xref: /openbmc/linux/drivers/leds/leds-tca6507.c (revision 6d99a79c)
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 	if (result < 0)
331 		return;
332 	dev_dbg(&tca->client->dev,
333 		"Chose on  times %d(%d) %d(%d) for %dms\n",
334 		c1, time_codes[c1],
335 		c2, time_codes[c2], tca->bank[bank].ontime);
336 	set_code(tca, TCA6507_FADE_ON, bank, c2);
337 	set_code(tca, TCA6507_FULL_ON, bank, c1);
338 	tca->bank[bank].ontime = result;
339 
340 	result = choose_times(tca->bank[bank].offtime, &c1, &c2);
341 	dev_dbg(&tca->client->dev,
342 		"Chose off times %d(%d) %d(%d) for %dms\n",
343 		c1, time_codes[c1],
344 		c2, time_codes[c2], tca->bank[bank].offtime);
345 	set_code(tca, TCA6507_FADE_OFF, bank, c2);
346 	set_code(tca, TCA6507_FIRST_OFF, bank, c1);
347 	set_code(tca, TCA6507_SECOND_OFF, bank, c1);
348 	tca->bank[bank].offtime = result;
349 
350 	set_code(tca, TCA6507_INITIALIZE, bank, INIT_CODE);
351 }
352 
353 /* Write all needed register of tca6507 */
354 
355 static void tca6507_work(struct work_struct *work)
356 {
357 	struct tca6507_chip *tca = container_of(work, struct tca6507_chip,
358 						work);
359 	struct i2c_client *cl = tca->client;
360 	int set;
361 	u8 file[TCA6507_REG_CNT];
362 	int r;
363 
364 	spin_lock_irq(&tca->lock);
365 	set = tca->reg_set;
366 	memcpy(file, tca->reg_file, TCA6507_REG_CNT);
367 	tca->reg_set = 0;
368 	spin_unlock_irq(&tca->lock);
369 
370 	for (r = 0; r < TCA6507_REG_CNT; r++)
371 		if (set & (1<<r))
372 			i2c_smbus_write_byte_data(cl, r, file[r]);
373 }
374 
375 static void led_release(struct tca6507_led *led)
376 {
377 	/* If led owns any resource, release it. */
378 	struct tca6507_chip *tca = led->chip;
379 	if (led->bank >= 0) {
380 		struct bank *b = tca->bank + led->bank;
381 		if (led->blink)
382 			b->time_use--;
383 		b->level_use--;
384 	}
385 	led->blink = 0;
386 	led->bank = -1;
387 }
388 
389 static int led_prepare(struct tca6507_led *led)
390 {
391 	/* Assign this led to a bank, configuring that bank if
392 	 * necessary. */
393 	int level = TO_LEVEL(led->led_cdev.brightness);
394 	struct tca6507_chip *tca = led->chip;
395 	int c1, c2;
396 	int i;
397 	struct bank *b;
398 	int need_init = 0;
399 
400 	led->led_cdev.brightness = TO_BRIGHT(level);
401 	if (level == 0) {
402 		set_select(tca, led->num, TCA6507_LS_LED_OFF);
403 		return 0;
404 	}
405 
406 	if (led->ontime == 0 || led->offtime == 0) {
407 		/*
408 		 * Just set the brightness, choosing first usable
409 		 * bank.  If none perfect, choose best.  Count
410 		 * backwards so we check MASTER bank first to avoid
411 		 * wasting a timer.
412 		 */
413 		int best = -1;/* full-on */
414 		int diff = 15-level;
415 
416 		if (level == 15) {
417 			set_select(tca, led->num, TCA6507_LS_LED_ON);
418 			return 0;
419 		}
420 
421 		for (i = MASTER; i >= BANK0; i--) {
422 			int d;
423 			if (tca->bank[i].level == level ||
424 			    tca->bank[i].level_use == 0) {
425 				best = i;
426 				break;
427 			}
428 			d = abs(level - tca->bank[i].level);
429 			if (d < diff) {
430 				diff = d;
431 				best = i;
432 			}
433 		}
434 		if (best == -1) {
435 			/* Best brightness is full-on */
436 			set_select(tca, led->num, TCA6507_LS_LED_ON);
437 			led->led_cdev.brightness = LED_FULL;
438 			return 0;
439 		}
440 
441 		if (!tca->bank[best].level_use)
442 			set_level(tca, best, level);
443 
444 		tca->bank[best].level_use++;
445 		led->bank = best;
446 		set_select(tca, led->num, bank_source[best]);
447 		led->led_cdev.brightness = TO_BRIGHT(tca->bank[best].level);
448 		return 0;
449 	}
450 
451 	/*
452 	 * We have on/off time so we need to try to allocate a timing
453 	 * bank.  First check if times are compatible with hardware
454 	 * and give up if not.
