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 struct gpio_desc;
  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 = gpio_to_desc(ret + gc->base);
  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 gpios property of node '%s[%d]'\n",
  86                         __func__, 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 exited with status %d\n", __func__,
  94                  PTR_ERR_OR_ZERO(gg_data.out_gpio));
  95         return gg_data.out_gpio;
  96 }
  97 EXPORT_SYMBOL(of_get_named_gpiod_flags);
  98
  99 /**
 100  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 101  * @gc:         pointer to the gpio_chip structure
 102  * @np:         device node of the GPIO chip
 103  * @gpio_spec:  gpio specifier as found in the device tree
 104  * @flags:      a flags pointer to fill in
 105  *
 106  * This is simple translation function, suitable for the most 1:1 mapped
 107  * gpio chips. This function performs only one sanity check: whether gpio
 108  * is less than ngpios (that is specified in the gpio_chip).
 109  */
 110 int of_gpio_simple_xlate(struct gpio_chip *gc,
 111                          const struct of_phandle_args *gpiospec, u32 *flags)
 112 {
 113         /*
 114          * We're discouraging gpio_cells < 2, since that way you'll have to
 115          * write your own xlate function (that will have to retrive the GPIO
 116          * number and the flags from a single gpio cell -- this is possible,
 117          * but not recommended).
 118          */
 119         if (gc->of_gpio_n_cells < 2) {
 120                 WARN_ON(1);
 121                 return -EINVAL;
 122         }
 123
 124         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 125                 return -EINVAL;
 126
 127         if (gpiospec->args[0] >= gc->ngpio)
 128                 return -EINVAL;
 129
 130         if (flags)
 131                 *flags = gpiospec->args[1];
 132
 133         return gpiospec->args[0];
 134 }
 135 EXPORT_SYMBOL(of_gpio_simple_xlate);
 136
 137 /**
 138  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
 139  * @np:         device node of the GPIO chip
 140  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 141  *
 142  * To use this function you should allocate and fill mm_gc with:
 143  *
 144  * 1) In the gpio_chip structure:
 145  *    - all the callbacks
 146  *    - of_gpio_n_cells
 147  *    - of_xlate callback (optional)
 148  *
 149  * 3) In the of_mm_gpio_chip structure:
 150  *    - save_regs callback (optional)
 151  *
 152  * If succeeded, this function will map bank's memory and will
 153  * do all necessary work for you. Then you'll able to use .regs
 154  * to manage GPIOs from the callbacks.
 155  */
 156 int of_mm_gpiochip_add(struct device_node *np,
 157                        struct of_mm_gpio_chip *mm_gc)
 158 {
 159         int ret = -ENOMEM;
 160         struct gpio_chip *gc = &mm_gc->gc;
 161
 162         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 163         if (!gc->label)
 164                 goto err0;
 165
 166         mm_gc->regs = of_iomap(np, 0);
 167         if (!mm_gc->regs)
 168                 goto err1;
 169
 170         gc->base = -1;
 171
 172         if (mm_gc->save_regs)
 173                 mm_gc->save_regs(mm_gc);
 174
 175         mm_gc->gc.of_node = np;
 176
 177         ret = gpiochip_add(gc);
 178         if (ret)
 179                 goto err2;
 180
 181         return 0;
 182 err2:
 183         iounmap(mm_gc->regs);
 184 err1:
 185         kfree(gc->label);
 186 err0:
 187         pr_err("%s: GPIO chip registration failed with status %d\n",
 188                np->full_name, ret);
 189         return ret;
 190 }
 191 EXPORT_SYMBOL(of_mm_gpiochip_add);
 192
 193 #ifdef CONFIG_PINCTRL
 194 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 195 {
 196         struct device_node *np = chip->of_node;
 197         struct of_phandle_args pinspec;
 198         struct pinctrl_dev *pctldev;
 199         int index = 0, ret;
 200         const char *name;
 201         static const char group_names_propname[] = "gpio-ranges-group-names";
 202         struct property *group_names;
 203
 204         if (!np)
 205                 return;
 206
 207         group_names = of_find_property(np, group_names_propname, NULL);
 208
 209         for (;; index++) {
 210                 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
 211                                 index, &pinspec);
 212                 if (ret)
 213                         break;
 214
 215                 pctldev = of_pinctrl_get(pinspec.np);
 216                 if (!pctldev)
 217                         break;
 218
 219                 if (pinspec.args[2]) {
 220                         if (group_names) {
 221                                 ret = of_property_read_string_index(np,
 222                                                 group_names_propname,
 223                                                 index, &name);
 224                                 if (strlen(name)) {
 225                                         pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
 226                                                 np->full_name);
 227                                         break;
 228                                 }
 229                         }
 230                         /* npins != 0: linear range */
 231                         ret = gpiochip_add_pin_range(chip,
 232                                         pinctrl_dev_get_devname(pctldev),
 233                                         pinspec.args[0],
 234                                         pinspec.args[1],
 235                                         pinspec.args[2]);
 236                         if (ret)
 237                                 break;
 238                 } else {
 239                         /* npins == 0: special range */
 240                         if (pinspec.args[1]) {
 241                                 pr_err("%s: Illegal gpio-range format.\n",
 242                                         np->full_name);
 243                                 break;
 244                         }
 245
 246                         if (!group_names) {
 247                                 pr_err("%s: GPIO group range requested but no %s property.\n",
 248                                         np->full_name, group_names_propname);
 249                                 break;
 250                         }
 251
 252                         ret = of_property_read_string_index(np,
 253                                                 group_names_propname,
 254                                                 index, &name);
 255                         if (ret)
 256                                 break;
 257
 258                         if (!strlen(name)) {
 259                                 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
 260                                 np->full_name);
 261                                 break;
 262                         }
 263
 264                         ret = gpiochip_add_pingroup_range(chip, pctldev,
 265                                                 pinspec.args[0], name);
 266                         if (ret)
 267                                 break;
 268                 }
 269         }
 270 }
 271
 272 #else
 273 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
 274 #endif
 275
 276 void of_gpiochip_add(struct gpio_chip *chip)
 277 {
 278         if ((!chip->of_node) && (chip->dev))
 279                 chip->of_node = chip->dev->of_node;
 280
 281         if (!chip->of_node)
 282                 return;
 283
 284         if (!chip->of_xlate) {
 285                 chip->of_gpio_n_cells = 2;
 286                 chip->of_xlate = of_gpio_simple_xlate;
 287         }
 288
 289         of_gpiochip_add_pin_range(chip);
 290         of_node_get(chip->of_node);
 291 }
 292
 293 void of_gpiochip_remove(struct gpio_chip *chip)
 294 {
 295         gpiochip_remove_pin_ranges(chip);
 296
 297         if (chip->of_node)
 298                 of_node_put(chip->of_node);
 299 }