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/bitops.h>
41 #include <linux/ctype.h>
42 #include <linux/delay.h>
43 #include <linux/err.h>
44 #include <linux/gpio/driver.h>
45 #include <linux/i2c.h>
46 #include <linux/leds.h>
47 #include <linux/module.h>
48 #include <linux/of.h>
49 #include <linux/property.h>
50 #include <linux/slab.h>
51 #include <linux/string.h>
52 
53 #include <dt-bindings/leds/leds-pca955x.h>
54 
55 /* LED select registers determine the source that drives LED outputs */
56 #define PCA955X_LS_LED_ON	0x0	/* Output LOW */
57 #define PCA955X_LS_LED_OFF	0x1	/* Output HI-Z */
58 #define PCA955X_LS_BLINK0	0x2	/* Blink at PWM0 rate */
59 #define PCA955X_LS_BLINK1	0x3	/* Blink at PWM1 rate */
60 
61 #define PCA955X_GPIO_INPUT	LED_OFF
62 #define PCA955X_GPIO_HIGH	LED_OFF
63 #define PCA955X_GPIO_LOW	LED_FULL
64 
65 enum pca955x_type {
66 	pca9550,
67 	pca9551,
68 	pca9552,
69 	ibm_pca9552,
70 	pca9553,
71 };
72 
73 struct pca955x_chipdef {
74 	int			bits;
75 	u8			slv_addr;	/* 7-bit slave address mask */
76 	int			slv_addr_shift;	/* Number of bits to ignore */
77 };
78 
79 static struct pca955x_chipdef pca955x_chipdefs[] = {
80 	[pca9550] = {
81 		.bits		= 2,
82 		.slv_addr	= /* 110000x */ 0x60,
83 		.slv_addr_shift	= 1,
84 	},
85 	[pca9551] = {
86 		.bits		= 8,
87 		.slv_addr	= /* 1100xxx */ 0x60,
88 		.slv_addr_shift	= 3,
89 	},
90 	[pca9552] = {
91 		.bits		= 16,
92 		.slv_addr	= /* 1100xxx */ 0x60,
93 		.slv_addr_shift	= 3,
94 	},
95 	[ibm_pca9552] = {
96 		.bits		= 16,
97 		.slv_addr	= /* 0110xxx */ 0x30,
98 		.slv_addr_shift	= 3,
99 	},
100 	[pca9553] = {
101 		.bits		= 4,
102 		.slv_addr	= /* 110001x */ 0x62,
103 		.slv_addr_shift	= 1,
104 	},
105 };
106 
107 static const struct i2c_device_id pca955x_id[] = {
108 	{ "pca9550", pca9550 },
109 	{ "pca9551", pca9551 },
110 	{ "pca9552", pca9552 },
111 	{ "ibm-pca9552", ibm_pca9552 },
112 	{ "pca9553", pca9553 },
113 	{ }
114 };
115 MODULE_DEVICE_TABLE(i2c, pca955x_id);
116 
117 struct pca955x {
118 	struct mutex lock;
119 	struct pca955x_led *leds;
120 	struct pca955x_chipdef	*chipdef;
121 	struct i2c_client	*client;
122 	unsigned long active_pins;
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 	u32			type;
133 	int			default_state;
134 	struct fwnode_handle	*fwnode;
135 };
136 
137 struct pca955x_platform_data {
138 	struct pca955x_led	*leds;
139 	int			num_leds;
140 };
141 
142 /* 8 bits per input register */
pca95xx_num_input_regs(int bits)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 */
pca95xx_num_led_regs(int bits)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  */
pca955x_ledsel(u8 oldval,int led_num,int state)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  */
pca955x_write_psc(struct i2c_client * client,int n,u8 val)168 static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
169 {
170 	struct pca955x *pca955x = i2c_get_clientdata(client);
171 	u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + (2 * n);
172 	int ret;
173 
174 	ret = i2c_smbus_write_byte_data(client, cmd, val);
175 	if (ret < 0)
176 		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
177 			__func__, n, val, ret);
178 	return ret;
179 }
180 
181 /*
182  * Write to PWM register, which determines the duty cycle of the
183  * output.  LED is OFF when the count is less than the value of this
184  * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
185  *
186  * Duty cycle is (256 - PWMx) / 256
187  */
pca955x_write_pwm(struct i2c_client * client,int n,u8 val)188 static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
189 {
190 	struct pca955x *pca955x = i2c_get_clientdata(client);
191 	u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + (2 * n);
192 	int ret;
193 
194 	ret = i2c_smbus_write_byte_data(client, cmd, 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  */
pca955x_write_ls(struct i2c_client * client,int n,u8 val)205 static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
206 {
207 	struct pca955x *pca955x = i2c_get_clientdata(client);
208 	u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n;
209 	int ret;
210 
211 	ret = i2c_smbus_write_byte_data(client, cmd, val);
212 	if (ret < 0)
213 		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
214 			__func__, n, val, ret);
215 	return ret;
216 }
217 
218 /*
219  * Read the LED selector register, which determines the source that
220  * drives the LED output.
