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/io-mapping.h>
  20 #include <linux/gpio/consumer.h>
  21 #include <linux/of.h>
  22 #include <linux/of_address.h>
  23 #include <linux/of_gpio.h>
  24 #include <linux/pinctrl/pinctrl.h>
  25 #include <linux/slab.h>
  26 #include <linux/gpio/machine.h>
  27
  28 #include "gpiolib.h"
  29
  30 static int of_gpiochip_match_node(struct gpio_chip *chip, void *data)
  31 {
  32         return chip->gpiodev->dev.of_node == data;
  33 }
  34
  35 static struct gpio_chip *of_find_gpiochip_by_node(struct device_node *np)
  36 {
  37         return gpiochip_find(np, of_gpiochip_match_node);
  38 }
  39
  40 static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
  41                                         struct of_phandle_args *gpiospec,
  42                                         enum of_gpio_flags *flags)
  43 {
  44         int ret;
  45
  46         if (chip->of_gpio_n_cells != gpiospec->args_count)
  47                 return ERR_PTR(-EINVAL);
  48
  49         ret = chip->of_xlate(chip, gpiospec, flags);
  50         if (ret < 0)
  51                 return ERR_PTR(ret);
  52
  53         return gpiochip_get_desc(chip, ret);
  54 }
  55
  56 /**
  57  * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
  58  * @np:         device node to get GPIO from
  59  * @propname:   property name containing gpio specifier(s)
  60  * @index:      index of the GPIO
  61  * @flags:      a flags pointer to fill in
  62  *
  63  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
  64  * value on the error condition. If @flags is not NULL the function also fills
  65  * in flags for the GPIO.
  66  */
  67 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
  68                      const char *propname, int index, enum of_gpio_flags *flags)
  69 {
  70         struct of_phandle_args gpiospec;
  71         struct gpio_chip *chip;
  72         struct gpio_desc *desc;
  73         int ret;
  74
  75         ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
  76                                          &gpiospec);
  77         if (ret) {
  78                 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
  79                         __func__, propname, np->full_name, index);
  80                 return ERR_PTR(ret);
  81         }
  82
  83         chip = of_find_gpiochip_by_node(gpiospec.np);
  84         if (!chip) {
  85                 desc = ERR_PTR(-EPROBE_DEFER);
  86                 goto out;
  87         }
  88
  89         desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
  90         if (IS_ERR(desc))
  91                 goto out;
  92
  93         pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
  94                  __func__, propname, np->full_name, index,
  95                  PTR_ERR_OR_ZERO(desc));
  96
  97 out:
  98         of_node_put(gpiospec.np);
  99
 100         return desc;
 101 }
 102
 103 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
 104                             int index, enum of_gpio_flags *flags)
 105 {
 106         struct gpio_desc *desc;
 107
 108         desc = of_get_named_gpiod_flags(np, list_name, index, flags);
 109
 110         if (IS_ERR(desc))
 111                 return PTR_ERR(desc);
 112         else
 113                 return desc_to_gpio(desc);
 114 }
 115 EXPORT_SYMBOL(of_get_named_gpio_flags);
 116
 117 /**
 118  * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
 119  * @np:         device node to get GPIO from
 120  * @chip:       GPIO chip whose hog is parsed
 121  * @name:       GPIO line name
 122  * @lflags:     gpio_lookup_flags - returned from of_find_gpio() or
 123  *              of_parse_own_gpio()
 124  * @dflags:     gpiod_flags - optional GPIO initialization flags
 125  *
 126  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
 127  * value on the error condition.
 128  */
 129 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
 130                                            struct gpio_chip *chip,
 131                                            const char **name,
 132                                            enum gpio_lookup_flags *lflags,
 133                                            enum gpiod_flags *dflags)
 134 {
 135         struct device_node *chip_np;
 136         enum of_gpio_flags xlate_flags;
 137         struct of_phandle_args gpiospec;
 138         struct gpio_desc *desc;
 139         u32 tmp;
 140         int ret;
 141
 142         chip_np = chip->of_node;
 143         if (!chip_np)
 144                 return ERR_PTR(-EINVAL);
 145
 146         xlate_flags = 0;
 147         *lflags = 0;
 148         *dflags = 0;
 149
 150         ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
 151         if (ret)
 152                 return ERR_PTR(ret);
 153
 154         gpiospec.np = chip_np;
 155         gpiospec.args_count = tmp;
 156
 157         ret = of_property_read_u32_array(np, "gpios", gpiospec.args, tmp);
 158         if (ret)
 159                 return ERR_PTR(ret);
 160
 161         desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
 162         if (IS_ERR(desc))
 163                 return desc;
 164
 165         if (xlate_flags & OF_GPIO_ACTIVE_LOW)
 166                 *lflags |= GPIO_ACTIVE_LOW;
 167
 168         if (of_property_read_bool(np, "input"))
 169                 *dflags |= GPIOD_IN;
 170         else if (of_property_read_bool(np, "output-low"))
 171                 *dflags |= GPIOD_OUT_LOW;
 172         else if (of_property_read_bool(np, "output-high"))
 173                 *dflags |= GPIOD_OUT_HIGH;
 174         else {
 175                 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
 176                         desc_to_gpio(desc), np->name);
 177                 return ERR_PTR(-EINVAL);
 178         }
 179
 180         if (name && of_property_read_string(np, "line-name", name))
 181                 *name = np->name;
 182
 183         return desc;
 184 }
 185
 186 /**
 187  * of_gpiochip_set_names() - set up the names of the lines
 188  * @chip: GPIO chip whose lines should be named, if possible
 189  */
 190 static void of_gpiochip_set_names(struct gpio_chip *gc)
 191 {
 192         struct gpio_device *gdev = gc->gpiodev;
 193         struct device_node *np = gc->of_node;
 194         int i;
 195         int nstrings;
 196
 197         nstrings = of_property_count_strings(np, "gpio-line-names");
 198         if (nstrings <= 0)
 199                 /* Lines names not present */
 200                 return;
 201
 202         /* This is normally not what you want */
 203         if (gdev->ngpio != nstrings)
 204                 dev_info(&gdev->dev, "gpio-line-names specifies %d line "
 205                          "names but there are %d lines on the chip\n",
 206                          nstrings, gdev->ngpio);
 207
 208         /*
 209          * Make sure to not index beyond the end of the number of descriptors
 210          * of the GPIO device.
