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 of node '%s[%d]'\n",
  80                         __func__, np->full_name, index);
  81                 return ret;
  82         }
  83
  84         gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
  85
  86         of_node_put(gg_data.gpiospec.np);
  87         pr_debug("%s exited with status %d\n", __func__, gg_data.out_gpio);
  88         return gg_data.out_gpio;
  89 }
  90 EXPORT_SYMBOL(of_get_named_gpio_flags);
  91
  92 /**
  93  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
  94  * @gc:         pointer to the gpio_chip structure
  95  * @np:         device node of the GPIO chip
  96  * @gpio_spec:  gpio specifier as found in the device tree
  97  * @flags:      a flags pointer to fill in
  98  *
  99  * This is simple translation function, suitable for the most 1:1 mapped
 100  * gpio chips. This function performs only one sanity check: whether gpio
 101  * is less than ngpios (that is specified in the gpio_chip).
 102  */
 103 int of_gpio_simple_xlate(struct gpio_chip *gc,
 104                          const struct of_phandle_args *gpiospec, u32 *flags)
 105 {
 106         /*
 107          * We're discouraging gpio_cells < 2, since that way you'll have to
 108          * write your own xlate function (that will have to retrive the GPIO
 109          * number and the flags from a single gpio cell -- this is possible,
 110          * but not recommended).
 111          */
 112         if (gc->of_gpio_n_cells < 2) {
 113                 WARN_ON(1);
 114                 return -EINVAL;
 115         }
 116
 117         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 118                 return -EINVAL;
 119
 120         if (gpiospec->args[0] >= gc->ngpio)
 121                 return -EINVAL;
 122
 123         if (flags)
 124                 *flags = gpiospec->args[1];
 125
 126         return gpiospec->args[0];
 127 }
 128 EXPORT_SYMBOL(of_gpio_simple_xlate);
 129
 130 /**
 131  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
 132  * @np:         device node of the GPIO chip
 133  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 134  *
 135  * To use this function you should allocate and fill mm_gc with:
 136  *
 137  * 1) In the gpio_chip structure:
 138  *    - all the callbacks
 139  *    - of_gpio_n_cells
 140  *    - of_xlate callback (optional)
 141  *
 142  * 3) In the of_mm_gpio_chip structure:
 143  *    - save_regs callback (optional)
 144  *
 145  * If succeeded, this function will map bank's memory and will
 146  * do all necessary work for you. Then you'll able to use .regs
 147  * to manage GPIOs from the callbacks.
 148  */
 149 int of_mm_gpiochip_add(struct device_node *np,
 150                        struct of_mm_gpio_chip *mm_gc)
 151 {
 152         int ret = -ENOMEM;
 153         struct gpio_chip *gc = &mm_gc->gc;
 154
 155         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 156         if (!gc->label)
 157                 goto err0;
 158
 159         mm_gc->regs = of_iomap(np, 0);
 160         if (!mm_gc->regs)
 161                 goto err1;
 162
 163         gc->base = -1;
 164
 165         if (mm_gc->save_regs)
 166                 mm_gc->save_regs(mm_gc);
 167
 168         mm_gc->gc.of_node = np;
 169
 170         ret = gpiochip_add(gc);
 171         if (ret)
 172                 goto err2;
 173
 174         return 0;
 175 err2:
 176         iounmap(mm_gc->regs);
 177 err1:
 178         kfree(gc->label);
 179 err0:
 180         pr_err("%s: GPIO chip registration failed with status %d\n",
 181                np->full_name, ret);
 182         return ret;
 183 }
 184 EXPORT_SYMBOL(of_mm_gpiochip_add);
 185
 186 #ifdef CONFIG_PINCTRL
 187 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 188 {
 189         struct device_node *np = chip->of_node;
 190         struct of_phandle_args pinspec;
 191         struct pinctrl_dev *pctldev;
 192         int index = 0, ret;
 193
 194         if (!np)
 195                 return;
 196
 197         for (;; index++) {
 198                 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
 199                                 index, &pinspec);
 200                 if (ret)
 201                         break;
 202
 203                 pctldev = of_pinctrl_get(pinspec.np);
 204                 if (!pctldev)
 205                         break;
 206
 207                 ret = gpiochip_add_pin_range(chip,
 208                                              pinctrl_dev_get_devname(pctldev),
 209                                              pinspec.args[0],
 210                                              pinspec.args[1],
 211                                              pinspec.args[2]);
 212
 213                 if (ret)
 214                         break;
 215         }
 216 }
 217
 218 #else
 219 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
 220 #endif
 221
 222 void of_gpiochip_add(struct gpio_chip *chip)
 223 {
 224         if ((!chip->of_node) && (chip->dev))
 225                 chip->of_node = chip->dev->of_node;
 226
 227         if (!chip->of_node)
 228                 return;
 229
 230         if (!chip->of_xlate) {
 231                 chip->of_gpio_n_cells = 2;
 232                 chip->of_xlate = of_gpio_simple_xlate;
 233         }
 234
 235         of_gpiochip_add_pin_range(chip);
 236         of_node_get(chip->of_node);
 237 }
 238
 239 void of_gpiochip_remove(struct gpio_chip *chip)
 240 {
 241         gpiochip_remove_pin_ranges(chip);
 242
 243         if (chip->of_node)
 244                 of_node_put(chip->of_node);
 245 }