221  */
pca955x_read_ls(struct i2c_client * client,int n,u8 * val)222 static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
223 {
224 	struct pca955x *pca955x = i2c_get_clientdata(client);
225 	u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n;
226 	int ret;
227 
228 	ret = i2c_smbus_read_byte_data(client, cmd);
229 	if (ret < 0) {
230 		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
231 			__func__, n, ret);
232 		return ret;
233 	}
234 	*val = (u8)ret;
235 	return 0;
236 }
237 
pca955x_read_pwm(struct i2c_client * client,int n,u8 * val)238 static int pca955x_read_pwm(struct i2c_client *client, int n, u8 *val)
239 {
240 	struct pca955x *pca955x = i2c_get_clientdata(client);
241 	u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + (2 * n);
242 	int ret;
243 
244 	ret = i2c_smbus_read_byte_data(client, cmd);
245 	if (ret < 0) {
246 		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
247 			__func__, n, ret);
248 		return ret;
249 	}
250 	*val = (u8)ret;
251 	return 0;
252 }
253 
pca955x_led_get(struct led_classdev * led_cdev)254 static enum led_brightness pca955x_led_get(struct led_classdev *led_cdev)
255 {
256 	struct pca955x_led *pca955x_led = container_of(led_cdev,
257 						       struct pca955x_led,
258 						       led_cdev);
259 	struct pca955x *pca955x = pca955x_led->pca955x;
260 	u8 ls, pwm;
261 	int ret;
262 
263 	ret = pca955x_read_ls(pca955x->client, pca955x_led->led_num / 4, &ls);
264 	if (ret)
265 		return ret;
266 
267 	ls = (ls >> ((pca955x_led->led_num % 4) << 1)) & 0x3;
268 	switch (ls) {
269 	case PCA955X_LS_LED_ON:
270 		ret = LED_FULL;
271 		break;
272 	case PCA955X_LS_LED_OFF:
273 		ret = LED_OFF;
274 		break;
275 	case PCA955X_LS_BLINK0:
276 		ret = LED_HALF;
277 		break;
278 	case PCA955X_LS_BLINK1:
279 		ret = pca955x_read_pwm(pca955x->client, 1, &pwm);
280 		if (ret)
281 			return ret;
282 		ret = 255 - pwm;
283 		break;
284 	}
285 
286 	return ret;
287 }
288 
pca955x_led_set(struct led_classdev * led_cdev,enum led_brightness value)289 static int pca955x_led_set(struct led_classdev *led_cdev,
290 			    enum led_brightness value)
291 {
292 	struct pca955x_led *pca955x_led;
293 	struct pca955x *pca955x;
294 	u8 ls;
295 	int chip_ls;	/* which LSx to use (0-3 potentially) */
296 	int ls_led;	/* which set of bits within LSx to use (0-3) */
297 	int ret;
298 
299 	pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
300 	pca955x = pca955x_led->pca955x;
301 
302 	chip_ls = pca955x_led->led_num / 4;
303 	ls_led = pca955x_led->led_num % 4;
304 
305 	mutex_lock(&pca955x->lock);
306 
307 	ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
308 	if (ret)
309 		goto out;
310 
311 	switch (value) {
312 	case LED_FULL:
313 		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
314 		break;
315 	case LED_OFF:
316 		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
317 		break;
318 	case LED_HALF:
319 		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
320 		break;
321 	default:
322 		/*
323 		 * Use PWM1 for all other values.  This has the unwanted
324 		 * side effect of making all LEDs on the chip share the
325 		 * same brightness level if set to a value other than
326 		 * OFF, HALF, or FULL.  But, this is probably better than
327 		 * just turning off for all other values.
328 		 */
329 		ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
330 		if (ret)
331 			goto out;
332 		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
333 		break;
334 	}
335 
336 	ret = pca955x_write_ls(pca955x->client, chip_ls, ls);
337 
338 out:
339 	mutex_unlock(&pca955x->lock);
340 
341 	return ret;
342 }
343 
344 #ifdef CONFIG_LEDS_PCA955X_GPIO
345 /*
346  * Read the INPUT register, which contains the state of LEDs.
