xref: /device/soc/rockchip/common/sdk_linux/drivers/gpio/gpiolib-of.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * OF helpers for the GPIO API
 *
 * Copyright (c) 2007-2008  MontaVista Software, Inc.
 *
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/io.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"
#include "gpiolib-of.h"

/**
 * of_gpio_spi_cs_get_count() - special GPIO counting for SPI
 * @dev:    Consuming device
 * @con_id: Function within the GPIO consumer
 *
 * Some elder GPIO controllers need special quirks. Currently we handle
 * the Freescale and PPC GPIO controller with bindings that doesn't use the
 * established "cs-gpios" for chip selects but instead rely on
 * "gpios" for the chip select lines. If we detect this, we redirect
 * the counting of "cs-gpios" to count "gpios" transparent to the
 * driver.
 */
static int of_gpio_spi_cs_get_count(struct device *dev, const char *con_id)
{
    struct device_node *np = dev->of_node;

    if (!IS_ENABLED(CONFIG_SPI_MASTER)) {
        return 0;
    }
    if (!con_id || strcmp(con_id, "cs")) {
        return 0;
    }
    if (!of_device_is_compatible(np, "fsl,spi") && !of_device_is_compatible(np, "aeroflexgaisler,spictrl") &&
        !of_device_is_compatible(np, "ibm,ppc4xx-spi")) {
        return 0;
    }
    return of_gpio_named_count(np, "gpios");
}

/*
 * This is used by external users of of_gpio_count() from <linux/of_gpio.h>
 *
 * get rid of those external users by converting them to GPIO
 * descriptors and let them all use gpiod_count()
 */
int of_gpio_get_count(struct device *dev, const char *con_id)
{
    int ret;
    char propname[32];
    unsigned int i;

    ret = of_gpio_spi_cs_get_count(dev, con_id);
    if (ret > 0) {
        return ret;
    }

    for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
        if (con_id) {
            snprintf(propname, sizeof(propname), "%s-%s", con_id, gpio_suffixes[i]);
        } else {
            snprintf(propname, sizeof(propname), "%s", gpio_suffixes[i]);
        }

        ret = of_gpio_named_count(dev->of_node, propname);
        if (ret > 0) {
            break;
        }
    }
    return ret ? ret : -ENOENT;
}

static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data)
{
    struct of_phandle_args *gpiospec = data;

    return chip->gpiodev->dev.of_node == gpiospec->np && chip->of_xlate && chip->of_xlate(chip, gpiospec, NULL) >= 0;
}

static struct gpio_chip *of_find_gpiochip_by_xlate(struct of_phandle_args *gpiospec)
{
    return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate);
}

static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip, struct of_phandle_args *gpiospec,
                                                      enum of_gpio_flags *flags)
{
    int ret;

    if (chip->of_gpio_n_cells != gpiospec->args_count) {
        return ERR_PTR(-EINVAL);
    }

    ret = chip->of_xlate(chip, gpiospec, flags);
    if (ret < 0) {
        return ERR_PTR(ret);
    }

    return gpiochip_get_desc(chip, ret);
}

/**
 * of_gpio_need_valid_mask() - figure out if the OF GPIO driver needs
 * to set the .valid_mask
 * @gc: the target gpio_chip
 *
 * Return: true if the valid mask needs to be set
 */
bool of_gpio_need_valid_mask(const struct gpio_chip *gc)
{
    int size;
    struct device_node *np = gc->of_node;

    size = of_property_count_u32_elems(np, "gpio-reserved-ranges");
    if (size > 0 && size % 2 == 0) {
        return true;
    }
    return false;
}

