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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
65enum pca955x_type {
66 pca9550,
67 pca9551,
68 pca9552,
69 ibm_pca9552,
70 pca9553,
71};
72
73struct 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
79static 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
107static 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};
115MODULE_DEVICE_TABLE(i2c, pca955x_id);
116
117struct 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
128struct 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
137struct pca955x_platform_data {
138 struct pca955x_led *leds;
139 int num_leds;
140};
141
142/* 8 bits per input register */
143static inline int pca95xx_num_input_regs(int bits)
144{
145 return (bits + 7) / 8;
146}
147
148/*
149 * Return an LED selector register value based on an existing one, with
150 * the appropriate 2-bit state value set for the given LED number (0-3).
151 */
152static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
153{
154 return (oldval & (~(0x3 << (led_num << 1)))) |
155 ((state & 0x3) << (led_num << 1));
156}
157
158/*
159 * Write to frequency prescaler register, used to program the
160 * period of the PWM output. period = (PSCx + 1) / 38
161 */
162static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
163{
164 struct pca955x *pca955x = i2c_get_clientdata(client);
165 u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + (2 * n);
166 int ret;
167
168 ret = i2c_smbus_write_byte_data(client, cmd, val);
169 if (ret < 0)
170 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
171 __func__, n, val, ret);
172 return ret;
173}
174
175/*
176 * Write to PWM register, which determines the duty cycle of the
177 * output. LED is OFF when the count is less than the value of this
178 * register, and ON when it is greater. If PWMx == 0, LED is always OFF.
179 *
180 * Duty cycle is (256 - PWMx) / 256
181 */
182static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
183{
184 struct pca955x *pca955x = i2c_get_clientdata(client);
185 u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + (2 * n);
186 int ret;
187
188 ret = i2c_smbus_write_byte_data(client, cmd, val);
189 if (ret < 0)
190 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
191 __func__, n, val, ret);
192 return ret;
193}
194
195/*
196 * Write to LED selector register, which determines the source that
197 * drives the LED output.
198 */
199static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
200{
201 struct pca955x *pca955x = i2c_get_clientdata(client);
202 u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n;
203 int ret;
204
205 ret = i2c_smbus_write_byte_data(client, cmd, val);
206 if (ret < 0)
207 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
208 __func__, n, val, ret);
209 return ret;
210}
211
212/*
213 * Read the LED selector register, which determines the source that
214 * drives the LED output.
215 */
216static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
217{
218 struct pca955x *pca955x = i2c_get_clientdata(client);
219 u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n;
220 int ret;
221
222 ret = i2c_smbus_read_byte_data(client, cmd);
223 if (ret < 0) {
224 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
225 __func__, n, ret);
226 return ret;
227 }
228 *val = (u8)ret;
229 return 0;
230}
231
232static int pca955x_read_pwm(struct i2c_client *client, int n, u8 *val)
233{
234 struct pca955x *pca955x = i2c_get_clientdata(client);
