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
  26 #include "gpiolib.h"
  27
  28 /* Private data structure for of_gpiochip_find_and_xlate */
  29 struct gg_data {
  30         enum of_gpio_flags *flags;
  31         struct of_phandle_args gpiospec;
  32
  33         struct gpio_desc *out_gpio;
  34 };
  35
  36 /* Private function for resolving node pointer to gpio_chip */
  37 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
  38 {
  39         struct gg_data *gg_data = data;
  40         int ret;
  41
  42         if ((gc->of_node != gg_data->gpiospec.np) ||
  43             (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
  44             (!gc->of_xlate))
  45                 return false;
  46
  47         ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
  48         if (ret < 0) {
  49                 /* We've found a gpio chip, but the translation failed.
  50                  * Store translation error in out_gpio.
  51                  * Return false to keep looking, as more than one gpio chip
  52                  * could be registered per of-node.
  53                  */
  54                 gg_data->out_gpio = ERR_PTR(ret);
  55                 return false;
  56          }
  57
  58         gg_data->out_gpio = gpiochip_get_desc(gc, ret);
  59         return true;
  60 }
  61
  62 /**
  63  * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
  64  * @np:         device node to get GPIO from
  65  * @propname:   property name containing gpio specifier(s)
  66  * @index:      index of the GPIO
  67  * @flags:      a flags pointer to fill in
  68  *
  69  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
  70  * value on the error condition. If @flags is not NULL the function also fills
  71  * in flags for the GPIO.
  72  */
  73 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
  74                      const char *propname, int index, enum of_gpio_flags *flags)
  75 {
  76         /* Return -EPROBE_DEFER to support probe() functions to be called
  77          * later when the GPIO actually becomes available
  78          */
  79         struct gg_data gg_data = {
  80                 .flags = flags,
  81                 .out_gpio = ERR_PTR(-EPROBE_DEFER)
  82         };
  83         int ret;
  84
  85         /* .of_xlate might decide to not fill in the flags, so clear it. */
  86         if (flags)
  87                 *flags = 0;
  88
  89         ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
  90                                          &gg_data.gpiospec);
  91         if (ret) {
  92                 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
  93                         __func__, propname, np->full_name, index);
  94                 return ERR_PTR(ret);
  95         }
  96
  97         gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
  98
  99         of_node_put(gg_data.gpiospec.np);
 100         pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
 101                  __func__, propname, np->full_name, index,
 102                  PTR_ERR_OR_ZERO(gg_data.out_gpio));
 103         return gg_data.out_gpio;
 104 }
 105
 106 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
 107                             int index, enum of_gpio_flags *flags)
 108 {
 109         struct gpio_desc *desc;
 110
 111         desc = of_get_named_gpiod_flags(np, list_name, index, flags);
 112
 113         if (IS_ERR(desc))
 114                 return PTR_ERR(desc);
 115         else
 116                 return desc_to_gpio(desc);
 117 }
 118 EXPORT_SYMBOL(of_get_named_gpio_flags);
 119
 120 /**
 121  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 122  * @gc:         pointer to the gpio_chip structure
 123  * @np:         device node of the GPIO chip
 124  * @gpio_spec:  gpio specifier as found in the device tree
 125  * @flags:      a flags pointer to fill in
 126  *
 127  * This is simple translation function, suitable for the most 1:1 mapped
 128  * gpio chips. This function performs only one sanity check: whether gpio
 129  * is less than ngpios (that is specified in the gpio_chip).
 130  */
 131 int of_gpio_simple_xlate(struct gpio_chip *gc,
 132                          const struct of_phandle_args *gpiospec, u32 *flags)
 133 {
 134         /*
 135          * We're discouraging gpio_cells < 2, since that way you'll have to
 136          * write your own xlate function (that will have to retrive the GPIO
 137          * number and the flags from a single gpio cell -- this is possible,
 138          * but not recommended).
 139          */
 140         if (gc->of_gpio_n_cells < 2) {
 141                 WARN_ON(1);
 142                 return -EINVAL;
 143         }
 144
 145         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 146                 return -EINVAL;
 147
 148         if (gpiospec->args[0] >= gc->ngpio)
 149                 return -EINVAL;
 150
 151         if (flags)
 152                 *flags = gpiospec->args[1];
 153
 154         return gpiospec->args[0];
 155 }
 156 EXPORT_SYMBOL(of_gpio_simple_xlate);
 157
 158 /**
 159  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
 160  * @np:         device node of the GPIO chip
 161  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 162  *
 163  * To use this function you should allocate and fill mm_gc with:
 164  *
 165  * 1) In the gpio_chip structure:
 166  *    - all the callbacks
 167  *    - of_gpio_n_cells
 168  *    - of_xlate callback (optional)
 169  *
 170  * 3) In the of_mm_gpio_chip structure:
 171  *    - save_regs callback (optional)
 172  *
 173  * If succeeded, this function will map bank's memory and will
 174  * do all necessary work for you. Then you'll able to use .regs
 175  * to manage GPIOs from the callbacks.
