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.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 /* Private data structure for of_gpiochip_find_and_xlate */
  26 struct gg_data {
  27         enum of_gpio_flags *flags;
  28         struct of_phandle_args gpiospec;
  29
  30         int out_gpio;
  31 };
  32
  33 /* Private function for resolving node pointer to gpio_chip */
  34 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
  35 {
  36         struct gg_data *gg_data = data;
  37         int ret;
  38
  39         if ((gc->of_node != gg_data->gpiospec.np) ||
  40             (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
  41             (!gc->of_xlate))
  42                 return false;
  43
  44         ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
  45         if (ret < 0)
  46                 return false;
  47
  48         gg_data->out_gpio = ret + gc->base;
  49         return true;
  50 }
  51
  52 /**
  53  * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
  54  * @np:         device node to get GPIO from
  55  * @propname:   property name containing gpio specifier(s)
  56  * @index:      index of the GPIO
  57  * @flags:      a flags pointer to fill in
  58  *
  59  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
  60  * value on the error condition. If @flags is not NULL the function also fills
  61  * in flags for the GPIO.
  62  */
  63 int of_get_named_gpio_flags(struct device_node *np, const char *propname,
  64                            int index, enum of_gpio_flags *flags)
  65 {
  66         /* Return -EPROBE_DEFER to support probe() functions to be called
  67          * later when the GPIO actually becomes available
  68          */
  69         struct gg_data gg_data = { .flags = flags, .out_gpio = -EPROBE_DEFER };
  70         int ret;
  71
  72         /* .of_xlate might decide to not fill in the flags, so clear it. */
  73         if (flags)
  74                 *flags = 0;
  75
  76         ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
  77                                          &gg_data.gpiospec);
  78         if (ret) {
  79                 pr_debug("%s: can't parse gpios property\n", __func__);
  80                 return ret;
  81         }
  82
  83         gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
  84
  85         of_node_put(gg_data.gpiospec.np);
  86         pr_debug("%s exited with status %d\n", __func__, gg_data.out_gpio);
  87         return gg_data.out_gpio;
  88 }
  89 EXPORT_SYMBOL(of_get_named_gpio_flags);
  90
  91 /**
  92  * of_gpio_named_count - Count GPIOs for a device
  93  * @np:         device node to count GPIOs for
  94  * @propname:   property name containing gpio specifier(s)
  95  *
  96  * The function returns the count of GPIOs specified for a node.
  97  *
  98  * Note that the empty GPIO specifiers counts too. For example,
  99  *
 100  * gpios = <0
 101  *          &pio1 1 2
 102  *          0
 103  *          &pio2 3 4>;
 104  *
 105  * defines four GPIOs (so this function will return 4), two of which
 106  * are not specified.
 107  */
 108 unsigned int of_gpio_named_count(struct device_node *np, const char* propname)
 109 {
 110         unsigned int cnt = 0;
 111
 112         do {
 113                 int ret;
 114
 115                 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells",
 116                                                  cnt, NULL);
 117                 /* A hole in the gpios = <> counts anyway. */
 118                 if (ret < 0 && ret != -EEXIST)
 119                         break;
 120         } while (++cnt);
 121
 122         return cnt;
 123 }
 124 EXPORT_SYMBOL(of_gpio_named_count);
 125
 126 /**
 127  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 128  * @gc:         pointer to the gpio_chip structure
 129  * @np:         device node of the GPIO chip
 130  * @gpio_spec:  gpio specifier as found in the device tree
 131  * @flags:      a flags pointer to fill in
 132  *
 133  * This is simple translation function, suitable for the most 1:1 mapped
 134  * gpio chips. This function performs only one sanity check: whether gpio
 135  * is less than ngpios (that is specified in the gpio_chip).
 136  */
 137 int of_gpio_simple_xlate(struct gpio_chip *gc,
 138                          const struct of_phandle_args *gpiospec, u32 *flags)
 139 {
 140         /*
 141          * We're discouraging gpio_cells < 2, since that way you'll have to
 142          * write your own xlate function (that will have to retrive the GPIO
 143          * number and the flags from a single gpio cell -- this is possible,
 144          * but not recommended).