 211          */
 212         for (i = 0; i < gdev->ngpio; i++) {
 213                 const char *name;
 214                 int ret;
 215
 216                 ret = of_property_read_string_index(np,
 217                                                     "gpio-line-names",
 218                                                     i,
 219                                                     &name);
 220                 if (ret) {
 221                         if (ret != -ENODATA)
 222                                 dev_err(&gdev->dev,
 223                                         "unable to name line %d: %d\n",
 224                                         i, ret);
 225                         break;
 226                 }
 227                 gdev->descs[i].name = name;
 228         }
 229 }
 230
 231 /**
 232  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
 233  * @chip:       gpio chip to act on
 234  *
 235  * This is only used by of_gpiochip_add to request/set GPIO initial
 236  * configuration.
 237  * It retures error if it fails otherwise 0 on success.
 238  */
 239 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
 240 {
 241         struct gpio_desc *desc = NULL;
 242         struct device_node *np;
 243         const char *name;
 244         enum gpio_lookup_flags lflags;
 245         enum gpiod_flags dflags;
 246         int ret;
 247
 248         for_each_available_child_of_node(chip->of_node, np) {
 249                 if (!of_property_read_bool(np, "gpio-hog"))
 250                         continue;
 251
 252                 desc = of_parse_own_gpio(np, chip, &name, &lflags, &dflags);
 253                 if (IS_ERR(desc))
 254                         continue;
 255
 256                 ret = gpiod_hog(desc, name, lflags, dflags);
 257                 if (ret < 0)
 258                         return ret;
 259         }
 260
 261         return 0;
 262 }
 263
 264 /**
 265  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 266  * @gc:         pointer to the gpio_chip structure
 267  * @np:         device node of the GPIO chip
 268  * @gpio_spec:  gpio specifier as found in the device tree
 269  * @flags:      a flags pointer to fill in
 270  *
 271  * This is simple translation function, suitable for the most 1:1 mapped
 272  * gpio chips. This function performs only one sanity check: whether gpio
 273  * is less than ngpios (that is specified in the gpio_chip).
 274  */
 275 int of_gpio_simple_xlate(struct gpio_chip *gc,
 276                          const struct of_phandle_args *gpiospec, u32 *flags)
 277 {
 278         /*
 279          * We're discouraging gpio_cells < 2, since that way you'll have to
 280          * write your own xlate function (that will have to retrieve the GPIO
 281          * number and the flags from a single gpio cell -- this is possible,
 282          * but not recommended).
 283          */
 284         if (gc->of_gpio_n_cells < 2) {
 285                 WARN_ON(1);
 286                 return -EINVAL;
 287         }
 288
 289         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 290                 return -EINVAL;
 291
 292         if (gpiospec->args[0] >= gc->ngpio)
 293                 return -EINVAL;
 294
 295         if (flags)
 296                 *flags = gpiospec->args[1];
 297
 298         return gpiospec->args[0];
 299 }
 300 EXPORT_SYMBOL(of_gpio_simple_xlate);
 301
 302 /**
 303  * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
 304  * @np:         device node of the GPIO chip
 305  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 306  * @data:       driver data to store in the struct gpio_chip
 307  *
 308  * To use this function you should allocate and fill mm_gc with:
 309  *
 310  * 1) In the gpio_chip structure:
 311  *    - all the callbacks
 312  *    - of_gpio_n_cells
 313  *    - of_xlate callback (optional)
 314  *
 315  * 3) In the of_mm_gpio_chip structure:
 316  *    - save_regs callback (optional)
 317  *
 318  * If succeeded, this function will map bank's memory and will
 319  * do all necessary work for you. Then you'll able to use .regs
 320  * to manage GPIOs from the callbacks.
