister(&tca->leds[i].led_cdev);
789 	}
790 	return err;
791 }
792 
793 static void tca6507_remove(struct i2c_client *client)
794 {
795 	int i;
796 	struct tca6507_chip *tca = i2c_get_clientdata(client);
797 	struct tca6507_led *tca_leds = tca->leds;
798 
799 	for (i = 0; i < NUM_LEDS; i++) {
800 		if (tca_leds[i].led_cdev.name)
801 			led_classdev_unregister(&tca_leds[i].led_cdev);
802 	}
803 	tca6507_remove_gpio(tca);
804 	cancel_work_sync(&tca->work);
805 }
806 
807 static struct i2c_driver tca6507_driver = {
808 	.driver   = {
809 		.name    = "leds-tca6507",
810 		.of_match_table = of_match_ptr(of_tca6507_leds_match),
811 	},
812 	.probe    = tca6507_probe,
813 	.remove   = tca6507_remove,
814 	.id_table = tca6507_id,
815 };
816 
817 module_i2c_driver(tca6507_driver);
818 
819 MODULE_AUTHOR("NeilBrown <neilb@suse.de>");
820 MODULE_DESCRIPTION("TCA6507 LED/GPO driver");
821 MODULE_LICENSE("GPL v2");
822