xref: /openbmc/linux/drivers/leds/leds-tca6507.c (revision 4f3db074)
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
8  * blink or double-blink.
9  *
10  * This driver can configure each line either as a 'GPIO' which is
11  * out-only (pull-up resistor required) or as an LED with variable
12  * brightness and hardware-assisted blinking.
13  *
14  * Apart from OFF and ON there are three programmable brightness
15  * levels which can be programmed from 0 to 15 and indicate how many
16  * 500usec intervals in each 8msec that the led is 'on'.  The levels
17  * are named MASTER, BANK0 and BANK1.
18  *
19  * There are two different blink rates that can be programmed, each
20  * with separate time for rise, on, fall, off and second-off.  Thus if
21  * 3 or more different non-trivial rates are required, software must
22  * be used for the extra rates. The two different blink rates must
23  * align with the two levels BANK0 and BANK1.  This driver does not
24  * support double-blink so 'second-off' always matches 'off'.
25  *
26  * Only 16 different times can be programmed in a roughly logarithmic
27  * scale from 64ms to 16320ms.  To be precise the possible times are:
28  *    0, 64, 128, 192, 256, 384, 512, 768,
29  *    1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320
30  *
31  * Times that cannot be closely matched with these must be handled in
32  * software.  This driver allows 12.5% error in matching.
33  *
34  * This driver does not allow rise/fall rates to be set explicitly.
35  * When trying to match a given 'on' or 'off' period, an appropriate
36  * pair of 'change' and 'hold' times are chosen to get a close match.
37  * If the target delay is even, the 'change' number will be the
38  * smaller; if odd, the 'hold' number will be the smaller.
39 
40  * Choosing pairs of delays with 12.5% errors allows us to match
41  * delays in the ranges: 56-72, 112-144, 168-216, 224-27504,
42  * 28560-36720.
43  * 26% of the achievable sums can be matched by multiple pairings.
44  * For example 1536 == 1536+0, 1024+512, or 768+768.
45  * This driver will always choose the pairing with the least
46  * maximum - 768+768 in this case.  Other pairings are not available.
47  *
48  * Access to the 3 levels and 2 blinks are on a first-come,
49  * first-served basis.  Access can be shared by multiple leds if they
50  * have the same level and either same blink rates, or some don't
51  * blink.  When a led changes, it relinquishes access and tries again,
52  * so it might lose access to hardware blink.
53  *
54  * If a blink engine cannot be allocated, software blink is used.  If
55  * the desired brightness cannot be allocated, the closest available
56  * non-zero brightness is used.  As 'full' is always available, the
57  * worst case would be to have two different blink rates at '1', with
58  * Max at '2', then other leds will have to choose between '2' and
59  * '16'.  Hopefully this is not likely.
60  *
61  * Each bank (BANK0 and BANK1) has two usage counts - LEDs using the
62  * brightness and LEDs using the blink.  It can only be reprogrammed
63  * when the appropriate counter is zero.  The MASTER level has a
64  * single usage count.
65  *
66  * Each LED has programmable 'on' and 'off' time as milliseconds.
67  * With each there is a flag saying if it was explicitly requested or
68  * defaulted.  Similarly the banks know if each time was explicit or a
69  * default.  Defaults are permitted to be changed freely - they are
70  * not recognised when matching.
71  *
72  *
73  * An led-tca6507 device must be provided with platform data or
74  * configured via devicetree.
75  *
76  * The platform-data lists for each output: the name, default trigger,
77  * and whether the signal is being used as a GPIO rather than an LED.
78  * 'struct led_plaform_data' is used for this.  If 'name' is NULL, the
79  * output isn't used.  If 'flags' is TCA6507_MAKE_GPIO, the output is
80  * a GPO.  The "struct led_platform_data" can be embedded in a "struct
81  * tca6507_platform_data" which adds a 'gpio_base' for the GPIOs, and
82  * a 'setup' callback which is called once the GPIOs are available.
