1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2007-2008 Extreme Engineering Solutions, Inc.
4 *
5 * Author: Nate Case <ncase@xes-inc.com>
6 *
7 * LED driver for various PCA955x I2C LED drivers
8 *
9 * Supported devices:
10 *
11 *	Device		Description		7-bit slave address
12 *	------		-----------		-------------------
13 *	PCA9550		2-bit driver		0x60 .. 0x61
14 *	PCA9551		8-bit driver		0x60 .. 0x67
15 *	PCA9552		16-bit driver		0x60 .. 0x67
16 *	PCA9553/01	4-bit driver		0x62
17 *	PCA9553/02	4-bit driver		0x63
18 *
19 * Philips PCA955x LED driver chips follow a register map as shown below:
20 *
21 *	Control Register		Description
22 *	----------------		-----------
23 *	0x0				Input register 0
24 *					..
25 *	NUM_INPUT_REGS - 1		Last Input register X
26 *
27 *	NUM_INPUT_REGS			Frequency prescaler 0
28 *	NUM_INPUT_REGS + 1		PWM register 0
29 *	NUM_INPUT_REGS + 2		Frequency prescaler 1
30 *	NUM_INPUT_REGS + 3		PWM register 1
31 *
32 *	NUM_INPUT_REGS + 4		LED selector 0
33 *	NUM_INPUT_REGS + 4
34 *	    + NUM_LED_REGS - 1		Last LED selector
35 *
36 *  where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many
37 *  bits the chip supports.
38 */
39
40#include <linux/ctype.h>
41#include <linux/delay.h>
42#include <linux/err.h>
43#include <linux/gpio/driver.h>
44#include <linux/i2c.h>
45#include <linux/leds.h>
46#include <linux/module.h>
47#include <linux/of.h>
48#include <linux/property.h>
49#include <linux/slab.h>
50#include <linux/string.h>
51
52#include <dt-bindings/leds/leds-pca955x.h>
53
54/* LED select registers determine the source that drives LED outputs */
55#define PCA955X_LS_LED_ON	0x0	/* Output LOW */
56#define PCA955X_LS_LED_OFF	0x1	/* Output HI-Z */
57#define PCA955X_LS_BLINK0	0x2	/* Blink at PWM0 rate */
58#define PCA955X_LS_BLINK1	0x3	/* Blink at PWM1 rate */
59
60#define PCA955X_GPIO_INPUT	LED_OFF
61#define PCA955X_GPIO_HIGH	LED_OFF
62#define PCA955X_GPIO_LOW	LED_FULL
63
64enum pca955x_type {
65	pca9550,
66	pca9551,
67	pca9552,
68	ibm_pca9552,
69	pca9553,
70};
71
72struct pca955x_chipdef {
73	int			bits;
74	u8			slv_addr;	/* 7-bit slave address mask */
75	int			slv_addr_shift;	/* Number of bits to ignore */
76};
77
78static struct pca955x_chipdef pca955x_chipdefs[] = {
79	[pca9550] = {
80		.bits		= 2,
81		.slv_addr	= /* 110000x */ 0x60,
82		.slv_addr_shift	= 1,
83	},
84	[pca9551] = {
85		.bits		= 8,
86		.slv_addr	= /* 1100xxx */ 0x60,
87		.slv_addr_shift	= 3,
88	},
89	[pca9552] = {
90		.bits		= 16,
91		.slv_addr	= /* 1100xxx */ 0x60,
92		.slv_addr_shift	= 3,
93	},
94	[ibm_pca9552] = {
95		.bits		= 16,
96		.slv_addr	= /* 0110xxx */ 0x30,
97		.slv_addr_shift	= 3,
98	},
99	[pca9553] = {
100		.bits		= 4,
101		.slv_addr	= /* 110001x */ 0x62,
102		.slv_addr_shift	= 1,
103	},
104};
105
106static const struct i2c_device_id pca955x_id[] = {
107	{ "pca9550", pca9550 },
108	{ "pca9551", pca9551 },
109	{ "pca9552", pca9552 },
110	{ "ibm-pca9552", ibm_pca9552 },
111	{ "pca9553", pca9553 },
112	{ }
113};
114MODULE_DEVICE_TABLE(i2c, pca955x_id);
115
116struct pca955x {
117	struct mutex lock;
118	struct pca955x_led *leds;
119	struct pca955x_chipdef	*chipdef;
120	struct i2c_client	*client;
121#ifdef CONFIG_LEDS_PCA955X_GPIO
122	struct gpio_chip gpio;
123#endif
124};
125
126struct pca955x_led {
127	struct pca955x	*pca955x;
128	struct led_classdev	led_cdev;
129	int			led_num;	/* 0 .. 15 potentially */
130	char			name[32];
131	u32			type;
132	const char		*default_trigger;
133};
134
135struct pca955x_platform_data {
136	struct pca955x_led	*leds;
137	int			num_leds;
138};
139
140/* 8 bits per input register */
141static inline int pca95xx_num_input_regs(int bits)
142{
143	return (bits + 7) / 8;
144}
145
146/* 4 bits per LED selector register */
147static inline int pca95xx_num_led_regs(int bits)
148{
149	return (bits + 3)  / 4;
150}
151
152/*
153 * Return an LED selector register value based on an existing one, with
154 * the appropriate 2-bit state value set for the given LED number (0-3).