235 u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + (2 * n);
236 int ret;
237
238 ret = i2c_smbus_read_byte_data(client, cmd);
239 if (ret < 0) {
240 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
241 __func__, n, ret);
242 return ret;
243 }
244 *val = (u8)ret;
245 return 0;
246}
247
248static enum led_brightness pca955x_led_get(struct led_classdev *led_cdev)
249{
250 struct pca955x_led *pca955x_led = container_of(led_cdev,
251 struct pca955x_led,
252 led_cdev);
253 struct pca955x *pca955x = pca955x_led->pca955x;
254 u8 ls, pwm;
255 int ret;
256
257 ret = pca955x_read_ls(pca955x->client, pca955x_led->led_num / 4, &ls);
258 if (ret)
259 return ret;
260
261 ls = (ls >> ((pca955x_led->led_num % 4) << 1)) & 0x3;
262 switch (ls) {
263 case PCA955X_LS_LED_ON:
264 ret = LED_FULL;
265 break;
266 case PCA955X_LS_LED_OFF:
267 ret = LED_OFF;
268 break;
269 case PCA955X_LS_BLINK0:
270 ret = LED_HALF;
271 break;
272 case PCA955X_LS_BLINK1:
273 ret = pca955x_read_pwm(pca955x->client, 1, &pwm);
274 if (ret)
275 return ret;
276 ret = 255 - pwm;
277 break;
278 }
279
280 return ret;
281}
282
283static int pca955x_led_set(struct led_classdev *led_cdev,
284 enum led_brightness value)
285{
286 struct pca955x_led *pca955x_led;
287 struct pca955x *pca955x;
288 u8 ls;
289 int chip_ls; /* which LSx to use (0-3 potentially) */
290 int ls_led; /* which set of bits within LSx to use (0-3) */
291 int ret;
292
293 pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
294 pca955x = pca955x_led->pca955x;
295
296 chip_ls = pca955x_led->led_num / 4;
297 ls_led = pca955x_led->led_num % 4;
298
299 mutex_lock(&pca955x->lock);
300
301 ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
302 if (ret)
303 goto out;
304
305 switch (value) {
306 case LED_FULL:
307 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
308 break;
309 case LED_OFF:
310 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
311 break;
312 case LED_HALF:
313 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
314 break;
315 default:
316 /*
317 * Use PWM1 for all other values. This has the unwanted
318 * side effect of making all LEDs on the chip share the
319 * same brightness level if set to a value other than
320 * OFF, HALF, or FULL. But, this is probably better than
321 * just turning off for all other values.
322 */
323 ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
324 if (ret)
325 goto out;
326 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
327 break;
328 }
329
330 ret = pca955x_write_ls(pca955x->client, chip_ls, ls);
331
332out:
333 mutex_unlock(&pca955x->lock);
334
335 return ret;
336}
337
338#ifdef CONFIG_LEDS_PCA955X_GPIO
339/*
340 * Read the INPUT register, which contains the state of LEDs.
341 */
342static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
343{
344 int ret = i2c_smbus_read_byte_data(client, n);
345
346 if (ret < 0) {
347 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
348 __func__, n, ret);
349 return ret;
350 }
351 *val = (u8)ret;
352 return 0;
353
354}
355
356static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
357{
358 struct pca955x *pca955x = gpiochip_get_data(gc);
359
360 return test_and_set_bit(offset, &pca955x->active_pins) ? -EBUSY : 0;
361}
362
363static void pca955x_gpio_free_pin(struct gpio_chip *gc, unsigned int offset)
364{
365 struct pca955x *pca955x = gpiochip_get_data(gc);
366
367 clear_bit(offset, &pca955x->active_pins);
368}
369
370static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