static void of_gpio_flags_quirks(struct device_node *np, const char *propname, enum of_gpio_flags *flags, int index)
{
    /*
     * Some GPIO fixed regulator quirks.
     * Note that active low is the default.
     */
    if (IS_ENABLED(CONFIG_REGULATOR) &&
        (of_device_is_compatible(np, "regulator-fixed") || of_device_is_compatible(np, "reg-fixed-voltage") ||
         (!(strcmp(propname, "enable-gpio") && strcmp(propname, "enable-gpios")) &&
          of_device_is_compatible(np, "regulator-gpio")))) {
        bool active_low = !of_property_read_bool(np, "enable-active-high");
        /*
         * The regulator GPIO handles are specified such that the
         * presence or absence of "enable-active-high" solely controls
         * the polarity of the GPIO line. Any phandle flags must
         * be actively ignored.
         */
        if ((*flags & OF_GPIO_ACTIVE_LOW) && !active_low) {
            pr_warn("%s GPIO handle specifies active low - ignored\n", of_node_full_name(np));
            *flags &= ~OF_GPIO_ACTIVE_LOW;
        }
        if (active_low) {
            *flags |= OF_GPIO_ACTIVE_LOW;
        }
    }
    /*
     * Legacy open drain handling for fixed voltage regulators.
     */
    if (IS_ENABLED(CONFIG_REGULATOR) && of_device_is_compatible(np, "reg-fixed-voltage") &&
        of_property_read_bool(np, "gpio-open-drain")) {
        *flags |= (OF_GPIO_SINGLE_ENDED | OF_GPIO_OPEN_DRAIN);
        pr_info("%s uses legacy open drain flag - update the DTS if you can\n", of_node_full_name(np));
    }

    /*
     * Legacy handling of SPI active high chip select. If we have a
     * property named "cs-gpios" we need to inspect the child node
     * to determine if the flags should have inverted semantics.
     */
    if (IS_ENABLED(CONFIG_SPI_MASTER) && !strcmp(propname, "cs-gpios") && of_property_read_bool(np, "cs-gpios")) {
        struct device_node *child;
        u32 cs;
        int ret;

        for_each_child_of_node(np, child)
        {
            ret = of_property_read_u32(child, "reg", &cs);
            if (ret) {
                continue;
            }
            if (cs == index) {
                /*
                 * SPI children have active low chip selects
                 * by default. This can be specified negatively
                 * by just omitting "spi-cs-high" in the
                 * device node, or actively by tagging on
                 * GPIO_ACTIVE_LOW as flag in the device
                 * tree. If the line is simultaneously
                 * tagged as active low in the device tree
                 * and has the "spi-cs-high" set, we get a
                 * conflict and the "spi-cs-high" flag will
                 * take precedence.
                 */
                if (of_property_read_bool(child, "spi-cs-high")) {
                    if (*flags & OF_GPIO_ACTIVE_LOW) {
                        pr_warn("%s GPIO handle specifies active low - ignored\n", of_node_full_name(child));
                        *flags &= ~OF_GPIO_ACTIVE_LOW;
                    }
                } else {
                    if (!(*flags & OF_GPIO_ACTIVE_LOW)) {
                        pr_info("%s enforce active low on chipselect handle\n", of_node_full_name(child));
                    }
                    *flags |= OF_GPIO_ACTIVE_LOW;
                }
                of_node_put(child);
                break;
            }
        }
    }

    /* Legacy handling of stmmac's active-low PHY reset line */
    if (IS_ENABLED(CONFIG_STMMAC_ETH) && !strcmp(propname, "snps,reset-gpio") &&
        of_property_read_bool(np, "snps,reset-active-low")) {
        *flags |= OF_GPIO_ACTIVE_LOW;
    }
}

/**
 * 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.
 */
static struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, const char *propname, int index,
                                                  enum of_gpio_flags *flags)
{
    struct of_phandle_args gpiospec;
    struct gpio_chip *chip;
    struct gpio_desc *desc;
    int ret;

    ret = of_parse_phandle_with_args_map(np, propname, "gpio", index, &gpiospec);
    if (ret) {
        pr_debug("%s: can't parse '%s' property of node '%pOF[%d]'\n", __func__, propname, np, index);
        return ERR_PTR(ret);
    }

    chip = of_find_gpiochip_by_xlate(&gpiospec);
    if (!chip) {
        desc = ERR_PTR(-EPROBE_DEFER);
        goto out;
    }

    desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
    if (IS_ERR(desc)) {
        goto out;
    }

    if (flags) {
        of_gpio_flags_quirks(np, propname, flags, index);
    }

    pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n", __func__, propname, np, index,
             PTR_ERR_OR_ZERO(desc));

out:
    of_node_put(gpiospec.np);

    return desc;
}

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_GPL(of_get_named_gpio_flags);

