1 /* 2 * OF helpers for the GPIO API 3 * 4 * Copyright (c) 2007-2008 MontaVista Software, Inc. 5 * 6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 */ 13 14 #include <linux/device.h> 15 #include <linux/err.h> 16 #include <linux/errno.h> 17 #include <linux/module.h> 18 #include <linux/io.h> 19 #include <linux/gpio/consumer.h> 20 #include <linux/of.h> 21 #include <linux/of_address.h> 22 #include <linux/of_gpio.h> 23 #include <linux/pinctrl/pinctrl.h> 24 #include <linux/slab.h> 25 #include <linux/gpio/machine.h> 26 27 #include "gpiolib.h" 28 29 static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data) 30 { 31 struct of_phandle_args *gpiospec = data; 32 33 return chip->gpiodev->dev.of_node == gpiospec->np && 34 chip->of_xlate(chip, gpiospec, NULL) >= 0; 35 } 36 37 static struct gpio_chip *of_find_gpiochip_by_xlate( 38 struct of_phandle_args *gpiospec) 39 { 40 return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate); 41 } 42 43 static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip, 44 struct of_phandle_args *gpiospec, 45 enum of_gpio_flags *flags) 46 { 47 int ret; 48 49 if (chip->of_gpio_n_cells != gpiospec->args_count) 50 return ERR_PTR(-EINVAL); 51 52 ret = chip->of_xlate(chip, gpiospec, flags); 53 if (ret < 0) 54 return ERR_PTR(ret); 55 56 return gpiochip_get_desc(chip, ret); 57 } 58 59 static void of_gpio_flags_quirks(struct device_node *np, 60 enum of_gpio_flags *flags) 61 { 62 /* 63 * Some GPIO fixed regulator quirks. 64 * Note that active low is the default. 65 */ 66 if (IS_ENABLED(CONFIG_REGULATOR) && 67 (of_device_is_compatible(np, "reg-fixed-voltage") || 68 of_device_is_compatible(np, "regulator-gpio"))) { 69 /* 70 * The regulator GPIO handles are specified such that the 71 * presence or absence of "enable-active-high" solely controls 72 * the polarity of the GPIO line. Any phandle flags must 73 * be actively ignored. 74 */ 75 if (*flags & OF_GPIO_ACTIVE_LOW) { 76 pr_warn("%s GPIO handle specifies active low - ignored\n", 77 of_node_full_name(np)); 78 *flags &= ~OF_GPIO_ACTIVE_LOW; 79 } 80 if (!of_property_read_bool(np, "enable-active-high")) 81 *flags |= OF_GPIO_ACTIVE_LOW; 82 } 83 /* 84 * Legacy open drain handling for fixed voltage regulators. 85 */ 86 if (IS_ENABLED(CONFIG_REGULATOR) && 87 of_device_is_compatible(np, "reg-fixed-voltage") && 88 of_property_read_bool(np, "gpio-open-drain")) { 89 *flags |= (OF_GPIO_SINGLE_ENDED | OF_GPIO_OPEN_DRAIN); 90 pr_info("%s uses legacy open drain flag - update the DTS if you can\n", 91 of_node_full_name(np)); 92 } 93 } 94 95 /** 96 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API 97 * @np: device node to get GPIO from 98 * @propname: property name containing gpio specifier(s) 99 * @index: index of the GPIO 100 * @flags: a flags pointer to fill in 101 * 102 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 103 * value on the error condition. If @flags is not NULL the function also fills 104 * in flags for the GPIO. 105 */ 106 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 107 const char *propname, int index, enum of_gpio_flags *flags) 108 { 109 struct of_phandle_args gpiospec; 110 struct gpio_chip *chip; 111 struct gpio_desc *desc; 112 int ret; 113 114 ret = of_parse_phandle_with_args_map(np, propname, "gpio", index, 115 &gpiospec); 116 if (ret) { 117 pr_debug("%s: can't parse '%s' property of node '%pOF[%d]'\n", 118 __func__, propname, np, index); 119 return ERR_PTR(ret); 120 } 121 122 chip = of_find_gpiochip_by_xlate(&gpiospec); 123 if (!chip) { 124 desc = ERR_PTR(-EPROBE_DEFER); 125 goto out; 126 } 127 128 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags); 129 if (IS_ERR(desc)) 130 goto out; 131 132 if (flags) 133 of_gpio_flags_quirks(np, flags); 134 135 pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n", 136 __func__, propname, np, index, 137 PTR_ERR_OR_ZERO(desc)); 138 139 out: 140 of_node_put(gpiospec.np); 141 142 return desc; 143 } 144 145 int of_get_named_gpio_flags(struct device_node *np, const char *list_name, 146 int index, enum of_gpio_flags *flags) 147 { 148 struct gpio_desc *desc; 149 150 desc = of_get_named_gpiod_flags(np, list_name, index, flags); 151 152 if (IS_ERR(desc)) 153 return PTR_ERR(desc); 154 else 155 return desc_to_gpio(desc); 156 } 157 EXPORT_SYMBOL(of_get_named_gpio_flags); 158 159 /* 160 * The SPI GPIO bindings happened before we managed to establish that GPIO 161 * properties should be named "foo-gpios" so we have this special kludge for 162 * them. 163 */ 164 static struct gpio_desc *of_find_spi_gpio(struct device *dev, const char *con_id, 165 enum of_gpio_flags *of_flags) 166 { 167 char prop_name[32]; /* 32 is max size of property name */ 168 struct device_node *np = dev->of_node; 169 struct gpio_desc *desc; 170 171 /* 172 * Hopefully the compiler stubs the rest of the function if this 173 * is false. 174 */ 175 if (!IS_ENABLED(CONFIG_SPI_MASTER)) 176 return ERR_PTR(-ENOENT); 177 178 /* Allow this specifically for "spi-gpio" devices */ 179 if (!of_device_is_compatible(np, "spi-gpio") || !con_id) 180 return ERR_PTR(-ENOENT); 181 182 /* Will be "gpio-sck", "gpio-mosi" or "gpio-miso" */ 183 snprintf(prop_name, sizeof(prop_name), "%s-%s", "gpio", con_id); 184 185 desc = of_get_named_gpiod_flags(np, prop_name, 0, of_flags); 186 return desc; 187 } 188 189 /* 190 * Some regulator bindings happened before we managed to establish that GPIO 191 * properties should be named "foo-gpios" so we have this special kludge for 192 * them. 193 */ 194 static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *con_id, 195 enum of_gpio_flags *of_flags) 196 { 197 /* These are the connection IDs we accept as legacy GPIO phandles */ 198 const char *whitelist[] = { 199 "wlf,ldoena", /* Arizona */ 200 "wlf,ldo1ena", /* WM8994 */ 201 "wlf,ldo2ena", /* WM8994 */ 202 }; 203 struct device_node *np = dev->of_node; 204 struct gpio_desc *desc; 205 int i; 206 207 if (!IS_ENABLED(CONFIG_REGULATOR)) 208 return ERR_PTR(-ENOENT); 209 210 if (!con_id) 211 return ERR_PTR(-ENOENT); 212 213 i = match_string(whitelist, ARRAY_SIZE(whitelist), con_id); 214 if (i < 0) 215 return ERR_PTR(-ENOENT); 216 217 desc = of_get_named_gpiod_flags(np, con_id, 0, of_flags); 218 return desc; 219 } 220 221 struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, 222 unsigned int idx, 223 enum gpio_lookup_flags *flags) 224 { 225 char prop_name[32]; /* 32 is max size of property name */ 226 enum of_gpio_flags of_flags; 227 struct gpio_desc *desc; 228 unsigned int i; 229 230 /* Try GPIO property "foo-gpios" and "foo-gpio" */ 231 for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) { 232 if (con_id) 233 snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id, 234 gpio_suffixes[i]); 235 else 236 snprintf(prop_name, sizeof(prop_name), "%s", 237 gpio_suffixes[i]); 238 239 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx, 240 &of_flags); 241 /* 242 * -EPROBE_DEFER in our case means that we found a 243 * valid GPIO property, but no controller has been 244 * registered so far. 245 * 246 * This means we don't need to look any further for 247 * alternate name conventions, and we should really 248 * preserve the return code for our user to be able to 249 * retry probing later. 