2 * Copyright 2007-2008 Extreme Engineering Solutions, Inc.
4 * Author: Nate Case <ncase@xes-inc.com>
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.
10 * LED driver for various PCA955x I2C LED drivers
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
22 * Philips PCA955x LED driver chips follow a register map as shown below:
24 * Control Register Description
25 * ---------------- -----------
26 * 0x0 Input register 0
28 * NUM_INPUT_REGS - 1 Last Input register X
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
35 * NUM_INPUT_REGS + 4 LED selector 0
37 * + NUM_LED_REGS - 1 Last LED selector
39 * where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many
40 * bits the chip supports.
43 #include <linux/ctype.h>
44 #include <linux/delay.h>
45 #include <linux/err.h>
46 #include <linux/gpio.h>
47 #include <linux/i2c.h>
48 #include <linux/leds.h>
49 #include <linux/module.h>
51 #include <linux/property.h>
52 #include <linux/slab.h>
53 #include <linux/string.h>
55 #include <dt-bindings/leds/leds-pca955x.h>
57 /* LED select registers determine the source that drives LED outputs */
58 #define PCA955X_LS_LED_ON 0x0 /* Output LOW */
59 #define PCA955X_LS_LED_OFF 0x1 /* Output HI-Z */
60 #define PCA955X_LS_BLINK0 0x2 /* Blink at PWM0 rate */
61 #define PCA955X_LS_BLINK1 0x3 /* Blink at PWM1 rate */
63 #define PCA955X_GPIO_INPUT LED_OFF
64 #define PCA955X_GPIO_HIGH LED_OFF
65 #define PCA955X_GPIO_LOW LED_FULL
74 struct pca955x_chipdef {
76 u8 slv_addr; /* 7-bit slave address mask */
77 int slv_addr_shift; /* Number of bits to ignore */
80 static struct pca955x_chipdef pca955x_chipdefs[] = {
83 .slv_addr = /* 110000x */ 0x60,
88 .slv_addr = /* 1100xxx */ 0x60,
93 .slv_addr = /* 1100xxx */ 0x60,
98 .slv_addr = /* 110001x */ 0x62,
103 static const struct i2c_device_id pca955x_id[] = {
104 { "pca9550", pca9550 },
105 { "pca9551", pca9551 },
106 { "pca9552", pca9552 },
107 { "pca9553", pca9553 },
110 MODULE_DEVICE_TABLE(i2c, pca955x_id);
114 struct pca955x_led *leds;
115 struct pca955x_chipdef *chipdef;
116 struct i2c_client *client;
117 #ifdef CONFIG_LEDS_PCA955X_GPIO
118 struct gpio_chip gpio;
123 struct pca955x *pca955x;
124 struct led_classdev led_cdev;
125 int led_num; /* 0 .. 15 potentially */
128 const char *default_trigger;
131 struct pca955x_platform_data {
132 struct pca955x_led *leds;
136 /* 8 bits per input register */
137 static inline int pca95xx_num_input_regs(int bits)
139 return (bits + 7) / 8;
142 /* 4 bits per LED selector register */
143 static inline int pca95xx_num_led_regs(int bits)
145 return (bits + 3) / 4;
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).
152 static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
154 return (oldval & (~(0x3 << (led_num << 1)))) |
155 ((state & 0x3) << (led_num << 1));
159 * Write to frequency prescaler register, used to program the
160 * period of the PWM output. period = (PSCx + 1) / 38
162 static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
164 struct pca955x *pca955x = i2c_get_clientdata(client);
167 ret = i2c_smbus_write_byte_data(client,
168 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
171 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
172 __func__, n, val, ret);
177 * Write to PWM register, which determines the duty cycle of the
178 * output. LED is OFF when the count is less than the value of this
179 * register, and ON when it is greater. If PWMx == 0, LED is always OFF.
181 * Duty cycle is (256 - PWMx) / 256
183 static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
185 struct pca955x *pca955x = i2c_get_clientdata(client);
188 ret = i2c_smbus_write_byte_data(client,
189 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
192 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
193 __func__, n, val, ret);
198 * Write to LED selector register, which determines the source that
199 * drives the LED output.
201 static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
203 struct pca955x *pca955x = i2c_get_clientdata(client);
206 ret = i2c_smbus_write_byte_data(client,
207 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
210 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
211 __func__, n, val, ret);
216 * Read the LED selector register, which determines the source that
217 * drives the LED output.
