xref: /linux/drivers/leds/leds-tca6507.c (revision 132db93572821ec2fdf81e354cc40f558faf7e4f)
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  * An led-tca6507 device must be provided with platform data or
75  * configured via devicetree.
76  *
77  * The platform-data lists for each output: the name, default trigger,
78  * and whether the signal is being used as a GPIO rather than an LED.
79  * 'struct led_plaform_data' is used for this.  If 'name' is NULL, the
80  * output isn't used.  If 'flags' is TCA6507_MAKE_GPIO, the output is
81  * a GPO.  The "struct led_platform_data" can be embedded in a "struct
82  * tca6507_platform_data" which adds a 'gpio_base' for the GPIOs, and
83  * a 'setup' callback which is called once the GPIOs are available.
84  *
85  * When configured via devicetree there is one child for each output.
86  * The "reg" determines the output number and "compatible" determines
87  * whether it is an LED or a GPIO.  "linux,default-trigger" can set a
88  * default trigger.
89  */
90 
91 #include <linux/module.h>
92 #include <linux/slab.h>
93 #include <linux/leds.h>
94 #include <linux/err.h>
95 #include <linux/i2c.h>
96 #include <linux/gpio/driver.h>
97 #include <linux/workqueue.h>
98 #include <linux/leds-tca6507.h>
99 #include <linux/of.h>
100 
101 /* LED select registers determine the source that drives LED outputs */
102 #define TCA6507_LS_LED_OFF	0x0	/* Output HI-Z (off) */
103 #define TCA6507_LS_LED_OFF1	0x1	/* Output HI-Z (off) - not used */
104 #define TCA6507_LS_LED_PWM0	0x2	/* Output LOW with Bank0 rate */
105 #define TCA6507_LS_LED_PWM1	0x3	/* Output LOW with Bank1 rate */
106 #define TCA6507_LS_LED_ON	0x4	/* Output LOW (on) */
107 #define TCA6507_LS_LED_MIR	0x5	/* Output LOW with Master Intensity */
108 #define TCA6507_LS_BLINK0	0x6	/* Blink at Bank0 rate */
109 #define TCA6507_LS_BLINK1	0x7	/* Blink at Bank1 rate */
110 
111 enum {
112 	BANK0,
113 	BANK1,
114 	MASTER,
115 };
116 static int bank_source[3] = {
117 	TCA6507_LS_LED_PWM0,
118 	TCA6507_LS_LED_PWM1,
119 	TCA6507_LS_LED_MIR,
120 };
121 static int blink_source[2] = {
122 	TCA6507_LS_BLINK0,
123 	TCA6507_LS_BLINK1,
124 };
125 
126 /* PWM registers */
127 #define	TCA6507_REG_CNT			11
128 
129 /*
130  * 0x00, 0x01, 0x02 encode the TCA6507_LS_* values, each output
131  * owns one bit in each register
132  */
133 #define	TCA6507_FADE_ON			0x03
134 #define	TCA6507_FULL_ON			0x04
135 #define	TCA6507_FADE_OFF		0x05
136 #define	TCA6507_FIRST_OFF		0x06
137 #define	TCA6507_SECOND_OFF		0x07
138 #define	TCA6507_MAX_INTENSITY		0x08
139 #define	TCA6507_MASTER_INTENSITY	0x09
140 #define	TCA6507_INITIALIZE		0x0A
141 
142 #define	INIT_CODE			0x8
143 
144 #define TIMECODES 16
145 static int time_codes[TIMECODES] = {
146 	0, 64, 128, 192, 256, 384, 512, 768,
147 	1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320
148 };
149 
150 /* Convert an led.brightness level (0..255) to a TCA6507 level (0..15) */
151 static inline int TO_LEVEL(int brightness)
152 {
153 	return brightness >> 4;
154 }
155 
156 /* ...and convert back */
157 static inline int TO_BRIGHT(int level)
