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/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> 50 #include <linux/of.h> 51 #include <linux/property.h> 52 #include <linux/slab.h> 53 #include <linux/string.h> 54 55 #include <dt-bindings/leds/leds-pca955x.h> 56 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 */ 62 63 #define PCA955X_GPIO_INPUT LED_OFF 64 #define PCA955X_GPIO_HIGH LED_OFF 65 #define PCA955X_GPIO_LOW LED_FULL 66 67 enum pca955x_type { 68 pca9550, 69 pca9551, 70 pca9552, 71 pca9553, 72 }; 73 74 struct pca955x_chipdef { 75 int bits; 76 u8 slv_addr; /* 7-bit slave address mask */ 77 int slv_addr_shift; /* Number of bits to ignore */ 78 }; 79 80 static struct pca955x_chipdef pca955x_chipdefs[] = { 81 [pca9550] = { 82 .bits = 2, 83 .slv_addr = /* 110000x */ 0x60, 84 .slv_addr_shift = 1, 85 }, 86 [pca9551] = { 87 .bits = 8, 88 .slv_addr = /* 1100xxx */ 0x60, 89 .slv_addr_shift = 3, 90 }, 91 [pca9552] = { 92 .bits = 16, 93 .slv_addr = /* 1100xxx */ 0x60, 94 .slv_addr_shift = 3, 95 }, 96 [pca9553] = { 97 .bits = 4, 98 .slv_addr = /* 110001x */ 0x62, 99 .slv_addr_shift = 1, 100 }, 101 }; 102 103 static const struct i2c_device_id pca955x_id[] = { 104 { "pca9550", pca9550 }, 105 { "pca9551", pca9551 }, 106 { "pca9552", pca9552 }, 107 { "pca9553", pca9553 }, 108 { } 109 }; 110 MODULE_DEVICE_TABLE(i2c, pca955x_id); 111 112 struct pca955x { 113 struct mutex lock; 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; 119 #endif 120 }; 121 122 struct pca955x_led { 123 struct pca955x *pca955x; 124 struct led_classdev led_cdev; 125 int led_num; /* 0 .. 15 potentially */ 126 char name[32]; 127 u32 type; 128 const char *default_trigger; 129 }; 130 131 struct pca955x_platform_data { 132 struct pca955x_led *leds; 133 int num_leds; 134 }; 135 136 /* 8 bits per input register */ 137 static inline int pca95xx_num_input_regs(int bits) 138 { 139 return (bits + 7) / 8; 140 } 141 142 /* 4 bits per LED selector register */ 143 static inline int pca95xx_num_led_regs(int bits) 144 { 145 return (bits + 3) / 4; 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 */ 152 static 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 */ 162 static int pca955x_write_psc(struct i2c_client *client, int n, u8 val) 163 { 164 struct pca955x *pca955x = i2c_get_clientdata(client); 165 int ret; 166 167 ret = i2c_smbus_write_byte_data(client, 168 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n, 169 val); 170 if (ret < 0) 171 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n", 172 __func__, n, val, ret); 173 return ret; 174 } 175 176 /* 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. 180 * 181 * Duty cycle is (256 - PWMx) / 256 182 */ 183 static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val) 184 { 185 struct pca955x *pca955x = i2c_get_clientdata(client); 186 int ret; 187 188 ret = i2c_smbus_write_byte_data(client, 189 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n, 190 val); 191 if (ret < 0) 192 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n", 193 __func__, n, val, ret); 194 return ret; 195 } 196 197 /* 198 * Write to LED selector register, which determines the source that 199 * drives the LED output. 200 */ 201 static int pca955x_write_ls(struct i2c_client *client, int n, u8 val) 202 { 203 struct pca955x *pca955x = i2c_get_clientdata(client); 204 int ret; 205 206 ret = i2c_smbus_write_byte_data(client, 207 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n, 208 val); 209 if (ret < 0) 210 dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n", 211 __func__, n, val, ret); 212 return ret; 213 } 214 215 /* 216 * Read the LED selector register, which determines the source that 217 * drives the LED output. 