83  *
84  * When configured via devicetree there is one child for each output.
85  * The "reg" determines the output number and "compatible" determines
86  * whether it is an LED or a GPIO.  "linux,default-trigger" can set a
87  * default trigger.
88  */
89 
90 #include <linux/module.h>
91 #include <linux/slab.h>
92 #include <linux/leds.h>
93 #include <linux/err.h>
94 #include <linux/i2c.h>
95 #include <linux/gpio.h>
96 #include <linux/workqueue.h>
97 #include <linux/leds-tca6507.h>
98 #include <linux/of.h>
99 
100 /* LED select registers determine the source that drives LED outputs */
101 #define TCA6507_LS_LED_OFF	0x0	/* Output HI-Z (off) */
102 #define TCA6507_LS_LED_OFF1	0x1	/* Output HI-Z (off) - not used */
103 #define TCA6507_LS_LED_PWM0	0x2	/* Output LOW with Bank0 rate */
104 #define TCA6507_LS_LED_PWM1	0x3	/* Output LOW with Bank1 rate */
105 #define TCA6507_LS_LED_ON	0x4	/* Output LOW (on) */
106 #define TCA6507_LS_LED_MIR	0x5	/* Output LOW with Master Intensity */
107 #define TCA6507_LS_BLINK0	0x6	/* Blink at Bank0 rate */
108 #define TCA6507_LS_BLINK1	0x7	/* Blink at Bank1 rate */
109 
110 enum {
111 	BANK0,
112 	BANK1,
113 	MASTER,
114 };
115 static int bank_source[3] = {
116 	TCA6507_LS_LED_PWM0,
117 	TCA6507_LS_LED_PWM1,
118 	TCA6507_LS_LED_MIR,
119 };
120 static int blink_source[2] = {
121 	TCA6507_LS_BLINK0,
122 	TCA6507_LS_BLINK1,
123 };
124 
125 /* PWM registers */
126 #define	TCA6507_REG_CNT			11
127 
128 /*
129  * 0x00, 0x01, 0x02 encode the TCA6507_LS_* values, each output
130  * owns one bit in each register
131  */
132 #define	TCA6507_FADE_ON			0x03
133 #define	TCA6507_FULL_ON			0x04
134 #define	TCA6507_FADE_OFF		0x05
135 #define	TCA6507_FIRST_OFF		0x06
136 #define	TCA6507_SECOND_OFF		0x07
137 #define	TCA6507_MAX_INTENSITY		0x08
138 #define	TCA6507_MASTER_INTENSITY	0x09
139 #define	TCA6507_INITIALIZE		0x0A
140 
141 #define	INIT_CODE			0x8
142 
143 #define TIMECODES 16
144 static int time_codes[TIMECODES] = {
145 	0, 64, 128, 192, 256, 384, 512, 768,
146 	1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320
147 };
148 
149 /* Convert an led.brightness level (0..255) to a TCA6507 level (0..15) */
150 static inline int TO_LEVEL(int brightness)
151 {
152 	return brightness >> 4;
153 }
154 
155 /* ...and convert back */
156 static inline int TO_BRIGHT(int level)
157 {
158 	if (level)
159 		return (level << 4) | 0xf;
160 	return 0;
161 }
162 
163 #define NUM_LEDS 7
164 struct tca6507_chip {
165 	int			reg_set;	/* One bit per register where
166 						 * a '1' means the register
167 						 * should be written */
168 	u8			reg_file[TCA6507_REG_CNT];
169 	/* Bank 2 is Master Intensity and doesn't use times */
170 	struct bank {
171 		int level;
172 		int ontime, offtime;
173 		int on_dflt, off_dflt;
174 		int time_use, level_use;
175 	} bank[3];
176 	struct i2c_client	*client;
177 	struct work_struct	work;
178 	spinlock_t		lock;
179 
180 	struct tca6507_led {
181 		struct tca6507_chip	*chip;
182 		struct led_classdev	led_cdev;
183 		int			num;
184 		int			ontime, offtime;
185 		int			on_dflt, off_dflt;
186 		int			bank;	/* Bank used, or -1 */
187 		int			blink;	/* Set if hardware-blinking */
188 	} leds[NUM_LEDS];
189 #ifdef CONFIG_GPIOLIB
190 	struct gpio_chip		gpio;
191 	const char			*gpio_name[NUM_LEDS];
192 	int				gpio_map[NUM_LEDS];
193 #endif
194 };
195 
196 static const struct i2c_device_id tca6507_id[] = {
197 	{ "tca6507" },
198 	{ }
199 };
200 MODULE_DEVICE_TABLE(i2c, tca6507_id);
201 
202 static int choose_times(int msec, int *c1p, int *c2p)
203 {
204 	/*
205 	 * Choose two timecodes which add to 'msec' as near as
206 	 * possible.  The first returned is the 'on' or 'off' time.