250 */ 251 if (IS_ERR(desc) && PTR_ERR(desc) == -EPROBE_DEFER) 252 return desc; 253 254 if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT)) 255 break; 256 } 257 258 /* Special handling for SPI GPIOs if used */ 259 if (IS_ERR(desc)) 260 desc = of_find_spi_gpio(dev, con_id, &of_flags); 261 262 /* Special handling for regulator GPIOs if used */ 263 if (IS_ERR(desc) && PTR_ERR(desc) != -EPROBE_DEFER) 264 desc = of_find_regulator_gpio(dev, con_id, &of_flags); 265 266 if (IS_ERR(desc)) 267 return desc; 268 269 if (of_flags & OF_GPIO_ACTIVE_LOW) 270 *flags |= GPIO_ACTIVE_LOW; 271 272 if (of_flags & OF_GPIO_SINGLE_ENDED) { 273 if (of_flags & OF_GPIO_OPEN_DRAIN) 274 *flags |= GPIO_OPEN_DRAIN; 275 else 276 *flags |= GPIO_OPEN_SOURCE; 277 } 278 279 if (of_flags & OF_GPIO_TRANSITORY) 280 *flags |= GPIO_TRANSITORY; 281 282 return desc; 283 } 284 285 /** 286 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API 287 * @np: device node to get GPIO from 288 * @chip: GPIO chip whose hog is parsed 289 * @idx: Index of the GPIO to parse 290 * @name: GPIO line name 291 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or 292 * of_parse_own_gpio() 293 * @dflags: gpiod_flags - optional GPIO initialization flags 294 * 295 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 296 * value on the error condition. 297 */ 298 static struct gpio_desc *of_parse_own_gpio(struct device_node *np, 299 struct gpio_chip *chip, 300 unsigned int idx, const char **name, 301 enum gpio_lookup_flags *lflags, 302 enum gpiod_flags *dflags) 303 { 304 struct device_node *chip_np; 305 enum of_gpio_flags xlate_flags; 306 struct of_phandle_args gpiospec; 307 struct gpio_desc *desc; 308 unsigned int i; 309 u32 tmp; 310 int ret; 311 312 chip_np = chip->of_node; 313 if (!chip_np) 314 return ERR_PTR(-EINVAL); 315 316 xlate_flags = 0; 317 *lflags = 0; 318 *dflags = 0; 319 320 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp); 321 if (ret) 322 return ERR_PTR(ret); 323 324 gpiospec.np = chip_np; 325 gpiospec.args_count = tmp; 326 327 for (i = 0; i < tmp; i++) { 328 ret = of_property_read_u32_index(np, "gpios", idx * tmp + i, 329 &gpiospec.args[i]); 330 if (ret) 331 return ERR_PTR(ret); 332 } 333 334 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags); 335 if (IS_ERR(desc)) 336 return desc; 337 338 if (xlate_flags & OF_GPIO_ACTIVE_LOW) 339 *lflags |= GPIO_ACTIVE_LOW; 340 if (xlate_flags & OF_GPIO_TRANSITORY) 341 *lflags |= GPIO_TRANSITORY; 342 343 if (of_property_read_bool(np, "input")) 344 *dflags |= GPIOD_IN; 345 else if (of_property_read_bool(np, "output-low")) 346 *dflags |= GPIOD_OUT_LOW; 347 else if (of_property_read_bool(np, "output-high")) 348 *dflags |= GPIOD_OUT_HIGH; 349 else { 350 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n", 351 desc_to_gpio(desc), np->name); 352 return ERR_PTR(-EINVAL); 353 } 354 355 if (name && of_property_read_string(np, "line-name", name)) 356 *name = np->name; 357 358 return desc; 359 } 360 361 /** 362 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions 363 * @chip: gpio chip to act on 364 * 365 * This is only used by of_gpiochip_add to request/set GPIO initial 366 * configuration. 367 * It returns error if it fails otherwise 0 on success. 