455 	 */
456 	if (choose_times(led->ontime, &c1, &c2) < 0)
457 		return -EINVAL;
458 	if (choose_times(led->offtime, &c1, &c2) < 0)
459 		return -EINVAL;
460 
461 	for (i = BANK0; i <= BANK1; i++) {
462 		if (tca->bank[i].level_use == 0)
463 			/* not in use - it is ours! */
464 			break;
465 		if (tca->bank[i].level != level)
466 			/* Incompatible level - skip */
467 			/* FIX: if timer matches we maybe should consider
468 			 * this anyway...
469 			 */
470 			continue;
471 
472 		if (tca->bank[i].time_use == 0)
473 			/* Timer not in use, and level matches - use it */
474 			break;
475 
476 		if (!(tca->bank[i].on_dflt ||
477 		      led->on_dflt ||
478 		      tca->bank[i].ontime == led->ontime))
479 			/* on time is incompatible */
480 			continue;
481 
482 		if (!(tca->bank[i].off_dflt ||
483 		      led->off_dflt ||
484 		      tca->bank[i].offtime == led->offtime))
485 			/* off time is incompatible */
486 			continue;
487 
488 		/* looks like a suitable match */
489 		break;
490 	}
491 
492 	if (i > BANK1)
493 		/* Nothing matches - how sad */
494 		return -EINVAL;
495 
496 	b = &tca->bank[i];
497 	if (b->level_use == 0)
498 		set_level(tca, i, level);
499 	b->level_use++;
500 	led->bank = i;
501 
502 	if (b->on_dflt ||
503 	    !led->on_dflt ||
504 	    b->time_use == 0) {
505 		b->ontime = led->ontime;
506 		b->on_dflt = led->on_dflt;
507 		need_init = 1;
508 	}
509 
510 	if (b->off_dflt ||
511 	    !led->off_dflt ||
512 	    b->time_use == 0) {
513 		b->offtime = led->offtime;
514 		b->off_dflt = led->off_dflt;
515 		need_init = 1;
516 	}
517 
518 	if (need_init)
519 		set_times(tca, i);
520 
521 	led->ontime = b->ontime;
522 	led->offtime = b->offtime;
523 
524 	b->time_use++;
525 	led->blink = 1;
526 	led->led_cdev.brightness = TO_BRIGHT(b->level);
527 	set_select(tca, led->num, blink_source[i]);
528 	return 0;
529 }
530 
531 static int led_assign(struct tca6507_led *led)
532 {
533 	struct tca6507_chip *tca = led->chip;
534 	int err;
535 	unsigned long flags;
536 
537 	spin_lock_irqsave(&tca->lock, flags);
538 	led_release(led);
539 	err = led_prepare(led);
540 	if (err) {
541 		/*
542 		 * Can only fail on timer setup.  In that case we need
543 		 * to re-establish as steady level.
544 		 */
545 		led->ontime = 0;
546 		led->offtime = 0;
547 		led_prepare(led);
548 	}
549 	spin_unlock_irqrestore(&tca->lock, flags);
550 
551 	if (tca->reg_set)
552 		schedule_work(&tca->work);
553 	return err;
554 }
555 
556 static void tca6507_brightness_set(struct led_classdev *led_cdev,
557 				   enum led_brightness brightness)
558 {
559 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
560 					       led_cdev);
561 	led->led_cdev.brightness = brightness;
562 	led->ontime = 0;
563 	led->offtime = 0;
564 	led_assign(led);
565 }
566 
567 static int tca6507_blink_set(struct led_classdev *led_cdev,
568 			     unsigned long *delay_on,
569 			     unsigned long *delay_off)
570 {
571 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
572 					       led_cdev);
573 
574 	if (*delay_on == 0)
575 		led->on_dflt = 1;
576 	else if (delay_on != &led_cdev->blink_delay_on)
577 		led->on_dflt = 0;
578 	led->ontime = *delay_on;
579 
580 	if (*delay_off == 0)
581 		led->off_dflt = 1;
582 	else if (delay_off != &led_cdev->blink_delay_off)
583 		led->off_dflt = 0;
584 	led->offtime = *delay_off;
585 
586 	if (led->ontime == 0)
587 		led->ontime = 512;
588 	if (led->offtime == 0)
589 		led->offtime = 512;
590 
591 	if (led->led_cdev.brightness == LED_OFF)
592 		led->led_cdev.brightness = LED_FULL;
593 	if (led_assign(led) < 0) {
594 		led->ontime = 0;
595 		led->offtime = 0;
596 		led->led_cdev.brightness = LED_OFF;
597 		return -EINVAL;
598 	}
599 	*delay_on = led->ontime;
600 	*delay_off = led->offtime;
601 	return 0;
602 }
603 
604 #ifdef CONFIG_GPIOLIB
605 static void tca6507_gpio_set_value(struct gpio_chip *gc,
606 				   unsigned offset, int val)
607 {
608 	struct tca6507_chip *tca = gpiochip_get_data(gc);
609 	unsigned long flags;
610 
611 	spin_lock_irqsave(&tca->lock, flags);
612 	/*
613 	 * 'OFF' is floating high, and 'ON' is pulled down, so it has
614 	 * the inverse sense of 'val'.