158 {
159 	if (level)
160 		return (level << 4) | 0xf;
161 	return 0;
162 }
163 
164 #define NUM_LEDS 7
165 struct tca6507_chip {
166 	int			reg_set;	/* One bit per register where
167 						 * a '1' means the register
168 						 * should be written */
169 	u8			reg_file[TCA6507_REG_CNT];
170 	/* Bank 2 is Master Intensity and doesn't use times */
171 	struct bank {
172 		int level;
173 		int ontime, offtime;
174 		int on_dflt, off_dflt;
175 		int time_use, level_use;
176 	} bank[3];
177 	struct i2c_client	*client;
178 	struct work_struct	work;
179 	spinlock_t		lock;
180 
181 	struct tca6507_led {
182 		struct tca6507_chip	*chip;
183 		struct led_classdev	led_cdev;
184 		int			num;
185 		int			ontime, offtime;
186 		int			on_dflt, off_dflt;
187 		int			bank;	/* Bank used, or -1 */
188 		int			blink;	/* Set if hardware-blinking */
189 	} leds[NUM_LEDS];
190 #ifdef CONFIG_GPIOLIB
191 	struct gpio_chip		gpio;
192 	const char			*gpio_name[NUM_LEDS];
193 	int				gpio_map[NUM_LEDS];
194 #endif
195 };
196 
197 static const struct i2c_device_id tca6507_id[] = {
198 	{ "tca6507" },
199 	{ }
200 };
201 MODULE_DEVICE_TABLE(i2c, tca6507_id);
202 
203 static int choose_times(int msec, int *c1p, int *c2p)
204 {
205 	/*
206 	 * Choose two timecodes which add to 'msec' as near as
207 	 * possible.  The first returned is the 'on' or 'off' time.
208 	 * The second is to be used as a 'fade-on' or 'fade-off' time.
209 	 * If 'msec' is even, the first will not be smaller than the
210 	 * second.  If 'msec' is odd, the first will not be larger
211 	 * than the second.
212 	 * If we cannot get a sum within 1/8 of 'msec' fail with
213 	 * -EINVAL, otherwise return the sum that was achieved, plus 1
214 	 * if the first is smaller.
215 	 * If two possibilities are equally good (e.g. 512+0,
216 	 * 256+256), choose the first pair so there is more
217 	 * change-time visible (i.e. it is softer).
218 	 */
219 	int c1, c2;
220 	int tmax = msec * 9 / 8;
221 	int tmin = msec * 7 / 8;
222 	int diff = 65536;
223 
224 	/* We start at '1' to ensure we never even think of choosing a
225 	 * total time of '0'.
226 	 */
227 	for (c1 = 1; c1 < TIMECODES; c1++) {
228 		int t = time_codes[c1];
229 		if (t*2 < tmin)
230 			continue;
231 		if (t > tmax)
232 			break;
233 		for (c2 = 0; c2 <= c1; c2++) {
234 			int tt = t + time_codes[c2];
235 			int d;
236 			if (tt < tmin)
237 				continue;
238 			if (tt > tmax)
239 				break;
240 			/* This works! */
241 			d = abs(msec - tt);
242 			if (d >= diff)
243 				continue;
244 			/* Best yet */
245 			*c1p = c1;
246 			*c2p = c2;
247 			diff = d;
248 			if (d == 0)
249 				return msec;
250 		}
251 	}
252 	if (diff < 65536) {
253 		int actual;
254 		if (msec & 1) {
255 			c1 = *c2p;
256 			*c2p = *c1p;
257 			*c1p = c1;
258 		}
259 		actual = time_codes[*c1p] + time_codes[*c2p];
260 		if (*c1p < *c2p)
261 			return actual + 1;
262 		else
263 			return actual;
264 	}
265 	/* No close match */
266 	return -EINVAL;
267 }
268 
269 /*
270  * Update the register file with the appropriate 3-bit state for the
271  * given led.
