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 /* Private data structure for of_gpiochip_find_and_xlate */
  30 struct gg_data {
  31         enum of_gpio_flags *flags;
  32         struct of_phandle_args gpiospec;
  33
  34         struct gpio_desc *out_gpio;
  35 };
  36
  37 /* Private function for resolving node pointer to gpio_chip */
  38 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
  39 {
  40         struct gg_data *gg_data = data;
  41         int ret;
  42
  43         if ((gc->of_node != gg_data->gpiospec.np) ||
  44             (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
  45             (!gc->of_xlate))
  46                 return false;
  47
  48         ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
  49         if (ret < 0) {
  50                 /* We've found a gpio chip, but the translation failed.
  51                  * Store translation error in out_gpio.
  52                  * Return false to keep looking, as more than one gpio chip
  53                  * could be registered per of-node.
  54                  */
  55                 gg_data->out_gpio = ERR_PTR(ret);
  56                 return false;
  57          }
  58
  59         gg_data->out_gpio = gpiochip_get_desc(gc, ret);
  60         return true;
  61 }
  62
  63 /**
  64  * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
  65  * @np:         device node to get GPIO from
  66  * @propname:   property name containing gpio specifier(s)
  67  * @index:      index of the GPIO
  68  * @flags:      a flags pointer to fill in
  69  *
  70  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
  71  * value on the error condition. If @flags is not NULL the function also fills
  72  * in flags for the GPIO.
  73  */
  74 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
  75                      const char *propname, int index, enum of_gpio_flags *flags)
  76 {
  77         /* Return -EPROBE_DEFER to support probe() functions to be called
  78          * later when the GPIO actually becomes available
  79          */
  80         struct gg_data gg_data = {
  81                 .flags = flags,
  82                 .out_gpio = ERR_PTR(-EPROBE_DEFER)
  83         };
  84         int ret;
  85
  86         /* .of_xlate might decide to not fill in the flags, so clear it. */
  87         if (flags)
  88                 *flags = 0;
  89
  90         ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
  91                                          &gg_data.gpiospec);
  92         if (ret) {
  93                 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
  94                         __func__, propname, np->full_name, index);
  95                 return ERR_PTR(ret);
  96         }
  97
  98         gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
  99
 100         of_node_put(gg_data.gpiospec.np);
 101         pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
 102                  __func__, propname, np->full_name, index,
 103                  PTR_ERR_OR_ZERO(gg_data.out_gpio));
 104         return gg_data.out_gpio;
 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 /**
 122  * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
 123  * @np:         device node to get GPIO from
 124  * @chip:       GPIO chip whose hog is parsed
 125  * @name:       GPIO line name
 126  * @lflags:     gpio_lookup_flags - returned from of_find_gpio() or
 127  *              of_parse_own_gpio()
 128  * @dflags:     gpiod_flags - optional GPIO initialization flags
 129  *
 130  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
 131  * value on the error condition.
 132  */
 133 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
 134                                            struct gpio_chip *chip,
 135                                            const char **name,
 136                                            enum gpio_lookup_flags *lflags,
 137                                            enum gpiod_flags *dflags)
 138 {
 139         struct device_node *chip_np;
 140         enum of_gpio_flags xlate_flags;
 141         struct of_phandle_args gpiospec;
 142         struct gpio_desc *desc;
 143         u32 tmp;
 144         int ret;
 145
 146         chip_np = chip->of_node;
 147         if (!chip_np)
 148                 return ERR_PTR(-EINVAL);
 149
 150         xlate_flags = 0;
 151         *lflags = 0;
 152         *dflags = 0;
 153
 154         ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
 155         if (ret)
 156                 return ERR_PTR(ret);
 157
 158         if (tmp != chip->of_gpio_n_cells)
 159                 return ERR_PTR(-EINVAL);
 160
 161         gpiospec.np = chip_np;
 162         gpiospec.args_count = tmp;
 163
 164         ret = of_property_read_u32_array(np, "gpios", gpiospec.args, tmp);
 165         if (ret)
 166                 return ERR_PTR(ret);
 167
 168         ret = chip->of_xlate(chip, &gpiospec, &xlate_flags);
 169         if (ret < 0)
 170                 return ERR_PTR(ret);
 171
 172         desc = gpiochip_get_desc(chip, ret);
 173         if (IS_ERR(desc))
 174                 return desc;
 175
 176         if (xlate_flags & OF_GPIO_ACTIVE_LOW)
 177                 *lflags |= GPIO_ACTIVE_LOW;
 178
 179         if (of_property_read_bool(np, "input"))
 180                 *dflags |= GPIOD_IN;
 181         else if (of_property_read_bool(np, "output-low"))
 182                 *dflags |= GPIOD_OUT_LOW;
 183         else if (of_property_read_bool(np, "output-high"))
 184                 *dflags |= GPIOD_OUT_HIGH;
 185         else {
 186                 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
 187                         desc_to_gpio(desc), np->name);
 188                 return ERR_PTR(-EINVAL);
 189         }
 190
 191         if (name && of_property_read_string(np, "line-name", name))
 192                 *name = np->name;
 193
 194         return desc;
 195 }
 196
 197 /**
 198  * of_gpiochip_set_names() - set up the names of the lines
 199  * @chip: GPIO chip whose lines should be named, if possible
 200  */
 201 static void of_gpiochip_set_names(struct gpio_chip *gc)
 202 {
 203         struct gpio_device *gdev = gc->gpiodev;
 204         struct device_node *np = gc->of_node;
 205         int i;
 206         int nstrings;
 207
 208         nstrings = of_property_count_strings(np, "gpio-line-names");
 209         if (nstrings <= 0)
 210                 /* Lines names not present */
 211                 return;
 212
 213         /* This is normally not what you want */
 214         if (gdev->ngpio != nstrings)
 215                 dev_info(&gdev->dev, "gpio-line-names specifies %d line "
 216                          "names but there are %d lines on the chip\n",
 217                          nstrings, gdev->ngpio);
 218
 219         /*
 220          * Make sure to not index beyond the end of the number of descriptors
 221          * of the GPIO device.
 222          */
 223         for (i = 0; i < gdev->ngpio; i++) {
 224                 const char *name;
 225                 int ret;
 226
 227                 ret = of_property_read_string_index(np,
 228                                                     "gpio-line-names",
 229                                                     i,
 230                                                     &name);
 231                 if (ret) {
 232                         if (ret != -ENODATA)
 233                                 dev_err(&gdev->dev,
 234                                         "unable to name line %d: %d\n",
 235                                         i, ret);
 236                         break;
 237                 }
 238                 gdev->descs[i].name = name;
 239         }
 240 }
 241
 242 /**
 243  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
 244  * @chip:       gpio chip to act on
 245  *
 246  * This is only used by of_gpiochip_add to request/set GPIO initial
 247  * configuration.
 248  * It retures error if it fails otherwise 0 on success.
 249  */
 250 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
 251 {
 252         struct gpio_desc *desc = NULL;
 253         struct device_node *np;
 254         const char *name;
 255         enum gpio_lookup_flags lflags;
 256         enum gpiod_flags dflags;
 257         int ret;
 258
 259         for_each_available_child_of_node(chip->of_node, np) {
 260                 if (!of_property_read_bool(np, "gpio-hog"))
 261                         continue;
 262
 263                 desc = of_parse_own_gpio(np, chip, &name, &lflags, &dflags);
 264                 if (IS_ERR(desc))
 265                         continue;
 266
 267                 ret = gpiod_hog(desc, name, lflags, dflags);
 268                 if (ret < 0)
 269                         return ret;
 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                 of_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 }