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 /** 60 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API 61 * @np: device node to get GPIO from 62 * @propname: property name containing gpio specifier(s) 63 * @index: index of the GPIO 64 * @flags: a flags pointer to fill in 65 * 66 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 67 * value on the error condition. If @flags is not NULL the function also fills 68 * in flags for the GPIO. 69 */ 70 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 71 const char *propname, int index, enum of_gpio_flags *flags) 72 { 73 struct of_phandle_args gpiospec; 74 struct gpio_chip *chip; 75 struct gpio_desc *desc; 76 int ret; 77 78 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, 79 &gpiospec); 80 if (ret) { 81 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n", 82 __func__, propname, np->full_name, index); 83 return ERR_PTR(ret); 84 } 85 86 chip = of_find_gpiochip_by_xlate(&gpiospec); 87 if (!chip) { 88 desc = ERR_PTR(-EPROBE_DEFER); 89 goto out; 90 } 91 92 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags); 93 if (IS_ERR(desc)) 94 goto out; 95 96 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", 97 __func__, propname, np->full_name, index, 98 PTR_ERR_OR_ZERO(desc)); 99 100 out: 101 of_node_put(gpiospec.np); 102 103 return desc; 104 } 105 106 int of_get_named_gpio_flags(struct device_node *np, const char *list_name, 107 int index, enum of_gpio_flags *flags) 108 { 109 struct gpio_desc *desc; 110 111 desc = of_get_named_gpiod_flags(np, list_name, index, flags); 112 113 if (IS_ERR(desc)) 114 return PTR_ERR(desc); 115 else 116 return desc_to_gpio(desc); 117 } 118 EXPORT_SYMBOL(of_get_named_gpio_flags); 119 120 struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, 121 unsigned int idx, 122 enum gpio_lookup_flags *flags) 123 { 124 char prop_name[32]; /* 32 is max size of property name */ 125 enum of_gpio_flags of_flags; 126 struct gpio_desc *desc; 127 unsigned int i; 128 129 for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) { 130 if (con_id) 131 snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id, 132 gpio_suffixes[i]); 133 else 134 snprintf(prop_name, sizeof(prop_name), "%s", 135 gpio_suffixes[i]); 136 137 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx, 138 &of_flags); 139 if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT)) 140 break; 141 } 142 143 if (IS_ERR(desc)) 144 return desc; 145 146 if (of_flags & OF_GPIO_ACTIVE_LOW) 147 *flags |= GPIO_ACTIVE_LOW; 148 149 if (of_flags & OF_GPIO_SINGLE_ENDED) { 150 if (of_flags & OF_GPIO_OPEN_DRAIN) 151 *flags |= GPIO_OPEN_DRAIN; 152 else 153 *flags |= GPIO_OPEN_SOURCE; 154 } 155 156 if (of_flags & OF_GPIO_SLEEP_MAY_LOOSE_VALUE) 157 *flags |= GPIO_SLEEP_MAY_LOOSE_VALUE; 158 159 return desc; 160 } 161 162 /** 163 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API 164 * @np: device node to get GPIO from 165 * @chip: GPIO chip whose hog is parsed 166 * @idx: Index of the GPIO to parse 167 * @name: GPIO line name 168 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or 169 * of_parse_own_gpio() 170 * @dflags: gpiod_flags - optional GPIO initialization flags 171 * 172 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 173 * value on the error condition. 174 */ 175 static struct gpio_desc *of_parse_own_gpio(struct device_node *np, 176 struct gpio_chip *chip, 177 unsigned int idx, const char **name, 178 enum gpio_lookup_flags *lflags, 179 enum gpiod_flags *dflags) 180 { 181 struct device_node *chip_np; 182 enum of_gpio_flags xlate_flags; 183 struct of_phandle_args gpiospec; 184 struct gpio_desc *desc; 185 unsigned int i; 186 u32 tmp; 187 int ret; 188 189 chip_np = chip->of_node; 190 if (!chip_np) 191 return ERR_PTR(-EINVAL); 192 193 xlate_flags = 0; 194 *lflags = 0; 195 *dflags = 0; 196 197 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp); 198 if (ret) 199 return