272  */
273 static void set_select(struct tca6507_chip *tca, int led, int val)
274 {
275 	int mask = (1 << led);
276 	int bit;
277 
278 	for (bit = 0; bit < 3; bit++) {
279 		int n = tca->reg_file[bit] & ~mask;
280 		if (val & (1 << bit))
281 			n |= mask;
282 		if (tca->reg_file[bit] != n) {
283 			tca->reg_file[bit] = n;
284 			tca->reg_set |= (1 << bit);
285 		}
286 	}
287 }
288 
289 /* Update the register file with the appropriate 4-bit code for one
290  * bank or other.  This can be used for timers, for levels, or for
291  * initialization.
292  */
293 static void set_code(struct tca6507_chip *tca, int reg, int bank, int new)
294 {
295 	int mask = 0xF;
296 	int n;
297 	if (bank) {
298 		mask <<= 4;
299 		new <<= 4;
300 	}
301 	n = tca->reg_file[reg] & ~mask;
302 	n |= new;
303 	if (tca->reg_file[reg] != n) {
304 		tca->reg_file[reg] = n;
305 		tca->reg_set |= 1 << reg;
306 	}
307 }
308 
309 /* Update brightness level. */
310 static void set_level(struct tca6507_chip *tca, int bank, int level)
311 {
312 	switch (bank) {
313 	case BANK0:
314 	case BANK1:
315 		set_code(tca, TCA6507_MAX_INTENSITY, bank, level);
316 		break;
317 	case MASTER:
318 		set_code(tca, TCA6507_MASTER_INTENSITY, 0, level);
319 		break;
320 	}
321 	tca->bank[bank].level = level;
322 }
323 
324 /* Record all relevant time codes for a given bank */
325 static void set_times(struct tca6507_chip *tca, int bank)
326 {
327 	int c1, c2;
328 	int result;
329 
330 	result = choose_times(tca->bank[bank].ontime, &c1, &c2);
331 	if (result < 0)
332 		return;
333 	dev_dbg(&tca->client->dev,
334 		"Chose on  times %d(%d) %d(%d) for %dms\n",
335 		c1, time_codes[c1],
336 		c2, time_codes[c2], tca->bank[bank].ontime);
337 	set_code(tca, TCA6507_FADE_ON, bank, c2);
338 	set_code(tca, TCA6507_FULL_ON, bank, c1);
339 	tca->bank[bank].ontime = result;
340 
341 	result = choose_times(tca->bank[bank].offtime, &c1, &c2);
342 	dev_dbg(&tca->client->dev,
343 		"Chose off times %d(%d) %d(%d) for %dms\n",
344 		c1, time_codes[c1],
345 		c2, time_codes[c2], tca->bank[bank].offtime);
346 	set_code(tca, TCA6507_FADE_OFF, bank, c2);
347 	set_code(tca, TCA6507_FIRST_OFF, bank, c1);
348 	set_code(tca, TCA6507_SECOND_OFF, bank, c1);
349 	tca->bank[bank].offtime = result;
350 
351 	set_code(tca, TCA6507_INITIALIZE, bank, INIT_CODE);
352 }
353 
354 /* Write all needed register of tca6507 */
355 
356 static void tca6507_work(struct work_struct *work)
357 {
358 	struct tca6507_chip *tca = container_of(work, struct tca6507_chip,
359 						work);
360 	struct i2c_client *cl = tca->client;
361 	int set;
362 	u8 file[TCA6507_REG_CNT];
363 	int r;
364 
365 	spin_lock_irq(&tca->lock);
366 	set = tca->reg_set;
367 	memcpy(file, tca->reg_file, TCA6507_REG_CNT);
368 	tca->reg_set = 0;
369 	spin_unlock_irq(&tca->lock);
370 
371 	for (r = 0; r < TCA6507_REG_CNT; r++)
372 		if (set & (1<<r))
373 			i2c_smbus_write_byte_data(cl, r, file[r]);
374 }
375 
376 static void led_release(struct tca6507_led *led)
377 {
378 	/* If led owns any resource, release it. */
379 	struct tca6507_chip *tca = led->chip;
380 	if (led->bank >= 0) {
381 		struct bank *b = tca->bank + led->bank;
382 		if (led->blink)
383 			b->time_use--;
384 		b->level_use--;
385 	}
386 	led->blink = 0;
387 	led->bank = -1;
388 }
389 
390 static int led_prepare(struct tca6507_led *led)
391 {
392 	/* Assign this led to a bank, configuring that bank if
393 	 * necessary. */
394 	int level = TO_LEVEL(led->led_cdev.brightness);
395 	struct tca6507_chip *tca = led->chip;
396 	int c1, c2;
397 	int i;
398 	struct bank *b;
399 	int need_init = 0;
400 
401 	led->led_cdev.brightness = TO_BRIGHT(level);
402 	if (level == 0) {
403 		set_select(tca, led->num, TCA6507_LS_LED_OFF);
404 		return 0;
405 	}
406 
407 	if (led->ontime == 0 || led->offtime == 0) {
408 		/*
409 		 * Just set the brightness, choosing first usable
410 		 * bank.  If none perfect, choose best.  Count
411 		 * backwards so we check MASTER bank first to avoid
412 		 * wasting a timer.
