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