371 int val)
372{
373 struct pca955x *pca955x = gpiochip_get_data(gc);
374 struct pca955x_led *led = &pca955x->leds[offset];
375
376 if (val)
377 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);
378
379 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW);
380}
381
382static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
383 int val)
384{
385 pca955x_set_value(gc, offset, val);
386}
387
388static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
389{
390 struct pca955x *pca955x = gpiochip_get_data(gc);
391 struct pca955x_led *led = &pca955x->leds[offset];
392 u8 reg = 0;
393
394 /* There is nothing we can do about errors */
395 pca955x_read_input(pca955x->client, led->led_num / 8, ®);
396
397 return !!(reg & (1 << (led->led_num % 8)));
398}
399
400static int pca955x_gpio_direction_input(struct gpio_chip *gc,
401 unsigned int offset)
402{
403 struct pca955x *pca955x = gpiochip_get_data(gc);
404 struct pca955x_led *led = &pca955x->leds[offset];
405
406 /* To use as input ensure pin is not driven. */
407 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
408}
409
410static int pca955x_gpio_direction_output(struct gpio_chip *gc,
411 unsigned int offset, int val)
412{
413 return pca955x_set_value(gc, offset, val);
414}
415#endif /* CONFIG_LEDS_PCA955X_GPIO */
416
417static struct pca955x_platform_data *
418pca955x_get_pdata(struct i2c_client *client, struct pca955x_chipdef *chip)
419{
420 struct pca955x_platform_data *pdata;
421 struct pca955x_led *led;
422 struct fwnode_handle *child;
423 int count;
424
425 count = device_get_child_node_count(&client->dev);
426 if (count > chip->bits)
427 return ERR_PTR(-ENODEV);
428
429 pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
430 if (!pdata)
431 return ERR_PTR(-ENOMEM);
432
433 pdata->leds = devm_kcalloc(&client->dev,
434 chip->bits, sizeof(struct pca955x_led),
435 GFP_KERNEL);
436 if (!pdata->leds)
437 return ERR_PTR(-ENOMEM);
438
439 device_for_each_child_node(&client->dev, child) {
440 const char *state;
441 u32 reg;
442 int res;
443
444 res = fwnode_property_read_u32(child, "reg", ®);
445 if ((res != 0) || (reg >= chip->bits))
446 continue;
447
448 led = &pdata->leds[reg];
449 led->type = PCA955X_TYPE_LED;
450 led->fwnode = child;
451 fwnode_property_read_u32(child, "type", &led->type);
452
453 if (!fwnode_property_read_string(child, "default-state",
454 &state)) {
455 if (!strcmp(state, "keep"))
456 led->default_state = LEDS_GPIO_DEFSTATE_KEEP;
457 else if (!strcmp(state, "on"))
458 led->default_state = LEDS_GPIO_DEFSTATE_ON;
459 else
460 led->default_state = LEDS_GPIO_DEFSTATE_OFF;
461 } else {
462 led->default_state = LEDS_GPIO_DEFSTATE_OFF;
463 }
464 }
465
466 pdata->num_leds = chip->bits;
467
468 return pdata;
469}
470
471static const struct of_device_id of_pca955x_match[] = {
472 { .compatible = "nxp,pca9550", .data = (void *)pca9550 },
473 { .compatible = "nxp,pca9551", .data = (void *)pca9551 },
474 { .compatible = "nxp,pca9552", .data = (void *)pca9552 },
475 { .compatible = "ibm,pca9552", .data = (void *)ibm_pca9552 },
476 { .compatible = "nxp,pca9553", .data = (void *)pca9553 },
477 {},
478};
479MODULE_DEVICE_TABLE(of, of_pca955x_match);
480
481static int pca955x_probe(struct i2c_client *client)
482{
483 struct pca955x *pca955x;
484 struct pca955x_led *pca955x_led;
485 struct pca955x_chipdef *chip;
486 struct led_classdev *led;
487 struct led_init_data init_data;
488 struct i2c_adapter *adapter;
489 int i, err;