/**
 * gpiod_get_from_of_node() - obtain a GPIO from an OF node
 * @node:    handle of the OF node
 * @propname:    name of the DT property representing the GPIO
 * @index:    index of the GPIO to obtain for the consumer
 * @dflags:    GPIO initialization flags
 * @label:    label to attach to the requested GPIO
 *
 * Returns:
 * On successful request the GPIO pin is configured in accordance with
 * provided @dflags.
 *
 * In case of error an ERR_PTR() is returned.
 */
struct gpio_desc *gpiod_get_from_of_node(struct device_node *node, const char *propname, int index,
                                         enum gpiod_flags dflags, const char *label)
{
    unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
    struct gpio_desc *desc;
    enum of_gpio_flags flags;
    bool active_low = false;
    bool single_ended = false;
    bool open_drain = false;
    bool transitory = false;
    int ret;

    desc = of_get_named_gpiod_flags(node, propname, index, &flags);
    if (!desc || IS_ERR(desc)) {
        return desc;
    }

    active_low = flags & OF_GPIO_ACTIVE_LOW;
    single_ended = flags & OF_GPIO_SINGLE_ENDED;
    open_drain = flags & OF_GPIO_OPEN_DRAIN;
    transitory = flags & OF_GPIO_TRANSITORY;

    ret = gpiod_request(desc, label);
    if (ret == -EBUSY && (dflags & GPIOD_FLAGS_BIT_NONEXCLUSIVE)) {
        return desc;
    }
    if (ret) {
        return ERR_PTR(ret);
    }

    if (active_low) {
        lflags |= GPIO_ACTIVE_LOW;
    }

    if (single_ended) {
        if (open_drain) {
            lflags |= GPIO_OPEN_DRAIN;
        } else {
            lflags |= GPIO_OPEN_SOURCE;
        }
    }

    if (transitory) {
        lflags |= GPIO_TRANSITORY;
    }

    if (flags & OF_GPIO_PULL_UP) {
        lflags |= GPIO_PULL_UP;
    }

    if (flags & OF_GPIO_PULL_DOWN) {
        lflags |= GPIO_PULL_DOWN;
    }

    ret = gpiod_configure_flags(desc, propname, lflags, dflags);
    if (ret < 0) {
        gpiod_put(desc);
        return ERR_PTR(ret);
    }

    return desc;
}
EXPORT_SYMBOL_GPL(gpiod_get_from_of_node);

/*
 * The SPI GPIO bindings happened before we managed to establish that GPIO
 * properties should be named "foo-gpios" so we have this special kludge for
 * them.
 */
static struct gpio_desc *of_find_spi_gpio(struct device *dev, const char *con_id, enum of_gpio_flags *of_flags)
{
    char prop_name[32]; /* 32 is max size of property name */
    struct device_node *np = dev->of_node;
    struct gpio_desc *desc;
    int ret = 0;
    /*
     * Hopefully the compiler stubs the rest of the function if this
     * is false.
     */
    if (!IS_ENABLED(CONFIG_SPI_MASTER)) {
        return ERR_PTR(-ENOENT);
    }

    /* Allow this specifically for "spi-gpio" devices */
    if (!of_device_is_compatible(np, "spi-gpio") || !con_id) {
        return ERR_PTR(-ENOENT);
    }

    /* Will be "gpio-sck", "gpio-mosi" or "gpio-miso" */
    ret = snprintf(prop_name, sizeof(prop_name), "%s-%s", "gpio", con_id);

    desc = of_get_named_gpiod_flags(np, prop_name, 0, of_flags);
    return desc;
}

/*
 * The old Freescale bindings use simply "gpios" as name for the chip select
 * lines rather than "cs-gpios" like all other SPI hardware. Account for this
 * with a special quirk.
 */
static struct gpio_desc *of_find_spi_cs_gpio(struct device *dev, const char *con_id, unsigned int idx,
                                             unsigned long *flags)
{
    struct device_node *np = dev->of_node;

    if (!IS_ENABLED(CONFIG_SPI_MASTER)) {
        return ERR_PTR(-ENOENT);
    }

    /* Allow this specifically for Freescale and PPC devices */
    if (!of_device_is_compatible(np, "fsl,spi") && !of_device_is_compatible(np, "aeroflexgaisler,spictrl") &&
        !of_device_is_compatible(np, "ibm,ppc4xx-spi")) {
        return ERR_PTR(-ENOENT);
    }
    /* Allow only if asking for "cs-gpios" */
    if (!con_id || strcmp(con_id, "cs")) {
        return ERR_PTR(-ENOENT);
    }