413 		 */
414 		int best = -1;/* full-on */
415 		int diff = 15-level;
416 
417 		if (level == 15) {
418 			set_select(tca, led->num, TCA6507_LS_LED_ON);
419 			return 0;
420 		}
421 
422 		for (i = MASTER; i >= BANK0; i--) {
423 			int d;
424 			if (tca->bank[i].level == level ||
425 			    tca->bank[i].level_use == 0) {
426 				best = i;
427 				break;
428 			}
429 			d = abs(level - tca->bank[i].level);
430 			if (d < diff) {
431 				diff = d;
432 				best = i;
433 			}
434 		}
435 		if (best == -1) {
436 			/* Best brightness is full-on */
437 			set_select(tca, led->num, TCA6507_LS_LED_ON);
438 			led->led_cdev.brightness = LED_FULL;
439 			return 0;
440 		}
441 
442 		if (!tca->bank[best].level_use)
443 			set_level(tca, best, level);
444 
445 		tca->bank[best].level_use++;
446 		led->bank = best;
447 		set_select(tca, led->num, bank_source[best]);
448 		led->led_cdev.brightness = TO_BRIGHT(tca->bank[best].level);
449 		return 0;
450 	}
451 
452 	/*
453 	 * We have on/off time so we need to try to allocate a timing
454 	 * bank.  First check if times are compatible with hardware
455 	 * and give up if not.
456 	 */
457 	if (choose_times(led->ontime, &c1, &c2) < 0)
458 		return -EINVAL;
459 	if (choose_times(led->offtime, &c1, &c2) < 0)
460 		return -EINVAL;
461 
462 	for (i = BANK0; i <= BANK1; i++) {
463 		if (tca->bank[i].level_use == 0)
464 			/* not in use - it is ours! */
465 			break;
466 		if (tca->bank[i].level != level)
467 			/* Incompatible level - skip */
468 			/* FIX: if timer matches we maybe should consider
469 			 * this anyway...
470 			 */
471 			continue;
472 
473 		if (tca->bank[i].time_use == 0)
474 			/* Timer not in use, and level matches - use it */
475 			break;
476 
477 		if (!(tca->bank[i].on_dflt ||
478 		      led->on_dflt ||
479 		      tca->bank[i].ontime == led->ontime))
480 			/* on time is incompatible */
481 			continue;
482 
483 		if (!(tca->bank[i].off_dflt ||
484 		      led->off_dflt ||
485 		      tca->bank[i].offtime == led->offtime))
486 			/* off time is incompatible */
487 			continue;
488 
489 		/* looks like a suitable match */
490 		break;
491 	}
492 
493 	if (i > BANK1)
494 		/* Nothing matches - how sad */
495 		return -EINVAL;
496 
497 	b = &tca->bank[i];
498 	if (b->level_use == 0)
499 		set_level(tca, i, level);
500 	b->level_use++;
501 	led->bank = i;
502 
503 	if (b->on_dflt ||
504 	    !led->on_dflt ||
505 	    b->time_use == 0) {
506 		b->ontime = led->ontime;
507 		b->on_dflt = led->on_dflt;
508 		need_init = 1;
509 	}
510 
511 	if (b->off_dflt ||
512 	    !led->off_dflt ||
513 	    b->time_use == 0) {
514 		b->offtime = led->offtime;
515 		b->off_dflt = led->off_dflt;
516 		need_init = 1;
517 	}
518 
519 	if (need_init)
520 		set_times(tca, i);
521 
522 	led->ontime = b->ontime;
523 	led->offtime = b->offtime;
524 
525 	b->time_use++;
526 	led->blink = 1;
527 	led->led_cdev.brightness = TO_BRIGHT(b->level);
528 	set_select(tca, led->num, blink_source[i]);
529 	return 0;
530 }
531 
532 static int led_assign(struct tca6507_led *led)
533 {
534 	struct tca6507_chip *tca = led->chip;
535 	int err;
536 	unsigned long flags;
537 
538 	spin_lock_irqsave(&tca->lock, flags);
539 	led_release(led);
540 	err = led_prepare(led);
541 	if (err) {
542 		/*
543 		 * Can only fail on timer setup.  In that case we need
544 		 * to re-establish as steady level.