490 struct pca955x_platform_data *pdata;
491 bool set_default_label = false;
492 bool keep_pwm = false;
493 char default_label[8];
494 enum pca955x_type chip_type;
495 const void *md = device_get_match_data(&client->dev);
496
497 if (md) {
498 chip_type = (enum pca955x_type)md;
499 } else {
500 const struct i2c_device_id *id = i2c_match_id(pca955x_id,
501 client);
502
503 if (id) {
504 chip_type = (enum pca955x_type)id->driver_data;
505 } else {
506 dev_err(&client->dev, "unknown chip\n");
507 return -ENODEV;
508 }
509 }
510
511 chip = &pca955x_chipdefs[chip_type];
512 adapter = client->adapter;
513 pdata = dev_get_platdata(&client->dev);
514 if (!pdata) {
515 pdata = pca955x_get_pdata(client, chip);
516 if (IS_ERR(pdata))
517 return PTR_ERR(pdata);
518 }
519
520 /* Make sure the slave address / chip type combo given is possible */
521 if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
522 chip->slv_addr) {
523 dev_err(&client->dev, "invalid slave address %02x\n",
524 client->addr);
525 return -ENODEV;
526 }
527
528 dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
529 "slave address 0x%02x\n", client->name, chip->bits,
530 client->addr);
531
532 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
533 return -EIO;
534
535 if (pdata->num_leds != chip->bits) {
536 dev_err(&client->dev,
537 "board info claims %d LEDs on a %d-bit chip\n",
538 pdata->num_leds, chip->bits);
539 return -ENODEV;
540 }
541
542 pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
543 if (!pca955x)
544 return -ENOMEM;
545
546 pca955x->leds = devm_kcalloc(&client->dev, chip->bits,
547 sizeof(*pca955x_led), GFP_KERNEL);
548 if (!pca955x->leds)
549 return -ENOMEM;
550
551 i2c_set_clientdata(client, pca955x);
552
553 mutex_init(&pca955x->lock);
554 pca955x->client = client;
555 pca955x->chipdef = chip;
556
557 init_data.devname_mandatory = false;
558 init_data.devicename = "pca955x";
559
560 for (i = 0; i < chip->bits; i++) {
561 pca955x_led = &pca955x->leds[i];
562 pca955x_led->led_num = i;
563 pca955x_led->pca955x = pca955x;
564 pca955x_led->type = pdata->leds[i].type;
565
566 switch (pca955x_led->type) {
567 case PCA955X_TYPE_NONE:
568 case PCA955X_TYPE_GPIO:
569 break;
570 case PCA955X_TYPE_LED:
571 led = &pca955x_led->led_cdev;
572 led->brightness_set_blocking = pca955x_led_set;
573 led->brightness_get = pca955x_led_get;
574
575 if (pdata->leds[i].default_state ==
576 LEDS_GPIO_DEFSTATE_OFF) {
577 err = pca955x_led_set(led, LED_OFF);
578 if (err)
579 return err;
580 } else if (pdata->leds[i].default_state ==
581 LEDS_GPIO_DEFSTATE_ON) {
582 err = pca955x_led_set(led, LED_FULL);
583 if (err)
584 return err;
585 }
586
587 init_data.fwnode = pdata->leds[i].fwnode;
588
589 if (is_of_node(init_data.fwnode)) {
590 if (to_of_node(init_data.fwnode)->name[0] ==
591 '\0')
592 set_default_label = true;
593 else
594 set_default_label = false;
595 } else {
596 set_default_label = true;
597 }
598
599 if (set_default_label) {
600 snprintf(default_label, sizeof(default_label),
601 "%d", i);
602 init_data.default_label = default_label;
603 } else {
604 init_data.default_label = NULL;
605 }
606
607 err = devm_led_classdev_register_ext(&client->dev, led,
608 &init_data);
609 if (err)
610 return err;
611
612 set_bit(i, &pca955x->active_pins);
613
614 /*
615 * For default-state == "keep", let the core update the
616 * brightness from the hardware, then check the
617 * brightness to see if it's using PWM1. If so, PWM1
618 * should not be written below.