    /*
     * While all other SPI controllers use "cs-gpios" the Freescale
     * uses just "gpios" so translate to that when "cs-gpios" is
     * requested.
     */
    return of_find_gpio(dev, NULL, idx, flags);
}

/*
 * Some regulator bindings happened before we managed to establish that GPIO
 * properties should be named "foo-gpios" so we have this special kludge for
 * them.
 */
static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *con_id, enum of_gpio_flags *of_flags)
{
    /* These are the connection IDs we accept as legacy GPIO phandles */
    const char *whitelist[] = {
        "wlf,ldoena",  /* Arizona */
        "wlf,ldo1ena", /* WM8994 */
        "wlf,ldo2ena", /* WM8994 */
    };
    struct device_node *np = dev->of_node;
    struct gpio_desc *desc;
    int i;

    if (!IS_ENABLED(CONFIG_REGULATOR)) {
        return ERR_PTR(-ENOENT);
    }

    if (!con_id) {
        return ERR_PTR(-ENOENT);
    }

    i = match_string(whitelist, ARRAY_SIZE(whitelist), con_id);
    if (i < 0) {
        return ERR_PTR(-ENOENT);
    }

    desc = of_get_named_gpiod_flags(np, con_id, 0, of_flags);
    return desc;
}

static struct gpio_desc *of_find_arizona_gpio(struct device *dev, const char *con_id, enum of_gpio_flags *of_flags)
{
    if (!IS_ENABLED(CONFIG_MFD_ARIZONA)) {
        return ERR_PTR(-ENOENT);
    }

    if (!con_id || strcmp(con_id, "wlf,reset")) {
        return ERR_PTR(-ENOENT);
    }

    return of_get_named_gpiod_flags(dev->of_node, con_id, 0, of_flags);
}

static struct gpio_desc *of_find_usb_gpio(struct device *dev, const char *con_id, enum of_gpio_flags *of_flags)
{
    /*
     * Currently this USB quirk is only for the Fairchild FUSB302 host which is using
     * an undocumented DT GPIO line named "fcs,int_n" without the compulsory "-gpios"
     * suffix.
     */
    if (!IS_ENABLED(CONFIG_TYPEC_FUSB302)) {
        return ERR_PTR(-ENOENT);
    }

    if (!con_id || strcmp(con_id, "fcs,int_n")) {
        return ERR_PTR(-ENOENT);
    }

    return of_get_named_gpiod_flags(dev->of_node, con_id, 0, of_flags);
}

struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, unsigned int idx, unsigned long *flags)
{
    char prop_name[32]; /* 32 is max size of property name */
    enum of_gpio_flags of_flags;
    struct gpio_desc *desc;
    unsigned int i;

    /* Try GPIO property "foo-gpios" and "foo-gpio" */
    for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
        if (con_id) {
            snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id, gpio_suffixes[i]);
        } else {
            snprintf(prop_name, sizeof(prop_name), "%s", gpio_suffixes[i]);
        }

        desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx, &of_flags);
        if (!IS_ERR(desc) || PTR_ERR(desc) != -ENOENT) {
            break;
        }
    }

    if (PTR_ERR(desc) == -ENOENT) {
        /* Special handling for SPI GPIOs if used */
        desc = of_find_spi_gpio(dev, con_id, &of_flags);
    }

    if (PTR_ERR(desc) == -ENOENT) {
        /* This quirk looks up flags and all */
        desc = of_find_spi_cs_gpio(dev, con_id, idx, flags);
        if (!IS_ERR(desc)) {
            return desc;
        }
    }

    if (PTR_ERR(desc) == -ENOENT) {
        /* Special handling for regulator GPIOs if used */
        desc = of_find_regulator_gpio(dev, con_id, &of_flags);
    }

    if (PTR_ERR(desc) == -ENOENT) {
        desc = of_find_arizona_gpio(dev, con_id, &of_flags);
    }

    if (PTR_ERR(desc) == -ENOENT) {
        desc = of_find_usb_gpio(dev, con_id, &of_flags);
    }

    if (IS_ERR(desc)) {
        return desc;
    }

    if (of_flags & OF_GPIO_ACTIVE_LOW) {
        *flags |= GPIO_ACTIVE_LOW;
    }

    if (of_flags & OF_GPIO_SINGLE_ENDED) {
        if (of_flags & OF_GPIO_OPEN_DRAIN) {
            *flags |= GPIO_OPEN_DRAIN;
        } else {
            *flags |= GPIO_OPEN_SOURCE;
        }
    }

