xref: /openbmc/linux/drivers/leds/leds-pca955x.c (revision 6aa7de05)
1 /*
2  * Copyright 2007-2008 Extreme Engineering Solutions, Inc.
3  *
4  * Author: Nate Case <ncase@xes-inc.com>
5  *
6  * This file is subject to the terms and conditions of version 2 of
7  * the GNU General Public License.  See the file COPYING in the main
8  * directory of this archive for more details.
9  *
10  * LED driver for various PCA955x I2C LED drivers
11  *
12  * Supported devices:
13  *
14  *	Device		Description		7-bit slave address
15  *	------		-----------		-------------------
16  *	PCA9550		2-bit driver		0x60 .. 0x61
17  *	PCA9551		8-bit driver		0x60 .. 0x67
18  *	PCA9552		16-bit driver		0x60 .. 0x67
19  *	PCA9553/01	4-bit driver		0x62
20  *	PCA9553/02	4-bit driver		0x63
21  *
22  * Philips PCA955x LED driver chips follow a register map as shown below:
23  *
24  *	Control Register		Description
25  *	----------------		-----------
26  *	0x0				Input register 0
27  *					..
28  *	NUM_INPUT_REGS - 1		Last Input register X
29  *
30  *	NUM_INPUT_REGS			Frequency prescaler 0
31  *	NUM_INPUT_REGS + 1		PWM register 0
32  *	NUM_INPUT_REGS + 2		Frequency prescaler 1
33  *	NUM_INPUT_REGS + 3		PWM register 1
34  *
35  *	NUM_INPUT_REGS + 4		LED selector 0
36  *	NUM_INPUT_REGS + 4
37  *	    + NUM_LED_REGS - 1		Last LED selector
38  *
39  *  where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many
40  *  bits the chip supports.
41  */
42 
43 #include <linux/acpi.h>
44 #include <linux/ctype.h>
45 #include <linux/delay.h>
46 #include <linux/err.h>
47 #include <linux/gpio.h>
48 #include <linux/i2c.h>
49 #include <linux/leds.h>
50 #include <linux/module.h>
51 #include <linux/of_device.h>
52 #include <linux/of.h>
53 #include <linux/slab.h>
54 #include <linux/string.h>
55 
56 #include <dt-bindings/leds/leds-pca955x.h>
57 
58 /* LED select registers determine the source that drives LED outputs */
59 #define PCA955X_LS_LED_ON	0x0	/* Output LOW */
60 #define PCA955X_LS_LED_OFF	0x1	/* Output HI-Z */
61 #define PCA955X_LS_BLINK0	0x2	/* Blink at PWM0 rate */
62 #define PCA955X_LS_BLINK1	0x3	/* Blink at PWM1 rate */
63 
64 enum pca955x_type {
65 	pca9550,
66 	pca9551,
67 	pca9552,
68 	pca9553,
69 };
70 
71 struct pca955x_chipdef {
72 	int			bits;
73 	u8			slv_addr;	/* 7-bit slave address mask */
74 	int			slv_addr_shift;	/* Number of bits to ignore */
75 };
76 
77 static struct pca955x_chipdef pca955x_chipdefs[] = {
78 	[pca9550] = {
79 		.bits		= 2,
80 		.slv_addr	= /* 110000x */ 0x60,
81 		.slv_addr_shift	= 1,
82 	},
83 	[pca9551] = {
84 		.bits		= 8,
85 		.slv_addr	= /* 1100xxx */ 0x60,
86 		.slv_addr_shift	= 3,
87 	},
88 	[pca9552] = {
89 		.bits		= 16,
90 		.slv_addr	= /* 1100xxx */ 0x60,
91 		.slv_addr_shift	= 3,
92 	},
93 	[pca9553] = {
94 		.bits		= 4,
95 		.slv_addr	= /* 110001x */ 0x62,
96 		.slv_addr_shift	= 1,
97 	},
98 };
99 
100 static const struct i2c_device_id pca955x_id[] = {
101 	{ "pca9550", pca9550 },
102 	{ "pca9551", pca9551 },
103 	{ "pca9552", pca9552 },
104 	{ "pca9553", pca9553 },
105 	{ }
106 };
107 MODULE_DEVICE_TABLE(i2c, pca955x_id);
108 
109 static const struct acpi_device_id pca955x_acpi_ids[] = {
110 	{ "PCA9550",  pca9550 },