207 	 * The second is to be used as a 'fade-on' or 'fade-off' time.
208 	 * If 'msec' is even, the first will not be smaller than the
209 	 * second.  If 'msec' is odd, the first will not be larger
210 	 * than the second.
211 	 * If we cannot get a sum within 1/8 of 'msec' fail with
212 	 * -EINVAL, otherwise return the sum that was achieved, plus 1
213 	 * if the first is smaller.
214 	 * If two possibilities are equally good (e.g. 512+0,
215 	 * 256+256), choose the first pair so there is more
216 	 * change-time visible (i.e. it is softer).
217 	 */
218 	int c1, c2;
219 	int tmax = msec * 9 / 8;
220 	int tmin = msec * 7 / 8;
221 	int diff = 65536;
222 
223 	/* We start at '1' to ensure we never even think of choosing a
224 	 * total time of '0'.
225 	 */
226 	for (c1 = 1; c1 < TIMECODES; c1++) {
227 		int t = time_codes[c1];
228 		if (t*2 < tmin)
229 			continue;
230 		if (t > tmax)
231 			break;
232 		for (c2 = 0; c2 <= c1; c2++) {
233 			int tt = t + time_codes[c2];
234 			int d;
235 			if (tt < tmin)
236 				continue;
237 			if (tt > tmax)
238 				break;
239 			/* This works! */
240 			d = abs(msec - tt);
241 			if (d >= diff)
242 				continue;
243 			/* Best yet */
244 			*c1p = c1;
245 			*c2p = c2;
246 			diff = d;
247 			if (d == 0)
248 				return msec;
249 		}
250 	}
251 	if (diff < 65536) {
252 		int actual;
253 		if (msec & 1) {
254 			c1 = *c2p;
255 			*c2p = *c1p;
256 			*c1p = c1;
257 		}
258 		actual = time_codes[*c1p] + time_codes[*c2p];
259 		if (*c1p < *c2p)
260 			return actual + 1;
261 		else
262 			return actual;
263 	}
264 	/* No close match */
265 	return -EINVAL;
266 }
267 
268 /*
269  * Update the register file with the appropriate 3-bit state for the
270  * given led.
271  */
272 static void set_select(struct tca6507_chip *tca, int led, int val)
273 {
274 	int mask = (1 << led);
275 	int bit;
276 
277 	for (bit = 0; bit < 3; bit++) {
278 		int n = tca->reg_file[bit] & ~mask;
279 		if (val & (1 << bit))
280 			n |= mask;
281 		if (tca->reg_file[bit] != n) {
282 			tca->reg_file[bit] = n;
283 			tca->reg_set |= (1 << bit);
284 		}
285 	}
286 }
287 
288 /* Update the register file with the appropriate 4-bit code for one
289  * bank or other.  This can be used for timers, for levels, or for
290  * initialization.