    if (of_flags & OF_GPIO_TRANSITORY) {
        *flags |= GPIO_TRANSITORY;
    }

    if (of_flags & OF_GPIO_PULL_UP) {
        *flags |= GPIO_PULL_UP;
    }
    if (of_flags & OF_GPIO_PULL_DOWN) {
        *flags |= GPIO_PULL_DOWN;
    }

    return desc;
}

/**
 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
 * @np:        device node to get GPIO from
 * @chip:    GPIO chip whose hog is parsed
 * @idx:    Index of the GPIO to parse
 * @name:    GPIO line name
 * @lflags:    bitmask of gpio_lookup_flags GPIO_* values - 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, struct gpio_chip *chip, unsigned int idx,
                                           const char **name, unsigned long *lflags, enum gpiod_flags *dflags)
{
    struct device_node *chip_np;
    enum of_gpio_flags xlate_flags;
    struct of_phandle_args gpiospec;
    struct gpio_desc *desc;
    unsigned int i;
    u32 tmp;
    int ret;

    chip_np = chip->of_node;
    if (!chip_np) {
        return ERR_PTR(-EINVAL);
    }

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

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

    gpiospec.np = chip_np;
    gpiospec.args_count = tmp;

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

    desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
    if (IS_ERR(desc)) {
        return desc;
    }

    if (xlate_flags & OF_GPIO_ACTIVE_LOW) {
        *lflags |= GPIO_ACTIVE_LOW;
    }
    if (xlate_flags & OF_GPIO_TRANSITORY) {
        *lflags |= GPIO_TRANSITORY;
    }
    if (xlate_flags & OF_GPIO_PULL_UP) {
        *lflags |= GPIO_PULL_UP;
    }
    if (xlate_flags & OF_GPIO_PULL_DOWN) {
        *lflags |= GPIO_PULL_DOWN;
    }

    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 (%pOFn): no hogging state specified, bailing out\n", desc_to_gpio(desc), np);
        return ERR_PTR(-EINVAL);
    }

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

    return desc;
}

/**
 * of_gpiochip_add_hog - Add all hogs in a hog device node
 * @chip:    gpio chip to act on
 * @hog:    device node describing the hogs
 *
 * Returns error if it fails otherwise 0 on success.
 */
static int of_gpiochip_add_hog(struct gpio_chip *chip, struct device_node *hog)
{
    enum gpiod_flags dflags;
    struct gpio_desc *desc;
    unsigned long lflags;
    const char *name;
    unsigned int i;
    int ret;

    for (i = 0;; i++) {
        desc = of_parse_own_gpio(hog, chip, i, &name, &lflags, &dflags);
        if (IS_ERR(desc)) {
            break;
        }

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

#ifdef CONFIG_OF_DYNAMIC
        desc->hog = hog;
#endif
    }

    return 0;
}

/**
 * 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 returns error if it fails otherwise 0 on success.
 */
static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
{
    struct device_node *np;
    int ret;

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

        ret = of_gpiochip_add_hog(chip, np);
        if (ret < 0) {
            of_node_put(np);
            return ret;
        }

        of_node_set_flag(np, OF_POPULATED);
    }

    return 0;
}

#ifdef CONFIG_OF_DYNAMIC
/**
 * of_gpiochip_remove_hog - Remove all hogs in a hog device node
 * @chip:    gpio chip to act on
 * @hog:    device node describing the hogs
 */
static void of_gpiochip_remove_hog(struct gpio_chip *chip, struct device_node *hog)
{
    struct gpio_desc *descs = chip->gpiodev->descs;
    unsigned int i;

    for (i = 0; i < chip->ngpio; i++) {
        if (test_bit(FLAG_IS_HOGGED, &descs[i].flags) && descs[i].hog == hog) {
            gpiochip_free_own_desc(&descs[i]);
        }
    }
}

static int of_gpiochip_match_node(struct gpio_chip *chip, void *data)
{
    return chip->gpiodev->dev.of_node == data;
}

static struct gpio_chip *of_find_gpiochip_by_node(struct device_node *np)
{
    return gpiochip_find(np, of_gpiochip_match_node);
}

static int of_gpio_notify(struct notifier_block *nb, unsigned long action, void *arg)
{
    struct of_reconfig_data *rd = arg;
    struct gpio_chip *chip;
    int ret;

