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_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 }