291  */
292 static void set_code(struct tca6507_chip *tca, int reg, int bank, int new)
293 {
294 	int mask = 0xF;
295 	int n;
296 	if (bank) {
297 		mask <<= 4;
298 		new <<= 4;
299 	}
300 	n = tca->reg_file[reg] & ~mask;
301 	n |= new;
302 	if (tca->reg_file[reg] != n) {
303 		tca->reg_file[reg] = n;
304 		tca->reg_set |= 1 << reg;
305 	}
306 }
307 
308 /* Update brightness level. */
309 static void set_level(struct tca6507_chip *tca, int bank, int level)
310 {
311 	switch (bank) {
312 	case BANK0:
313 	case BANK1:
314 		set_code(tca, TCA6507_MAX_INTENSITY, bank, level);
315 		break;
316 	case MASTER:
317 		set_code(tca, TCA6507_MASTER_INTENSITY, 0, level);
318 		break;
319 	}
320 	tca->bank[bank].level = level;
321 }
322 
323 /* Record all relevant time codes for a given bank */
324 static void set_times(struct tca6507_chip *tca, int bank)
325 {
326 	int c1, c2;
327 	int result;
328 
329 	result = choose_times(tca->bank[bank].ontime, &c1, &c2);
330 	dev_dbg(&tca->client->dev,
331 		"Chose on  times %d(%d) %d(%d) for %dms\n",
332 		c1, time_codes[c1],
333 		c2, time_codes[c2], tca->bank[bank].ontime);
334 	set_code(tca, TCA6507_FADE_ON, bank, c2);
335 	set_code(tca, TCA6507_FULL_ON, bank, c1);
336 	tca->bank[bank].ontime = result;
337 
338 	result = choose_times(tca->bank[bank].offtime, &c1, &c2);
339 	dev_dbg(&tca->client->dev,
340 		"Chose off times %d(%d) %d(%d) for %dms\n",
341 		c1, time_codes[c1],
342 		c2, time_codes[c2], tca->bank[bank].offtime);
343 	set_code(tca, TCA6507_FADE_OFF, bank, c2);
344 	set_code(tca, TCA6507_FIRST_OFF, bank, c1);
345 	set_code(tca, TCA6507_SECOND_OFF, bank, c1);
346 	tca->bank[bank].offtime = result;
347 
348 	set_code(tca, TCA6507_INITIALIZE, bank, INIT_CODE);
349 }
350 
351 /* Write all needed register of tca6507 */
352 
353 static void tca6507_work(struct work_struct *work)
354 {
355 	struct tca6507_chip *tca = container_of(work, struct tca6507_chip,
356 						work);
357 	struct i2c_client *cl = tca->client;
358 	int set;
359 	u8 file[TCA6507_REG_CNT];
360 	int r;
361 
362 	spin_lock_irq(&tca->lock);
363 	set = tca->reg_set;
364 	memcpy(file, tca->reg_file, TCA6507_REG_CNT);
365 	tca->reg_set = 0;
366 	spin_unlock_irq(&tca->lock);
367 
368 	for (r = 0; r < TCA6507_REG_CNT; r++)
369 		if (set & (1<<r))
370 			i2c_smbus_write_byte_data(cl, r, file[r]);
371 }
372 
373 static void led_release(struct tca6507_led *led)
374 {
375 	/* If led owns any resource, release it. */
376 	struct tca6507_chip *tca = led->chip;
377 	if (led->bank >= 0) {
378 		struct bank *b = tca->bank + led->bank;
379 		if (led->blink)
380 			b->time_use--;
381 		b->level_use--;
382 	}
383 	led->blink = 0;
384 	led->bank = -1;
385 }
386 
387 static int led_prepare(struct tca6507_led *led)
388 {
389 	/* Assign this led to a bank, configuring that bank if
390 	 * necessary. */
391 	int level = TO_LEVEL(led->led_cdev.brightness);
392 	struct tca6507_chip *tca = led->chip;
393 	int c1, c2;
394 	int i;
395 	struct bank *b;
396 	int need_init = 0;
397 
398 	led->led_cdev.brightness = TO_BRIGHT(level);
399 	if (level == 0) {
400 		set_select(tca, led->num, TCA6507_LS_LED_OFF);
401 		return 0;
402 	}
403 
404 	if (led->ontime == 0 || led->offtime == 0) {
405 		/*
406 		 * Just set the brightness, choosing first usable
407 		 * bank.  If none perfect, choose best.  Count
408 		 * backwards so we check MASTER bank first to avoid
409 		 * wasting a timer.