619 */
620 if (pdata->leds[i].default_state ==
621 LEDS_GPIO_DEFSTATE_KEEP) {
622 if (led->brightness != LED_FULL &&
623 led->brightness != LED_OFF &&
624 led->brightness != LED_HALF)
625 keep_pwm = true;
626 }
627 }
628 }
629
630 /* PWM0 is used for half brightness or 50% duty cycle */
631 err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
632 if (err)
633 return err;
634
635 if (!keep_pwm) {
636 /* PWM1 is used for variable brightness, default to OFF */
637 err = pca955x_write_pwm(client, 1, 0);
638 if (err)
639 return err;
640 }
641
642 /* Set to fast frequency so we do not see flashing */
643 err = pca955x_write_psc(client, 0, 0);
644 if (err)
645 return err;
646 err = pca955x_write_psc(client, 1, 0);
647 if (err)
648 return err;
649
650#ifdef CONFIG_LEDS_PCA955X_GPIO
651 pca955x->gpio.label = "gpio-pca955x";
652 pca955x->gpio.direction_input = pca955x_gpio_direction_input;
653 pca955x->gpio.direction_output = pca955x_gpio_direction_output;
654 pca955x->gpio.set = pca955x_gpio_set_value;
655 pca955x->gpio.get = pca955x_gpio_get_value;
656 pca955x->gpio.request = pca955x_gpio_request_pin;
657 pca955x->gpio.free = pca955x_gpio_free_pin;
658 pca955x->gpio.can_sleep = 1;
659 pca955x->gpio.base = -1;
660 pca955x->gpio.ngpio = chip->bits;
661 pca955x->gpio.parent = &client->dev;
662 pca955x->gpio.owner = THIS_MODULE;
663
664 err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
665 pca955x);
666 if (err) {
667 /* Use data->gpio.dev as a flag for freeing gpiochip */
668 pca955x->gpio.parent = NULL;
669 dev_warn(&client->dev, "could not add gpiochip\n");
670 return err;
671 }
672 dev_info(&client->dev, "gpios %i...%i\n",
673 pca955x->gpio.base, pca955x->gpio.base +
674 pca955x->gpio.ngpio - 1);
675#endif
676
677 return 0;
678}
679
680static struct i2c_driver pca955x_driver = {
681 .driver = {
682 .name = "leds-pca955x",
683 .of_match_table = of_pca955x_match,
684 },
685 .probe_new = pca955x_probe,
686 .id_table = pca955x_id,
687};
688
689module_i2c_driver(pca955x_driver);
690
691MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
692MODULE_DESCRIPTION("PCA955x LED driver");
693MODULE_LICENSE("GPL v2");
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/module.h>
44#include <linux/delay.h>
45#include <linux/string.h>
46#include <linux/ctype.h>
47#include <linux/leds.h>
48#include <linux/err.h>
49#include <linux/i2c.h>
50#include <linux/slab.h>
51
52/* LED select registers determine the source that drives LED outputs */
53#define PCA955X_LS_LED_ON 0x0 /* Output LOW */
54#define PCA955X_LS_LED_OFF 0x1 /* Output HI-Z */
55#define PCA955X_LS_BLINK0 0x2 /* Blink at PWM0 rate */
56#define PCA955X_LS_BLINK1 0x3 /* Blink at PWM1 rate */
57
58enum pca955x_type {
59 pca9550,
60 pca9551,
61 pca9552,
62 pca9553,
63};
64
65struct pca955x_chipdef {
66 int bits;
67 u8 slv_addr; /* 7-bit slave address mask */
68 int slv_addr_shift; /* Number of bits to ignore */
69};
70
71static struct pca955x_chipdef pca955x_chipdefs[] = {
72 [pca9550] = {
73 .bits = 2,
74 .slv_addr = /* 110000x */ 0x60,
75 .slv_addr_shift = 1,
76 },
77 [pca9551] = {
78 .bits = 8,
79 .slv_addr = /* 1100xxx */ 0x60,
80 .slv_addr_shift = 3,
81 },
82 [pca9552] = {
83 .bits = 16,
84 .slv_addr = /* 1100xxx */ 0x60,
85 .slv_addr_shift = 3,
86 },
87 [pca9553] = {
88 .bits = 4,
89 .slv_addr = /* 110001x */ 0x62,
90 .slv_addr_shift = 1,
91 },
92};
93
94static const struct i2c_device_id pca955x_id[] = {
95 { "pca9550", pca9550 },
96 { "pca9551", pca9551 },
97 { "pca9552", pca9552 },
98 { "pca9553", pca9553 },
99 { }
100};
101MODULE_DEVICE_TABLE(i2c, pca955x_id);
102
103struct pca955x {
104 struct mutex lock;
105 struct pca955x_led *leds;
106 struct pca955x_chipdef *chipdef;
107 struct i2c_client *client;
108};
109
110struct pca955x_led {
111 struct pca955x *pca955x;
112 struct led_classdev led_cdev;
113 int led_num; /* 0 .. 15 potentially */
114 char name[32];
115};
116
117/* 8 bits per input register */
118static inline int pca95xx_num_input_regs(int bits)
119{
120 return (bits + 7) / 8;
121}
122
123/* 4 bits per LED selector register */
124static inline int pca95xx_num_led_regs(int bits)
125{
126 return (bits + 3) / 4;
127}
128
129/*
130 * Return an LED selector register value based on an existing one, with
131 * the appropriate 2-bit state value set for the given LED number (0-3).
