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_get_gpio_hog() - 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_get_gpio_hog()
 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_get_gpio_hog(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 gpio_desc *desc;
 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         desc = gg_data.out_gpio;
 197
 198         return desc;
 199 }
 200
 201 /**
 202  * of_gpiochip_scan_hogs - Scan gpio-controller and apply GPIO hog as requested
 203  * @chip:       gpio chip to act on
 204  *
 205  * This is only used by of_gpiochip_add to request/set GPIO initial
 206  * configuration.
 207  */
 208 static void of_gpiochip_scan_hogs(struct gpio_chip *chip)
 209 {
 210         struct gpio_desc *desc = NULL;
 211         struct device_node *np;
 212         const char *name;
 213         enum gpio_lookup_flags lflags;
 214         enum gpiod_flags dflags;
 215
 216         for_each_child_of_node(chip->of_node, np) {
 217                 if (!of_property_read_bool(np, "gpio-hog"))
 218                         continue;
 219
 220                 desc = of_get_gpio_hog(np, &name, &lflags, &dflags);
 221                 if (IS_ERR(desc))
 222                         continue;
 223
 224                 if (gpiod_hog(desc, name, lflags, dflags))
 225                         continue;
 226         }
 227 }
 228
 229 /**
 230  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 231  * @gc:         pointer to the gpio_chip structure
 232  * @np:         device node of the GPIO chip
 233  * @gpio_spec:  gpio specifier as found in the device tree
 234  * @flags:      a flags pointer to fill in
 235  *
 236  * This is simple translation function, suitable for the most 1:1 mapped
 237  * gpio chips. This function performs only one sanity check: whether gpio
 238  * is less than ngpios (that is specified in the gpio_chip).
 239  */
 240 int of_gpio_simple_xlate(struct gpio_chip *gc,
 241                          const struct of_phandle_args *gpiospec, u32 *flags)
 242 {
 243         /*
 244          * We're discouraging gpio_cells < 2, since that way you'll have to
 245          * write your own xlate function (that will have to retrieve the GPIO
 246          * number and the flags from a single gpio cell -- this is possible,
 247          * but not recommended).
 248          */
 249         if (gc->of_gpio_n_cells < 2) {
 250                 WARN_ON(1);
 251                 return -EINVAL;
 252         }
 253
 254         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 255                 return -EINVAL;
 256
 257         if (gpiospec->args[0] >= gc->ngpio)
 258                 return -EINVAL;
 259
 260         if (flags)
 261                 *flags = gpiospec->args[1];
 262
 263         return gpiospec->args[0];
 264 }
 265 EXPORT_SYMBOL(of_gpio_simple_xlate);
 266
 267 /**
 268  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
 269  * @np:         device node of the GPIO chip
 270  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 271  *
 272  * To use this function you should allocate and fill mm_gc with:
 273  *
 274  * 1) In the gpio_chip structure:
 275  *    - all the callbacks
 276  *    - of_gpio_n_cells
 277  *    - of_xlate callback (optional)
 278  *
 279  * 3) In the of_mm_gpio_chip structure:
 280  *    - save_regs callback (optional)
 281  *
 282  * If succeeded, this function will map bank's memory and will
 283  * do all necessary work for you. Then you'll able to use .regs
 284  * to manage GPIOs from the callbacks.