219 static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
221 struct pca955x *pca955x = i2c_get_clientdata(client);
224 ret = i2c_smbus_read_byte_data(client,
225 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
227 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
235 static int pca955x_led_set(struct led_classdev *led_cdev,
236 enum led_brightness value)
238 struct pca955x_led *pca955x_led;
239 struct pca955x *pca955x;
241 int chip_ls; /* which LSx to use (0-3 potentially) */
242 int ls_led; /* which set of bits within LSx to use (0-3) */
245 pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
246 pca955x = pca955x_led->pca955x;
248 chip_ls = pca955x_led->led_num / 4;
249 ls_led = pca955x_led->led_num % 4;
251 mutex_lock(&pca955x->lock);
253 ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
259 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
262 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
265 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
269 * Use PWM1 for all other values. This has the unwanted
270 * side effect of making all LEDs on the chip share the
271 * same brightness level if set to a value other than
272 * OFF, HALF, or FULL. But, this is probably better than
273 * just turning off for all other values.
275 ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
278 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
282 ret = pca955x_write_ls(pca955x->client, chip_ls, ls);
285 mutex_unlock(&pca955x->lock);
290 #ifdef CONFIG_LEDS_PCA955X_GPIO
292 * Read the INPUT register, which contains the state of LEDs.
294 static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
296 int ret = i2c_smbus_read_byte_data(client, n);
299 dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
308 static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
310 struct pca955x *pca955x = gpiochip_get_data(gc);
311 struct pca955x_led *led = &pca955x->leds[offset];
313 if (led->type == PCA955X_TYPE_GPIO)
319 static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
322 struct pca955x *pca955x = gpiochip_get_data(gc);
323 struct pca955x_led *led = &pca955x->leds[offset];
326 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);
328 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW);
331 static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
334 pca955x_set_value(gc, offset, val);
337 static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
339 struct pca955x *pca955x = gpiochip_get_data(gc);
340 struct pca955x_led *led = &pca955x->leds[offset];
343 /* There is nothing we can do about errors */
344 pca955x_read_input(pca955x->client, led->led_num / 8, ®);
346 return !!(reg & (1 << (led->led_num % 8)));
349 static int pca955x_gpio_direction_input(struct gpio_chip *gc,
352 struct pca955x *pca955x = gpiochip_get_data(gc);
353 struct pca955x_led *led = &pca955x->leds[offset];
355 /* To use as input ensure pin is not driven. */
356 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
359 static int pca955x_gpio_direction_output(struct gpio_chip *gc,
360 unsigned int offset, int val)
362 return pca955x_set_value(gc, offset, val);
364 #endif /* CONFIG_LEDS_PCA955X_GPIO */
366 static struct pca955x_platform_data *
367 pca955x_get_pdata(struct i2c_client *client, struct pca955x_chipdef *chip)
369 struct pca955x_platform_data *pdata;
370 struct fwnode_handle *child;
373 count = device_get_child_node_count(&client->dev);
374 if (!count || count > chip->bits)
375 return ERR_PTR(-ENODEV);
377 pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
379 return ERR_PTR(-ENOMEM);
381 pdata->leds = devm_kcalloc(&client->dev,
382 chip->bits, sizeof(struct pca955x_led),
385 return ERR_PTR(-ENOMEM);
387 device_for_each_child_node(&client->dev, child) {
392 res = fwnode_property_read_u32(child, "reg", ®);
393 if ((res != 0) || (reg >= chip->bits))
396 res = fwnode_property_read_string(child, "label", &name);
397 if ((res != 0) && is_of_node(child))
398 name = to_of_node(child)->name;
400 snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name),
403 pdata->leds[reg].type = PCA955X_TYPE_LED;
404 fwnode_property_read_u32(child, "type", &pdata->leds[reg].type);
405 fwnode_property_read_string(child, "linux,default-trigger",