 321  */
 322 int of_mm_gpiochip_add_data(struct device_node *np,
 323                             struct of_mm_gpio_chip *mm_gc,
 324                             void *data)
 325 {
 326         int ret = -ENOMEM;
 327         struct gpio_chip *gc = &mm_gc->gc;
 328
 329         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 330         if (!gc->label)
 331                 goto err0;
 332
 333         mm_gc->regs = of_iomap(np, 0);
 334         if (!mm_gc->regs)
 335                 goto err1;
 336
 337         gc->base = -1;
 338
 339         if (mm_gc->save_regs)
 340                 mm_gc->save_regs(mm_gc);
 341
 342         mm_gc->gc.of_node = np;
 343
 344         ret = gpiochip_add_data(gc, data);
 345         if (ret)
 346                 goto err2;
 347
 348         return 0;
 349 err2:
 350         iounmap(mm_gc->regs);
 351 err1:
 352         kfree(gc->label);
 353 err0:
 354         pr_err("%s: GPIO chip registration failed with status %d\n",
 355                np->full_name, ret);
 356         return ret;
 357 }
 358 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
 359
 360 /**
 361  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
 362  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 363  */
 364 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
 365 {
 366         struct gpio_chip *gc = &mm_gc->gc;
 367
 368         if (!mm_gc)
 369                 return;
 370
 371         gpiochip_remove(gc);
 372         iounmap(mm_gc->regs);
 373         kfree(gc->label);
 374 }
 375 EXPORT_SYMBOL(of_mm_gpiochip_remove);
 376
 377 #ifdef CONFIG_PINCTRL
 378 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
 379 {
 380         struct device_node *np = chip->of_node;
 381         struct of_phandle_args pinspec;
 382         struct pinctrl_dev *pctldev;
 383         int index = 0, ret;
 384         const char *name;
 385         static const char group_names_propname[] = "gpio-ranges-group-names";
 386         struct property *group_names;
 387
 388         if (!np)
 389                 return 0;
 390
 391         group_names = of_find_property(np, group_names_propname, NULL);
 392
 393         for (;; index++) {
 394                 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
 395                                 index, &pinspec);
 396                 if (ret)
 397                         break;
 398
 399                 pctldev = of_pinctrl_get(pinspec.np);
 400                 of_node_put(pinspec.np);
 401                 if (!pctldev)
 402                         return -EPROBE_DEFER;
 403
 404                 if (pinspec.args[2]) {
 405                         if (group_names) {
 406                                 of_property_read_string_index(np,
 407                                                 group_names_propname,
 408                                                 index, &name);
 409                                 if (strlen(name)) {
 410                                         pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
 411                                                 np->full_name);
 412                                         break;
 413                                 }
 414                         }
 415                         /* npins != 0: linear range */
 416                         ret = gpiochip_add_pin_range(chip,
 417                                         pinctrl_dev_get_devname(pctldev),
 418                                         pinspec.args[0],
 419                                         pinspec.args[1],
 420                                         pinspec.args[2]);
 421                         if (ret)
 422                                 return ret;
 423                 } else {
 424                         /* npins == 0: special range */
 425                         if (pinspec.args[1]) {
 426                                 pr_err("%s: Illegal gpio-range format.\n",
 427                                         np->full_name);
 428                                 break;
 429                         }
 430
 431                         if (!group_names) {
 432                                 pr_err("%s: GPIO group range requested but no %s property.\n",
 433                                         np->full_name, group_names_propname);
 434                                 break;
 435                         }
 436
 437                         ret = of_property_read_string_index(np,
 438                                                 group_names_propname,
 439                                                 index, &name);
 440                         if (ret)
 441                                 break;
 442
 443                         if (!strlen(name)) {
 444                                 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
 445                                 np->full_name);
 446                                 break;
 447                         }
 448
 449                         ret = gpiochip_add_pingroup_range(chip, pctldev,
 450                                                 pinspec.args[0], name);
 451                         if (ret)
 452                                 return ret;
 453                 }
 454         }
 455
 456         return 0;
 457 }
 458
 459 #else
 460 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
 461 #endif
 462
 463 int of_gpiochip_add(struct gpio_chip *chip)
 464 {
 465         int status;
 466
 467         if ((!chip->of_node) && (chip->parent))
 468                 chip->of_node = chip->parent->of_node;
 469
 470         if (!chip->of_node)
 471                 return 0;
 472
 473         if (!chip->of_xlate) {
 474                 chip->of_gpio_n_cells = 2;
 475                 chip->of_xlate = of_gpio_simple_xlate;
 476         }
 477
 478         if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
 479                 return -EINVAL;
 480
 481         status = of_gpiochip_add_pin_range(chip);
 482         if (status)
 483                 return status;
 484
 485         /* If the chip defines names itself, these take precedence */
 486         if (!chip->names)
 487                 of_gpiochip_set_names(chip);
 488
 489         of_node_get(chip->of_node);
 490
 491         return of_gpiochip_scan_gpios(chip);
 492 }
 493
 494 void of_gpiochip_remove(struct gpio_chip *chip)
 495 {
 496         gpiochip_remove_pin_ranges(chip);
 497         of_node_put(chip->of_node);
 498 }