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(np, propname, "#gpio-cells", 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 for (i = 0; i < ARRAY_SIZE(whitelist); i++) 214 if (!strcmp(con_id, whitelist[i])) 215 break; 216 217 if (i == ARRAY_SIZE(whitelist)) 218 return ERR_PTR(-ENOENT); 219 220 desc = of_get_named_gpiod_flags(np, con_id, 0, of_flags); 221 return desc; 222 } 223 224 struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, 225 unsigned int idx, 226 enum gpio_lookup_flags *flags) 227 { 228 char prop_name[32]; /* 32 is max size of property name */ 229 enum of_gpio_flags of_flags; 230 struct gpio_desc *desc; 231 unsigned int i; 232 233 /* Try GPIO property "foo-gpios" and "foo-gpio" */ 234 for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) { 235 if (con_id) 236 snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id, 237 gpio_suffixes[i]); 238 else 239 snprintf(prop_name, sizeof(prop_name), "%s", 240 gpio_suffixes[i]); 241 242 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx, 243 &of_flags); 244 if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT)) 245 break; 246 } 247 248 /* Special handling for SPI GPIOs if used */ 249 if (IS_ERR(desc)) 250 desc = of_find_spi_gpio(dev, con_id, &of_flags); 251 252 /* Special handling for regulator GPIOs if used */ 253 if (IS_ERR(desc)) 254 desc = of_find_regulator_gpio(dev, con_id, &of_flags); 255 256 if (IS_ERR(desc)) 257 return desc; 258 259 if (of_flags & OF_GPIO_ACTIVE_LOW) 260 *flags |= GPIO_ACTIVE_LOW; 261 262 if (of_flags & OF_GPIO_SINGLE_ENDED) { 263 if (of_flags & OF_GPIO_OPEN_DRAIN) 264 *flags |= GPIO_OPEN_DRAIN; 265 else 266 *flags |= GPIO_OPEN_SOURCE; 267 } 268 269 if (of_flags & OF_GPIO_TRANSITORY) 270 *flags |= GPIO_TRANSITORY; 271 272 return desc; 273 } 274 275 /** 276 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API 277 * @np: device node to get GPIO from 278 * @chip: GPIO chip whose hog is parsed 279 * @idx: Index of the GPIO to parse 280 * @name: GPIO line name 281 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or 282 * of_parse_own_gpio() 283 * @dflags: gpiod_flags - optional GPIO initialization flags 284 * 285 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 286 * value on the error condition. 287 */ 288 static struct gpio_desc *of_parse_own_gpio(struct device_node *np, 289 struct gpio_chip *chip, 290 unsigned int idx, const char **name, 291 enum gpio_lookup_flags *lflags, 292 enum gpiod_flags *dflags) 293 { 294 struct device_node *chip_np; 295 enum of_gpio_flags xlate_flags; 296 struct of_phandle_args gpiospec; 297 struct gpio_desc *desc; 298 unsigned int i; 299 u32 tmp; 300 int ret; 301 302 chip_np = chip->of_node; 303 if (!chip_np) 304 return ERR_PTR(-EINVAL); 305 306 xlate_flags = 0; 307 *lflags = 0; 308 *dflags = 0; 309 310 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp); 311 if (ret) 312 return ERR_PTR(ret); 313 314 gpiospec.np = chip_np; 315 gpiospec.args_count = tmp; 316 317 for (i = 0; i < tmp; i++) { 318 ret = of_property_read_u32_index(np, "gpios", idx * tmp + i, 319 &gpiospec.args[i]); 320 if (ret) 321 return ERR_PTR(ret); 322 } 323 324 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags); 325 if (IS_ERR(desc)) 326 return desc; 327 328 if (xlate_flags & OF_GPIO_ACTIVE_LOW) 329 *lflags |= GPIO_ACTIVE_LOW; 330 if (xlate_flags & OF_GPIO_TRANSITORY) 331 *lflags |= GPIO_TRANSITORY; 332 333 if (of_property_read_bool(np, "input")) 334 *dflags |= GPIOD_IN; 335 else if (of_property_read_bool(np, "output-low")) 336 *dflags |= GPIOD_OUT_LOW; 337 else if (of_property_read_bool(np, "output-high")) 338 *dflags |= GPIOD_OUT_HIGH; 339 else { 340 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n", 341 desc_to_gpio(desc), np->name); 342 return ERR_PTR(-EINVAL); 343 } 344 345 if (name && of_property_read_string(np, "line-name", name)) 346 *name = np->name; 347 348 return desc; 349 } 350 351 /** 352 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions 353 * @chip: gpio chip to act on 354 * 355 * This is only used by of_gpiochip_add to request/set GPIO initial 356 * configuration. 