/*
 * OF helpers for the GPIO API
 *
 * Copyright (c) 2007-2008  MontaVista Software, Inc.
 *
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/io-mapping.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/slab.h>
#include <linux/gpio/machine.h>

#include "gpiolib.h"

/* Private data structure for of_gpiochip_find_and_xlate */
struct gg_data {
        enum of_gpio_flags *flags;
        struct of_phandle_args gpiospec;

        struct gpio_desc *out_gpio;
};

/* Private function for resolving node pointer to gpio_chip */
static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
{
        struct gg_data *gg_data = data;
        int ret;

        if ((gc->of_node != gg_data->gpiospec.np) ||
            (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
            (!gc->of_xlate))
                return false;

        ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
        if (ret < 0) {
                /* We've found a gpio chip, but the translation failed.
                 * Store translation error in out_gpio.
                 * Return false to keep looking, as more than one gpio chip
                 * could be registered per of-node.
                 */
                gg_data->out_gpio = ERR_PTR(ret);
                return false;
         }

        gg_data->out_gpio = gpiochip_get_desc(gc, ret);
        return true;
}

/**
 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
 * @np:         device node to get GPIO from
 * @propname:   property name containing gpio specifier(s)
 * @index:      index of the GPIO
 * @flags:      a flags pointer to fill in
 *
 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
 * value on the error condition. If @flags is not NULL the function also fills
 * in flags for the GPIO.
 */
struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
                     const char *propname, int index, enum of_gpio_flags *flags)
{
        /* Return -EPROBE_DEFER to support probe() functions to be called
         * later when the GPIO actually becomes available
         */
        struct gg_data gg_data = {
                .flags = flags,
                .out_gpio = ERR_PTR(-EPROBE_DEFER)
        };
        int ret;

        /* .of_xlate might decide to not fill in the flags, so clear it. */
        if (flags)
                *flags = 0;

        ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
                                         &gg_data.gpiospec);
        if (ret) {
                pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
                        __func__, propname, np->full_name, index);
                return ERR_PTR(ret);
        }

        gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);

        of_node_put(gg_data.gpiospec.np);
        pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
                 __func__, propname, np->full_name, index,
                 PTR_ERR_OR_ZERO(gg_data.out_gpio));
        return gg_data.out_gpio;
}

int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
                            int index, enum of_gpio_flags *flags)
{
        struct gpio_desc *desc;

        desc = of_get_named_gpiod_flags(np, list_name, index, flags);

        if (IS_ERR(desc))
                return PTR_ERR(desc);
        else
                return desc_to_gpio(desc);
}
EXPORT_SYMBOL(of_get_named_gpio_flags);

/**
 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
 * @np:         device node to get GPIO from
 * @name:       GPIO line name
 * @lflags:     gpio_lookup_flags - returned from of_find_gpio() or
 *              of_parse_own_gpio()
 * @dflags:     gpiod_flags - optional GPIO initialization flags
 *
 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
 * value on the error condition.
 */
static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
                                           const char **name,
                                           enum gpio_lookup_flags *lflags,
                                           enum gpiod_flags *dflags)
{
        struct device_node *chip_np;
        enum of_gpio_flags xlate_flags;
        struct gg_data gg_data = {
                .flags = &xlate_flags,
        };
        u32 tmp;
        int i, ret;

        chip_np = np->parent;
        if (!chip_np)
                return ERR_PTR(-EINVAL);

        xlate_flags = 0;
        *lflags = 0;
        *dflags = 0;

        ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
        if (ret)
                return ERR_PTR(ret);

        if (tmp > MAX_PHANDLE_ARGS)
                return ERR_PTR(-EINVAL);

        gg_data.gpiospec.args_count = tmp;
        gg_data.gpiospec.np = chip_np;
        for (i = 0; i < tmp; i++) {
                ret = of_property_read_u32_index(np, "gpios", i,
                                           &gg_data.gpiospec.args[i]);
                if (ret)
                        return ERR_PTR(ret);
        }

        gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
        if (!gg_data.out_gpio) {
                if (np->parent == np)
                        return ERR_PTR(-ENXIO);
                else
                        return ERR_PTR(-EINVAL);
        }

        if (xlate_flags & OF_GPIO_ACTIVE_LOW)
                *lflags |= GPIO_ACTIVE_LOW;

