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