368 */ 369 static int of_gpiochip_scan_gpios(struct gpio_chip *chip) 370 { 371 struct gpio_desc *desc = NULL; 372 struct device_node *np; 373 const char *name; 374 enum gpio_lookup_flags lflags; 375 enum gpiod_flags dflags; 376 unsigned int i; 377 int ret; 378 379 for_each_available_child_of_node(chip->of_node, np) { 380 if (!of_property_read_bool(np, "gpio-hog")) 381 continue; 382 383 for (i = 0;; i++) { 384 desc = of_parse_own_gpio(np, chip, i, &name, &lflags, 385 &dflags); 386 if (IS_ERR(desc)) 387 break; 388 389 ret = gpiod_hog(desc, name, lflags, dflags); 390 if (ret < 0) { 391 of_node_put(np); 392 return ret; 393 } 394 } 395 } 396 397 return 0; 398 } 399 400 /** 401 * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags 402 * @gc: pointer to the gpio_chip structure 403 * @gpiospec: GPIO specifier as found in the device tree 404 * @flags: a flags pointer to fill in 405 * 406 * This is simple translation function, suitable for the most 1:1 mapped 407 * GPIO chips. This function performs only one sanity check: whether GPIO 408 * is less than ngpios (that is specified in the gpio_chip). 409 */ 410 int of_gpio_simple_xlate(struct gpio_chip *gc, 411 const struct of_phandle_args *gpiospec, u32 *flags) 412 { 413 /* 414 * We're discouraging gpio_cells < 2, since that way you'll have to 415 * write your own xlate function (that will have to retrieve the GPIO 416 * number and the flags from a single gpio cell -- this is possible, 417 * but not recommended). 418 */ 419 if (gc->of_gpio_n_cells < 2) { 420 WARN_ON(1); 421 return -EINVAL; 422 } 423 424 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 425 return -EINVAL; 426 427 if (gpiospec->args[0] >= gc->ngpio) 428 return -EINVAL; 429 430 if (flags) 431 *flags = gpiospec->args[1]; 432 433 return gpiospec->args[0]; 434 } 435 EXPORT_SYMBOL(of_gpio_simple_xlate); 436 437 /** 438 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank) 439 * @np: device node of the GPIO chip 440 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 441 * @data: driver data to store in the struct gpio_chip 442 * 443 * To use this function you should allocate and fill mm_gc with: 444 * 445 * 1) In the gpio_chip structure: 446 * - all the callbacks 447 * - of_gpio_n_cells 448 * - of_xlate callback (optional) 449 * 450 * 3) In the of_mm_gpio_chip structure: 451 * - save_regs callback (optional) 452 * 453 * If succeeded, this function will map bank's memory and will 454 * do all necessary work for you. Then you'll able to use .regs 455 * to manage GPIOs from the callbacks. 456 */ 457 int of_mm_gpiochip_add_data(struct device_node *np, 458 struct of_mm_gpio_chip *mm_gc, 459 void *data) 460 { 461 int ret = -ENOMEM; 462 struct gpio_chip *gc = &mm_gc->gc; 463 464 gc->label = kasprintf(GFP_KERNEL, "%pOF", np); 465 if (!gc->label) 466 goto err0; 467 468 mm_gc->regs = of_iomap(np, 0); 469 if (!mm_gc->regs) 470 goto err1; 471 472 gc->base = -1; 473 474 if (mm_gc->save_regs) 475 mm_gc->save_regs(mm_gc); 476 477 mm_gc->gc.of_node = np; 478 479 ret = gpiochip_add_data(gc, data); 480 if (ret) 481 goto err2; 482 483 return 0; 484 err2: 485 iounmap(mm_gc->regs); 486 err1: 487 kfree(gc->label); 488 err0: 489 pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret); 490 return ret; 491 } 492 EXPORT_SYMBOL(of_mm_gpiochip_add_data); 493 494 /** 495 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank) 496 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 497 */ 498 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) 499 { 500 struct gpio_chip *gc = &mm_gc->gc; 501 502 if (!mm_gc) 503 return; 504 505 gpiochip_remove(gc); 506 iounmap(mm_gc->regs); 507 kfree(gc->label); 508 } 509 