410 		 */
411 		int best = -1;/* full-on */
412 		int diff = 15-level;
413 
414 		if (level == 15) {
415 			set_select(tca, led->num, TCA6507_LS_LED_ON);
416 			return 0;
417 		}
418 
419 		for (i = MASTER; i >= BANK0; i--) {
420 			int d;
421 			if (tca->bank[i].level == level ||
422 			    tca->bank[i].level_use == 0) {
423 				best = i;
424 				break;
425 			}
426 			d = abs(level - tca->bank[i].level);
427 			if (d < diff) {
428 				diff = d;
429 				best = i;
430 			}
431 		}
432 		if (best == -1) {
433 			/* Best brightness is full-on */
434 			set_select(tca, led->num, TCA6507_LS_LED_ON);
435 			led->led_cdev.brightness = LED_FULL;
436 			return 0;
437 		}
438 
439 		if (!tca->bank[best].level_use)
440 			set_level(tca, best, level);
441 
442 		tca->bank[best].level_use++;
443 		led->bank = best;
444 		set_select(tca, led->num, bank_source[best]);
445 		led->led_cdev.brightness = TO_BRIGHT(tca->bank[best].level);
446 		return 0;
447 	}
448 
449 	/*
450 	 * We have on/off time so we need to try to allocate a timing
451 	 * bank.  First check if times are compatible with hardware
452 	 * and give up if not.
453 	 */
454 	if (choose_times(led->ontime, &c1, &c2) < 0)
455 		return -EINVAL;
456 	if (choose_times(led->offtime, &c1, &c2) < 0)
457 		return -EINVAL;
458 
459 	for (i = BANK0; i <= BANK1; i++) {
460 		if (tca->bank[i].level_use == 0)
461 			/* not in use - it is ours! */
462 			break;
463 		if (tca->bank[i].level != level)
464 			/* Incompatible level - skip */
465 			/* FIX: if timer matches we maybe should consider
466 			 * this anyway...
467 			 */
468 			continue;
469 
470 		if (tca->bank[i].time_use == 0)
471 			/* Timer not in use, and level matches - use it */
472 			break;
473 
474 		if (!(tca->bank[i].on_dflt ||
475 		      led->on_dflt ||
476 		      tca->bank[i].ontime == led->ontime))
477 			/* on time is incompatible */
478 			continue;
479 
480 		if (!(tca->bank[i].off_dflt ||
481 		      led->off_dflt ||
482 		      tca->bank[i].offtime == led->offtime))
483 			/* off time is incompatible */
484 			continue;
485 
486 		/* looks like a suitable match */
487 		break;
488 	}
489 
490 	if (i > BANK1)
491 		/* Nothing matches - how sad */
492 		return -EINVAL;
493 
494 	b = &tca->bank[i];
495 	if (b->level_use == 0)
496 		set_level(tca, i, level);
497 	b->level_use++;
498 	led->bank = i;
499 
500 	if (b->on_dflt ||
501 	    !led->on_dflt ||
502 	    b->time_use == 0) {
503 		b->ontime = led->ontime;
504 		b->on_dflt = led->on_dflt;
505 		need_init = 1;
506 	}
507 
508 	if (b->off_dflt ||
509 	    !led->off_dflt ||
510 	    b->time_use == 0) {
511 		b->offtime = led->offtime;
512 		b->off_dflt = led->off_dflt;
513 		need_init = 1;
514 	}
515 
516 	if (need_init)
517 		set_times(tca, i);
518 
519 	led->ontime = b->ontime;
520 	led->offtime = b->offtime;
521 
522 	b->time_use++;
523 	led->blink = 1;
524 	led->led_cdev.brightness = TO_BRIGHT(b->level);
525 	set_select(tca, led->num, blink_source[i]);
526 	return 0;
527 }
528 
529 static int led_assign(struct tca6507_led *led)
530 {
531 	struct tca6507_chip *tca = led->chip;
532 	int err;
533 	unsigned long flags;
534 
535 	spin_lock_irqsave(&tca->lock, flags);
536 	led_release(led);
537 	err = led_prepare(led);
538 	if (err) {
539 		/*
540 		 * Can only fail on timer setup.  In that case we need
541 		 * to re-establish as steady level.
