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