 145          */
 146         if (gc->of_gpio_n_cells < 2) {
 147                 WARN_ON(1);
 148                 return -EINVAL;
 149         }
 150
 151         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 152                 return -EINVAL;
 153
 154         if (gpiospec->args[0] >= gc->ngpio)
 155                 return -EINVAL;
 156
 157         if (flags)
 158                 *flags = gpiospec->args[1];
 159
 160         return gpiospec->args[0];
 161 }
 162 EXPORT_SYMBOL(of_gpio_simple_xlate);
 163
 164 /**
 165  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
 166  * @np:         device node of the GPIO chip
 167  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 168  *
 169  * To use this function you should allocate and fill mm_gc with:
 170  *
 171  * 1) In the gpio_chip structure:
 172  *    - all the callbacks
 173  *    - of_gpio_n_cells
 174  *    - of_xlate callback (optional)
 175  *
 176  * 3) In the of_mm_gpio_chip structure:
 177  *    - save_regs callback (optional)
 178  *
 179  * If succeeded, this function will map bank's memory and will
 180  * do all necessary work for you. Then you'll able to use .regs
 181  * to manage GPIOs from the callbacks.
 182  */
 183 int of_mm_gpiochip_add(struct device_node *np,
 184                        struct of_mm_gpio_chip *mm_gc)
 185 {
 186         int ret = -ENOMEM;
 187         struct gpio_chip *gc = &mm_gc->gc;
 188
 189         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 190         if (!gc->label)
 191                 goto err0;
 192
 193         mm_gc->regs = of_iomap(np, 0);
 194         if (!mm_gc->regs)
 195                 goto err1;
 196
 197         gc->base = -1;
 198
 199         if (mm_gc->save_regs)
 200                 mm_gc->save_regs(mm_gc);
 201
 202         mm_gc->gc.of_node = np;
 203
 204         ret = gpiochip_add(gc);
 205         if (ret)
 206                 goto err2;
 207
 208         return 0;
 209 err2:
 210         iounmap(mm_gc->regs);
 211 err1:
 212         kfree(gc->label);
 213 err0:
 214         pr_err("%s: GPIO chip registration failed with status %d\n",
 215                np->full_name, ret);
 216         return ret;
 217 }
 218 EXPORT_SYMBOL(of_mm_gpiochip_add);
 219
 220 #ifdef CONFIG_PINCTRL
 221 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 222 {
 223         struct device_node *np = chip->of_node;
 224         struct gpio_pin_range *pin_range;
 225         struct of_phandle_args pinspec;
 226         int index = 0, ret;
 227
 228         if (!np)
 229                 return;
 230
 231         do {
 232                 ret = of_parse_phandle_with_args(np, "gpio-ranges",
 233                                 "#gpio-range-cells", index, &pinspec);
 234                 if (ret)
 235                         break;
 236
 237                 pin_range = devm_kzalloc(chip->dev, sizeof(*pin_range),
 238                                 GFP_KERNEL);
 239                 if (!pin_range) {
 240                         pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
 241                                         chip->label);
 242                         break;
 243                 }
 244
 245                 pin_range->range.name = chip->label;
 246                 pin_range->range.base = chip->base;
 247                 pin_range->range.pin_base = pinspec.args[0];
 248                 pin_range->range.npins = pinspec.args[1];
 249                 pin_range->pctldev = of_pinctrl_add_gpio_range(pinspec.np,
 250                                 &pin_range->range);
 251
 252                 list_add_tail(&pin_range->node, &chip->pin_ranges);
 253
 254         } while (index++);
 255 }
 256
 257 #else
 258 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
 259 #endif
 260
 261 void of_gpiochip_add(struct gpio_chip *chip)
 262 {
 263         if ((!chip->of_node) && (chip->dev))
 264                 chip->of_node = chip->dev->of_node;
 265
 266         if (!chip->of_node)
 267                 return;
 268
 269         if (!chip->of_xlate) {
 270                 chip->of_gpio_n_cells = 2;
 271                 chip->of_xlate = of_gpio_simple_xlate;
 272         }
 273
 274         of_gpiochip_add_pin_range(chip);
 275         of_node_get(chip->of_node);
 276 }
 277
 278 void of_gpiochip_remove(struct gpio_chip *chip)
 279 {
 280         gpiochip_remove_pin_ranges(chip);
 281
 282         if (chip->of_node)
 283                 of_node_put(chip->of_node);
 284 }