111 	{ "PCA9551",  pca9551 },
112 	{ "PCA9552",  pca9552 },
113 	{ "PCA9553",  pca9553 },
114 	{ }
115 };
116 MODULE_DEVICE_TABLE(acpi, pca955x_acpi_ids);
117 
118 struct pca955x {
119 	struct mutex lock;
120 	struct pca955x_led *leds;
121 	struct pca955x_chipdef	*chipdef;
122 	struct i2c_client	*client;
123 #ifdef CONFIG_LEDS_PCA955X_GPIO
124 	struct gpio_chip gpio;
125 #endif
126 };
127 
128 struct pca955x_led {
129 	struct pca955x	*pca955x;
130 	struct led_classdev	led_cdev;
131 	int			led_num;	/* 0 .. 15 potentially */
132 	char			name[32];
133 	u32			type;
134 	const char		*default_trigger;
135 };
136 
137 struct pca955x_platform_data {
138 	struct pca955x_led	*leds;
139 	int			num_leds;
140 };
141 
142 /* 8 bits per input register */
143 static inline int pca95xx_num_input_regs(int bits)
144 {
145 	return (bits + 7) / 8;
146 }
147 
148 /* 4 bits per LED selector register */
149 static inline int pca95xx_num_led_regs(int bits)
150 {
151 	return (bits + 3)  / 4;
152 }
153 
154 /*
155  * Return an LED selector register value based on an existing one, with
156  * the appropriate 2-bit state value set for the given LED number (0-3).
157  */
158 static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
159 {
160 	return (oldval & (~(0x3 << (led_num << 1)))) |
161 		((state & 0x3) << (led_num << 1));
162 }
163 
164 /*
165  * Write to frequency prescaler register, used to program the
166  * period of the PWM output.  period = (PSCx + 1) / 38
167  */
168 static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
169 {
170 	struct pca955x *pca955x = i2c_get_clientdata(client);
171 	int ret;
172 
173 	ret = i2c_smbus_write_byte_data(client,
174 		pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
175 		val);
176 	if (ret < 0)
177 		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
178 			__func__, n, val, ret);
179 	return ret;
180 }
181 
182 /*
183  * Write to PWM register, which determines the duty cycle of the
184  * output.  LED is OFF when the count is less than the value of this
185  * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
186  *
187  * Duty cycle is (256 - PWMx) / 256
188  */
189 static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
190 {
191 	struct pca955x *pca955x = i2c_get_clientdata(client);
192 	int ret;
193 
194 	ret = i2c_smbus_write_byte_data(client,
195 		pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
196 		val);
197 	if (ret < 0)
198 		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
199 			__func__, n, val, ret);
200 	return ret;
201 }
202 
203 /*
204  * Write to LED selector register, which determines the source that
205  * drives the LED output.
206  */
207 static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
208 {
209 	struct pca955x *pca955x = i2c_get_clientdata(client);
210 	int ret;
211 
212 	ret = i2c_smbus_write_byte_data(client,
213 		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
214 		val);
215 	if (ret < 0)
216 		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
217 			__func__, n, val, ret);
218 	return ret;
219 }
220 
221 /*
222  * Read the LED selector register, which determines the source that
223  * drives the LED output.