ERR_PTR(ret); 200 201 gpiospec.np = chip_np; 202 gpiospec.args_count = tmp; 203 204 for (i = 0; i < tmp; i++) { 205 ret = of_property_read_u32_index(np, "gpios", idx * tmp + i, 206 &gpiospec.args[i]); 207 if (ret) 208 return ERR_PTR(ret); 209 } 210 211 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags); 212 if (IS_ERR(desc)) 213 return desc; 214 215 if (xlate_flags & OF_GPIO_ACTIVE_LOW) 216 *lflags |= GPIO_ACTIVE_LOW; 217 218 if (of_property_read_bool(np, "input")) 219 *dflags |= GPIOD_IN; 220 else if (of_property_read_bool(np, "output-low")) 221 *dflags |= GPIOD_OUT_LOW; 222 else if (of_property_read_bool(np, "output-high")) 223 *dflags |= GPIOD_OUT_HIGH; 224 else { 225 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n", 226 desc_to_gpio(desc), np->name); 227 return ERR_PTR(-EINVAL); 228 } 229 230 if (name && of_property_read_string(np, "line-name", name)) 231 *name = np->name; 232 233 return desc; 234 } 235 236 /** 237 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions 238 * @chip: gpio chip to act on 239 * 240 * This is only used by of_gpiochip_add to request/set GPIO initial 241 * configuration. 242 * It returns error if it fails otherwise 0 on success. 243 */ 244 static int of_gpiochip_scan_gpios(struct gpio_chip *chip) 245 { 246 struct gpio_desc *desc = NULL; 247 struct device_node *np; 248 const char *name; 249 enum gpio_lookup_flags lflags; 250 enum gpiod_flags dflags; 251 unsigned int i; 252 int ret; 253 254 for_each_available_child_of_node(chip->of_node, np) { 255 if (!of_property_read_bool(np, "gpio-hog")) 256 continue; 257 258 for (i = 0;; i++) { 259 desc = of_parse_own_gpio(np, chip, i, &name, &lflags, 260 &dflags); 261 if (IS_ERR(desc)) 262 break; 263 264 ret = gpiod_hog(desc, name, lflags, dflags); 265 if (ret < 0) { 266 of_node_put(np); 267 return ret; 268 } 269 } 270 } 271 272 return 0; 273 } 274 275 /** 276 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 277 * @gc: pointer to the gpio_chip structure 278 * @np: device node of the GPIO chip 279 * @gpio_spec: gpio specifier as found in the device tree 280 * @flags: a flags pointer to fill in 281 * 282 * This is simple translation function, suitable for the most 1:1 mapped 283 * gpio chips. This function performs only one sanity check: whether gpio 284 * is less than ngpios (that is specified in the gpio_chip). 285 */ 286 int of_gpio_simple_xlate(struct gpio_chip *gc, 287 const struct of_phandle_args *gpiospec, u32 *flags) 288 { 289 /* 290 * We're discouraging gpio_cells < 2, since that way you'll have to 291 * write your own xlate function (that will have to retrieve the GPIO 292 * number and the flags from a single gpio cell -- this is possible, 293 * but not recommended). 294 */ 295 if (gc->of_gpio_n_cells < 2) { 296 WARN_ON(1); 297 return -EINVAL; 298 } 299 300 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 301 return -EINVAL; 302 303 if (gpiospec->args[0] >= gc->ngpio) 304 return -EINVAL; 305 306 if (flags) 307 *flags = gpiospec->args[1]; 308 309 return gpiospec->args[0]; 310 } 311 EXPORT_SYMBOL(of_gpio_simple_xlate); 312 313 /** 314 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank) 315 * @np: device node of the GPIO chip 316 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 317 * @data: driver data to store in the struct gpio_chip 318 * 319 * To use this function you should allocate and fill mm_gc with: 320 * 321 * 1) In the gpio_chip structure: 322 * - all the callbacks 323 * - of_gpio_n_cells 324 * - of_xlate callback (optional) 325 * 326 * 3) In the of_mm_gpio_chip structure: 327 * - save_regs callback (optional) 328 * 329 * If succeeded, this function will map bank's memory and will 330 * do all necessary work for you. Then you'll able to use .regs 331 * to manage GPIOs from the callbacks. 