 176  */
 177 int of_mm_gpiochip_add(struct device_node *np,
 178                        struct of_mm_gpio_chip *mm_gc)
 179 {
 180         int ret = -ENOMEM;
 181         struct gpio_chip *gc = &mm_gc->gc;
 182
 183         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 184         if (!gc->label)
 185                 goto err0;
 186
 187         mm_gc->regs = of_iomap(np, 0);
 188         if (!mm_gc->regs)
 189                 goto err1;
 190
 191         gc->base = -1;
 192
 193         if (mm_gc->save_regs)
 194                 mm_gc->save_regs(mm_gc);
 195
 196         mm_gc->gc.of_node = np;
 197
 198         ret = gpiochip_add(gc);
 199         if (ret)
 200                 goto err2;
 201
 202         return 0;
 203 err2:
 204         iounmap(mm_gc->regs);
 205 err1:
 206         kfree(gc->label);
 207 err0:
 208         pr_err("%s: GPIO chip registration failed with status %d\n",
 209                np->full_name, ret);
 210         return ret;
 211 }
 212 EXPORT_SYMBOL(of_mm_gpiochip_add);
 213
 214 /**
 215  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
 216  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 217  */
 218 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
 219 {
 220         struct gpio_chip *gc = &mm_gc->gc;
 221
 222         if (!mm_gc)
 223                 return;
 224
 225         gpiochip_remove(gc);
 226         iounmap(mm_gc->regs);
 227         kfree(gc->label);
 228 }
 229 EXPORT_SYMBOL(of_mm_gpiochip_remove);
 230
 231 #ifdef CONFIG_PINCTRL
 232 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 233 {
 234         struct device_node *np = chip->of_node;
 235         struct of_phandle_args pinspec;
 236         struct pinctrl_dev *pctldev;
 237         int index = 0, ret;
 238         const char *name;
 239         static const char group_names_propname[] = "gpio-ranges-group-names";
 240         struct property *group_names;
 241
 242         if (!np)
 243                 return;
 244
 245         group_names = of_find_property(np, group_names_propname, NULL);
 246
 247         for (;; index++) {
 248                 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
 249                                 index, &pinspec);
 250                 if (ret)
 251                         break;
 252
 253                 pctldev = of_pinctrl_get(pinspec.np);
 254                 if (!pctldev)
 255                         break;
 256
 257                 if (pinspec.args[2]) {
 258                         if (group_names) {
 259                                 ret = of_property_read_string_index(np,
 260                                                 group_names_propname,
 261                                                 index, &name);
 262                                 if (strlen(name)) {
 263                                         pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
 264                                                 np->full_name);
 265                                         break;
 266                                 }
 267                         }
 268                         /* npins != 0: linear range */
 269                         ret = gpiochip_add_pin_range(chip,
 270                                         pinctrl_dev_get_devname(pctldev),
 271                                         pinspec.args[0],
 272                                         pinspec.args[1],
 273                                         pinspec.args[2]);
 274                         if (ret)
 275                                 break;
 276                 } else {
 277                         /* npins == 0: special range */
 278                         if (pinspec.args[1]) {
 279                                 pr_err("%s: Illegal gpio-range format.\n",
 280                                         np->full_name);
 281                                 break;
 282                         }
 283
 284                         if (!group_names) {
 285                                 pr_err("%s: GPIO group range requested but no %s property.\n",
 286                                         np->full_name, group_names_propname);
 287                                 break;
 288                         }
 289
 290                         ret = of_property_read_string_index(np,
 291                                                 group_names_propname,
 292                                                 index, &name);
 293                         if (ret)
 294                                 break;
 295
 296                         if (!strlen(name)) {
 297                                 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
 298                                 np->full_name);
 299                                 break;
 300                         }
 301
 302                         ret = gpiochip_add_pingroup_range(chip, pctldev,
 303                                                 pinspec.args[0], name);
 304                         if (ret)
 305                                 break;
 306                 }
 307         }
 308 }
 309
 310 #else
 311 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
 312 #endif
 313
 314 void of_gpiochip_add(struct gpio_chip *chip)
 315 {
 316         if ((!chip->of_node) && (chip->dev))
 317                 chip->of_node = chip->dev->of_node;
 318
 319         if (!chip->of_node)
 320                 return;
 321
 322         if (!chip->of_xlate) {
 323                 chip->of_gpio_n_cells = 2;
 324                 chip->of_xlate = of_gpio_simple_xlate;
 325         }
 326
 327         of_gpiochip_add_pin_range(chip);
 328         of_node_get(chip->of_node);
 329 }
 330
 331 void of_gpiochip_remove(struct gpio_chip *chip)
 332 {
 333         gpiochip_remove_pin_ranges(chip);
 334         of_node_put(chip->of_node);
 335 }