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 '%pOF[%d]'\n", 82 __func__, propname, np, 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 '%pOF[%d]' - status (%d)\n", 97 __func__, propname, np, 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 gpiospec to the GPIO number and flags 277 * @gc: pointer to the gpio_chip structure 278 * @gpiospec: GPIO specifier as found in the device tree 279 * @flags: a flags pointer to fill in 280 * 281 * This is simple translation function, suitable for the most 1:1 mapped 282 * GPIO chips. This function performs only one sanity check: whether GPIO 283 * is less than ngpios (that is specified in the gpio_chip). 284 */ 285 int of_gpio_simple_xlate(struct gpio_chip *gc, 286 const struct of_phandle_args *gpiospec, u32 *flags) 287 { 288 /* 289 * We're discouraging gpio_cells < 2, since that way you'll have to 290 * write your own xlate function (that will have to retrieve the GPIO 291 * number and the flags from a single gpio cell -- this is possible, 292 * but not recommended). 293 */ 294 if (gc->of_gpio_n_cells < 2) { 295 WARN_ON(1); 296 return -EINVAL; 297 } 298 299 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 300 return -EINVAL; 301 302 if (gpiospec->args[0] >= gc->ngpio) 303 return -EINVAL; 304 305 if (flags) 306 *flags = gpiospec->args[1]; 307 308 return gpiospec->args[0]; 309 } 310 EXPORT_SYMBOL(of_gpio_simple_xlate); 311 312 /** 313 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank) 314 * @np: device node of the GPIO chip 315 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 316 * @data: driver data to store in the struct gpio_chip 317 * 318 * To use this function you should allocate and fill mm_gc with: 319 * 320 * 1) In the gpio_chip structure: 321 * - all the callbacks 322 * - of_gpio_n_cells 323 * - of_xlate callback (optional) 324 * 325 * 3) In the of_mm_gpio_chip structure: 326 * - save_regs callback (optional) 327 * 328 * If succeeded, this function will map bank's memory and will 329 * do all necessary work for you. Then you'll able to use .regs 330 * to manage GPIOs from the callbacks. 331 */ 332 int of_mm_gpiochip_add_data(struct device_node *np, 333 struct of_mm_gpio_chip *mm_gc, 334 void *data) 335 { 336 int ret = -ENOMEM; 337 struct gpio_chip *gc = &mm_gc->gc; 338 339 gc->label = kasprintf(GFP_KERNEL, "%pOF", np); 340 if (!gc->label) 341 goto err0; 342 343 mm_gc->regs = of_iomap(np, 0); 344 if (!mm_gc->regs) 345 goto err1; 346 347 gc->base = -1; 348 349 if (mm_gc->save_regs) 350 mm_gc->save_regs(mm_gc); 351 352 mm_gc->gc.of_node = np; 353 354 ret = gpiochip_add_data(gc, data); 355 if (ret) 356 goto err2; 357 358 return 0; 359 err2: 360 iounmap(mm_gc->regs); 361 err1: 362 kfree(gc->label); 363 err0: 364 pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret); 365 return ret; 366 } 367 EXPORT_SYMBOL(of_mm_gpiochip_add_data); 368 369 /** 370 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank) 371 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 372 */ 373 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) 374 { 375 struct gpio_chip *gc = &mm_gc->gc; 376 377 if (!mm_gc) 378 return; 379 380 gpiochip_remove(gc); 381 iounmap(mm_gc->regs); 382 kfree(gc->label); 383 } 384 EXPORT_SYMBOL(of_mm_gpiochip_remove); 385 386 #ifdef CONFIG_PINCTRL 387 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) 388 { 389 struct device_node *np = chip->of_node; 390 struct of_phandle_args pinspec; 391 struct pinctrl_dev *pctldev; 392 int index = 0, ret; 393 const char *name; 394 static const char group_names_propname[] = "gpio-ranges-group-names"; 395 struct property *group_names; 396 397 if (!np) 398 return 0; 399 400 group_names = of_find_property(np, group_names_propname, NULL); 401 402 for (;; index++) { 403 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 404 index, &pinspec); 405 if (ret) 406 break; 407 408 pctldev = of_pinctrl_get(pinspec.np); 409 of_node_put(pinspec.np); 410 if (!pctldev) 411 return -EPROBE_DEFER; 412 413 if (pinspec.args[2]) { 414 if (group_names) { 415 of_property_read_string_index(np, 416 group_names_propname, 417 index, &name); 418 if (strlen(name)) { 419 pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n", 420 np); 421 break; 422 } 423 } 424 /* npins != 0: linear range */ 425 ret = gpiochip_add_pin_range(chip, 426 pinctrl_dev_get_devname(pctldev), 427 pinspec.args[0], 428 pinspec.args[1], 429 pinspec.args[2]); 430 if (ret) 431 return ret; 432 } else { 433 /* npins == 0: special range */ 434 if (pinspec.args[1]) { 435 pr_err("%pOF: Illegal gpio-range format.\n", 436 np); 437 break; 438 } 439 440 if (!group_names) { 441 pr_err("%pOF: GPIO group range requested but no %s property.\n", 442 np, group_names_propname); 443 break; 444 } 445 446 ret = of_property_read_string_index(np, 447 group_names_propname, 448 index, &name); 449 if (ret) 450 break; 451 452 if (!strlen(name)) { 453 pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n", 454 np); 455 break; 456 } 457 458 ret = gpiochip_add_pingroup_range(chip, pctldev, 459 pinspec.args[0], name); 460 if (ret) 461 return ret; 462 } 463 } 464 465 return 0; 466 } 467 468 #else 469 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; } 470 #endif 471 472 int of_gpiochip_add(struct gpio_chip *chip) 473 { 474 int status; 475 476 if ((!chip->of_node) && (chip->parent)) 477 chip->of_node = chip->parent->of_node; 478 479 if (!chip->of_node) 480 return 0; 481 482 if (!chip->of_xlate) { 483 chip->of_gpio_n_cells = 2; 484 chip->of_xlate = of_gpio_simple_xlate; 485 } 486 487 if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS) 488 return -EINVAL; 489 490 status = of_gpiochip_add_pin_range(chip); 491 if (status) 492 return status; 493 494 /* If the chip defines names itself, these take precedence */ 495 if (!chip->names) 496 devprop_gpiochip_set_names(chip); 497 498 of_node_get(chip->of_node); 499 500 return of_gpiochip_scan_gpios(chip); 501 } 502 503 void of_gpiochip_remove(struct gpio_chip *chip) 504 { 505 gpiochip_remove_pin_ranges(chip); 506 of_node_put(chip->of_node); 507 } 508