545 		 */
546 		led->ontime = 0;
547 		led->offtime = 0;
548 		led_prepare(led);
549 	}
550 	spin_unlock_irqrestore(&tca->lock, flags);
551 
552 	if (tca->reg_set)
553 		schedule_work(&tca->work);
554 	return err;
555 }
556 
557 static void tca6507_brightness_set(struct led_classdev *led_cdev,
558 				   enum led_brightness brightness)
559 {
560 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
561 					       led_cdev);
562 	led->led_cdev.brightness = brightness;
563 	led->ontime = 0;
564 	led->offtime = 0;
565 	led_assign(led);
566 }
567 
568 static int tca6507_blink_set(struct led_classdev *led_cdev,
569 			     unsigned long *delay_on,
570 			     unsigned long *delay_off)
571 {
572 	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
573 					       led_cdev);
574 
575 	if (*delay_on == 0)
576 		led->on_dflt = 1;
577 	else if (delay_on != &led_cdev->blink_delay_on)
578 		led->on_dflt = 0;
579 	led->ontime = *delay_on;
580 
581 	if (*delay_off == 0)
582 		led->off_dflt = 1;
583 	else if (delay_off != &led_cdev->blink_delay_off)
584 		led->off_dflt = 0;
585 	led->offtime = *delay_off;
586 
587 	if (led->ontime == 0)
588 		led->ontime = 512;
589 	if (led->offtime == 0)
590 		led->offtime = 512;
591 
592 	if (led->led_cdev.brightness == LED_OFF)
593 		led->led_cdev.brightness = LED_FULL;
594 	if (led_assign(led) < 0) {
595 		led->ontime = 0;
596 		led->offtime = 0;
597 		led->led_cdev.brightness = LED_OFF;
598 		return -EINVAL;
599 	}
600 	*delay_on = led->ontime;
601 	*delay_off = led->offtime;
602 	return 0;
603 }
604 
605 #ifdef CONFIG_GPIOLIB
606 static void tca6507_gpio_set_value(struct gpio_chip *gc,
607 				   unsigned offset, int val)
608 {
609 	struct tca6507_chip *tca = gpiochip_get_data(gc);
610 	unsigned long flags;
611 
612 	spin_lock_irqsave(&tca->lock, flags);
613 	/*
614 	 * 'OFF' is floating high, and 'ON' is pulled down, so it has
615 	 * the inverse sense of 'val'.