224  */
225 static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
226 {
227 	struct pca955x *pca955x = i2c_get_clientdata(client);
228 	int ret;
229 
230 	ret = i2c_smbus_read_byte_data(client,
231 		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
232 	if (ret < 0) {
233 		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
234 			__func__, n, ret);
235 		return ret;
236 	}
237 	*val = (u8)ret;
238 	return 0;
239 }
240 
241 static int pca955x_led_set(struct led_classdev *led_cdev,
242 			    enum led_brightness value)
243 {
244 	struct pca955x_led *pca955x_led;
245 	struct pca955x *pca955x;
246 	u8 ls;
247 	int chip_ls;	/* which LSx to use (0-3 potentially) */
248 	int ls_led;	/* which set of bits within LSx to use (0-3) */
249 	int ret;
250 
251 	pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
252 	pca955x = pca955x_led->pca955x;
253 
254 	chip_ls = pca955x_led->led_num / 4;
255 	ls_led = pca955x_led->led_num % 4;
256 
257 	mutex_lock(&pca955x->lock);
258 
259 	ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
260 	if (ret)
261 		goto out;
262 
263 	switch (value) {
264 	case LED_FULL:
265 		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
266 		break;
267 	case LED_OFF:
268 		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
269 		break;
270 	case LED_HALF:
271 		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
272 		break;
273 	default:
274 		/*
275 		 * Use PWM1 for all other values.  This has the unwanted
276 		 * side effect of making all LEDs on the chip share the
277 		 * same brightness level if set to a value other than
278 		 * OFF, HALF, or FULL.  But, this is probably better than
279 		 * just turning off for all other values.
280 		 */
281 		ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
282 		if (ret)
283 			goto out;
284 		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
285 		break;
286 	}
287 
288 	ret = pca955x_write_ls(pca955x->client, chip_ls, ls);
289 
290 out:
291 	mutex_unlock(&pca955x->lock);
292 
293 	return ret;
294 }
295 
296 #ifdef CONFIG_LEDS_PCA955X_GPIO
297 /*
298  * Read the INPUT register, which contains the state of LEDs.
299  */
300 static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
301 {
302 	int ret = i2c_smbus_read_byte_data(client, n);
303 
304 	if (ret < 0) {
305 		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
306 			__func__, n, ret);
307 		return ret;
308 	}
309 	*val = (u8)ret;
310 	return 0;
311 
312 }
313 
314 static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
315 {
316 	struct pca955x *pca955x = gpiochip_get_data(gc);
317 	struct pca955x_led *led = &pca955x->leds[offset];
318 
319 	if (led->type == PCA955X_TYPE_GPIO)
320 		return 0;
321 
322 	return -EBUSY;
323 }
324 
325 static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
326 			     int val)
327 {
328 	struct pca955x *pca955x = gpiochip_get_data(gc);
329 	struct pca955x_led *led = &pca955x->leds[offset];
330 
331 	if (val)
332 		return pca955x_led_set(&led->led_cdev, LED_FULL);
333 	else
334 		return pca955x_led_set(&led->led_cdev, LED_OFF);
335 }
336 
337 static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
338 				   int val)
339 {
340 	pca955x_set_value(gc, offset, val);
341 }
342 
343 static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
344 {
345 	struct pca955x *pca955x = gpiochip_get_data(gc);
346 	struct pca955x_led *led = &pca955x->leds[offset];
347 	u8 reg = 0;
348 
349 	/* There is nothing we can do about errors */
350 	pca955x_read_input(pca955x->client, led->led_num / 8, &reg);
351 
352 	return !!(reg & (1 << (led->led_num % 8)));
353 }
354 
355 static int pca955x_gpio_direction_input(struct gpio_chip *gc,
356 					unsigned int offset)
357 {
358 	/* To use as input ensure pin is not driven */
