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 &&
  35                                 chip->of_xlate(chip, gpiospec, NULL) >= 0;
  36 }
  37
  38 static struct gpio_chip *of_find_gpiochip_by_xlate(
  39                                         struct of_phandle_args *gpiospec)
  40 {
  41         return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate);
  42 }
  43
  44 static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
  45                                         struct of_phandle_args *gpiospec,
  46                                         enum of_gpio_flags *flags)
  47 {
  48         int ret;
  49
  50         if (chip->of_gpio_n_cells != gpiospec->args_count)
  51                 return ERR_PTR(-EINVAL);
  52
  53         ret = chip->of_xlate(chip, gpiospec, flags);
  54         if (ret < 0)
  55                 return ERR_PTR(ret);
  56
  57         return gpiochip_get_desc(chip, ret);
  58 }
  59
  60 /**
  61  * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
  62  * @np:         device node to get GPIO from
  63  * @propname:   property name containing gpio specifier(s)
  64  * @index:      index of the GPIO
  65  * @flags:      a flags pointer to fill in
  66  *
  67  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
  68  * value on the error condition. If @flags is not NULL the function also fills
  69  * in flags for the GPIO.
  70  */
  71 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
  72                      const char *propname, int index, enum of_gpio_flags *flags)
  73 {
  74         struct of_phandle_args gpiospec;
  75         struct gpio_chip *chip;
  76         struct gpio_desc *desc;
  77         int ret;
  78
  79         ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
  80                                          &gpiospec);
  81         if (ret) {
  82                 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
  83                         __func__, propname, np ? np->full_name : NULL, index);
  84                 return ERR_PTR(ret);
  85         }
  86
  87         chip = of_find_gpiochip_by_xlate(&gpiospec);
  88         if (!chip) {
  89                 desc = ERR_PTR(-EPROBE_DEFER);
  90                 goto out;
  91         }
  92
  93         desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
  94         if (IS_ERR(desc))
  95                 goto out;
  96
  97         pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
  98                  __func__, propname, np->full_name, index,
  99                  PTR_ERR_OR_ZERO(desc));
 100
 101 out:
 102         of_node_put(gpiospec.np);
 103
 104         return desc;
 105 }
 106
 107 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
 108                             int index, enum of_gpio_flags *flags)
 109 {
 110         struct gpio_desc *desc;
 111
 112         desc = of_get_named_gpiod_flags(np, list_name, index, flags);
 113
 114         if (IS_ERR(desc))
 115                 return PTR_ERR(desc);
 116         else
 117                 return desc_to_gpio(desc);
 118 }
 119 EXPORT_SYMBOL(of_get_named_gpio_flags);
 120
 121 struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
 122                                unsigned int idx,
 123                                enum gpio_lookup_flags *flags)
 124 {
 125         char prop_name[32]; /* 32 is max size of property name */
 126         enum of_gpio_flags of_flags;
 127         struct gpio_desc *desc;
 128         unsigned int i;
 129
 130         for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
 131                 if (con_id)
 132                         snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
 133                                  gpio_suffixes[i]);
 134                 else
 135                         snprintf(prop_name, sizeof(prop_name), "%s",
 136                                  gpio_suffixes[i]);
 137
 138                 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
 139                                                 &of_flags);
 140                 if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
 141                         break;
 142         }
 143
 144         if (IS_ERR(desc))
 145                 return desc;
 146
 147         if (of_flags & OF_GPIO_ACTIVE_LOW)
