linux/drivers/gpio/gpiolib-of.c
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   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 */
  26struct 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 */
  34static 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 */
  63int 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}
  89EXPORT_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 */
 102int 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}
 127EXPORT_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 */
 148int 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;
 174err2:
 175        iounmap(mm_gc->regs);
 176err1:
 177        kfree(gc->label);
 178err0:
 179        pr_err("%s: GPIO chip registration failed with status %d\n",
 180               np->full_name, ret);
 181        return ret;
 182}
 183EXPORT_SYMBOL(of_mm_gpiochip_add);
 184
 185#ifdef CONFIG_PINCTRL
 186static 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        for (;; index++) {
 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                ret = gpiochip_add_pin_range(chip,
 207                                             pinctrl_dev_get_devname(pctldev),
 208                                             pinspec.args[0],
 209                                             pinspec.args[1],
 210                                             pinspec.args[2]);
 211
 212                if (ret)
 213                        break;
 214        }
 215}
 216
 217#else
 218static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
 219#endif
 220
 221void of_gpiochip_add(struct gpio_chip *chip)
 222{
 223        if ((!chip->of_node) && (chip->dev))
 224                chip->of_node = chip->dev->of_node;
 225
 226        if (!chip->of_node)
 227                return;
 228
 229        if (!chip->of_xlate) {
 230                chip->of_gpio_n_cells = 2;
 231                chip->of_xlate = of_gpio_simple_xlate;
 232        }
 233
 234        of_gpiochip_add_pin_range(chip);
 235        of_node_get(chip->of_node);
 236}
 237
 238void of_gpiochip_remove(struct gpio_chip *chip)
 239{
 240        gpiochip_remove_pin_ranges(chip);
 241
 242        if (chip->of_node)
 243                of_node_put(chip->of_node);
 244}
 245
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