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