132 */
133static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
134{
135 return (oldval & (~(0x3 << (led_num << 1)))) |
136 ((state & 0x3) << (led_num << 1));
137}
138
139/*
140 * Write to frequency prescaler register, used to program the
141 * period of the PWM output. period = (PSCx + 1) / 38
142 */
143static void pca955x_write_psc(struct i2c_client *client, int n, u8 val)
144{
145 struct pca955x *pca955x = i2c_get_clientdata(client);
146
147 i2c_smbus_write_byte_data(client,
148 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
149 val);
150}
151
152/*
153 * Write to PWM register, which determines the duty cycle of the
154 * output. LED is OFF when the count is less than the value of this
155 * register, and ON when it is greater. If PWMx == 0, LED is always OFF.
156 *
157 * Duty cycle is (256 - PWMx) / 256
158 */
159static void pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
160{
161 struct pca955x *pca955x = i2c_get_clientdata(client);
162
163 i2c_smbus_write_byte_data(client,
164 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
165 val);
166}
167
168/*
169 * Write to LED selector register, which determines the source that
170 * drives the LED output.
171 */
172static void pca955x_write_ls(struct i2c_client *client, int n, u8 val)
173{
174 struct pca955x *pca955x = i2c_get_clientdata(client);
175
176 i2c_smbus_write_byte_data(client,
177 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
178 val);
179}
180
181/*
182 * Read the LED selector register, which determines the source that
183 * drives the LED output.
184 */
185static u8 pca955x_read_ls(struct i2c_client *client, int n)
186{
187 struct pca955x *pca955x = i2c_get_clientdata(client);
188
189 return (u8) i2c_smbus_read_byte_data(client,
190 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
191}
192
193static int pca955x_led_set(struct led_classdev *led_cdev,
194 enum led_brightness value)
195{
196 struct pca955x_led *pca955x_led;
197 struct pca955x *pca955x;
198 u8 ls;
199 int chip_ls; /* which LSx to use (0-3 potentially) */
200 int ls_led; /* which set of bits within LSx to use (0-3) */
201
202 pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
203 pca955x = pca955x_led->pca955x;
204
205 chip_ls = pca955x_led->led_num / 4;
206 ls_led = pca955x_led->led_num % 4;
207
208 mutex_lock(&pca955x->lock);
209
210 ls = pca955x_read_ls(pca955x->client, chip_ls);
211
212 switch (value) {
213 case LED_FULL:
214 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
215 break;
216 case LED_OFF:
217 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
218 break;
219 case LED_HALF:
220 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
221 break;
222 default:
223 /*
224 * Use PWM1 for all other values. This has the unwanted
225 * side effect of making all LEDs on the chip share the
226 * same brightness level if set to a value other than
227 * OFF, HALF, or FULL. But, this is probably better than
228 * just turning off for all other values.
