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_simple_xlate - translate gpio_spec to the GPIO number and flags
  93  * @gc:         pointer to the gpio_chip structure
  94  * @np:         device node of the GPIO chip
  95  * @gpio_spec:  gpio specifier as found in the device tree
  96  * @flags:      a flags pointer to fill in
  97  *
  98  * This is simple translation function, suitable for the most 1:1 mapped
  99  * gpio chips. This function performs only one sanity check: whether gpio
 100  * is less than ngpios (that is specified in the gpio_chip).
 101  */
 102 int of_gpio_simple_xlate(struct gpio_chip *gc,
 103                          const struct of_phandle_args *gpiospec, u32 *flags)
 104 {
 105         /*
 106          * We're discouraging gpio_cells < 2, since that way you'll have to
 107          * write your own xlate function (that will have to retrive the GPIO
 108          * number and the flags from a single gpio cell -- this is possible,
 109          * but not recommended).
 110          */
 111         if (gc->of_gpio_n_cells < 2) {
 112                 WARN_ON(1);
 113                 return -EINVAL;
 114         }
 115
 116         if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
 117                 return -EINVAL;
 118
 119         if (gpiospec->args[0] >= gc->ngpio)
 120                 return -EINVAL;
 121
 122         if (flags)
 123                 *flags = gpiospec->args[1];
 124
 125         return gpiospec->args[0];
 126 }
 127 EXPORT_SYMBOL(of_gpio_simple_xlate);
 128
 129 /**
 130  * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
 131  * @np:         device node of the GPIO chip
 132  * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 133  *
 134  * To use this function you should allocate and fill mm_gc with:
 135  *
 136  * 1) In the gpio_chip structure:
 137  *    - all the callbacks
 138  *    - of_gpio_n_cells
 139  *    - of_xlate callback (optional)
 140  *
 141  * 3) In the of_mm_gpio_chip structure:
 142  *    - save_regs callback (optional)
 143  *
 144  * If succeeded, this function will map bank's memory and will
 145  * do all necessary work for you. Then you'll able to use .regs
 146  * to manage GPIOs from the callbacks.
 147  */
 148 int of_mm_gpiochip_add(struct device_node *np,
 149                        struct of_mm_gpio_chip *mm_gc)
 150 {
 151         int ret = -ENOMEM;
 152         struct gpio_chip *gc = &mm_gc->gc;
 153
 154         gc->label = kstrdup(np->full_name, GFP_KERNEL);
 155         if (!gc->label)
 156                 goto err0;
 157
 158         mm_gc->regs = of_iomap(np, 0);
 159         if (!mm_gc->regs)
 160                 goto err1;
 161
 162         gc->base = -1;
 163
 164         if (mm_gc->save_regs)
 165                 mm_gc->save_regs(mm_gc);
 166
 167         mm_gc->gc.of_node = np;
 168
 169         ret = gpiochip_add(gc);
 170         if (ret)
 171                 goto err2;
 172
 173         return 0;
 174 err2:
 175         iounmap(mm_gc->regs);
 176 err1:
 177         kfree(gc->label);
 178 err0:
 179         pr_err("%s: GPIO chip registration failed with status %d\n",
 180                np->full_name, ret);
 181         return ret;
 182 }
 183 EXPORT_SYMBOL(of_mm_gpiochip_add);
 184
 185 #ifdef CONFIG_PINCTRL
 186 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 187 {
 188         struct device_node *np = chip->of_node;
 189         struct of_phandle_args pinspec;
 190         struct pinctrl_dev *pctldev;
 191         int index = 0, ret;
 192
 193         if (!np)
 194                 return;
 195
 196         do {
 197                 ret = of_parse_phandle_with_args(np, "gpio-ranges",
 198                                 "#gpio-range-cells", index, &pinspec);
 199                 if (ret)
 200                         break;
 201
 202                 pctldev = of_pinctrl_get(pinspec.np);
 203                 if (!pctldev)
 204                         break;
 205
 206                 /*
 207                  * This assumes that the n GPIO pins are consecutive in the
 208                  * GPIO number space, and that the pins are also consecutive
 209                  * in their local number space. Currently it is not possible
 210                  * to add different ranges for one and the same GPIO chip,
 211                  * as the code assumes that we have one consecutive range
 212                  * on both, mapping 1-to-1.
 213                  *
 214                  * TODO: make the OF bindings handle multiple sparse ranges
 215                  * on the same GPIO chip.
 216                  */
 217                 ret = gpiochip_add_pin_range(chip,
 218                                              pinctrl_dev_get_devname(pctldev),
 219                                              0, /* offset in gpiochip */
 220                                              pinspec.args[0],
 221                                              pinspec.args[1]);
 222
 223                 if (ret)
 224                         break;
 225
 226         } while (index++);
 227 }
 228
 229 #else
 230 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
 231 #endif
 232
 233 void of_gpiochip_add(struct gpio_chip *chip)
 234 {
 235         if ((!chip->of_node) && (chip->dev))
 236                 chip->of_node = chip->dev->of_node;
 237
 238         if (!chip->of_node)
 239                 return;
 240
 241         if (!chip->of_xlate) {
 242                 chip->of_gpio_n_cells = 2;
 243                 chip->of_xlate = of_gpio_simple_xlate;
 244         }
 245
 246         of_gpiochip_add_pin_range(chip);
 247         of_node_get(chip->of_node);
 248 }
 249
 250 void of_gpiochip_remove(struct gpio_chip *chip)
 251 {
 252         gpiochip_remove_pin_ranges(chip);
 253
 254         if (chip->of_node)
 255                 of_node_put(chip->of_node);
 256 }