542 		 */
543 		led->ontime = 0;
544 		led->offtime = 0;
545 		led_prepare(led);
546 	}
547 	spin_unlock_irqrestore(&tca->lock, flags);
548 
549 	if (tca->reg_set)
550 		schedule_work(&tca->work);
551 	return err;
552 }
553 
554 static void tca6507_brightness_set(struct led_classdev *led_cdev,
555 				   enum led_brightness brightness)
556 {
557 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
558 					       led_cdev);
559 	led->led_cdev.brightness = brightness;
560 	led->ontime = 0;
561 	led->offtime = 0;
562 	led_assign(led);
563 }
564 
565 static int tca6507_blink_set(struct led_classdev *led_cdev,
566 			     unsigned long *delay_on,
567 			     unsigned long *delay_off)
568 {
569 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
570 					       led_cdev);
571 
572 	if (*delay_on == 0)
573 		led->on_dflt = 1;
574 	else if (delay_on != &led_cdev->blink_delay_on)
575 		led->on_dflt = 0;
576 	led->ontime = *delay_on;
577 
578 	if (*delay_off == 0)
579 		led->off_dflt = 1;
580 	else if (delay_off != &led_cdev->blink_delay_off)
581 		led->off_dflt = 0;
582 	led->offtime = *delay_off;
583 
584 	if (led->ontime == 0)
585 		led->ontime = 512;
586 	if (led->offtime == 0)
587 		led->offtime = 512;
588 
589 	if (led->led_cdev.brightness == LED_OFF)
590 		led->led_cdev.brightness = LED_FULL;
591 	if (led_assign(led) < 0) {
592 		led->ontime = 0;
593 		led->offtime = 0;
594 		led->led_cdev.brightness = LED_OFF;
595 		return -EINVAL;
596 	}
597 	*delay_on = led->ontime;
598 	*delay_off = led->offtime;
599 	return 0;
600 }
601 
602 #ifdef CONFIG_GPIOLIB
603 static void tca6507_gpio_set_value(struct gpio_chip *gc,
604 				   unsigned offset, int val)
605 {
606 	struct tca6507_chip *tca = container_of(gc, struct tca6507_chip, gpio);
607 	unsigned long flags;
608 
609 	spin_lock_irqsave(&tca->lock, flags);
610 	/*
611 	 * 'OFF' is floating high, and 'ON' is pulled down, so it has
612 	 * the inverse sense of 'val'.