347  */
pca955x_read_input(struct i2c_client * client,int n,u8 * val)348 static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
349 {
350 	int ret = i2c_smbus_read_byte_data(client, n);
351 
352 	if (ret < 0) {
353 		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
354 			__func__, n, ret);
355 		return ret;
356 	}
357 	*val = (u8)ret;
358 	return 0;
359 
360 }
361 
pca955x_gpio_request_pin(struct gpio_chip * gc,unsigned int offset)362 static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
363 {
364 	struct pca955x *pca955x = gpiochip_get_data(gc);
365 
366 	return test_and_set_bit(offset, &pca955x->active_pins) ? -EBUSY : 0;
367 }
368 
pca955x_gpio_free_pin(struct gpio_chip * gc,unsigned int offset)369 static void pca955x_gpio_free_pin(struct gpio_chip *gc, unsigned int offset)
370 {
371 	struct pca955x *pca955x = gpiochip_get_data(gc);
372 
373 	clear_bit(offset, &pca955x->active_pins);
374 }
375 
pca955x_set_value(struct gpio_chip * gc,unsigned int offset,int val)376 static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
377 			     int val)
378 {
379 	struct pca955x *pca955x = gpiochip_get_data(gc);
380 	struct pca955x_led *led = &pca955x->leds[offset];
381 
382 	if (val)
383 		return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);
384 
385 	return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW);
386 }
387 
pca955x_gpio_set_value(struct gpio_chip * gc,unsigned int offset,int val)388 static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
389 				   int val)
390 {
391 	pca955x_set_value(gc, offset, val);
392 }
393 
pca955x_gpio_get_value(struct gpio_chip * gc,unsigned int offset)394 static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
395 {
396 	struct pca955x *pca955x = gpiochip_get_data(gc);
397 	struct pca955x_led *led = &pca955x->leds[offset];
398 	u8 reg = 0;
399 
400 	/* There is nothing we can do about errors */
401 	pca955x_read_input(pca955x->client, led->led_num / 8, &reg);
402 
403 	return !!(reg & (1 << (led->led_num % 8)));
404 }
405 
pca955x_gpio_direction_input(struct gpio_chip * gc,unsigned int offset)406 static int pca955x_gpio_direction_input(struct gpio_chip *gc,
407 					unsigned int offset)
408 {
409 	struct pca955x *pca955x = gpiochip_get_data(gc);
410 	struct pca955x_led *led = &pca955x->leds[offset];
411 
412 	/* To use as input ensure pin is not driven. */
413 	return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
414 }
415 
pca955x_gpio_direction_output(struct gpio_chip * gc,unsigned int offset,int val)416 static int pca955x_gpio_direction_output(struct gpio_chip *gc,
417 					 unsigned int offset, int val)
418 {
419 	return pca955x_set_value(gc, offset, val);
420 }
421 #endif /* CONFIG_LEDS_PCA955X_GPIO */
422 
423 static struct pca955x_platform_data *
pca955x_get_pdata(struct i2c_client * client,struct pca955x_chipdef * chip)424 pca955x_get_pdata(struct i2c_client *client, struct pca955x_chipdef *chip)
425 {
426 	struct pca955x_platform_data *pdata;
427 	struct pca955x_led *led;
428 	struct fwnode_handle *child;
429 	int count;
430 
431 	count = device_get_child_node_count(&client->dev);
432 	if (count > chip->bits)
433 		return ERR_PTR(-ENODEV);
434 
435 	pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
436 	if (!pdata)
437 		return ERR_PTR(-ENOMEM);
438 
439 	pdata->leds = devm_kcalloc(&client->dev,
440 				   chip->bits, sizeof(struct pca955x_led),
441 				   GFP_KERNEL);
442 	if (!pdata->leds)
443 		return ERR_PTR(-ENOMEM);
444 
445 	device_for_each_child_node(&client->dev, child) {
446 		const char *state;
447 		u32 reg;
448 		int res;
449 
450 		res = fwnode_property_read_u32(child, "reg", &reg);
451 		if ((res != 0) || (reg >= chip->bits))
452 			continue;
453 
454 		led = &pdata->leds[reg];