406 &pdata->leds[reg].default_trigger);
409 pdata->num_leds = chip->bits;
414 static const struct of_device_id of_pca955x_match[] = {
415 { .compatible = "nxp,pca9550", .data = (void *)pca9550 },
416 { .compatible = "nxp,pca9551", .data = (void *)pca9551 },
417 { .compatible = "nxp,pca9552", .data = (void *)pca9552 },
418 { .compatible = "nxp,pca9553", .data = (void *)pca9553 },
421 MODULE_DEVICE_TABLE(of, of_pca955x_match);
423 static int pca955x_probe(struct i2c_client *client,
424 const struct i2c_device_id *id)
426 struct pca955x *pca955x;
427 struct pca955x_led *pca955x_led;
428 struct pca955x_chipdef *chip;
429 struct i2c_adapter *adapter;
431 struct pca955x_platform_data *pdata;
434 chip = &pca955x_chipdefs[id->driver_data];
435 adapter = to_i2c_adapter(client->dev.parent);
436 pdata = dev_get_platdata(&client->dev);
438 pdata = pca955x_get_pdata(client, chip);
440 return PTR_ERR(pdata);
443 /* Make sure the slave address / chip type combo given is possible */
444 if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
446 dev_err(&client->dev, "invalid slave address %02x\n",
451 dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
452 "slave address 0x%02x\n",
453 client->name, chip->bits, client->addr);
455 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
458 if (pdata->num_leds != chip->bits) {
459 dev_err(&client->dev,
460 "board info claims %d LEDs on a %d-bit chip\n",
461 pdata->num_leds, chip->bits);
465 pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
469 pca955x->leds = devm_kcalloc(&client->dev,
470 chip->bits, sizeof(*pca955x_led), GFP_KERNEL);
474 i2c_set_clientdata(client, pca955x);
476 mutex_init(&pca955x->lock);
477 pca955x->client = client;
478 pca955x->chipdef = chip;
480 for (i = 0; i < chip->bits; i++) {
481 pca955x_led = &pca955x->leds[i];
482 pca955x_led->led_num = i;
483 pca955x_led->pca955x = pca955x;
484 pca955x_led->type = pdata->leds[i].type;
486 switch (pca955x_led->type) {
487 case PCA955X_TYPE_NONE:
489 case PCA955X_TYPE_GPIO:
492 case PCA955X_TYPE_LED:
494 * Platform data can specify LED names and
497 if (pdata->leds[i].name[0] == '\0')
498 snprintf(pdata->leds[i].name,
499 sizeof(pdata->leds[i].name), "%d", i);
501 snprintf(pca955x_led->name,
502 sizeof(pca955x_led->name), "pca955x:%s",
503 pdata->leds[i].name);
505 if (pdata->leds[i].default_trigger)
506 pca955x_led->led_cdev.default_trigger =
507 pdata->leds[i].default_trigger;
509 pca955x_led->led_cdev.name = pca955x_led->name;
510 pca955x_led->led_cdev.brightness_set_blocking =
513 err = devm_led_classdev_register(&client->dev,
514 &pca955x_led->led_cdev);
519 err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
525 /* PWM0 is used for half brightness or 50% duty cycle */
526 err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
530 /* PWM1 is used for variable brightness, default to OFF */
531 err = pca955x_write_pwm(client, 1, 0);
535 /* Set to fast frequency so we do not see flashing */
536 err = pca955x_write_psc(client, 0, 0);
539 err = pca955x_write_psc(client, 1, 0);
543 #ifdef CONFIG_LEDS_PCA955X_GPIO
545 pca955x->gpio.label = "gpio-pca955x";
546 pca955x->gpio.direction_input = pca955x_gpio_direction_input;
547 pca955x->gpio.direction_output = pca955x_gpio_direction_output;
548 pca955x->gpio.set = pca955x_gpio_set_value;
549 pca955x->gpio.get = pca955x_gpio_get_value;
550 pca955x->gpio.request = pca955x_gpio_request_pin;
551 pca955x->gpio.can_sleep = 1;
552 pca955x->gpio.base = -1;
553 pca955x->gpio.ngpio = ngpios;
554 pca955x->gpio.parent = &client->dev;
555 pca955x->gpio.owner = THIS_MODULE;
557 err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
560 /* Use data->gpio.dev as a flag for freeing gpiochip */
561 pca955x->gpio.parent = NULL;
562 dev_warn(&client->dev, "could not add gpiochip\n");
565 dev_info(&client->dev, "gpios %i...%i\n",
566 pca955x->gpio.base, pca955x->gpio.base +
567 pca955x->gpio.ngpio - 1);
574 static struct i2c_driver pca955x_driver = {
576 .name = "leds-pca955x",
577 .of_match_table = of_pca955x_match,
579 .probe = pca955x_probe,
580 .id_table = pca955x_id,
583 module_i2c_driver(pca955x_driver);
585 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
586 MODULE_DESCRIPTION("PCA955x LED driver");
587 MODULE_LICENSE("GPL v2");