613 	 */
614 	set_select(tca, tca->gpio_map[offset],
615 		   val ? TCA6507_LS_LED_OFF : TCA6507_LS_LED_ON);
616 	spin_unlock_irqrestore(&tca->lock, flags);
617 	if (tca->reg_set)
618 		schedule_work(&tca->work);
619 }
620 
621 static int tca6507_gpio_direction_output(struct gpio_chip *gc,
622 					  unsigned offset, int val)
623 {
624 	tca6507_gpio_set_value(gc, offset, val);
625 	return 0;
626 }
627 
628 static int tca6507_probe_gpios(struct i2c_client *client,
629 			       struct tca6507_chip *tca,
630 			       struct tca6507_platform_data *pdata)
631 {
632 	int err;
633 	int i = 0;
634 	int gpios = 0;
635 
636 	for (i = 0; i < NUM_LEDS; i++)
637 		if (pdata->leds.leds[i].name && pdata->leds.leds[i].flags) {
638 			/* Configure as a gpio */
639 			tca->gpio_name[gpios] = pdata->leds.leds[i].name;
640 			tca->gpio_map[gpios] = i;
641 			gpios++;
642 		}
643 
644 	if (!gpios)
645 		return 0;
646 
647 	tca->gpio.label = "gpio-tca6507";
648 	tca->gpio.names = tca->gpio_name;
649 	tca->gpio.ngpio = gpios;
650 	tca->gpio.base = pdata->gpio_base;
651 	tca->gpio.owner = THIS_MODULE;
652 	tca->gpio.direction_output = tca6507_gpio_direction_output;
653 	tca->gpio.set = tca6507_gpio_set_value;
654 	tca->gpio.dev = &client->dev;
655 #ifdef CONFIG_OF_GPIO
656 	tca->gpio.of_node = of_node_get(client->dev.of_node);
657 #endif
658 	err = gpiochip_add(&tca->gpio);
659 	if (err) {
660 		tca->gpio.ngpio = 0;
661 		return err;
662 	}
663 	if (pdata->setup)
664 		pdata->setup(tca->gpio.base, tca->gpio.ngpio);
665 	return 0;
666 }
667 
668 static void tca6507_remove_gpio(struct tca6507_chip *tca)
669 {
670 	if (tca->gpio.ngpio)
671 		gpiochip_remove(&tca->gpio);
672 }
673 #else /* CONFIG_GPIOLIB */
674 static int tca6507_probe_gpios(struct i2c_client *client,
675 			       struct tca6507_chip *tca,
676 			       struct tca6507_platform_data *pdata)
677 {
678 	return 0;
679 }
680 static void tca6507_remove_gpio(struct tca6507_chip *tca)
681 {
682 }
683 #endif /* CONFIG_GPIOLIB */
684 
685 #ifdef CONFIG_OF
686 static struct tca6507_platform_data *
687 tca6507_led_dt_init(struct i2c_client *client)
688 {
689 	struct device_node *np = client->dev.of_node, *child;
690 	struct tca6507_platform_data *pdata;
691 	struct led_info *tca_leds;
692 	int count;
693 
694 	count = of_get_child_count(np);
695 	if (!count || count > NUM_LEDS)
696 		return ERR_PTR(-ENODEV);
697 
698 	tca_leds = devm_kzalloc(&client->dev,
699 			sizeof(struct led_info) * NUM_LEDS, GFP_KERNEL);
700 	if (!tca_leds)
701 		return ERR_PTR(-ENOMEM);
702 
703 	for_each_child_of_node(np, child) {
704 		struct led_info led;
705 		u32 reg;
706 		int ret;
707 
708 		led.name =
709 			of_get_property(child, "label", NULL) ? : child->name;
710 		led.default_trigger =
711 			of_get_property(child, "linux,default-trigger", NULL);
712 		led.flags = 0;
713 		if (of_property_match_string(child, "compatible", "gpio") >= 0)
714 			led.flags |= TCA6507_MAKE_GPIO;
715 		ret = of_property_read_u32(child, "reg", &reg);
716 		if (ret != 0 || reg < 0 || reg >= NUM_LEDS)
717 			continue;
718 
719 		tca_leds[reg] = led;
720 	}
721 	pdata = devm_kzalloc(&client->dev,
722 			sizeof(struct tca6507_platform_data), GFP_KERNEL);
723 	if (!pdata)
724 		return ERR_PTR(-ENOMEM);
725 