357 * It returns error if it fails otherwise 0 on success. 358 */ 359 static int of_gpiochip_scan_gpios(struct gpio_chip *chip) 360 { 361 struct gpio_desc *desc = NULL; 362 struct device_node *np; 363 const char *name; 364 enum gpio_lookup_flags lflags; 365 enum gpiod_flags dflags; 366 unsigned int i; 367 int ret; 368 369 for_each_available_child_of_node(chip->of_node, np) { 370 if (!of_property_read_bool(np, "gpio-hog")) 371 continue; 372 373 for (i = 0;; i++) { 374 desc = of_parse_own_gpio(np, chip, i, &name, &lflags, 375 &dflags); 376 if (IS_ERR(desc)) 377 break; 378 379 ret = gpiod_hog(desc, name, lflags, dflags); 380 if (ret < 0) { 381 of_node_put(np); 382 return ret; 383 } 384 } 385 } 386 387 return 0; 388 } 389 390 /** 391 * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags 392 * @gc: pointer to the gpio_chip structure 393 * @gpiospec: GPIO specifier as found in the device tree 394 * @flags: a flags pointer to fill in 395 * 396 * This is simple translation function, suitable for the most 1:1 mapped 397 * GPIO chips. This function performs only one sanity check: whether GPIO 398 * is less than ngpios (that is specified in the gpio_chip). 399 */ 400 int of_gpio_simple_xlate(struct gpio_chip *gc, 401 const struct of_phandle_args *gpiospec, u32 *flags) 402 { 403 /* 404 * We're discouraging gpio_cells < 2, since that way you'll have to 405 * write your own xlate function (that will have to retrieve the GPIO 406 * number and the flags from a single gpio cell -- this is possible, 407 * but not recommended). 408 */ 409 if (gc->of_gpio_n_cells < 2) { 410 WARN_ON(1); 411 return -EINVAL; 412 } 413 414 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 415 return -EINVAL; 416 417 if (gpiospec->args[0] >= gc->ngpio) 418 return -EINVAL; 419 420 if (flags) 421 *flags = gpiospec->args[1]; 422 423 return gpiospec->args[0]; 424 } 425 EXPORT_SYMBOL(of_gpio_simple_xlate); 426 427 /** 428 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank) 429 * @np: device node of the GPIO chip 430 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 431 * @data: driver data to store in the struct gpio_chip 432 * 433 * To use this function you should allocate and fill mm_gc with: 434 * 435 * 1) In the gpio_chip structure: 436 * - all the callbacks 437 * - of_gpio_n_cells 438 * - of_xlate callback (optional) 439 * 440 * 3) In the of_mm_gpio_chip structure: 441 * - save_regs callback (optional) 442 * 443 * If succeeded, this function will map bank's memory and will 444 * do all necessary work for you. Then you'll able to use .regs 445 * to manage GPIOs from the callbacks. 