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  * @name:       GPIO line name
 125  * @lflags:     gpio_lookup_flags - returned from of_find_gpio() or
 126  *              of_parse_own_gpio()
 127  * @dflags:     gpiod_flags - optional GPIO initialization flags
 128  *
 129  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
 130  * value on the error condition.
 131  */
 132 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
 133                                            const char **name,
 134                                            enum gpio_lookup_flags *lflags,
 135                                            enum gpiod_flags *dflags)
 136 {
 137         struct device_node *chip_np;
 138         enum of_gpio_flags xlate_flags;
 139         struct gg_data gg_data = {
 140                 .flags = &xlate_flags,
 141         };
 142         u32 tmp;
 143         int i, ret;
 144
 145         chip_np = np->parent;
 146         if (!chip_np)
 147                 return ERR_PTR(-EINVAL);
 148
 149         xlate_flags = 0;
 150         *lflags = 0;
 151         *dflags = 0;
 152
 153         ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
 154         if (ret)
 155                 return ERR_PTR(ret);
 156
 157         if (tmp > MAX_PHANDLE_ARGS)
 158                 return ERR_PTR(-EINVAL);
 159
 160         gg_data.gpiospec.args_count = tmp;
 161         gg_data.gpiospec.np = chip_np;
 162         for (i = 0; i < tmp; i++) {
 163                 ret = of_property_read_u32_index(np, "gpios", i,
 164                                            &gg_data.gpiospec.args[i]);
 165                 if (ret)
 166                         return ERR_PTR(ret);
 167         }
 168
 169         gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
 170         if (!gg_data.out_gpio) {
 171                 if (np->parent == np)
 172                         return ERR_PTR(-ENXIO);
 173                 else
 174                         return ERR_PTR(-EINVAL);
 175         }
 176
 177         if (xlate_flags & OF_GPIO_ACTIVE_LOW)
 178                 *lflags |= GPIO_ACTIVE_LOW;
 179
 180         if (of_property_read_bool(np, "input"))
 181                 *dflags |= GPIOD_IN;
 182         else if (of_property_read_bool(np, "output-low"))
 183                 *dflags |= GPIOD_OUT_LOW;
 184         else if (of_property_read_bool(np, "output-high"))
 185                 *dflags |= GPIOD_OUT_HIGH;
 186         else {
 187                 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
 188                         desc_to_gpio(gg_data.out_gpio), np->name);
 189                 return ERR_PTR(-EINVAL);
 190         }
 191
 192         if (name && of_property_read_string(np, "line-name", name))
 193                 *name = np->name;
 194
 195         return gg_data.out_gpio;
 196 }
 197
 198 /**
 199  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
 200  * @chip:       gpio chip to act on
 201  *
 202  * This is only used by of_gpiochip_add to request/set GPIO initial
 203  * configuration.
 204  */
 205 static void of_gpiochip_scan_gpios(struct gpio_chip *chip)
 206 {
 207         struct gpio_desc *desc = NULL;
 208         struct device_node *np;
 209         const char *name;
 210         enum gpio_lookup_flags lflags;
 211         enum gpiod_flags dflags;
 212
 213         for_each_child_of_node(chip->of_node, np) {
 214                 if (!of_property_read_bool(np, "gpio-hog"))
 215                         continue;
 216
 217                 desc = of_parse_own_gpio(np, &name, &lflags, &dflags);
 218                 if (IS_ERR(desc))
 219                         continue;
 220
 221                 if (gpiod_hog(desc, name, lflags, dflags))
 222                         continue;
 223         }
 224 }
 225
 226 /**
 227  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 228  * @gc:         pointer to the gpio_chip structure
 229  * @np:         device node of the GPIO chip
 230  * @gpio_spec:  gpio specifier as found in the device tree
 231  * @flags:      a flags pointer to fill in
 232  *
 233  * This is simple translation function, suitable for the most 1:1 mapped
 234  * gpio chips. This function performs only one sanity check: whether gpio
 235  * is less than ngpios (that is specified in the gpio_chip).
 236  */
 237 int of_gpio_simple_xlate(struct gpio_chip *gc,
 238                          const struct of_phandle_args *gpiospec, u32 *flags)
 239 {
 240         /*
 241          * We're discouraging gpio_cells < 2, since that way you'll have to
 242          * write your own xlate function (that will have to retrieve the GPIO
 243          * number and the flags from a single gpio cell -- this is possible,
 244          * but not recommended).
 245          */
 246         if (gc->of_gpio_n_cells < 2) {
 247                 WARN_ON(1);
 248                 return -EINVAL;
 249         }
 250
 251         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 252                 return -EINVAL;
 253
 254         if (gpiospec->args[0] >= gc->ngpio)
 255                 return -EINVAL;
 256
 257         if (flags)
 258                 *flags = gpiospec->args[1];
 259
 260         return gpiospec->args[0];
 261 }
 262 EXPORT_SYMBOL(of_gpio_simple_xlate);
 263
 264 /**
 265  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
 266  * @np:         device node of the GPIO chip
 267  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 268  *
 269  * To use this function you should allocate and fill mm_gc with:
 270  *
 271  * 1) In the gpio_chip structure:
 272  *    - all the callbacks
 273  *    - of_gpio_n_cells
 274  *    - of_xlate callback (optional)
 275  *
 276  * 3) In the of_mm_gpio_chip structure:
 277  *    - save_regs callback (optional)
 278  *
 279  * If succeeded, this function will map bank's memory and will
 280  * do all necessary work for you. Then you'll able to use .regs
 281  * to manage GPIOs from the callbacks.