616 	 */
617 	set_select(tca, tca->gpio_map[offset],
618 		   val ? TCA6507_LS_LED_OFF : TCA6507_LS_LED_ON);
619 	spin_unlock_irqrestore(&tca->lock, flags);
620 	if (tca->reg_set)
621 		schedule_work(&tca->work);
622 }
623 
624 static int tca6507_gpio_direction_output(struct gpio_chip *gc,
625 					  unsigned offset, int val)
626 {
627 	tca6507_gpio_set_value(gc, offset, val);
628 	return 0;
629 }
630 
631 static int tca6507_probe_gpios(struct i2c_client *client,
632 			       struct tca6507_chip *tca,
633 			       struct tca6507_platform_data *pdata)
634 {
635 	int err;
636 	int i = 0;
637 	int gpios = 0;
638 
639 	for (i = 0; i < NUM_LEDS; i++)
640 		if (pdata->leds.leds[i].name && pdata->leds.leds[i].flags) {
641 			/* Configure as a gpio */
642 			tca->gpio_name[gpios] = pdata->leds.leds[i].name;
643 			tca->gpio_map[gpios] = i;
644 			gpios++;
645 		}
646 
647 	if (!gpios)
648 		return 0;
649 
650 	tca->gpio.label = "gpio-tca6507";
651 	tca->gpio.names = tca->gpio_name;
652 	tca->gpio.ngpio = gpios;
653 	tca->gpio.base = pdata->gpio_base;
654 	tca->gpio.owner = THIS_MODULE;
655 	tca->gpio.direction_output = tca6507_gpio_direction_output;
656 	tca->gpio.set = tca6507_gpio_set_value;
657 	tca->gpio.parent = &client->dev;
658 #ifdef CONFIG_OF_GPIO
659 	tca->gpio.of_node = of_node_get(client->dev.of_node);
660 #endif
661 	err = gpiochip_add_data(&tca->gpio, tca);
662 	if (err) {
663 		tca->gpio.ngpio = 0;
664 		return err;
665 	}
666 	if (pdata->setup)
667 		pdata->setup(tca->gpio.base, tca->gpio.ngpio);
668 	return 0;
669 }
670 
671 static void tca6507_remove_gpio(struct tca6507_chip *tca)
672 {
673 	if (tca->gpio.ngpio)
674 		gpiochip_remove(&tca->gpio);
675 }
676 #else /* CONFIG_GPIOLIB */
677 static int tca6507_probe_gpios(struct i2c_client *client,
678 			       struct tca6507_chip *tca,
679 			       struct tca6507_platform_data *pdata)
680 {
681 	return 0;
682 }
683 static void tca6507_remove_gpio(struct tca6507_chip *tca)
684 {
685 }
686 #endif /* CONFIG_GPIOLIB */
687 
688 #ifdef CONFIG_OF
689 static struct tca6507_platform_data *
690 tca6507_led_dt_init(struct i2c_client *client)
691 {
692 	struct device_node *np = client->dev.of_node, *child;
693 	struct tca6507_platform_data *pdata;
694 	struct led_info *tca_leds;
695 	int count;
696 
697 	count = of_get_child_count(np);
698 	if (!count || count > NUM_LEDS)
699 		return ERR_PTR(-ENODEV);
700 
701 	tca_leds = devm_kcalloc(&client->dev,
702 			NUM_LEDS, sizeof(struct led_info), GFP_KERNEL);
703 	if (!tca_leds)
704 		return ERR_PTR(-ENOMEM);
705 
706 	for_each_child_of_node(np, child) {
707 		struct led_info led;
708 		u32 reg;
709 		int ret;
710 
711 		led.name =
712 			of_get_property(child, "label", NULL) ? : child->name;
713 		led.default_trigger =
714 			of_get_property(child, "linux,default-trigger", NULL);
715 		led.flags = 0;
716 		if (of_property_match_string(child, "compatible", "gpio") >= 0)
717 			led.flags |= TCA6507_MAKE_GPIO;
718 		ret = of_property_read_u32(child, "reg", &reg);
719 		if (ret != 0 || reg >= NUM_LEDS)
720 			continue;
721 
722 		tca_leds[reg] = led;
723 	}
724 	pdata = devm_kzalloc(&client->dev,
725 			sizeof(struct tca6507_platform_data), GFP_KERNEL);
726 	if (!pdata)
727 		return ERR_PTR(-ENOMEM);
728 