726 	pdata->leds.leds = tca_leds;
727 	pdata->leds.num_leds = NUM_LEDS;
728 #ifdef CONFIG_GPIOLIB
729 	pdata->gpio_base = -1;
730 #endif
731 	return pdata;
732 }
733 
734 static const struct of_device_id of_tca6507_leds_match[] = {
735 	{ .compatible = "ti,tca6507", },
736 	{},
737 };
738 
739 #else
740 static struct tca6507_platform_data *
741 tca6507_led_dt_init(struct i2c_client *client)
742 {
743 	return ERR_PTR(-ENODEV);
744 }
745 
746 #endif
747 
748 static int tca6507_probe(struct i2c_client *client,
749 		const struct i2c_device_id *id)
750 {
751 	struct tca6507_chip *tca;
752 	struct i2c_adapter *adapter;
753 	struct tca6507_platform_data *pdata;
754 	int err;
755 	int i = 0;
756 
757 	adapter = to_i2c_adapter(client->dev.parent);
758 	pdata = dev_get_platdata(&client->dev);
759 
760 	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
761 		return -EIO;
762 
763 	if (!pdata || pdata->leds.num_leds != NUM_LEDS) {
764 		pdata = tca6507_led_dt_init(client);
765 		if (IS_ERR(pdata)) {
766 			dev_err(&client->dev, "Need %d entries in platform-data list\n",
767 				NUM_LEDS);
768 			return PTR_ERR(pdata);
769 		}
770 	}
771 	tca = devm_kzalloc(&client->dev, sizeof(*tca), GFP_KERNEL);
772 	if (!tca)
773 		return -ENOMEM;
774 
775 	tca->client = client;
776 	INIT_WORK(&tca->work, tca6507_work);
777 	spin_lock_init(&tca->lock);
778 	i2c_set_clientdata(client, tca);
779 
780 	for (i = 0; i < NUM_LEDS; i++) {
781 		struct tca6507_led *l = tca->leds + i;
782 
783 		l->chip = tca;
784 		l->num = i;
785 		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {
786 			l->led_cdev.name = pdata->leds.leds[i].name;
787 			l->led_cdev.default_trigger
788 				= pdata->leds.leds[i].default_trigger;
789 			l->led_cdev.brightness_set = tca6507_brightness_set;
790 			l->led_cdev.blink_set = tca6507_blink_set;
791 			l->bank = -1;
792 			err = led_classdev_register(&client->dev,
793 						    &l->led_cdev);
794 			if (err < 0)
795 				goto exit;
796 		}
797 	}
798 	err = tca6507_probe_gpios(client, tca, pdata);
799 	if (err)
800 		goto exit;
801 	/* set all registers to known state - zero */
802 	tca->reg_set = 0x7f;
803 	schedule_work(&tca->work);
804 
805 	return 0;
806 exit:
807 	while (i--) {
808 		if (tca->leds[i].led_cdev.name)
809 			led_classdev_unregister(&tca->leds[i].led_cdev);
810 	}
811 	return err;
812 }
813 
814 static int tca6507_remove(struct i2c_client *client)
815 {
816 	int i;
817 	struct tca6507_chip *tca = i2c_get_clientdata(client);
818 	struct tca6507_led *tca_leds = tca->leds;
819 
820 	for (i = 0; i < NUM_LEDS; i++) {
821 		if (tca_leds[i].led_cdev.name)
822 			led_classdev_unregister(&tca_leds[i].led_cdev);
823 	}
824 	tca6507_remove_gpio(tca);
825 	cancel_work_sync(&tca->work);
826 
827 	return 0;
828 }
829 
830 static struct i2c_driver tca6507_driver = {
831 	.driver   = {
832 		.name    = "leds-tca6507",
833 		.owner   = THIS_MODULE,
834 		.of_match_table = of_match_ptr(of_tca6507_leds_match),
835 	},
836 	.probe    = tca6507_probe,
837 	.remove   = tca6507_remove,
838 	.id_table = tca6507_id,
839 };
840 
841 module_i2c_driver(tca6507_driver);
842 
843 MODULE_AUTHOR("NeilBrown <neilb@suse.de>");
844 MODULE_DESCRIPTION("TCA6507 LED/GPO driver");
845 MODULE_LICENSE("GPL v2");
846