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 /* Private data structure for of_gpiochip_find_and_xlate */
  31 struct gg_data {
  32         enum of_gpio_flags *flags;
  33         struct of_phandle_args gpiospec;
  34
  35         struct gpio_desc *out_gpio;
  36 };
  37
  38 /* Private function for resolving node pointer to gpio_chip */
  39 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
  40 {
  41         struct gg_data *gg_data = data;
  42         int ret;
  43
  44         if ((gc->of_node != gg_data->gpiospec.np) ||
  45             (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
  46             (!gc->of_xlate))
  47                 return false;
  48
  49         ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
  50         if (ret < 0) {
  51                 /* We've found a gpio chip, but the translation failed.
  52                  * Store translation error in out_gpio.
  53                  * Return false to keep looking, as more than one gpio chip
  54                  * could be registered per of-node.
  55                  */
  56                 gg_data->out_gpio = ERR_PTR(ret);
  57                 return false;
  58          }
  59
  60         gg_data->out_gpio = gpiochip_get_desc(gc, ret);
  61         return true;
  62 }
  63
  64 /**
  65  * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
  66  * @np:         device node to get GPIO from
  67  * @propname:   property name containing gpio specifier(s)
  68  * @index:      index of the GPIO
  69  * @flags:      a flags pointer to fill in
  70  *
  71  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
  72  * value on the error condition. If @flags is not NULL the function also fills
  73  * in flags for the GPIO.
  74  */
  75 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
  76                      const char *propname, int index, enum of_gpio_flags *flags)
  77 {
  78         /* Return -EPROBE_DEFER to support probe() functions to be called
  79          * later when the GPIO actually becomes available
  80          */
  81         struct gg_data gg_data = {
  82                 .flags = flags,
  83                 .out_gpio = ERR_PTR(-EPROBE_DEFER)
  84         };
  85         int ret;
  86
  87         /* .of_xlate might decide to not fill in the flags, so clear it. */
  88         if (flags)
  89                 *flags = 0;
  90
  91         ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
  92                                          &gg_data.gpiospec);
  93         if (ret) {
  94                 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
  95                         __func__, propname, np->full_name, index);
  96                 return ERR_PTR(ret);
  97         }
  98
  99         gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
 100
 101         of_node_put(gg_data.gpiospec.np);
 102         pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
 103                  __func__, propname, np->full_name, index,
 104                  PTR_ERR_OR_ZERO(gg_data.out_gpio));
 105         return gg_data.out_gpio;
 106 }
 107
 108 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
 109                             int index, enum of_gpio_flags *flags)
 110 {
 111         struct gpio_desc *desc;
 112
 113         desc = of_get_named_gpiod_flags(np, list_name, index, flags);
 114
 115         if (IS_ERR(desc))
 116                 return PTR_ERR(desc);
 117         else
 118                 return desc_to_gpio(desc);
 119 }
 120 EXPORT_SYMBOL(of_get_named_gpio_flags);
 121
 122 /**
 123  * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
 124  * @np:         device node to get GPIO from
 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                                            const char **name,
 135                                            enum gpio_lookup_flags *lflags,
 136                                            enum gpiod_flags *dflags)
 137 {
 138         struct device_node *chip_np;
 139         enum of_gpio_flags xlate_flags;
 140         struct gg_data gg_data = {
 141                 .flags = &xlate_flags,
 142         };
 143         u32 tmp;
 144         int i, ret;
 145
 146         chip_np = np->parent;
 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 > MAX_PHANDLE_ARGS)
 159                 return ERR_PTR(-EINVAL);
 160
 161         gg_data.gpiospec.args_count = tmp;
 162         gg_data.gpiospec.np = chip_np;
 163         for (i = 0; i < tmp; i++) {
 164                 ret = of_property_read_u32_index(np, "gpios", i,
 165                                            &gg_data.gpiospec.args[i]);
 166                 if (ret)
 167                         return ERR_PTR(ret);
 168         }
 169
 170         gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
 171         if (!gg_data.out_gpio) {
 172                 if (np->parent == np)
 173                         return ERR_PTR(-ENXIO);
 174                 else
 175                         return ERR_PTR(-EINVAL);
 176         }
 177
 178         if (xlate_flags & OF_GPIO_ACTIVE_LOW)
 179                 *lflags |= GPIO_ACTIVE_LOW;
 180
 181         if (of_property_read_bool(np, "input"))
 182                 *dflags |= GPIOD_IN;
 183         else if (of_property_read_bool(np, "output-low"))
 184                 *dflags |= GPIOD_OUT_LOW;
 185         else if (of_property_read_bool(np, "output-high"))
 186                 *dflags |= GPIOD_OUT_HIGH;
 187         else {
 188                 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
 189                         desc_to_gpio(gg_data.out_gpio), np->name);
 190                 return ERR_PTR(-EINVAL);
 191         }
 192
 193         if (name && of_property_read_string(np, "line-name", name))
 194                 *name = np->name;
 195
 196         return gg_data.out_gpio;
 197 }
 198
 199 /**
 200  * of_gpiochip_set_names() - set up the names of the lines
 201  * @chip: GPIO chip whose lines should be named, if possible
 202  */
 203 static void of_gpiochip_set_names(struct gpio_chip *gc)
 204 {
 205         struct gpio_device *gdev = gc->gpiodev;
 206         struct device_node *np = gc->of_node;
 207         int i;
 208         int nstrings;
 209
 210         nstrings = of_property_count_strings(np, "gpio-line-names");
 211         if (nstrings <= 0)
 212                 /* Lines names not present */
 213                 return;
 214
 215         /* This is normally not what you want */
 216         if (gdev->ngpio != nstrings)
 217                 dev_info(&gdev->dev, "gpio-line-names specifies %d line "
 218                          "names but there are %d lines on the chip\n",
 219                          nstrings, gdev->ngpio);
 220
 221         /*
 222          * Make sure to not index beyond the end of the number of descriptors
 223          * of the GPIO device.