729 	pdata->leds.leds = tca_leds;
730 	pdata->leds.num_leds = NUM_LEDS;
731 #ifdef CONFIG_GPIOLIB
732 	pdata->gpio_base = -1;
733 #endif
734 	return pdata;
735 }
736 
737 static const struct of_device_id of_tca6507_leds_match[] = {
738 	{ .compatible = "ti,tca6507", },
739 	{},
740 };
741 MODULE_DEVICE_TABLE(of, of_tca6507_leds_match);
742 
743 #else
744 static struct tca6507_platform_data *
745 tca6507_led_dt_init(struct i2c_client *client)
746 {
747 	return ERR_PTR(-ENODEV);
748 }
749 
750 #endif
751 
752 static int tca6507_probe(struct i2c_client *client,
753 		const struct i2c_device_id *id)
754 {
755 	struct tca6507_chip *tca;
756 	struct i2c_adapter *adapter;
757 	struct tca6507_platform_data *pdata;
758 	int err;
759 	int i = 0;
760 
761 	adapter = client->adapter;
762 	pdata = dev_get_platdata(&client->dev);
763 
764 	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
765 		return -EIO;
766 
767 	if (!pdata || pdata->leds.num_leds != NUM_LEDS) {
768 		pdata = tca6507_led_dt_init(client);
769 		if (IS_ERR(pdata)) {
770 			dev_err(&client->dev, "Need %d entries in platform-data list\n",
771 				NUM_LEDS);
772 			return PTR_ERR(pdata);
773 		}
774 	}
775 	tca = devm_kzalloc(&client->dev, sizeof(*tca), GFP_KERNEL);
776 	if (!tca)
777 		return -ENOMEM;
778 
779 	tca->client = client;
780 	INIT_WORK(&tca->work, tca6507_work);
781 	spin_lock_init(&tca->lock);
782 	i2c_set_clientdata(client, tca);
783 
784 	for (i = 0; i < NUM_LEDS; i++) {
785 		struct tca6507_led *l = tca->leds + i;
786 
787 		l->chip = tca;
788 		l->num = i;
789 		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {
790 			l->led_cdev.name = pdata->leds.leds[i].name;
791 			l->led_cdev.default_trigger
792 				= pdata->leds.leds[i].default_trigger;
793 			l->led_cdev.brightness_set = tca6507_brightness_set;
794 			l->led_cdev.blink_set = tca6507_blink_set;
795 			l->bank = -1;
796 			err = led_classdev_register(&client->dev,
797 						    &l->led_cdev);
798 			if (err < 0)
799 				goto exit;
800 		}
801 	}
802 	err = tca6507_probe_gpios(client, tca, pdata);
803 	if (err)
804 		goto exit;
805 	/* set all registers to known state - zero */
806 	tca->reg_set = 0x7f;
807 	schedule_work(&tca->work);
808 
809 	return 0;
810 exit:
811 	while (i--) {
812 		if (tca->leds[i].led_cdev.name)
813 			led_classdev_unregister(&tca->leds[i].led_cdev);
814 	}
815 	return err;
816 }
817 
818 static int tca6507_remove(struct i2c_client *client)
819 {
820 	int i;
821 	struct tca6507_chip *tca = i2c_get_clientdata(client);
822 	struct tca6507_led *tca_leds = tca->leds;
823 
824 	for (i = 0; i < NUM_LEDS; i++) {
825 		if (tca_leds[i].led_cdev.name)
826 			led_classdev_unregister(&tca_leds[i].led_cdev);
827 	}
828 	tca6507_remove_gpio(tca);
829 	cancel_work_sync(&tca->work);
830 
831 	return 0;
832 }
833 
834 static struct i2c_driver tca6507_driver = {
835 	.driver   = {
836 		.name    = "leds-tca6507",
837 		.of_match_table = of_match_ptr(of_tca6507_leds_match),
838 	},
839 	.probe    = tca6507_probe,
840 	.remove   = tca6507_remove,
841 	.id_table = tca6507_id,
842 };
843 
844 module_i2c_driver(tca6507_driver);
845 
846 MODULE_AUTHOR("NeilBrown <neilb@suse.de>");
847 MODULE_DESCRIPTION("TCA6507 LED/GPO driver");
848 MODULE_LICENSE("GPL v2");
849