332 */ 333 int of_mm_gpiochip_add_data(struct device_node *np, 334 struct of_mm_gpio_chip *mm_gc, 335 void *data) 336 { 337 int ret = -ENOMEM; 338 struct gpio_chip *gc = &mm_gc->gc; 339 340 gc->label = kstrdup(np->full_name, GFP_KERNEL); 341 if (!gc->label) 342 goto err0; 343 344 mm_gc->regs = of_iomap(np, 0); 345 if (!mm_gc->regs) 346 goto err1; 347 348 gc->base = -1; 349 350 if (mm_gc->save_regs) 351 mm_gc->save_regs(mm_gc); 352 353 mm_gc->gc.of_node = np; 354 355 ret = gpiochip_add_data(gc, data); 356 if (ret) 357 goto err2; 358 359 return 0; 360 err2: 361 iounmap(mm_gc->regs); 362 err1: 363 kfree(gc->label); 364 err0: 365 pr_err("%s: GPIO chip registration failed with status %d\n", 366 np->full_name, ret); 367 return ret; 368 } 369 EXPORT_SYMBOL(of_mm_gpiochip_add_data); 370 371 /** 372 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank) 373 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 374 */ 375 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) 376 { 377 struct gpio_chip *gc = &mm_gc->gc; 378 379 if (!mm_gc) 380 return; 381 382 gpiochip_remove(gc); 383 iounmap(mm_gc->regs); 384 kfree(gc->label); 385 } 386 EXPORT_SYMBOL(of_mm_gpiochip_remove); 387 388 #ifdef CONFIG_PINCTRL 389 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) 390 { 391 struct device_node *np = chip->of_node; 392 struct of_phandle_args pinspec; 393 struct pinctrl_dev *pctldev; 394 int index = 0, ret; 395 const char *name; 396 static const char group_names_propname[] = "gpio-ranges-group-names"; 397 struct property *group_names; 398 399 if (!np) 400 return 0; 401 402 group_names = of_find_property(np, group_names_propname, NULL); 403 404 for (;; index++) { 405 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 406 index, &pinspec); 407 if (ret) 408 break; 409 410 pctldev = of_pinctrl_get(pinspec.np); 411 of_node_put(pinspec.np); 412 if (!pctldev) 413 return -EPROBE_DEFER; 414 415 if (pinspec.args[2]) { 416 if (group_names) { 417 of_property_read_string_index(np, 418 group_names_propname, 419 index, &name); 420 if (strlen(name)) { 421 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", 422 np->full_name); 423 break; 424 } 425 } 426 /* npins != 0: linear range */ 427 ret = gpiochip_add_pin_range(chip, 428 pinctrl_dev_get_devname(pctldev), 429 pinspec.args[0], 430 pinspec.args[1], 431 pinspec.args[2]); 432 if (ret) 433 return ret; 434 } else { 435 /* npins == 0: special range */ 436 if (pinspec.args[1]) { 437 pr_err("%s: Illegal gpio-range format.\n", 438 np->full_name); 439 break; 440 } 441 442 if (!group_names) { 443 pr_err("%s: GPIO group range requested but no %s property.\n", 444 np->full_name, group_names_propname); 445 break; 446 } 447 448 ret = of_property_read_string_index(np, 449 group_names_propname, 450 index, &name); 451 if (ret) 452 break; 453 454 if (!strlen(name)) { 455 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", 456 np->full_name); 457 break; 458 } 459 460 ret = gpiochip_add_pingroup_range(chip, pctldev, 461 pinspec.args[0], name); 462 if (ret) 463 return ret; 464 } 465 } 466 467 return 0; 468 } 469 470 #else 471 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; } 472 #endif 473 474 int of_gpiochip_add(struct gpio_chip *chip) 475 { 476 int status; 477 478 if ((!chip->of_node) && (chip->parent)) 479 chip->of_node = chip->parent->of_node; 480 481 if (!chip->of_node) 482 return 0; 483 484 if (!chip->of_xlate) { 485 chip->of_gpio_n_cells = 2; 486 chip->of_xlate = of_gpio_simple_xlate; 487 } 488 489 if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS) 490 return -EINVAL; 491 492 status = of_gpiochip_add_pin_range(chip); 493 if (status) 494 return status; 495 496 /* If the chip defines names itself, these take precedence */ 497 if (!chip->names) 498 devprop_gpiochip_set_names(chip); 499 500 of_node_get(chip->of_node); 501 502 return of_gpiochip_scan_gpios(chip); 503 } 504 505 void of_gpiochip_remove(struct gpio_chip *chip) 506 { 507 gpiochip_remove_pin_ranges(chip); 508 of_node_put(chip->of_node); 509 } 510