drivers/gpio/gpiolib-of.c

   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 }