359 	return pca955x_set_value(gc, offset, 0);
360 }
361 
362 static int pca955x_gpio_direction_output(struct gpio_chip *gc,
363 					 unsigned int offset, int val)
364 {
365 	return pca955x_set_value(gc, offset, val);
366 }
367 #endif /* CONFIG_LEDS_PCA955X_GPIO */
368 
369 #if IS_ENABLED(CONFIG_OF)
370 static struct pca955x_platform_data *
371 pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
372 {
373 	struct device_node *np = client->dev.of_node;
374 	struct device_node *child;
375 	struct pca955x_platform_data *pdata;
376 	int count;
377 
378 	count = of_get_child_count(np);
379 	if (!count || count > chip->bits)
380 		return ERR_PTR(-ENODEV);
381 
382 	pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
383 	if (!pdata)
384 		return ERR_PTR(-ENOMEM);
385 
386 	pdata->leds = devm_kzalloc(&client->dev,
387 				   sizeof(struct pca955x_led) * chip->bits,
388 				   GFP_KERNEL);
389 	if (!pdata->leds)
390 		return ERR_PTR(-ENOMEM);
391 
392 	for_each_child_of_node(np, child) {
393 		const char *name;
394 		u32 reg;
395 		int res;
396 
397 		res = of_property_read_u32(child, "reg", &reg);
398 		if ((res != 0) || (reg >= chip->bits))
399 			continue;
400 
401 		if (of_property_read_string(child, "label", &name))
402 			name = child->name;
403 
404 		snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name),
405 			 "%s", name);
406 
407 		pdata->leds[reg].type = PCA955X_TYPE_LED;
408 		of_property_read_u32(child, "type", &pdata->leds[reg].type);
409 		of_property_read_string(child, "linux,default-trigger",
410 					&pdata->leds[reg].default_trigger);
411 	}
412 
413 	pdata->num_leds = chip->bits;
414 
415 	return pdata;
416 }
417 
418 static const struct of_device_id of_pca955x_match[] = {
419 	{ .compatible = "nxp,pca9550", .data = (void *)pca9550 },
420 	{ .compatible = "nxp,pca9551", .data = (void *)pca9551 },
421 	{ .compatible = "nxp,pca9552", .data = (void *)pca9552 },
422 	{ .compatible = "nxp,pca9553", .data = (void *)pca9553 },
423 	{},
424 };
425 
426 MODULE_DEVICE_TABLE(of, of_pca955x_match);
427 #else
428 static struct pca955x_platform_data *
429 pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
430 {
431 	return ERR_PTR(-ENODEV);
432 }
433 #endif
434 
435 static int pca955x_probe(struct i2c_client *client,
436 					const struct i2c_device_id *id)
437 {
438 	struct pca955x *pca955x;
439 	struct pca955x_led *pca955x_led;
440 	struct pca955x_chipdef *chip;
441 	struct i2c_adapter *adapter;
442 	int i, err;
443 	struct pca955x_platform_data *pdata;
444 	int ngpios = 0;
445 
446 	if (id) {
447 		chip = &pca955x_chipdefs[id->driver_data];
448 	} else {
449 		const struct acpi_device_id *acpi_id;
450 
451 		acpi_id = acpi_match_device(pca955x_acpi_ids, &client->dev);
452 		if (!acpi_id)
453 			return -ENODEV;
454 		chip = &pca955x_chipdefs[acpi_id->driver_data];
455 	}
456 	adapter = to_i2c_adapter(client->dev.parent);
457 	pdata = dev_get_platdata(&client->dev);
458 	if (!pdata) {
459 		pdata =	pca955x_pdata_of_init(client, chip);
460 		if (IS_ERR(pdata))
461 			return PTR_ERR(pdata);
462 	}
463 
464 	/* Make sure the slave address / chip type combo given is possible */
465 	if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
466 	    chip->slv_addr) {
467 		dev_err(&client->dev, "invalid slave address %02x\n",
468 				client->addr);
469 		return -ENODEV;
470 	}
471 
472 	dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
473 			"slave address 0x%02x\n",
474 			client->name, chip->bits, client->addr);
475 
476 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
477 		return -EIO;
478 
479 	if (pdata->num_leds != chip->bits) {
480 		dev_err(&client->dev,
481 			"board info claims %d LEDs on a %d-bit chip\n",
482 			pdata->num_leds, chip->bits);