EXPORT_SYMBOL(of_mm_gpiochip_remove); 510 511 static void of_gpiochip_init_valid_mask(struct gpio_chip *chip) 512 { 513 int len, i; 514 u32 start, count; 515 struct device_node *np = chip->of_node; 516 517 len = of_property_count_u32_elems(np, "gpio-reserved-ranges"); 518 if (len < 0 || len % 2 != 0) 519 return; 520 521 for (i = 0; i < len; i += 2) { 522 of_property_read_u32_index(np, "gpio-reserved-ranges", 523 i, &start); 524 of_property_read_u32_index(np, "gpio-reserved-ranges", 525 i + 1, &count); 526 if (start >= chip->ngpio || start + count >= chip->ngpio) 527 continue; 528 529 bitmap_clear(chip->valid_mask, start, count); 530 } 531 }; 532 533 #ifdef CONFIG_PINCTRL 534 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) 535 { 536 struct device_node *np = chip->of_node; 537 struct of_phandle_args pinspec; 538 struct pinctrl_dev *pctldev; 539 int index = 0, ret; 540 const char *name; 541 static const char group_names_propname[] = "gpio-ranges-group-names"; 542 struct property *group_names; 543 544 if (!np) 545 return 0; 546 547 group_names = of_find_property(np, group_names_propname, NULL); 548 549 for (;; index++) { 550 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 551 index, &pinspec); 552 if (ret) 553 break; 554 555 pctldev = of_pinctrl_get(pinspec.np); 556 of_node_put(pinspec.np); 557 if (!pctldev) 558 return -EPROBE_DEFER; 559 560 if (pinspec.args[2]) { 561 if (group_names) { 562 of_property_read_string_index(np, 563 group_names_propname, 564 index, &name); 565 if (strlen(name)) { 566 pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n", 567 np); 568 break; 569 } 570 } 571 /* npins != 0: linear range */ 572 ret = gpiochip_add_pin_range(chip, 573 pinctrl_dev_get_devname(pctldev), 574 pinspec.args[0], 575 pinspec.args[1], 576 pinspec.args[2]); 577 if (ret) 578 return ret; 579 } else { 580 /* npins == 0: special range */ 581 if (pinspec.args[1]) { 582 pr_err("%pOF: Illegal gpio-range format.\n", 583 np); 584 break; 585 } 586 587 if (!group_names) { 588 pr_err("%pOF: GPIO group range requested but no %s property.\n", 589 np, group_names_propname); 590 break; 591 } 592 593 ret = of_property_read_string_index(np, 594 group_names_propname, 595 index, &name); 596 if (ret) 597 break; 598 599 if (!strlen(name)) { 600 pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n", 601 np); 602 break; 603 } 604 605 ret = gpiochip_add_pingroup_range(chip, pctldev, 606 pinspec.args[0], name); 607 if (ret) 608 return ret; 609 } 610 } 611 612 return 0; 613 } 614 615 #else 616 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; } 617 #endif 618 619 int of_gpiochip_add(struct gpio_chip *chip) 620 { 621 int status; 622 623 if ((!chip->of_node) && (chip->parent)) 624 chip->of_node = chip->parent->of_node; 625 626 if (!chip->of_node) 627 return 0; 628 629 if (!chip->of_xlate) { 630 chip->of_gpio_n_cells = 2; 631 chip->of_xlate = of_gpio_simple_xlate; 632 } 633 634 if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS) 635 return -EINVAL; 636 637 of_gpiochip_init_valid_mask(chip); 638 639 status = of_gpiochip_add_pin_range(chip); 640 if (status) 641 return status; 642 643 /* If the chip defines names itself, these take precedence */ 644 if (!chip->names) 645 devprop_gpiochip_set_names(chip, 646 of_fwnode_handle(chip->of_node)); 647 648 of_node_get(chip->of_node); 649 650 return of_gpiochip_scan_gpios(chip); 651 } 652 653 void of_gpiochip_remove(struct gpio_chip *chip) 654 { 655 gpiochip_remove_pin_ranges(chip); 656 of_node_put(chip->of_node); 657 } 658