615 	 */
616 	set_select(tca, tca->gpio_map[offset],
617 		   val ? TCA6507_LS_LED_OFF : TCA6507_LS_LED_ON);
618 	spin_unlock_irqrestore(&tca->lock, flags);
619 	if (tca->reg_set)
620 		schedule_work(&tca->work);
621 }
622 
623 static int tca6507_gpio_direction_output(struct gpio_chip *gc,
624 					  unsigned offset, int val)
625 {
626 	tca6507_gpio_set_value(gc, offset, val);
627 	return 0;
628 }
629 
630 static int tca6507_probe_gpios(struct i2c_client *client,
631 			       struct tca6507_chip *tca,
632 			       struct tca6507_platform_data *pdata)
633 {
634 	int err;
635 	int i = 0;
636 	int gpios = 0;
637 
638 	for (i = 0; i < NUM_LEDS; i++)
639 		if (pdata->leds.leds[i].name && pdata->leds.leds[i].flags) {
640 			/* Configure as a gpio */
641 			tca->gpio_name[gpios] = pdata->leds.leds[i].name;
642 			tca->gpio_map[gpios] = i;
643 			gpios++;
644 		}
645 
646 	if (!gpios)
647 		return 0;
648 
649 	tca->gpio.label = "gpio-tca6507";
650 	tca->gpio.names = tca->gpio_name;
651 	tca->gpio.ngpio = gpios;
652 	tca->gpio.base = pdata->gpio_base;
653 	tca->gpio.owner = THIS_MODULE;
654 	tca->gpio.direction_output = tca6507_gpio_direction_output;
655 	tca->gpio.set = tca6507_gpio_set_value;
656 	tca->gpio.parent = &client->dev;
657 #ifdef CONFIG_OF_GPIO
658 	tca->gpio.of_node = of_node_get(client->dev.of_node);
659 #endif
660 	err = gpiochip_add_data(&tca->gpio, tca);
661 	if (err) {
662 		tca->gpio.ngpio = 0;
663 		return err;
664 	}
665 	if (pdata->setup)
666 		pdata->setup(tca->gpio.base, tca->gpio.ngpio);
667 	return 0;
668 }
669 
670 static void tca6507_remove_gpio(struct tca6507_chip *tca)
671 {
672 	if (tca->gpio.ngpio)
673 		gpiochip_remove(&tca->gpio);
674 }
675 #else /* CONFIG_GPIOLIB */
676 static int tca6507_probe_gpios(struct i2c_client *client,
677 			       struct tca6507_chip *tca,
678 			       struct tca6507_platform_data *pdata)
679 {
680 	return 0;
681 }
682 static void tca6507_remove_gpio(struct tca6507_chip *tca)
683 {
684 }
685 #endif /* CONFIG_GPIOLIB */
686 
687 #ifdef CONFIG_OF
688 static struct tca6507_platform_data *
689 tca6507_led_dt_init(struct i2c_client *client)
690 {
691 	struct device_node *np = client->dev.of_node, *child;
692 	struct tca6507_platform_data *pdata;
693 	struct led_info *tca_leds;
694 	int count;
695 
696 	count = of_get_child_count(np);
697 	if (!count || count > NUM_LEDS)
698 		return ERR_PTR(-ENODEV);
699 
700 	tca_leds = devm_kcalloc(&client->dev,
701 			NUM_LEDS, sizeof(struct led_info), GFP_KERNEL);
702 	if (!tca_leds)
703 		return ERR_PTR(-ENOMEM);
704 
705 	for_each_child_of_node(np, child) {
706 		struct led_info led;
707 		u32 reg;
708 		int ret;
709 
710 		led.name =
711 			of_get_property(child, "label", NULL) ? : child->name;
712 		led.default_trigger =
713 			of_get_property(child, "linux,default-trigger", NULL);
714 		led.flags = 0;
715 		if (of_property_match_string(child, "compatible", "gpio") >= 0)
716 			led.flags |= TCA6507_MAKE_GPIO;
717 		ret = of_property_read_u32(child, "reg", &reg);
718 		if (ret != 0 || reg >= NUM_LEDS)
719 			continue;
720 
721 		tca_leds[reg] = led;
722 	}
723 	pdata = devm_kzalloc(&client->dev,
724 			sizeof(struct tca6507_platform_data), GFP_KERNEL);
725 	if (!pdata)
726 		return ERR_PTR(-ENOMEM);
727 