483 		return -ENODEV;
484 	}
485 
486 	pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
487 	if (!pca955x)
488 		return -ENOMEM;
489 
490 	pca955x->leds = devm_kzalloc(&client->dev,
491 			sizeof(*pca955x_led) * chip->bits, GFP_KERNEL);
492 	if (!pca955x->leds)
493 		return -ENOMEM;
494 
495 	i2c_set_clientdata(client, pca955x);
496 
497 	mutex_init(&pca955x->lock);
498 	pca955x->client = client;
499 	pca955x->chipdef = chip;
500 
501 	for (i = 0; i < chip->bits; i++) {
502 		pca955x_led = &pca955x->leds[i];
503 		pca955x_led->led_num = i;
504 		pca955x_led->pca955x = pca955x;
505 		pca955x_led->type = pdata->leds[i].type;
506 
507 		switch (pca955x_led->type) {
508 		case PCA955X_TYPE_NONE:
509 			break;
510 		case PCA955X_TYPE_GPIO:
511 			ngpios++;
512 			break;
513 		case PCA955X_TYPE_LED:
514 			/*
515 			 * Platform data can specify LED names and
516 			 * default triggers
517 			 */
518 			if (pdata->leds[i].name[0] == '\0')
519 				snprintf(pdata->leds[i].name,
520 					sizeof(pdata->leds[i].name), "%d", i);
521 
522 			snprintf(pca955x_led->name,
523 				sizeof(pca955x_led->name), "pca955x:%s",
524 				pdata->leds[i].name);
525 
526 			if (pdata->leds[i].default_trigger)
527 				pca955x_led->led_cdev.default_trigger =
528 					pdata->leds[i].default_trigger;
529 
530 			pca955x_led->led_cdev.name = pca955x_led->name;
531 			pca955x_led->led_cdev.brightness_set_blocking =
532 				pca955x_led_set;
533 
534 			err = devm_led_classdev_register(&client->dev,
535 							&pca955x_led->led_cdev);
536 			if (err)
537 				return err;
538 
539 			/* Turn off LED */
540 			err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
541 			if (err)
542 				return err;
543 		}
544 	}
545 
546 	/* PWM0 is used for half brightness or 50% duty cycle */
547 	err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
548 	if (err)
549 		return err;
550 
551 	/* PWM1 is used for variable brightness, default to OFF */
552 	err = pca955x_write_pwm(client, 1, 0);
553 	if (err)
554 		return err;
555 
556 	/* Set to fast frequency so we do not see flashing */
557 	err = pca955x_write_psc(client, 0, 0);
558 	if (err)
559 		return err;
560 	err = pca955x_write_psc(client, 1, 0);
561 	if (err)
562 		return err;
563 
564 #ifdef CONFIG_LEDS_PCA955X_GPIO
565 	if (ngpios) {
566 		pca955x->gpio.label = "gpio-pca955x";
567 		pca955x->gpio.direction_input = pca955x_gpio_direction_input;
568 		pca955x->gpio.direction_output = pca955x_gpio_direction_output;
569 		pca955x->gpio.set = pca955x_gpio_set_value;
570 		pca955x->gpio.get = pca955x_gpio_get_value;
571 		pca955x->gpio.request = pca955x_gpio_request_pin;
572 		pca955x->gpio.can_sleep = 1;
573 		pca955x->gpio.base = -1;
574 		pca955x->gpio.ngpio = ngpios;
575 		pca955x->gpio.parent = &client->dev;
576 		pca955x->gpio.owner = THIS_MODULE;
577 
578 		err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
579 					     pca955x);
580 		if (err) {
581 			/* Use data->gpio.dev as a flag for freeing gpiochip */
582 			pca955x->gpio.parent = NULL;
583 			dev_warn(&client->dev, "could not add gpiochip\n");
584 			return err;
585 		}
586 		dev_info(&client->dev, "gpios %i...%i\n",
587 			 pca955x->gpio.base, pca955x->gpio.base +
588 			 pca955x->gpio.ngpio - 1);
589 	}
590 #endif
591 
592 	return 0;
593 }
594 
595 static struct i2c_driver pca955x_driver = {
596 	.driver = {
597 		.name	= "leds-pca955x",
598 		.acpi_match_table = ACPI_PTR(pca955x_acpi_ids),
599 		.of_match_table = of_match_ptr(of_pca955x_match),
600 	},
601 	.probe	= pca955x_probe,
602 	.id_table = pca955x_id,
603 };
604 
605 module_i2c_driver(pca955x_driver);
606 
607 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
608 MODULE_DESCRIPTION("PCA955x LED driver");
609 MODULE_LICENSE("GPL v2");
610