155 */
156static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
157{
158	return (oldval & (~(0x3 << (led_num << 1)))) |
159		((state & 0x3) << (led_num << 1));
160}
161
162/*
163 * Write to frequency prescaler register, used to program the
164 * period of the PWM output.  period = (PSCx + 1) / 38
165 */
166static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
167{
168	struct pca955x *pca955x = i2c_get_clientdata(client);
169	int ret;
170
171	ret = i2c_smbus_write_byte_data(client,
172		pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
173		val);
174	if (ret < 0)
175		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
176			__func__, n, val, ret);
177	return ret;
178}
179
180/*
181 * Write to PWM register, which determines the duty cycle of the
182 * output.  LED is OFF when the count is less than the value of this
183 * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
184 *
185 * Duty cycle is (256 - PWMx) / 256
186 */
187static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
188{
189	struct pca955x *pca955x = i2c_get_clientdata(client);
190	int ret;
191
192	ret = i2c_smbus_write_byte_data(client,
193		pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
194		val);
195	if (ret < 0)
196		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
197			__func__, n, val, ret);
198	return ret;
199}
200
201/*
202 * Write to LED selector register, which determines the source that
203 * drives the LED output.
204 */
205static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
206{
207	struct pca955x *pca955x = i2c_get_clientdata(client);
208	int ret;
209
210	ret = i2c_smbus_write_byte_data(client,
211		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
212		val);
213	if (ret < 0)
214		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
215			__func__, n, val, ret);
216	return ret;
217}
218
219/*
220 * Read the LED selector register, which determines the source that
221 * drives the LED output.
222 */
223static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
224{
225	struct pca955x *pca955x = i2c_get_clientdata(client);
226	int ret;
227
228	ret = i2c_smbus_read_byte_data(client,
229		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
230	if (ret < 0) {
231		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
232			__func__, n, ret);
233		return ret;
234	}
235	*val = (u8)ret;
236	return 0;
237}
238
239static int pca955x_led_set(struct led_classdev *led_cdev,
240			    enum led_brightness value)
241{
242	struct pca955x_led *pca955x_led;
243	struct pca955x *pca955x;
244	u8 ls;
245	int chip_ls;	/* which LSx to use (0-3 potentially) */
246	int ls_led;	/* which set of bits within LSx to use (0-3) */
247	int ret;
248
249	pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
250	pca955x = pca955x_led->pca955x;
251
252	chip_ls = pca955x_led->led_num / 4;
253	ls_led = pca955x_led->led_num % 4;
254
255	mutex_lock(&pca955x->lock);
256
257	ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
258	if (ret)
259		goto out;
260
261	switch (value) {
262	case LED_FULL:
263		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
264		break;
265	case LED_OFF:
266		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
267		break;
268	case LED_HALF:
269		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
270		break;
271	default:
272		/*
273		 * Use PWM1 for all other values.  This has the unwanted
274		 * side effect of making all LEDs on the chip share the
275		 * same brightness level if set to a value other than
276		 * OFF, HALF, or FULL.  But, this is probably better than
277		 * just turning off for all other values.
278		 */
279		ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
280		if (ret)
281			goto out;
282		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
283		break;
284	}
285
286	ret = pca955x_write_ls(pca955x->client, chip_ls, ls);
287
288out:
289	mutex_unlock(&pca955x->lock);
290
291	return ret;
292}
293
294#ifdef CONFIG_LEDS_PCA955X_GPIO
295/*
296 * Read the INPUT register, which contains the state of LEDs.