728 	pdata->leds.leds = tca_leds;
729 	pdata->leds.num_leds = NUM_LEDS;
730 #ifdef CONFIG_GPIOLIB
731 	pdata->gpio_base = -1;
732 #endif
733 	return pdata;
734 }
735 
736 static const struct of_device_id of_tca6507_leds_match[] = {
737 	{ .compatible = "ti,tca6507", },
738 	{},
739 };
740 MODULE_DEVICE_TABLE(of, of_tca6507_leds_match);
741 
742 #else
743 static struct tca6507_platform_data *
744 tca6507_led_dt_init(struct i2c_client *client)
745 {
746 	return ERR_PTR(-ENODEV);
747 }
748 
749 #endif
750 
751 static int tca6507_probe(struct i2c_client *client,
752 		const struct i2c_device_id *id)
753 {
754 	struct tca6507_chip *tca;
755 	struct i2c_adapter *adapter;
756 	struct tca6507_platform_data *pdata;
757 	int err;
758 	int i = 0;
759 
760 	adapter = to_i2c_adapter(client->dev.parent);
761 	pdata = dev_get_platdata(&client->dev);
762 
763 	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
764 		return -EIO;
765 
766 	if (!pdata || pdata->leds.num_leds != NUM_LEDS) {
767 		pdata = tca6507_led_dt_init(client);
768 		if (IS_ERR(pdata)) {
769 			dev_err(&client->dev, "Need %d entries in platform-data list\n",
770 				NUM_LEDS);
771 			return PTR_ERR(pdata);
772 		}
773 	}
774 	tca = devm_kzalloc(&client->dev, sizeof(*tca), GFP_KERNEL);
775 	if (!tca)
776 		return -ENOMEM;
777 
778 	tca->client = client;
779 	INIT_WORK(&tca->work, tca6507_work);
780 	spin_lock_init(&tca->lock);
781 	i2c_set_clientdata(client, tca);
782 
783 	for (i = 0; i < NUM_LEDS; i++) {
784 		struct tca6507_led *l = tca->leds + i;
785 
786 		l->chip = tca;
787 		l->num = i;
788 		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {
789 			l->led_cdev.name = pdata->leds.leds[i].name;
790 			l->led_cdev.default_trigger
791 				= pdata->leds.leds[i].default_trigger;
792 			l->led_cdev.brightness_set = tca6507_brightness_set;
793 			l->led_cdev.blink_set = tca6507_blink_set;
794 			l->bank = -1;
795 			err = led_classdev_register(&client->dev,
796 						    &l->led_cdev);
797 			if (err < 0)
798 				goto exit;
799 		}
800 	}
801 	err = tca6507_probe_gpios(client, tca, pdata);
802 	if (err)
803 		goto exit;
804 	/* set all registers to known state - zero */
805 	tca->reg_set = 0x7f;
806 	schedule_work(&tca->work);
807 
808 	return 0;
809 exit:
810 	while (i--) {
811 		if (tca->leds[i].led_cdev.name)
812 			led_classdev_unregister(&tca->leds[i].led_cdev);
813 	}
814 	return err;
815 }
816 
817 static int tca6507_remove(struct i2c_client *client)
818 {
819 	int i;
820 	struct tca6507_chip *tca = i2c_get_clientdata(client);
821 	struct tca6507_led *tca_leds = tca->leds;
822 
823 	for (i = 0; i < NUM_LEDS; i++) {
824 		if (tca_leds[i].led_cdev.name)
825 			led_classdev_unregister(&tca_leds[i].led_cdev);
826 	}
827 	tca6507_remove_gpio(tca);
828 	cancel_work_sync(&tca->work);
829 
830 	return 0;
831 }
832 
833 static struct i2c_driver tca6507_driver = {
834 	.driver   = {
835 		.name    = "leds-tca6507",
836 		.of_match_table = of_match_ptr(of_tca6507_leds_match),
837 	},
838 	.probe    = tca6507_probe,
839 	.remove   = tca6507_remove,
840 	.id_table = tca6507_id,
841 };
842 
843 module_i2c_driver(tca6507_driver);
844 
845 MODULE_AUTHOR("NeilBrown <neilb@suse.de>");
846 MODULE_DESCRIPTION("TCA6507 LED/GPO driver");
847 MODULE_LICENSE("GPL v2");
848