        if (of_property_read_bool(np, "input"))
                *dflags |= GPIOD_IN;
        else if (of_property_read_bool(np, "output-low"))
                *dflags |= GPIOD_OUT_LOW;
        else if (of_property_read_bool(np, "output-high"))
                *dflags |= GPIOD_OUT_HIGH;
        else {
                pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
                        desc_to_gpio(gg_data.out_gpio), np->name);
                return ERR_PTR(-EINVAL);
        }

        if (name && of_property_read_string(np, "line-name", name))
                *name = np->name;

        return gg_data.out_gpio;
}

/**
 * of_gpiochip_set_names() - set up the names of the lines
 * @chip: GPIO chip whose lines should be named, if possible
 */
static void of_gpiochip_set_names(struct gpio_chip *gc)
{
        struct gpio_device *gdev = gc->gpiodev;
        struct device_node *np = gc->of_node;
        int i;
        int nstrings;

        nstrings = of_property_count_strings(np, "gpio-line-names");
        if (nstrings <= 0)
                /* Lines names not present */
                return;

        /* This is normally not what you want */
        if (gdev->ngpio != nstrings)
                dev_info(&gdev->dev, "gpio-line-names specifies %d line "
                         "names but there are %d lines on the chip\n",
                         nstrings, gdev->ngpio);

        /*
         * Make sure to not index beyond the end of the number of descriptors
         * of the GPIO device.
         */
        for (i = 0; i < gdev->ngpio; i++) {
                const char *name;
                int ret;

                ret = of_property_read_string_index(np,
                                                    "gpio-line-names",
                                                    i,
                                                    &name);
                if (ret) {
                        if (ret != -ENODATA)
                                dev_err(&gdev->dev,
                                        "unable to name line %d: %d\n",
                                        i, ret);
                        break;
                }
                gdev->descs[i].name = name;
        }
}

/**
 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
 * @chip:       gpio chip to act on
 *
 * This is only used by of_gpiochip_add to request/set GPIO initial
 * configuration.
 * It retures error if it fails otherwise 0 on success.
 */
static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
{
        struct gpio_desc *desc = NULL;
        struct device_node *np;
        const char *name;
        enum gpio_lookup_flags lflags;
        enum gpiod_flags dflags;
        int ret;

        for_each_available_child_of_node(chip->of_node, np) {
                if (!of_property_read_bool(np, "gpio-hog"))
                        continue;

                desc = of_parse_own_gpio(np, &name, &lflags, &dflags);
                if (IS_ERR(desc))
                        continue;

                ret = gpiod_hog(desc, name, lflags, dflags);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

/**
 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
 * @gc:         pointer to the gpio_chip structure
 * @np:         device node of the GPIO chip
 * @gpio_spec:  gpio specifier as found in the device tree
 * @flags:      a flags pointer to fill in
 *
 * This is simple translation function, suitable for the most 1:1 mapped
 * gpio chips. This function performs only one sanity check: whether gpio
 * is less than ngpios (that is specified in the gpio_chip).
 */
int of_gpio_simple_xlate(struct gpio_chip *gc,
                         const struct of_phandle_args *gpiospec, u32 *flags)
{
        /*
         * We're discouraging gpio_cells < 2, since that way you'll have to
         * write your own xlate function (that will have to retrieve the GPIO
         * number and the flags from a single gpio cell -- this is possible,
         * but not recommended).
         */
        if (gc->of_gpio_n_cells < 2) {
                WARN_ON(1);
                return -EINVAL;
        }

        if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
                return -EINVAL;

        if (gpiospec->args[0] >= gc->ngpio)
                return -EINVAL;

        if (flags)
                *flags = gpiospec->args[1];

        return gpiospec->args[0];
}
EXPORT_SYMBOL(of_gpio_simple_xlate);