218 */ 219 static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val) 220 { 221 struct pca955x *pca955x = i2c_get_clientdata(client); 222 int ret; 223 224 ret = i2c_smbus_read_byte_data(client, 225 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n); 226 if (ret < 0) { 227 dev_err(&client->dev, "%s: reg 0x%x, err %d\n", 228 __func__, n, ret); 229 return ret; 230 } 231 *val = (u8)ret; 232 return 0; 233 } 234 235 static int pca955x_led_set(struct led_classdev *led_cdev, 236 enum led_brightness value) 237 { 238 struct pca955x_led *pca955x_led; 239 struct pca955x *pca955x; 240 u8 ls; 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) */ 243 int ret; 244 245 pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev); 246 pca955x = pca955x_led->pca955x; 247 248 chip_ls = pca955x_led->led_num / 4; 249 ls_led = pca955x_led->led_num % 4; 250 251 mutex_lock(&pca955x->lock); 252 253 ret = pca955x_read_ls(pca955x->client, chip_ls, &ls); 254 if (ret) 255 goto out; 256 257 switch (value) { 258 case LED_FULL: 259 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON); 260 break; 261 case LED_OFF: 262 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF); 263 break; 264 case LED_HALF: 265 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0); 266 break; 267 default: 268 /* 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. 274 */ 275 ret = pca955x_write_pwm(pca955x->client, 1, 255 - value); 276 if (ret) 277 goto out; 278 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1); 279 break; 280 } 281 282 ret = pca955x_write_ls(pca955x->client, chip_ls, ls); 283 284 out: 285 mutex_unlock(&pca955x->lock); 286 287 return ret; 288 } 289 290 #ifdef CONFIG_LEDS_PCA955X_GPIO 291 /* 292 * Read the INPUT register, which contains the state of LEDs. 293 */ 294 static int pca955x_read_input(struct i2c_client *client, int n, u8 *val) 295 { 296 int ret = i2c_smbus_read_byte_data(client, n); 297 298 if (ret < 0) { 299 dev_err(&client->dev, "%s: reg 0x%x, err %d\n", 300 __func__, n, ret); 301 return ret; 302 } 303 *val = (u8)ret; 304 return 0; 305 306 } 307 308 static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset) 309 { 310 struct pca955x *pca955x = gpiochip_get_data(gc); 311 struct pca955x_led *led = &pca955x->leds[offset]; 312 313 if (led->type == PCA955X_TYPE_GPIO) 314 return 0; 315 316 return -EBUSY; 317 } 318 319 static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset, 320 int val) 321 { 322 struct pca955x *pca955x = gpiochip_get_data(gc); 323 struct pca955x_led *led = &pca955x->leds[offset]; 324 325 if (val) 326 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH); 327 328 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW); 329 } 330 331 static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset, 332 int val) 333 { 334 pca955x_set_value(gc, offset, val); 335 } 336 337 static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset) 338 { 339 struct pca955x *pca955x = gpiochip_get_data(gc); 340 struct pca955x_led *led = &pca955x->leds[offset]; 341 u8 reg = 0; 342 343 /* There is nothing we can do about errors */ 344 pca955x_read_input(pca955x->client, led->led_num / 8, ®); 345 346 return !!(reg & (1 << (led->led_num % 8))); 347 } 348 349 static int pca955x_gpio_direction_input(struct gpio_chip *gc, 350 unsigned int offset) 351 { 352 struct pca955x *pca955x = gpiochip_get_data(gc); 353 struct pca955x_led *led = &pca955x->leds[offset]; 354 355 /* To use as input ensure pin is not driven. */ 356 return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT); 357 } 358 359 static int pca955x_gpio_direction_output(struct gpio_chip *gc, 360 unsigned int offset, int val) 361 { 362 return pca955x_set_value(gc, offset, val); 363 } 364 #endif /* CONFIG_LEDS_PCA955X_GPIO */ 365 366 static struct pca955x_platform_data * 367 pca955x_get_pdata(struct i2c_client *client, struct pca955x_chipdef *chip) 368 { 369 struct pca955x_platform_data *pdata; 370 struct fwnode_handle *child; 371 int count; 372 373 count = device_get_child_node_count(&client->dev); 374 if (!count || count > chip->bits) 375 return ERR_PTR(-ENODEV); 376 377 pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL); 378 if (!pdata) 379 return ERR_PTR(-ENOMEM); 380 381 pdata->leds = devm_kcalloc(&client->dev, 382 chip->bits, sizeof(struct pca955x_led), 383 GFP_KERNEL); 384 if (!pdata->leds) 385 return ERR_PTR(-ENOMEM); 386 387 device_for_each_child_node(&client->dev, child) { 388 const char *name; 389 u32 reg; 390 int res; 391 392 res = fwnode_property_read_u32(child, "reg", ®); 393 if ((res != 0) || (reg >= chip->bits)) 394 continue; 395 396 res = fwnode_property_read_string(child, "label", &name); 397 if ((res != 0) && is_of_node(child)) 398 name = to_of_node(child)->name; 399 400 snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name), 401 "%s", name); 402 403 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); 407 } 408 409 pdata->num_leds = chip->bits; 410 411 return pdata; 412 } 413 414 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 }, 419 {}, 420 }; 421 MODULE_DEVICE_TABLE(of, of_pca955x_match); 422 423 static int pca955x_probe(struct i2c_client *client, 424 const struct i2c_device_id *id) 425 { 426 struct pca955x *pca955x; 427 struct pca955x_led *pca955x_led; 428 struct pca955x_chipdef *chip; 429 struct i2c_adapter *adapter; 430 int i, err; 431 struct pca955x_platform_data *pdata; 432 int ngpios = 0; 433 434 chip = &pca955x_chipdefs[id->driver_data]; 435 adapter = to_i2c_adapter(client->dev.parent); 436 pdata = dev_get_platdata(&client->dev); 437 if (!pdata) { 438 pdata = pca955x_get_pdata(client, chip); 439 if (IS_ERR(pdata)) 440 return PTR_ERR(pdata); 441 } 442 443 /* Make sure the slave address / chip type combo given is possible */ 444 if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) != 445 chip->slv_addr) { 446 dev_err(&client->dev, "invalid slave address %02x\n", 447 client->addr); 448 return -ENODEV; 449 } 450 451 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); 454 455 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 456 return -EIO; 457 458 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); 462 return -ENODEV; 463 } 464 465 pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL); 466 if (!pca955x) 467 return -ENOMEM; 468 469 pca955x->leds = devm_kcalloc(&client->dev, 470 chip->bits, sizeof(*pca955x_led), GFP_KERNEL); 471 if (!pca955x->leds) 472 return -ENOMEM; 473 474 i2c_set_clientdata(client, pca955x); 475 476 mutex_init(&pca955x->lock); 477 pca955x->client = client; 478 pca955x->chipdef = chip; 479 480 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; 485 486 switch (pca955x_led->type) { 487 case PCA955X_TYPE_NONE: 488 break; 489 case PCA955X_TYPE_GPIO: 490 ngpios++; 491 break; 492 case PCA955X_TYPE_LED: 493 /* 494 * Platform data can specify LED names and 495 * default triggers 496 */ 497 if (pdata->leds[i].name[0] == '\0') 498 snprintf(pdata->leds[i].name, 499 sizeof(pdata->leds[i].name), "%d", i); 500 501 snprintf(pca955x_led->name, 502 sizeof(pca955x_led->name), "pca955x:%s", 503 pdata->leds[i].name); 504 505 if (pdata->leds[i].default_trigger) 506 pca955x_led->led_cdev.default_trigger = 507 pdata->leds[i].default_trigger; 508 509 pca955x_led->led_cdev.name = pca955x_led->name; 510 pca955x_led->led_cdev.brightness_set_blocking = 511 pca955x_led_set; 512 513 err = devm_led_classdev_register(&client->dev, 514 &pca955x_led->led_cdev); 515 if (err) 516 return err; 517 518 /* Turn off LED */ 519 err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF); 520 if (err) 521 return err; 522 } 523 } 524 525 /* PWM0 is used for half brightness or 50% duty cycle */ 526 err = pca955x_write_pwm(client, 0, 255 - LED_HALF); 527 if (err) 528 return err; 529 530 /* PWM1 is used for variable brightness, default to OFF */ 531 err = pca955x_write_pwm(client, 1, 0); 532 if (err) 533 return err; 534 535 /* Set to fast frequency so we do not see flashing */ 536 err = pca955x_write_psc(client, 0, 0); 537 if (err) 538 return err; 539 err = pca955x_write_psc(client, 1, 0); 540 if (err) 541 return err; 542 543 #ifdef CONFIG_LEDS_PCA955X_GPIO 544 if (ngpios) { 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; 556 557 err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio, 558 pca955x); 559 if (err) { 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"); 563 return err; 564 } 565 dev_info(&client->dev, "gpios %i...%i\n", 566 pca955x->gpio.base, pca955x->gpio.base + 567 pca955x->gpio.ngpio - 1); 568 } 569 #endif 570 571 return 0; 572 } 573 574 static struct i2c_driver pca955x_driver = { 575 .driver = { 576 .name = "leds-pca955x", 577 .of_match_table = of_pca955x_match, 578 }, 579 .probe = pca955x_probe, 580 .id_table = pca955x_id, 581 }; 582 583 module_i2c_driver(pca955x_driver); 584 585 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>"); 586 MODULE_DESCRIPTION("PCA955x LED driver"); 587 MODULE_LICENSE("GPL v2"); 588