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/errno.h>
  16 #include <linux/module.h>
  17 #include <linux/io.h>
  18 #include <linux/gpio/consumer.h>
  19 #include <linux/of.h>
  20 #include <linux/of_address.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/pinctrl/pinctrl.h>
  23 #include <linux/slab.h>
  24
  25 struct gpio_desc;
  26
  27 /* Private data structure for of_gpiochip_find_and_xlate */
  28 struct gg_data {
  29         enum of_gpio_flags *flags;
  30         struct of_phandle_args gpiospec;
  31
  32         struct gpio_desc *out_gpio;
  33 };
  34
  35 /* Private function for resolving node pointer to gpio_chip */
  36 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
  37 {
  38         struct gg_data *gg_data = data;
  39         int ret;
  40
  41         if ((gc->of_node != gg_data->gpiospec.np) ||
  42             (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
  43             (!gc->of_xlate))
  44                 return false;
  45
  46         ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
  47         if (ret < 0)
  48                 return false;
  49
  50         gg_data->out_gpio = gpio_to_desc(ret + gc->base);
  51         return true;
  52 }
  53
  54 /**
  55  * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
  56  * @np:         device node to get GPIO from
  57  * @propname:   property name containing gpio specifier(s)
  58  * @index:      index of the GPIO
  59  * @flags:      a flags pointer to fill in
  60  *
  61  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
  62  * value on the error condition. If @flags is not NULL the function also fills
  63  * in flags for the GPIO.
  64  */
  65 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
  66                      const char *propname, int index, enum of_gpio_flags *flags)
  67 {
  68         /* Return -EPROBE_DEFER to support probe() functions to be called
  69          * later when the GPIO actually becomes available
  70          */
  71         struct gg_data gg_data = {
  72                 .flags = flags,
  73                 .out_gpio = ERR_PTR(-EPROBE_DEFER)
  74         };
  75         int ret;
  76
  77         /* .of_xlate might decide to not fill in the flags, so clear it. */
  78         if (flags)
  79                 *flags = 0;
  80
  81         ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
  82                                          &gg_data.gpiospec);
  83         if (ret) {
  84                 pr_debug("%s: can't parse gpios property of node '%s[%d]'\n",
  85                         __func__, np->full_name, index);
  86                 return ERR_PTR(ret);
  87         }
  88
  89         gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
  90
  91         of_node_put(gg_data.gpiospec.np);
  92         pr_debug("%s exited with status %d\n", __func__,
  93                  PTR_RET(gg_data.out_gpio));
  94         return gg_data.out_gpio;
  95 }
  96 EXPORT_SYMBOL(of_get_named_gpiod_flags);
  97
  98 /**
  99  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 100  * @gc:         pointer to the gpio_chip structure
 101  * @np:         device node of the GPIO chip
 102  * @gpio_spec:  gpio specifier as found in the device tree
 103  * @flags:      a flags pointer to fill in
 104  *
 105  * This is simple translation function, suitable for the most 1:1 mapped
 106  * gpio chips. This function performs only one sanity check: whether gpio
 107  * is less than ngpios (that is specified in the gpio_chip).
 108  */
 109 int of_gpio_simple_xlate(struct gpio_chip *gc,
 110                          const struct of_phandle_args *gpiospec, u32 *flags)
 111 {
 112         /*
 113          * We're discouraging gpio_cells < 2, since that way you'll have to
 114          * write your own xlate function (that will have to retrive the GPIO
 115          * number and the flags from a single gpio cell -- this is possible,
 116          * but not recommended).
 117          */
 118         if (gc->of_gpio_n_cells < 2) {
 119                 WARN_ON(1);
 120                 return -EINVAL;
 121         }
 122
 123         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 124                 return -EINVAL;
 125
 126         if (gpiospec->args[0] >= gc->ngpio)
 127                 return -EINVAL;
 128
 129         if (flags)
 130                 *flags = gpiospec->args[1];
 131
 132         return gpiospec->args[0];
 133 }
 134 EXPORT_SYMBOL(of_gpio_simple_xlate);
 135
 136 /**
 137  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
 138  * @np:         device node of the GPIO chip
 139  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 140  *
 141  * To use this function you should allocate and fill mm_gc with:
 142  *
 143  * 1) In the gpio_chip structure:
 144  *    - all the callbacks
 145  *    - of_gpio_n_cells
 146  *    - of_xlate callback (optional)
 147  *
 148  * 3) In the of_mm_gpio_chip structure:
 149  *    - save_regs callback (optional)
 150  *
 151  * If succeeded, this function will map bank's memory and will
 152  * do all necessary work for you. Then you'll able to use .regs
 153  * to manage GPIOs from the callbacks.