297 */
298static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
299{
300	int ret = i2c_smbus_read_byte_data(client, n);
301
302	if (ret < 0) {
303		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
304			__func__, n, ret);
305		return ret;
306	}
307	*val = (u8)ret;
308	return 0;
309
310}
311
312static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
313{
314	struct pca955x *pca955x = gpiochip_get_data(gc);
315	struct pca955x_led *led = &pca955x->leds[offset];
316
317	if (led->type == PCA955X_TYPE_GPIO)
318		return 0;
319
320	return -EBUSY;
321}
322
323static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
324			     int val)
325{
326	struct pca955x *pca955x = gpiochip_get_data(gc);
327	struct pca955x_led *led = &pca955x->leds[offset];
328
329	if (val)
330		return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);
331
332	return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW);
333}
334
335static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
336				   int val)
337{
338	pca955x_set_value(gc, offset, val);
339}
340
341static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
342{
343	struct pca955x *pca955x = gpiochip_get_data(gc);
344	struct pca955x_led *led = &pca955x->leds[offset];
345	u8 reg = 0;
346
347	/* There is nothing we can do about errors */
348	pca955x_read_input(pca955x->client, led->led_num / 8, &reg);
349
350	return !!(reg & (1 << (led->led_num % 8)));
351}
352
353static int pca955x_gpio_direction_input(struct gpio_chip *gc,
354					unsigned int offset)
355{
356	struct pca955x *pca955x = gpiochip_get_data(gc);
357	struct pca955x_led *led = &pca955x->leds[offset];
358
359	/* To use as input ensure pin is not driven. */
360	return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
361}
362
363static int pca955x_gpio_direction_output(struct gpio_chip *gc,
364					 unsigned int offset, int val)
365{
366	return pca955x_set_value(gc, offset, val);
367}
368#endif /* CONFIG_LEDS_PCA955X_GPIO */
369
370static struct pca955x_platform_data *
371pca955x_get_pdata(struct i2c_client *client, struct pca955x_chipdef *chip)
372{
373	struct pca955x_platform_data *pdata;
374	struct fwnode_handle *child;
375	int count;
376
377	count = device_get_child_node_count(&client->dev);
378	if (!count || count > chip->bits)
379		return ERR_PTR(-ENODEV);
380
381	pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
382	if (!pdata)
383		return ERR_PTR(-ENOMEM);
384
385	pdata->leds = devm_kcalloc(&client->dev,
386				   chip->bits, sizeof(struct pca955x_led),
387				   GFP_KERNEL);
388	if (!pdata->leds)
389		return ERR_PTR(-ENOMEM);
390
391	device_for_each_child_node(&client->dev, child) {
392		const char *name;
393		u32 reg;
394		int res;
395
396		res = fwnode_property_read_u32(child, "reg", &reg);
397		if ((res != 0) || (reg >= chip->bits))
398			continue;
399
400		res = fwnode_property_read_string(child, "label", &name);
401		if ((res != 0) && is_of_node(child))
402			name = to_of_node(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		fwnode_property_read_u32(child, "type", &pdata->leds[reg].type);
409		fwnode_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
418static 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 = "ibm,pca9552", .data = (void *)ibm_pca9552 },
423	{ .compatible = "nxp,pca9553", .data = (void *)pca9553 },
424	{},
425};
426MODULE_DEVICE_TABLE(of, of_pca955x_match);
427
428static int pca955x_probe(struct i2c_client *client,
429					const struct i2c_device_id *id)
430{
431	struct pca955x *pca955x;
432	struct pca955x_led *pca955x_led;
433	struct pca955x_chipdef *chip;
434	struct i2c_adapter *adapter;
435	int i, err;
436	struct pca955x_platform_data *pdata;
437	int ngpios = 0;
438
439	chip = &pca955x_chipdefs[id->driver_data];
440	adapter = client->adapter;
441	pdata = dev_get_platdata(&client->dev);
442	if (!pdata) {
443		pdata =	pca955x_get_pdata(client, chip);
444		if (IS_ERR(pdata))
445			return PTR_ERR(pdata);
446	}
447
448	/* Make sure the slave address / chip type combo given is possible */
449	if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