 285  */
 286 int of_mm_gpiochip_add(struct device_node *np,
 287                        struct of_mm_gpio_chip *mm_gc)
 288 {
 289         int ret = -ENOMEM;
 290         struct gpio_chip *gc = &mm_gc->gc;
 291
 292         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 293         if (!gc->label)
 294                 goto err0;
 295
 296         mm_gc->regs = of_iomap(np, 0);
 297         if (!mm_gc->regs)
 298                 goto err1;
 299
 300         gc->base = -1;
 301
 302         if (mm_gc->save_regs)
 303                 mm_gc->save_regs(mm_gc);
 304
 305         mm_gc->gc.of_node = np;
 306
 307         ret = gpiochip_add(gc);
 308         if (ret)
 309                 goto err2;
 310
 311         return 0;
 312 err2:
 313         iounmap(mm_gc->regs);
 314 err1:
 315         kfree(gc->label);
 316 err0:
 317         pr_err("%s: GPIO chip registration failed with status %d\n",
 318                np->full_name, ret);
 319         return ret;
 320 }
 321 EXPORT_SYMBOL(of_mm_gpiochip_add);
 322
 323 /**
 324  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
 325  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 326  */
 327 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
 328 {
 329         struct gpio_chip *gc = &mm_gc->gc;
 330
 331         if (!mm_gc)
 332                 return;
 333
 334         gpiochip_remove(gc);
 335         iounmap(mm_gc->regs);
 336         kfree(gc->label);
 337 }
 338 EXPORT_SYMBOL(of_mm_gpiochip_remove);
 339
 340 #ifdef CONFIG_PINCTRL
 341 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 342 {
 343         struct device_node *np = chip->of_node;
 344         struct of_phandle_args pinspec;
 345         struct pinctrl_dev *pctldev;
 346         int index = 0, ret;
 347         const char *name;
 348         static const char group_names_propname[] = "gpio-ranges-group-names";
 349         struct property *group_names;
 350
 351         if (!np)
 352                 return;
 353
 354         group_names = of_find_property(np, group_names_propname, NULL);
 355
 356         for (;; index++) {
 357                 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
 358                                 index, &pinspec);
 359                 if (ret)
 360                         break;
 361
 362                 pctldev = of_pinctrl_get(pinspec.np);
 363                 if (!pctldev)
 364                         break;
 365
 366                 if (pinspec.args[2]) {
 367                         if (group_names) {
 368                                 ret = of_property_read_string_index(np,
 369                                                 group_names_propname,
 370                                                 index, &name);
 371                                 if (strlen(name)) {
 372                                         pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
 373                                                 np->full_name);
 374                                         break;
 375                                 }
 376                         }
 377                         /* npins != 0: linear range */
 378                         ret = gpiochip_add_pin_range(chip,
 379                                         pinctrl_dev_get_devname(pctldev),
 380                                         pinspec.args[0],
 381                                         pinspec.args[1],
 382                                         pinspec.args[2]);
 383                         if (ret)
 384                                 break;
 385                 } else {
 386                         /* npins == 0: special range */
 387                         if (pinspec.args[1]) {
 388                                 pr_err("%s: Illegal gpio-range format.\n",
 389                                         np->full_name);
 390                                 break;
 391                         }
 392
 393                         if (!group_names) {
 394                                 pr_err("%s: GPIO group range requested but no %s property.\n",
 395                                         np->full_name, group_names_propname);
 396                                 break;
 397                         }
 398
 399                         ret = of_property_read_string_index(np,
 400                                                 group_names_propname,
 401                                                 index, &name);
 402                         if (ret)
 403                                 break;
 404
 405                         if (!strlen(name)) {
 406                                 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
 407                                 np->full_name);
 408                                 break;
 409                         }
 410
 411                         ret = gpiochip_add_pingroup_range(chip, pctldev,
 412                                                 pinspec.args[0], name);
 413                         if (ret)
 414                                 break;
 415                 }
 416         }
 417 }
 418
 419 #else
 420 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
 421 #endif
 422
 423 void of_gpiochip_add(struct gpio_chip *chip)
 424 {
 425         if ((!chip->of_node) && (chip->dev))
 426                 chip->of_node = chip->dev->of_node;
 427
 428         if (!chip->of_node)
 429                 return;
 430
 431         if (!chip->of_xlate) {
 432                 chip->of_gpio_n_cells = 2;
 433                 chip->of_xlate = of_gpio_simple_xlate;
 434         }
 435
 436         of_gpiochip_add_pin_range(chip);
 437         of_node_get(chip->of_node);
 438
 439         of_gpiochip_scan_hogs(chip);
 440 }
 441
 442 void of_gpiochip_remove(struct gpio_chip *chip)
 443 {
 444         gpiochip_remove_pin_ranges(chip);
 445         of_node_put(chip->of_node);
 446 }