455 		led->type = PCA955X_TYPE_LED;
456 		led->fwnode = child;
457 		fwnode_property_read_u32(child, "type", &led->type);
458 
459 		if (!fwnode_property_read_string(child, "default-state",
460 						 &state)) {
461 			if (!strcmp(state, "keep"))
462 				led->default_state = LEDS_GPIO_DEFSTATE_KEEP;
463 			else if (!strcmp(state, "on"))
464 				led->default_state = LEDS_GPIO_DEFSTATE_ON;
465 			else
466 				led->default_state = LEDS_GPIO_DEFSTATE_OFF;
467 		} else {
468 			led->default_state = LEDS_GPIO_DEFSTATE_OFF;
469 		}
470 	}
471 
472 	pdata->num_leds = chip->bits;
473 
474 	return pdata;
475 }
476 
477 static const struct of_device_id of_pca955x_match[] = {
478 	{ .compatible = "nxp,pca9550", .data = (void *)pca9550 },
479 	{ .compatible = "nxp,pca9551", .data = (void *)pca9551 },
480 	{ .compatible = "nxp,pca9552", .data = (void *)pca9552 },
481 	{ .compatible = "ibm,pca9552", .data = (void *)ibm_pca9552 },
482 	{ .compatible = "nxp,pca9553", .data = (void *)pca9553 },
483 	{},
484 };
485 MODULE_DEVICE_TABLE(of, of_pca955x_match);
486 
pca955x_probe(struct i2c_client * client)487 static int pca955x_probe(struct i2c_client *client)
488 {
489 	struct pca955x *pca955x;
490 	struct pca955x_led *pca955x_led;
491 	struct pca955x_chipdef *chip;
492 	struct led_classdev *led;
493 	struct led_init_data init_data;
494 	struct i2c_adapter *adapter;
495 	int i, err;
496 	struct pca955x_platform_data *pdata;
497 	bool set_default_label = false;
498 	bool keep_pwm = false;
499 	char default_label[8];
500 	enum pca955x_type chip_type;
501 	const void *md = device_get_match_data(&client->dev);
502 
503 	if (md) {
504 		chip_type = (enum pca955x_type)md;
505 	} else {
506 		const struct i2c_device_id *id = i2c_match_id(pca955x_id,
507 							      client);
508 
509 		if (id) {
510 			chip_type = (enum pca955x_type)id->driver_data;
511 		} else {
512 			dev_err(&client->dev, "unknown chip\n");
513 			return -ENODEV;
514 		}
515 	}
516 
517 	chip = &pca955x_chipdefs[chip_type];
518 	adapter = client->adapter;
519 	pdata = dev_get_platdata(&client->dev);
520 	if (!pdata) {
521 		pdata =	pca955x_get_pdata(client, chip);
522 		if (IS_ERR(pdata))
523 			return PTR_ERR(pdata);
524 	}
525 
526 	/* Make sure the slave address / chip type combo given is possible */
527 	if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
528 	    chip->slv_addr) {
529 		dev_err(&client->dev, "invalid slave address %02x\n",
530 			client->addr);
531 		return -ENODEV;
532 	}
533 
534 	dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
535 		 "slave address 0x%02x\n", client->name, chip->bits,
536 		 client->addr);
537 
538 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
539 		return -EIO;
540 
541 	if (pdata->num_leds != chip->bits) {
542 		dev_err(&client->dev,
543 			"board info claims %d LEDs on a %d-bit chip\n",
544 			pdata->num_leds, chip->bits);
545 		return -ENODEV;
546 	}
547 
548 	pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
549 	if (!pca955x)
550 		return -ENOMEM;
551 
552 	pca955x->leds = devm_kcalloc(&client->dev, chip->bits,
553 				     sizeof(*pca955x_led), GFP_KERNEL);
554 	if (!pca955x->leds)
555 		return -ENOMEM;
556 
557 	i2c_set_clientdata(client, pca955x);
558 
559 	mutex_init(&pca955x->lock);
560 	pca955x->client = client;
561 	pca955x->chipdef = chip;
562 
563 	init_data.devname_mandatory = false;
564 	init_data.devicename = "pca955x";
565 
566 	for (i = 0; i < chip->bits; i++) {
567 		pca955x_led = &pca955x->leds[i];
568 		pca955x_led->led_num = i;
569 		pca955x_led->pca955x = pca955x;
570 		pca955x_led->type = pdata->leds[i].type;
571 
572 		switch (pca955x_led->type) {
573 		case PCA955X_TYPE_NONE:
574 		case PCA955X_TYPE_GPIO:
575 			break;