 224          */
 225         for (i = 0; i < gdev->ngpio; i++) {
 226                 const char *name;
 227                 int ret;
 228
 229                 ret = of_property_read_string_index(np,
 230                                                     "gpio-line-names",
 231                                                     i,
 232                                                     &name);
 233                 if (ret) {
 234                         if (ret != -ENODATA)
 235                                 dev_err(&gdev->dev,
 236                                         "unable to name line %d: %d\n",
 237                                         i, ret);
 238                         break;
 239                 }
 240                 gdev->descs[i].name = name;
 241         }
 242 }
 243
 244 /**
 245  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
 246  * @chip:       gpio chip to act on
 247  *
 248  * This is only used by of_gpiochip_add to request/set GPIO initial
 249  * configuration.
 250  * It retures error if it fails otherwise 0 on success.
 251  */
 252 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
 253 {
 254         struct gpio_desc *desc = NULL;
 255         struct device_node *np;
 256         const char *name;
 257         enum gpio_lookup_flags lflags;
 258         enum gpiod_flags dflags;
 259         int ret;
 260
 261         for_each_available_child_of_node(chip->of_node, np) {
 262                 if (!of_property_read_bool(np, "gpio-hog"))
 263                         continue;
 264
 265                 desc = of_parse_own_gpio(np, &name, &lflags, &dflags);
 266                 if (IS_ERR(desc))
 267                         continue;
 268
 269                 ret = gpiod_hog(desc, name, lflags, dflags);
 270                 if (ret < 0)
 271                         return ret;
 272         }
 273
 274         return 0;
 275 }
 276
 277 /**
 278  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 279  * @gc:         pointer to the gpio_chip structure
 280  * @np:         device node of the GPIO chip
 281  * @gpio_spec:  gpio specifier as found in the device tree
 282  * @flags:      a flags pointer to fill in
 283  *
 284  * This is simple translation function, suitable for the most 1:1 mapped
 285  * gpio chips. This function performs only one sanity check: whether gpio
 286  * is less than ngpios (that is specified in the gpio_chip).
 287  */
 288 int of_gpio_simple_xlate(struct gpio_chip *gc,
 289                          const struct of_phandle_args *gpiospec, u32 *flags)
 290 {
 291         /*
 292          * We're discouraging gpio_cells < 2, since that way you'll have to
 293          * write your own xlate function (that will have to retrieve the GPIO
 294          * number and the flags from a single gpio cell -- this is possible,
 295          * but not recommended).
 296          */
 297         if (gc->of_gpio_n_cells < 2) {
 298                 WARN_ON(1);
 299                 return -EINVAL;
 300         }
 301
 302         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 303                 return -EINVAL;
 304
 305         if (gpiospec->args[0] >= gc->ngpio)
 306                 return -EINVAL;
 307
 308         if (flags)
 309                 *flags = gpiospec->args[1];
 310
 311         return gpiospec->args[0];
 312 }
 313 EXPORT_SYMBOL(of_gpio_simple_xlate);
 314
 315 /**
 316  * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
 317  * @np:         device node of the GPIO chip
 318  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 319  * @data:       driver data to store in the struct gpio_chip
 320  *
 321  * To use this function you should allocate and fill mm_gc with:
 322  *
 323  * 1) In the gpio_chip structure:
 324  *    - all the callbacks
 325  *    - of_gpio_n_cells
 326  *    - of_xlate callback (optional)
 327  *
 328  * 3) In the of_mm_gpio_chip structure:
 329  *    - save_regs callback (optional)
 330  *
 331  * If succeeded, this function will map bank's memory and will
 332  * do all necessary work for you. Then you'll able to use .regs
 333  * to manage GPIOs from the callbacks.
