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