 154  */
 155 int of_mm_gpiochip_add(struct device_node *np,
 156                        struct of_mm_gpio_chip *mm_gc)
 157 {
 158         int ret = -ENOMEM;
 159         struct gpio_chip *gc = &mm_gc->gc;
 160
 161         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 162         if (!gc->label)
 163                 goto err0;
 164
 165         mm_gc->regs = of_iomap(np, 0);
 166         if (!mm_gc->regs)
 167                 goto err1;
 168
 169         gc->base = -1;
 170
 171         if (mm_gc->save_regs)
 172                 mm_gc->save_regs(mm_gc);
 173
 174         mm_gc->gc.of_node = np;
 175
 176         ret = gpiochip_add(gc);
 177         if (ret)
 178                 goto err2;
 179
 180         return 0;
 181 err2:
 182         iounmap(mm_gc->regs);
 183 err1:
 184         kfree(gc->label);
 185 err0:
 186         pr_err("%s: GPIO chip registration failed with status %d\n",
 187                np->full_name, ret);
 188         return ret;
 189 }
 190 EXPORT_SYMBOL(of_mm_gpiochip_add);
 191
 192 #ifdef CONFIG_PINCTRL
 193 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 194 {
 195         struct device_node *np = chip->of_node;
 196         struct of_phandle_args pinspec;
 197         struct pinctrl_dev *pctldev;
 198         int index = 0, ret;
 199         const char *name;
 200         static const char group_names_propname[] = "gpio-ranges-group-names";
 201         struct property *group_names;
 202
 203         if (!np)
 204                 return;
 205
 206         group_names = of_find_property(np, group_names_propname, NULL);
 207
 208         for (;; index++) {
 209                 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
 210                                 index, &pinspec);
 211                 if (ret)
 212                         break;
 213
 214                 pctldev = of_pinctrl_get(pinspec.np);
 215                 if (!pctldev)
 216                         break;
 217
 218                 if (pinspec.args[2]) {
 219                         if (group_names) {
 220                                 ret = of_property_read_string_index(np,
 221                                                 group_names_propname,
 222                                                 index, &name);
 223                                 if (strlen(name)) {
 224                                         pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
 225                                                 np->full_name);
 226                                         break;
 227                                 }
 228                         }
 229                         /* npins != 0: linear range */
 230                         ret = gpiochip_add_pin_range(chip,
 231                                         pinctrl_dev_get_devname(pctldev),
 232                                         pinspec.args[0],
 233                                         pinspec.args[1],
 234                                         pinspec.args[2]);
 235                         if (ret)
 236                                 break;
 237                 } else {
 238                         /* npins == 0: special range */
 239                         if (pinspec.args[1]) {
 240                                 pr_err("%s: Illegal gpio-range format.\n",
 241                                         np->full_name);
 242                                 break;
 243                         }
 244
 245                         if (!group_names) {
 246                                 pr_err("%s: GPIO group range requested but no %s property.\n",
 247                                         np->full_name, group_names_propname);
 248                                 break;
 249                         }
 250
 251                         ret = of_property_read_string_index(np,
 252                                                 group_names_propname,
 253                                                 index, &name);
 254                         if (ret)
 255                                 break;
 256
 257                         if (!strlen(name)) {
 258                                 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
 259                                 np->full_name);
 260                                 break;
 261                         }
 262
 263                         ret = gpiochip_add_pingroup_range(chip, pctldev,
 264                                                 pinspec.args[0], name);
 265                         if (ret)
 266                                 break;
 267                 }
 268         }
 269 }
 270
 271 #else
 272 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
 273 #endif
 274
 275 void of_gpiochip_add(struct gpio_chip *chip)
 276 {
 277         if ((!chip->of_node) && (chip->dev))
 278                 chip->of_node = chip->dev->of_node;
 279
 280         if (!chip->of_node)
 281                 return;
 282
 283         if (!chip->of_xlate) {
 284                 chip->of_gpio_n_cells = 2;
 285                 chip->of_xlate = of_gpio_simple_xlate;
 286         }
 287
 288         of_gpiochip_add_pin_range(chip);
 289         of_node_get(chip->of_node);
 290 }
 291
 292 void of_gpiochip_remove(struct gpio_chip *chip)
 293 {
 294         gpiochip_remove_pin_ranges(chip);
 295
 296         if (chip->of_node)
 297                 of_node_put(chip->of_node);
 298 }