 334  */
 335 int of_mm_gpiochip_add_data(struct device_node *np,
 336                             struct of_mm_gpio_chip *mm_gc,
 337                             void *data)
 338 {
 339         int ret = -ENOMEM;
 340         struct gpio_chip *gc = &mm_gc->gc;
 341
 342         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 343         if (!gc->label)
 344                 goto err0;
 345
 346         mm_gc->regs = of_iomap(np, 0);
 347         if (!mm_gc->regs)
 348                 goto err1;
 349
 350         gc->base = -1;
 351
 352         if (mm_gc->save_regs)
 353                 mm_gc->save_regs(mm_gc);
 354
 355         mm_gc->gc.of_node = np;
 356
 357         ret = gpiochip_add_data(gc, data);
 358         if (ret)
 359                 goto err2;
 360
 361         return 0;
 362 err2:
 363         iounmap(mm_gc->regs);
 364 err1:
 365         kfree(gc->label);
 366 err0:
 367         pr_err("%s: GPIO chip registration failed with status %d\n",
 368                np->full_name, ret);
 369         return ret;
 370 }
 371 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
 372
 373 /**
 374  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
 375  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 376  */
 377 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
 378 {
 379         struct gpio_chip *gc = &mm_gc->gc;
 380
 381         if (!mm_gc)
 382                 return;
 383
 384         gpiochip_remove(gc);
 385         iounmap(mm_gc->regs);
 386         kfree(gc->label);
 387 }
 388 EXPORT_SYMBOL(of_mm_gpiochip_remove);
 389
 390 #ifdef CONFIG_PINCTRL
 391 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
 392 {
 393         struct device_node *np = chip->of_node;
 394         struct of_phandle_args pinspec;
 395         struct pinctrl_dev *pctldev;
 396         int index = 0, ret;
 397         const char *name;
 398         static const char group_names_propname[] = "gpio-ranges-group-names";
 399         struct property *group_names;
 400
 401         if (!np)
 402                 return 0;
 403
 404         group_names = of_find_property(np, group_names_propname, NULL);
 405
 406         for (;; index++) {
 407                 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
 408                                 index, &pinspec);
 409                 if (ret)
 410                         break;
 411
 412                 pctldev = of_pinctrl_get(pinspec.np);
 413                 if (!pctldev)
 414                         return -EPROBE_DEFER;
 415
 416                 if (pinspec.args[2]) {
 417                         if (group_names) {
 418                                 of_property_read_string_index(np,
 419                                                 group_names_propname,
 420                                                 index, &name);
 421                                 if (strlen(name)) {
 422                                         pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
 423                                                 np->full_name);
 424                                         break;
 425                                 }
 426                         }
 427                         /* npins != 0: linear range */
 428                         ret = gpiochip_add_pin_range(chip,
 429                                         pinctrl_dev_get_devname(pctldev),
 430                                         pinspec.args[0],
 431                                         pinspec.args[1],
 432                                         pinspec.args[2]);
 433                         if (ret)
 434                                 return ret;
 435                 } else {
 436                         /* npins == 0: special range */
 437                         if (pinspec.args[1]) {
 438                                 pr_err("%s: Illegal gpio-range format.\n",
 439                                         np->full_name);
 440                                 break;
 441                         }
 442
 443                         if (!group_names) {
 444                                 pr_err("%s: GPIO group range requested but no %s property.\n",
 445                                         np->full_name, group_names_propname);
 446                                 break;
 447                         }
 448
 449                         ret = of_property_read_string_index(np,
 450                                                 group_names_propname,
 451                                                 index, &name);
 452                         if (ret)
 453                                 break;
 454
 455                         if (!strlen(name)) {
 456                                 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
 457                                 np->full_name);
 458                                 break;
 459                         }
 460
 461                         ret = gpiochip_add_pingroup_range(chip, pctldev,
 462                                                 pinspec.args[0], name);
 463                         if (ret)
 464                                 return ret;
 465                 }
 466         }
 467
 468         return 0;
 469 }
 470
 471 #else
 472 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
 473 #endif
 474
 475 int of_gpiochip_add(struct gpio_chip *chip)
 476 {
 477         int status;
 478
 479         if ((!chip->of_node) && (chip->parent))
 480                 chip->of_node = chip->parent->of_node;
 481
 482         if (!chip->of_node)
 483                 return 0;
 484
 485         if (!chip->of_xlate) {
 486                 chip->of_gpio_n_cells = 2;
 487                 chip->of_xlate = of_gpio_simple_xlate;
 488         }
 489
 490         status = of_gpiochip_add_pin_range(chip);
 491         if (status)
 492                 return status;
 493
 494         /* If the chip defines names itself, these take precedence */
 495         if (!chip->names)
 496                 of_gpiochip_set_names(chip);
 497
 498         of_node_get(chip->of_node);
 499
 500         return of_gpiochip_scan_gpios(chip);
 501 }
 502
 503 void of_gpiochip_remove(struct gpio_chip *chip)
 504 {
 505         gpiochip_remove_pin_ranges(chip);
 506         of_node_put(chip->of_node);
 507 }