 148                 *flags |= GPIO_ACTIVE_LOW;
 149
 150         if (of_flags & OF_GPIO_SINGLE_ENDED) {
 151                 if (of_flags & OF_GPIO_ACTIVE_LOW)
 152                         *flags |= GPIO_OPEN_DRAIN;
 153                 else
 154                         *flags |= GPIO_OPEN_SOURCE;
 155         }
 156
 157         return desc;
 158 }
 159
 160 /**
 161  * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
 162  * @np:         device node to get GPIO from
 163  * @chip:       GPIO chip whose hog is parsed
 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                                            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         u32 tmp;
 183         int ret;
 184
 185         chip_np = chip->of_node;
 186         if (!chip_np)
 187                 return ERR_PTR(-EINVAL);
 188
 189         xlate_flags = 0;
 190         *lflags = 0;
 191         *dflags = 0;
 192
 193         ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
 194         if (ret)
 195                 return ERR_PTR(ret);
 196
 197         gpiospec.np = chip_np;
 198         gpiospec.args_count = tmp;
 199
 200         ret = of_property_read_u32_array(np, "gpios", gpiospec.args, tmp);
 201         if (ret)
 202                 return ERR_PTR(ret);
 203
 204         desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
 205         if (IS_ERR(desc))
 206                 return desc;
 207
 208         if (xlate_flags & OF_GPIO_ACTIVE_LOW)
 209                 *lflags |= GPIO_ACTIVE_LOW;
 210
 211         if (of_property_read_bool(np, "input"))
 212                 *dflags |= GPIOD_IN;
 213         else if (of_property_read_bool(np, "output-low"))
 214                 *dflags |= GPIOD_OUT_LOW;
 215         else if (of_property_read_bool(np, "output-high"))
 216                 *dflags |= GPIOD_OUT_HIGH;
 217         else {
 218                 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
 219                         desc_to_gpio(desc), np->name);
 220                 return ERR_PTR(-EINVAL);
 221         }
 222
 223         if (name && of_property_read_string(np, "line-name", name))
 224                 *name = np->name;
 225
 226         return desc;
 227 }
 228
 229 /**
 230  * of_gpiochip_set_names() - set up the names of the lines
 231  * @chip: GPIO chip whose lines should be named, if possible
 232  */
 233 static void of_gpiochip_set_names(struct gpio_chip *gc)
 234 {
 235         struct gpio_device *gdev = gc->gpiodev;
 236         struct device_node *np = gc->of_node;
 237         int i;
 238         int nstrings;
 239
 240         nstrings = of_property_count_strings(np, "gpio-line-names");
 241         if (nstrings <= 0)
 242                 /* Lines names not present */
 243                 return;
 244
 245         /* This is normally not what you want */
 246         if (gdev->ngpio != nstrings)
 247                 dev_info(&gdev->dev, "gpio-line-names specifies %d line "
 248                          "names but there are %d lines on the chip\n",
 249                          nstrings, gdev->ngpio);
 250
 251         /*
 252          * Make sure to not index beyond the end of the number of descriptors
 253          * of the GPIO device.
 254          */
 255         for (i = 0; i < gdev->ngpio; i++) {
 256                 const char *name;
 257                 int ret;
 258
 259                 ret = of_property_read_string_index(np,
 260                                                     "gpio-line-names",
 261                                                     i,
 262                                                     &name);
 263                 if (ret) {
 264                         if (ret != -ENODATA)
 265                                 dev_err(&gdev->dev,
 266                                         "unable to name line %d: %d\n",
 267                                         i, ret);
 268                         break;
 269                 }
 270                 gdev->descs[i].name = name;
 271         }
 272 }
 273
 274 /**
 275  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
 276  * @chip:       gpio chip to act on
 277  *
 278  * This is only used by of_gpiochip_add to request/set GPIO initial
 279  * configuration.
 280  * It retures error if it fails otherwise 0 on success.