576 		case PCA955X_TYPE_LED:
577 			led = &pca955x_led->led_cdev;
578 			led->brightness_set_blocking = pca955x_led_set;
579 			led->brightness_get = pca955x_led_get;
580 
581 			if (pdata->leds[i].default_state ==
582 			    LEDS_GPIO_DEFSTATE_OFF) {
583 				err = pca955x_led_set(led, LED_OFF);
584 				if (err)
585 					return err;
586 			} else if (pdata->leds[i].default_state ==
587 				   LEDS_GPIO_DEFSTATE_ON) {
588 				err = pca955x_led_set(led, LED_FULL);
589 				if (err)
590 					return err;
591 			}
592 
593 			init_data.fwnode = pdata->leds[i].fwnode;
594 
595 			if (is_of_node(init_data.fwnode)) {
596 				if (to_of_node(init_data.fwnode)->name[0] ==
597 				    '\0')
598 					set_default_label = true;
599 				else
600 					set_default_label = false;
601 			} else {
602 				set_default_label = true;
603 			}
604 
605 			if (set_default_label) {
606 				snprintf(default_label, sizeof(default_label),
607 					 "%d", i);
608 				init_data.default_label = default_label;
609 			} else {
610 				init_data.default_label = NULL;
611 			}
612 
613 			err = devm_led_classdev_register_ext(&client->dev, led,
614 							     &init_data);
615 			if (err)
616 				return err;
617 
618 			set_bit(i, &pca955x->active_pins);
619 
620 			/*
621 			 * For default-state == "keep", let the core update the
622 			 * brightness from the hardware, then check the
623 			 * brightness to see if it's using PWM1. If so, PWM1
624 			 * should not be written below.
625 			 */
626 			if (pdata->leds[i].default_state ==
627 			    LEDS_GPIO_DEFSTATE_KEEP) {
628 				if (led->brightness != LED_FULL &&
629 				    led->brightness != LED_OFF &&
630 				    led->brightness != LED_HALF)
631 					keep_pwm = true;
632 			}
633 		}
634 	}
635 
636 	/* PWM0 is used for half brightness or 50% duty cycle */
637 	err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
638 	if (err)
639 		return err;
640 
641 	if (!keep_pwm) {
642 		/* PWM1 is used for variable brightness, default to OFF */
643 		err = pca955x_write_pwm(client, 1, 0);
644 		if (err)
645 			return err;
646 	}
647 
648 	/* Set to fast frequency so we do not see flashing */
649 	err = pca955x_write_psc(client, 0, 0);
650 	if (err)
651 		return err;
652 	err = pca955x_write_psc(client, 1, 0);
653 	if (err)
654 		return err;
655 
656 #ifdef CONFIG_LEDS_PCA955X_GPIO
657 	pca955x->gpio.label = "gpio-pca955x";
658 	pca955x->gpio.direction_input = pca955x_gpio_direction_input;
659 	pca955x->gpio.direction_output = pca955x_gpio_direction_output;
660 	pca955x->gpio.set = pca955x_gpio_set_value;
661 	pca955x->gpio.get = pca955x_gpio_get_value;
662 	pca955x->gpio.request = pca955x_gpio_request_pin;
663 	pca955x->gpio.free = pca955x_gpio_free_pin;
664 	pca955x->gpio.can_sleep = 1;
665 	pca955x->gpio.base = -1;
666 	pca955x->gpio.ngpio = chip->bits;
667 	pca955x->gpio.parent = &client->dev;
668 	pca955x->gpio.owner = THIS_MODULE;
669 
670 	err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
671 				     pca955x);
672 	if (err) {
673 		/* Use data->gpio.dev as a flag for freeing gpiochip */
674 		pca955x->gpio.parent = NULL;
675 		dev_warn(&client->dev, "could not add gpiochip\n");
676 		return err;
677 	}
678 	dev_info(&client->dev, "gpios %i...%i\n",
679 		 pca955x->gpio.base, pca955x->gpio.base +
680 		 pca955x->gpio.ngpio - 1);
681 #endif
682 
683 	return 0;
684 }
685 
686 static struct i2c_driver pca955x_driver = {
687 	.driver = {
688 		.name	= "leds-pca955x",
689 		.of_match_table = of_pca955x_match,
690 	},
691 	.probe_new = pca955x_probe,
692 	.id_table = pca955x_id,
693 };
694 
695 module_i2c_driver(pca955x_driver);
696 
697 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
698 MODULE_DESCRIPTION("PCA955x LED driver");
699 MODULE_LICENSE("GPL v2");
700