 282  */
 283 int of_mm_gpiochip_add(struct device_node *np,
 284                        struct of_mm_gpio_chip *mm_gc)
 285 {
 286         int ret = -ENOMEM;
 287         struct gpio_chip *gc = &mm_gc->gc;
 288
 289         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 290         if (!gc->label)
 291                 goto err0;
 292
 293         mm_gc->regs = of_iomap(np, 0);
 294         if (!mm_gc->regs)
 295                 goto err1;
 296
 297         gc->base = -1;
 298
 299         if (mm_gc->save_regs)
 300                 mm_gc->save_regs(mm_gc);
 301
 302         mm_gc->gc.of_node = np;
 303
 304         ret = gpiochip_add(gc);
 305         if (ret)
 306                 goto err2;
 307
 308         return 0;
 309 err2:
 310         iounmap(mm_gc->regs);
 311 err1:
 312         kfree(gc->label);
 313 err0:
 314         pr_err("%s: GPIO chip registration failed with status %d\n",
 315                np->full_name, ret);
 316         return ret;
 317 }
 318 EXPORT_SYMBOL(of_mm_gpiochip_add);
 319
 320 /**
 321  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
 322  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 323  */
 324 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
 325 {
 326         struct gpio_chip *gc = &mm_gc->gc;
 327
 328         if (!mm_gc)
 329                 return;
 330
 331         gpiochip_remove(gc);
 332         iounmap(mm_gc->regs);
 333         kfree(gc->label);
 334 }
 335 EXPORT_SYMBOL(of_mm_gpiochip_remove);
 336
 337 #ifdef CONFIG_PINCTRL
 338 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
 339 {
 340         struct device_node *np = chip->of_node;
 341         struct of_phandle_args pinspec;
 342         struct pinctrl_dev *pctldev;
 343         int index = 0, ret;
 344         const char *name;
 345         static const char group_names_propname[] = "gpio-ranges-group-names";
 346         struct property *group_names;
 347
 348         if (!np)
 349                 return 0;
 350
 351         group_names = of_find_property(np, group_names_propname, NULL);
 352
 353         for (;; index++) {
 354                 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
 355                                 index, &pinspec);
 356                 if (ret)
 357                         break;
 358
 359                 pctldev = of_pinctrl_get(pinspec.np);
 360                 if (!pctldev)
 361                         return -EPROBE_DEFER;
 362
 363                 if (pinspec.args[2]) {
 364                         if (group_names) {
 365                                 of_property_read_string_index(np,
 366                                                 group_names_propname,
 367                                                 index, &name);
 368                                 if (strlen(name)) {
 369                                         pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
 370                                                 np->full_name);
 371                                         break;
 372                                 }
 373                         }
 374                         /* npins != 0: linear range */
 375                         ret = gpiochip_add_pin_range(chip,
 376                                         pinctrl_dev_get_devname(pctldev),
 377                                         pinspec.args[0],
 378                                         pinspec.args[1],
 379                                         pinspec.args[2]);
 380                         if (ret)
 381                                 return ret;
 382                 } else {
 383                         /* npins == 0: special range */
 384                         if (pinspec.args[1]) {
 385                                 pr_err("%s: Illegal gpio-range format.\n",
 386                                         np->full_name);
 387                                 break;
 388                         }
 389
 390                         if (!group_names) {
 391                                 pr_err("%s: GPIO group range requested but no %s property.\n",
 392                                         np->full_name, group_names_propname);
 393                                 break;
 394                         }
 395
 396                         ret = of_property_read_string_index(np,
 397                                                 group_names_propname,
 398                                                 index, &name);
 399                         if (ret)
 400                                 break;
 401
 402                         if (!strlen(name)) {
 403                                 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
 404                                 np->full_name);
 405                                 break;
 406                         }
 407
 408                         ret = gpiochip_add_pingroup_range(chip, pctldev,
 409                                                 pinspec.args[0], name);
 410                         if (ret)
 411                                 return ret;
 412                 }
 413         }
 414
 415         return 0;
 416 }
 417
 418 #else
 419 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
 420 #endif
 421
 422 int of_gpiochip_add(struct gpio_chip *chip)
 423 {
 424         int status;
 425
 426         if ((!chip->of_node) && (chip->dev))
 427                 chip->of_node = chip->dev->of_node;
 428
 429         if (!chip->of_node)
 430                 return 0;
 431
 432         if (!chip->of_xlate) {
 433                 chip->of_gpio_n_cells = 2;
 434                 chip->of_xlate = of_gpio_simple_xlate;
 435         }
 436
 437         status = of_gpiochip_add_pin_range(chip);
 438         if (status)
 439                 return status;
 440
 441         of_node_get(chip->of_node);
 442
 443         of_gpiochip_scan_gpios(chip);
 444
 445         return 0;
 446 }
 447
 448 void of_gpiochip_remove(struct gpio_chip *chip)
 449 {
 450         gpiochip_remove_pin_ranges(chip);
 451         of_node_put(chip->of_node);
 452 }