/**
 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
 * @np:         device node of the GPIO chip
 * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 * @data:       driver data to store in the struct gpio_chip
 *
 * To use this function you should allocate and fill mm_gc with:
 *
 * 1) In the gpio_chip structure:
 *    - all the callbacks
 *    - of_gpio_n_cells
 *    - of_xlate callback (optional)
 *
 * 3) In the of_mm_gpio_chip structure:
 *    - save_regs callback (optional)
 *
 * If succeeded, this function will map bank's memory and will
 * do all necessary work for you. Then you'll able to use .regs
 * to manage GPIOs from the callbacks.
 */
int of_mm_gpiochip_add_data(struct device_node *np,
                            struct of_mm_gpio_chip *mm_gc,
                            void *data)
{
        int ret = -ENOMEM;
        struct gpio_chip *gc = &mm_gc->gc;

        gc->label = kstrdup(np->full_name, GFP_KERNEL);
        if (!gc->label)
                goto err0;

        mm_gc->regs = of_iomap(np, 0);
        if (!mm_gc->regs)
                goto err1;

        gc->base = -1;

        if (mm_gc->save_regs)
                mm_gc->save_regs(mm_gc);

        mm_gc->gc.of_node = np;

        ret = gpiochip_add_data(gc, data);
        if (ret)
                goto err2;

        return 0;
err2:
        iounmap(mm_gc->regs);
err1:
        kfree(gc->label);
err0:
        pr_err("%s: GPIO chip registration failed with status %d\n",
               np->full_name, ret);
        return ret;
}
EXPORT_SYMBOL(of_mm_gpiochip_add_data);

/**
 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
 * @mm_gc:      pointer to the of_mm_gpio_chip allocated structure
 */
void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
{
        struct gpio_chip *gc = &mm_gc->gc;

        if (!mm_gc)
                return;

        gpiochip_remove(gc);
        iounmap(mm_gc->regs);
        kfree(gc->label);
}
EXPORT_SYMBOL(of_mm_gpiochip_remove);

#ifdef CONFIG_PINCTRL
static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
{
        struct device_node *np = chip->of_node;
        struct of_phandle_args pinspec;
        struct pinctrl_dev *pctldev;
        int index = 0, ret;
        const char *name;
        static const char group_names_propname[] = "gpio-ranges-group-names";
        struct property *group_names;

        if (!np)
                return 0;

        group_names = of_find_property(np, group_names_propname, NULL);

        for (;; index++) {
                ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
                                index, &pinspec);
                if (ret)
                        break;

                pctldev = of_pinctrl_get(pinspec.np);
                if (!pctldev)
                        return -EPROBE_DEFER;

                if (pinspec.args[2]) {
                        if (group_names) {
                                of_property_read_string_index(np,
                                                group_names_propname,
                                                index, &name);
                                if (strlen(name)) {
                                        pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
                                                np->full_name);
                                        break;
                                }
                        }
                        /* npins != 0: linear range */
                        ret = gpiochip_add_pin_range(chip,
                                        pinctrl_dev_get_devname(pctldev),
                                        pinspec.args[0],
                                        pinspec.args[1],
                                        pinspec.args[2]);
                        if (ret)
                                return ret;
                } else {
                        /* npins == 0: special range */
                        if (pinspec.args[1]) {
                                pr_err("%s: Illegal gpio-range format.\n",
                                        np->full_name);
                                break;
                        }

                        if (!group_names) {
                                pr_err("%s: GPIO group range requested but no %s property.\n",
                                        np->full_name, group_names_propname);
                                break;
                        }

                        ret = of_property_read_string_index(np,
                                                group_names_propname,
                                                index, &name);
                        if (ret)
                                break;

                        if (!strlen(name)) {
                                pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
                                np->full_name);
                                break;
                        }

                        ret = gpiochip_add_pingroup_range(chip, pctldev,
                                                pinspec.args[0], name);
                        if (ret)
                                return ret;
                }
        }

        return 0;
}

#else
static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
#endif

int of_gpiochip_add(struct gpio_chip *chip)
{
        int status;

        if ((!chip->of_node) && (chip->parent))
                chip->of_node = chip->parent->of_node;

        if (!chip->of_node)
                return 0;

        if (!chip->of_xlate) {
                chip->of_gpio_n_cells = 2;
                chip->of_xlate = of_gpio_simple_xlate;
        }

        status = of_gpiochip_add_pin_range(chip);
        if (status)
                return status;

        /* If the chip defines names itself, these take precedence */
        if (!chip->names)
                of_gpiochip_set_names(chip);

        of_node_get(chip->of_node);

        return of_gpiochip_scan_gpios(chip);
}

void of_gpiochip_remove(struct gpio_chip *chip)
{
        gpiochip_remove_pin_ranges(chip);
        of_node_put(chip->of_node);
}