229 */
230 pca955x_write_pwm(pca955x->client, 1,
231 255 - value);
232 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
233 break;
234 }
235
236 pca955x_write_ls(pca955x->client, chip_ls, ls);
237
238 mutex_unlock(&pca955x->lock);
239
240 return 0;
241}
242
243static int pca955x_probe(struct i2c_client *client,
244 const struct i2c_device_id *id)
245{
246 struct pca955x *pca955x;
247 struct pca955x_led *pca955x_led;
248 struct pca955x_chipdef *chip;
249 struct i2c_adapter *adapter;
250 struct led_platform_data *pdata;
251 int i, err;
252
253 chip = &pca955x_chipdefs[id->driver_data];
254 adapter = to_i2c_adapter(client->dev.parent);
255 pdata = dev_get_platdata(&client->dev);
256
257 /* Make sure the slave address / chip type combo given is possible */
258 if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
259 chip->slv_addr) {
260 dev_err(&client->dev, "invalid slave address %02x\n",
261 client->addr);
262 return -ENODEV;
263 }
264
265 dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
266 "slave address 0x%02x\n",
267 id->name, chip->bits, client->addr);
268
269 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
270 return -EIO;
271
272 if (pdata) {
273 if (pdata->num_leds != chip->bits) {
274 dev_err(&client->dev, "board info claims %d LEDs"
275 " on a %d-bit chip\n",
276 pdata->num_leds, chip->bits);
277 return -ENODEV;
278 }
279 }
280
281 pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
282 if (!pca955x)
283 return -ENOMEM;
284
285 pca955x->leds = devm_kzalloc(&client->dev,
286 sizeof(*pca955x_led) * chip->bits, GFP_KERNEL);
287 if (!pca955x->leds)
288 return -ENOMEM;
289
290 i2c_set_clientdata(client, pca955x);
291
292 mutex_init(&pca955x->lock);
293 pca955x->client = client;
294 pca955x->chipdef = chip;
295
296 for (i = 0; i < chip->bits; i++) {
297 pca955x_led = &pca955x->leds[i];
298 pca955x_led->led_num = i;
299 pca955x_led->pca955x = pca955x;
300
301 /* Platform data can specify LED names and default triggers */
302 if (pdata) {
303 if (pdata->leds[i].name)
304 snprintf(pca955x_led->name,
305 sizeof(pca955x_led->name), "pca955x:%s",
306 pdata->leds[i].name);
307 if (pdata->leds[i].default_trigger)
308 pca955x_led->led_cdev.default_trigger =
309 pdata->leds[i].default_trigger;
310 } else {
311 snprintf(pca955x_led->name, sizeof(pca955x_led->name),
312 "pca955x:%d", i);
313 }
314
315 pca955x_led->led_cdev.name = pca955x_led->name;
316 pca955x_led->led_cdev.brightness_set_blocking = pca955x_led_set;
317
318 err = led_classdev_register(&client->dev,
319 &pca955x_led->led_cdev);
320 if (err < 0)
321 goto exit;
322 }
323
324 /* Turn off LEDs */
325 for (i = 0; i < pca95xx_num_led_regs(chip->bits); i++)
326 pca955x_write_ls(client, i, 0x55);
327
328 /* PWM0 is used for half brightness or 50% duty cycle */
329 pca955x_write_pwm(client, 0, 255-LED_HALF);
330
331 /* PWM1 is used for variable brightness, default to OFF */
332 pca955x_write_pwm(client, 1, 0);
333
334 /* Set to fast frequency so we do not see flashing */
335 pca955x_write_psc(client, 0, 0);
336 pca955x_write_psc(client, 1, 0);
337
338 return 0;
339
340exit:
341 while (i--)
342 led_classdev_unregister(&pca955x->leds[i].led_cdev);
343
344 return err;
345}
346
347static int pca955x_remove(struct i2c_client *client)
348{
349 struct pca955x *pca955x = i2c_get_clientdata(client);
350 int i;
351
352 for (i = 0; i < pca955x->chipdef->bits; i++)
353 led_classdev_unregister(&pca955x->leds[i].led_cdev);
354
355 return 0;
356}
357
358static struct i2c_driver pca955x_driver = {
359 .driver = {
360 .name = "leds-pca955x",
361 },
362 .probe = pca955x_probe,
363 .remove = pca955x_remove,
364 .id_table = pca955x_id,
365};
366
367module_i2c_driver(pca955x_driver);
368
369MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
370MODULE_DESCRIPTION("PCA955x LED driver");
371MODULE_LICENSE("GPL v2");