446 */ 447 int of_mm_gpiochip_add_data(struct device_node *np, 448 struct of_mm_gpio_chip *mm_gc, 449 void *data) 450 { 451 int ret = -ENOMEM; 452 struct gpio_chip *gc = &mm_gc->gc; 453 454 gc->label = kasprintf(GFP_KERNEL, "%pOF", np); 455 if (!gc->label) 456 goto err0; 457 458 mm_gc->regs = of_iomap(np, 0); 459 if (!mm_gc->regs) 460 goto err1; 461 462 gc->base = -1; 463 464 if (mm_gc->save_regs) 465 mm_gc->save_regs(mm_gc); 466 467 mm_gc->gc.of_node = np; 468 469 ret = gpiochip_add_data(gc, data); 470 if (ret) 471 goto err2; 472 473 return 0; 474 err2: 475 iounmap(mm_gc->regs); 476 err1: 477 kfree(gc->label); 478 err0: 479 pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret); 480 return ret; 481 } 482 EXPORT_SYMBOL(of_mm_gpiochip_add_data); 483 484 /** 485 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank) 486 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 487 */ 488 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) 489 { 490 struct gpio_chip *gc = &mm_gc->gc; 491 492 if (!mm_gc) 493 return; 494 495 gpiochip_remove(gc); 496 iounmap(mm_gc->regs); 497 kfree(gc->label); 498 } 499 EXPORT_SYMBOL(of_mm_gpiochip_remove); 500 501 #ifdef CONFIG_PINCTRL 502 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) 503 { 504 struct device_node *np = chip->of_node; 505 struct of_phandle_args pinspec; 506 struct pinctrl_dev *pctldev; 507 int index = 0, ret; 508 const char *name; 509 static const char group_names_propname[] = "gpio-ranges-group-names"; 510 struct property *group_names; 511 512 if (!np) 513 return 0; 514 515 group_names = of_find_property(np, group_names_propname, NULL); 516 517 for (;; index++) { 518 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 519 index, &pinspec); 520 if (ret) 521 break; 522 523 pctldev = of_pinctrl_get(pinspec.np); 524 of_node_put(pinspec.np); 525 if (!pctldev) 526 return -EPROBE_DEFER; 527 528 if (pinspec.args[2]) { 529 if (group_names) { 530 of_property_read_string_index(np, 531 group_names_propname, 532 index, &name); 533 if (strlen(name)) { 534 pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n", 535 np); 536 break; 537 } 538 } 539 /* npins != 0: linear range */ 540 ret = gpiochip_add_pin_range(chip, 541 pinctrl_dev_get_devname(pctldev), 542 pinspec.args[0], 543 pinspec.args[1], 544 pinspec.args[2]); 545 if (ret) 546 return ret; 547 } else { 548 /* npins == 0: special range */ 549 if (pinspec.args[1]) { 550 pr_err("%pOF: Illegal gpio-range format.\n", 551 np); 552 break; 553 } 554 555 if (!group_names) { 556 pr_err("%pOF: GPIO group range requested but no %s property.\n", 557 np, group_names_propname); 558 break; 559 } 560 561 ret = of_property_read_string_index(np, 562 group_names_propname, 563 index, &name); 564 if (ret) 565 break; 566 567 if (!strlen(name)) { 568 pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n", 569 np); 570 break; 571 } 572 573 ret = gpiochip_add_pingroup_range(chip, pctldev, 574 pinspec.args[0], name); 575 if (ret) 576 return ret; 577 } 578 } 579 580 return 0; 581 } 582 583 #else 584 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; } 585 #endif 586 587 int of_gpiochip_add(struct gpio_chip *chip) 588 { 589 int status; 590 591 if ((!chip->of_node) && (chip->parent)) 592 chip->of_node = chip->parent->of_node; 593 594 if (!chip->of_node) 595 return 0; 596 597 if (!chip->of_xlate) { 598 chip->of_gpio_n_cells = 2; 599 chip->of_xlate = of_gpio_simple_xlate; 600 } 601 602 if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS) 603 return -EINVAL; 604 605 status = of_gpiochip_add_pin_range(chip); 606 if (status) 607 return status; 608 609 /* If the chip defines names itself, these take precedence */ 610 if (!chip->names) 611 devprop_gpiochip_set_names(chip, 612 of_fwnode_handle(chip->of_node)); 613 614 of_node_get(chip->of_node); 615 616 return of_gpiochip_scan_gpios(chip); 617 } 618 619 void of_gpiochip_remove(struct gpio_chip *chip) 620 { 621 gpiochip_remove_pin_ranges(chip); 622 of_node_put(chip->of_node); 623 } 624