450	    chip->slv_addr) {
451		dev_err(&client->dev, "invalid slave address %02x\n",
452				client->addr);
453		return -ENODEV;
454	}
455
456	dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
457			"slave address 0x%02x\n",
458			client->name, chip->bits, client->addr);
459
460	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
461		return -EIO;
462
463	if (pdata->num_leds != chip->bits) {
464		dev_err(&client->dev,
465			"board info claims %d LEDs on a %d-bit chip\n",
466			pdata->num_leds, chip->bits);
467		return -ENODEV;
468	}
469
470	pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
471	if (!pca955x)
472		return -ENOMEM;
473
474	pca955x->leds = devm_kcalloc(&client->dev,
475			chip->bits, sizeof(*pca955x_led), GFP_KERNEL);
476	if (!pca955x->leds)
477		return -ENOMEM;
478
479	i2c_set_clientdata(client, pca955x);
480
481	mutex_init(&pca955x->lock);
482	pca955x->client = client;
483	pca955x->chipdef = chip;
484
485	for (i = 0; i < chip->bits; i++) {
486		pca955x_led = &pca955x->leds[i];
487		pca955x_led->led_num = i;
488		pca955x_led->pca955x = pca955x;
489		pca955x_led->type = pdata->leds[i].type;
490
491		switch (pca955x_led->type) {
492		case PCA955X_TYPE_NONE:
493			break;
494		case PCA955X_TYPE_GPIO:
495			ngpios++;
496			break;
497		case PCA955X_TYPE_LED:
498			/*
499			 * Platform data can specify LED names and
500			 * default triggers
501			 */
502			if (pdata->leds[i].name[0] == '\0')
503				snprintf(pdata->leds[i].name,
504					sizeof(pdata->leds[i].name), "%d", i);
505
506			snprintf(pca955x_led->name,
507				sizeof(pca955x_led->name), "pca955x:%s",
508				pdata->leds[i].name);
509
510			if (pdata->leds[i].default_trigger)
511				pca955x_led->led_cdev.default_trigger =
512					pdata->leds[i].default_trigger;
513
514			pca955x_led->led_cdev.name = pca955x_led->name;
515			pca955x_led->led_cdev.brightness_set_blocking =
516				pca955x_led_set;
517
518			err = devm_led_classdev_register(&client->dev,
519							&pca955x_led->led_cdev);
520			if (err)
521				return err;
522
523			/* Turn off LED */
524			err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
525			if (err)
526				return err;
527		}
528	}
529
530	/* PWM0 is used for half brightness or 50% duty cycle */
531	err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
532	if (err)
533		return err;
534
535	/* PWM1 is used for variable brightness, default to OFF */
536	err = pca955x_write_pwm(client, 1, 0);
537	if (err)
538		return err;
539
540	/* Set to fast frequency so we do not see flashing */
541	err = pca955x_write_psc(client, 0, 0);
542	if (err)
543		return err;
544	err = pca955x_write_psc(client, 1, 0);
545	if (err)
546		return err;
547
548#ifdef CONFIG_LEDS_PCA955X_GPIO
549	if (ngpios) {
550		pca955x->gpio.label = "gpio-pca955x";
551		pca955x->gpio.direction_input = pca955x_gpio_direction_input;
552		pca955x->gpio.direction_output = pca955x_gpio_direction_output;
553		pca955x->gpio.set = pca955x_gpio_set_value;
554		pca955x->gpio.get = pca955x_gpio_get_value;
555		pca955x->gpio.request = pca955x_gpio_request_pin;
556		pca955x->gpio.can_sleep = 1;
557		pca955x->gpio.base = -1;
558		pca955x->gpio.ngpio = ngpios;
559		pca955x->gpio.parent = &client->dev;
560		pca955x->gpio.owner = THIS_MODULE;
561
562		err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
563					     pca955x);
564		if (err) {
565			/* Use data->gpio.dev as a flag for freeing gpiochip */
566			pca955x->gpio.parent = NULL;
567			dev_warn(&client->dev, "could not add gpiochip\n");
568			return err;
569		}
570		dev_info(&client->dev, "gpios %i...%i\n",
571			 pca955x->gpio.base, pca955x->gpio.base +
572			 pca955x->gpio.ngpio - 1);
573	}
574#endif
575
576	return 0;
577}
578
579static struct i2c_driver pca955x_driver = {
580	.driver = {
581		.name	= "leds-pca955x",
582		.of_match_table = of_pca955x_match,
583	},
584	.probe	= pca955x_probe,
585	.id_table = pca955x_id,
586};
587
588module_i2c_driver(pca955x_driver);
589
590MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
591MODULE_DESCRIPTION("PCA955x LED driver");
592MODULE_LICENSE("GPL v2");
593