 281  */
 282 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
 283 {
 284         struct gpio_desc *desc = NULL;
 285         struct device_node *np;
 286         const char *name;
 287         enum gpio_lookup_flags lflags;
 288         enum gpiod_flags dflags;
 289         int ret;
 290
 291         for_each_available_child_of_node(chip->of_node, np) {
 292                 if (!of_property_read_bool(np, "gpio-hog"))
 293                         continue;
 294
 295                 desc = of_parse_own_gpio(np, chip, &name, &lflags, &dflags);
 296                 if (IS_ERR(desc))
 297                         continue;
 298
 299                 ret = gpiod_hog(desc, name, lflags, dflags);
 300                 if (ret < 0)
 301                         return ret;
 302         }
 303
 304         return 0;
 305 }
 306
 307 /**
 308  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 309  * @gc:         pointer to the gpio_chip structure
 310  * @np:         device node of the GPIO chip
 311  * @gpio_spec:  gpio specifier as found in the device tree
 312  * @flags:      a flags pointer to fill in
 313  *
 314  * This is simple translation function, suitable for the most 1:1 mapped
 315  * gpio chips. This function performs only one sanity check: whether gpio
 316  * is less than ngpios (that is specified in the gpio_chip).
 317  */
 318 int of_gpio_simple_xlate(struct gpio_chip *gc,
 319                          const struct of_phandle_args *gpiospec, u32 *flags)
 320 {
 321         /*
 322          * We're discouraging gpio_cells < 2, since that way you'll have to
 323          * write your own xlate function (that will have to retrieve the GPIO
 324          * number and the flags from a single gpio cell -- this is possible,
 325          * but not recommended).
 326          */
 327         if (gc->of_gpio_n_cells < 2) {
 328                 WARN_ON(1);
 329                 return -EINVAL;
 330         }
 331
 332         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 333                 return -EINVAL;
 334
 335         if (gpiospec->args[0] >= gc->ngpio)
 336                 return -EINVAL;
 337
 338         if (flags)
 339                 *flags = gpiospec->args[1];
 340
 341         return gpiospec->args[0];
 342 }
 343 EXPORT_SYMBOL(of_gpio_simple_xlate);
 344
 345 /**
 346  * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
 347  * @np:         device node of the GPIO chip
 348  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 349  * @data:       driver data to store in the struct gpio_chip
 350  *
 351  * To use this function you should allocate and fill mm_gc with:
 352  *
 353  * 1) In the gpio_chip structure:
 354  *    - all the callbacks
 355  *    - of_gpio_n_cells
 356  *    - of_xlate callback (optional)
 357  *
 358  * 3) In the of_mm_gpio_chip structure:
 359  *    - save_regs callback (optional)
 360  *
 361  * If succeeded, this function will map bank's memory and will
 362  * do all necessary work for you. Then you'll able to use .regs
 363  * to manage GPIOs from the callbacks.
 364  */
 365 int of_mm_gpiochip_add_data(struct device_node *np,
 366                             struct of_mm_gpio_chip *mm_gc,
 367                             void *data)
 368 {
 369         int ret = -ENOMEM;
 370         struct gpio_chip *gc = &mm_gc->gc;
 371
 372         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 373         if (!gc->label)
 374                 goto err0;
 375
 376         mm_gc->regs = of_iomap(np, 0);
 377         if (!mm_gc->regs)
 378                 goto err1;
 379
 380         gc->base = -1;
 381
 382         if (mm_gc->save_regs)
 383                 mm_gc->save_regs(mm_gc);
 384
 385         mm_gc->gc.of_node = np;
 386
 387         ret = gpiochip_add_data(gc, data);
 388         if (ret)
 389                 goto err2;
 390
 391         return 0;
 392 err2:
 393         iounmap(mm_gc->regs);
 394 err1:
 395         kfree(gc->label);
 396 err0:
 397         pr_err("%s: GPIO chip registration failed with status %d\n",
 398                np->full_name, ret);
 399         return ret;
 400 }
 401 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
 402
 403 /**
 404  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
 405  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 406  */
 407 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
 408 {
 409         struct gpio_chip *gc = &mm_gc->gc;
 410
 411         if (!mm_gc)
 412                 return;
 413
 414         gpiochip_remove(gc);
 415         iounmap(mm_gc->regs);
 416         kfree(gc->label);
 417 }
 418 EXPORT_SYMBOL(of_mm_gpiochip_remove);
 419
 420 #ifdef CONFIG_PINCTRL
 421 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
 422 {
 423         struct device_node *np = chip->of_node;
 424         struct of_phandle_args pinspec;
