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.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 /* Private data structure for of_gpiochip_find_and_xlate */
  27 struct gg_data {
  28         enum of_gpio_flags *flags;
  29         struct of_phandle_args gpiospec;
  30
  31         int out_gpio;
  32 };
  33
  34 /* Private function for resolving node pointer to gpio_chip */
  35 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
  36 {
  37         struct gg_data *gg_data = data;
  38         int ret;
  39
  40         if ((gc->of_node != gg_data->gpiospec.np) ||
  41             (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
  42             (!gc->of_xlate))
  43                 return false;
  44
  45         ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
  46         if (ret < 0) {
  47                 /* We've found the gpio chip, but the translation failed.
  48                  * Return true to stop looking and return the translation
  49                  * error via out_gpio
  50                  */
  51                 gg_data->out_gpio = ret;
  52                 return true;
  53          }
  54
  55         gg_data->out_gpio = ret + gc->base;
  56         return true;
  57 }
  58
  59 /**
  60  * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
  61  * @np:         device node to get GPIO from
  62  * @propname:   property name containing gpio specifier(s)
  63  * @index:      index of the GPIO
  64  * @flags:      a flags pointer to fill in
  65  *
  66  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
  67  * value on the error condition. If @flags is not NULL the function also fills
  68  * in flags for the GPIO.
  69  */
  70 int of_get_named_gpio_flags(struct device_node *np, const char *propname,
  71                            int index, enum of_gpio_flags *flags)
  72 {
  73         /* Return -EPROBE_DEFER to support probe() functions to be called
  74          * later when the GPIO actually becomes available
  75          */
  76         struct gg_data gg_data = { .flags = flags, .out_gpio = -EPROBE_DEFER };
  77         int ret;
  78
  79         /* .of_xlate might decide to not fill in the flags, so clear it. */
  80         if (flags)
  81                 *flags = 0;
  82
  83         ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
  84                                          &gg_data.gpiospec);
  85         if (ret) {
  86                 pr_debug("%s: can't parse gpios property\n", __func__);
  87                 return 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__, gg_data.out_gpio);
  94         return gg_data.out_gpio;
  95 }
  96 EXPORT_SYMBOL(of_get_named_gpio_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
 200         if (!np)
 201                 return;
 202
 203         for (;; index++) {
 204                 ret = of_parse_phandle_with_args(np, "gpio-ranges",
 205                                 "#gpio-range-cells", index, &pinspec);
 206                 if (ret)
 207                         break;
 208
 209                 pctldev = of_pinctrl_get(pinspec.np);
 210                 if (!pctldev)
 211                         break;
 212
 213                 ret = gpiochip_add_pin_range(chip,
 214                                              pinctrl_dev_get_devname(pctldev),
 215                                              pinspec.args[0],
 216                                              pinspec.args[1],
 217                                              pinspec.args[2]);
 218
 219                 if (ret)
 220                         break;
 221         }
 222 }
 223
 224 #else
 225 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
 226 #endif
 227
 228 void of_gpiochip_add(struct gpio_chip *chip)
 229 {
 230         if ((!chip->of_node) && (chip->dev))
 231                 chip->of_node = chip->dev->of_node;
 232
 233         if (!chip->of_node)
 234                 return;
 235
 236         if (!chip->of_xlate) {
 237                 chip->of_gpio_n_cells = 2;
 238                 chip->of_xlate = of_gpio_simple_xlate;
 239         }
 240
 241         of_gpiochip_add_pin_range(chip);
 242         of_node_get(chip->of_node);
 243 }
 244
 245 void of_gpiochip_remove(struct gpio_chip *chip)
 246 {
 247         gpiochip_remove_pin_ranges(chip);
 248
 249         if (chip->of_node)
 250                 of_node_put(chip->of_node);
 251 }