 425         struct pinctrl_dev *pctldev;
 426         int index = 0, ret;
 427         const char *name;
 428         static const char group_names_propname[] = "gpio-ranges-group-names";
 429         struct property *group_names;
 430
 431         if (!np)
 432                 return 0;
 433
 434         group_names = of_find_property(np, group_names_propname, NULL);
 435
 436         for (;; index++) {
 437                 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
 438                                 index, &pinspec);
 439                 if (ret)
 440                         break;
 441
 442                 pctldev = of_pinctrl_get(pinspec.np);
 443                 of_node_put(pinspec.np);
 444                 if (!pctldev)
 445                         return -EPROBE_DEFER;
 446
 447                 if (pinspec.args[2]) {
 448                         if (group_names) {
 449                                 of_property_read_string_index(np,
 450                                                 group_names_propname,
 451                                                 index, &name);
 452                                 if (strlen(name)) {
 453                                         pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
 454                                                 np->full_name);
 455                                         break;
 456                                 }
 457                         }
 458                         /* npins != 0: linear range */
 459                         ret = gpiochip_add_pin_range(chip,
 460                                         pinctrl_dev_get_devname(pctldev),
 461                                         pinspec.args[0],
 462                                         pinspec.args[1],
 463                                         pinspec.args[2]);
 464                         if (ret)
 465                                 return ret;
 466                 } else {
 467                         /* npins == 0: special range */
 468                         if (pinspec.args[1]) {
 469                                 pr_err("%s: Illegal gpio-range format.\n",
 470                                         np->full_name);
 471                                 break;
 472                         }
 473
 474                         if (!group_names) {
 475                                 pr_err("%s: GPIO group range requested but no %s property.\n",
 476                                         np->full_name, group_names_propname);
 477                                 break;
 478                         }
 479
 480                         ret = of_property_read_string_index(np,
 481                                                 group_names_propname,
 482                                                 index, &name);
 483                         if (ret)
 484                                 break;
 485
 486                         if (!strlen(name)) {
 487                                 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
 488                                 np->full_name);
 489                                 break;
 490                         }
 491
 492                         ret = gpiochip_add_pingroup_range(chip, pctldev,
 493                                                 pinspec.args[0], name);
 494                         if (ret)
 495                                 return ret;
 496                 }
 497         }
 498
 499         return 0;
 500 }
 501
 502 #else
 503 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
 504 #endif
 505
 506 int of_gpiochip_add(struct gpio_chip *chip)
 507 {
 508         int status;
 509
 510         if ((!chip->of_node) && (chip->parent))
 511                 chip->of_node = chip->parent->of_node;
 512
 513         if (!chip->of_node)
 514                 return 0;
 515
 516         if (!chip->of_xlate) {
 517                 chip->of_gpio_n_cells = 2;
 518                 chip->of_xlate = of_gpio_simple_xlate;
 519         }
 520
 521         if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
 522                 return -EINVAL;
 523
 524         status = of_gpiochip_add_pin_range(chip);
 525         if (status)
 526                 return status;
 527
 528         /* If the chip defines names itself, these take precedence */
 529         if (!chip->names)
 530                 of_gpiochip_set_names(chip);
 531
 532         of_node_get(chip->of_node);
 533
 534         status = of_gpiochip_scan_gpios(chip);
 535         if (status) {
 536                 of_node_put(chip->of_node);
 537                 gpiochip_remove_pin_ranges(chip);
 538         }
 539
 540         return status;
 541 }
 542
 543 void of_gpiochip_remove(struct gpio_chip *chip)
 544 {
 545         gpiochip_remove_pin_ranges(chip);
 546         of_node_put(chip->of_node);
 547 }