    /*
     * This only supports adding and removing complete gpio-hog nodes.
     * Modifying an existing gpio-hog node is not supported (except for
     * changing its "status" property, which is treated the same as
     * addition/removal).
     */
    switch (of_reconfig_get_state_change(action, arg)) {
        case OF_RECONFIG_CHANGE_ADD:
            if (!of_property_read_bool(rd->dn, "gpio-hog")) {
                return NOTIFY_OK; /* not for us */
            }

            if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
                return NOTIFY_OK;
            }

            chip = of_find_gpiochip_by_node(rd->dn->parent);
            if (chip == NULL) {
                return NOTIFY_OK; /* not for us */
            }

            ret = of_gpiochip_add_hog(chip, rd->dn);
            if (ret < 0) {
                pr_err("%s: failed to add hogs for %pOF\n", __func__, rd->dn);
                of_node_clear_flag(rd->dn, OF_POPULATED);
                return notifier_from_errno(ret);
            }
            break;

        case OF_RECONFIG_CHANGE_REMOVE:
            if (!of_node_check_flag(rd->dn, OF_POPULATED)) {
                return NOTIFY_OK; /* already depopulated */
            }

            chip = of_find_gpiochip_by_node(rd->dn->parent);
            if (chip == NULL) {
                return NOTIFY_OK; /* not for us */
            }

            of_gpiochip_remove_hog(chip, rd->dn);
            of_node_clear_flag(rd->dn, OF_POPULATED);
            break;
    }

    return NOTIFY_OK;
}

struct notifier_block gpio_of_notifier = {
    .notifier_call = of_gpio_notify,
};
#endif /* CONFIG_OF_DYNAMIC */

/**
 * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags
 * @gc:        pointer to the gpio_chip structure
 * @gpiospec:    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).
 */
static 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];
}

/**
 * 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 = kasprintf(GFP_KERNEL, "%pOF", np);
    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);
    }
        of_node_put(mm_gc->gc.of_node);
    mm_gc->gc.of_node = of_node_get(np);
    ret = gpiochip_add_data(gc, data);
    if (ret) {
        goto err2;
    }

    return 0;
err2:
    of_node_put(np);
    iounmap(mm_gc->regs);
err1:
    kfree(gc->label);
err0:
    pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret);
    return ret;
}
EXPORT_SYMBOL_GPL(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_GPL(of_mm_gpiochip_remove);

static void of_gpiochip_init_valid_mask(struct gpio_chip *chip)
{
    int len, i;
    u32 start, count;
    struct device_node *np = chip->of_node;

    len = of_property_count_u32_elems(np, "gpio-reserved-ranges");
    if (len < 0 || len % 0x2 != 0) {
        return;
    }

    for (i = 0; i < len; i += 0x2) {
        of_property_read_u32_index(np, "gpio-reserved-ranges", i, &start);
        of_property_read_u32_index(np, "gpio-reserved-ranges", i + 1, &count);
        if (start >= chip->ngpio || start + count > chip->ngpio) {
            continue;
        }

        bitmap_clear(chip->valid_mask, start, count);
    }
};

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

    if (!np) {
        return 0;
    }

    if (!of_property_read_bool(np, "gpio-ranges") &&
        chip->of_gpio_ranges_fallback) {
        return chip->of_gpio_ranges_fallback(chip, np);
    }

    group_names = of_find_property(np, group_names_propname, NULL);

    for (;; index++) {
        ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 0x3, index, &pinspec);
        if (ret) {
            break;
        }

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

        if (pinspec.args[0x2]) {
            if (group_names) {
                of_property_read_string_index(np, group_names_propname, index, &name);
                if (strlen(name)) {
                    pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n", np);
                    break;
                }
            }
            /* npins != 0: linear range */
            ret = gpiochip_add_pin_range(chip, pinctrl_dev_get_devname(pctldev), pinspec.args[0x0], pinspec.args[0x1],
                                         pinspec.args[0x2]);
            if (ret) {
                return ret;
            }
        } else {
            /* npins == 0: special range */
            if (pinspec.args[1]) {
                pr_err("%pOF: Illegal gpio-range format.\n", np);
                break;
            }

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

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

            if (!strlen(name)) {
                pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n", np);
                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 ret;

    if (!chip->of_node) {
        return 0;
    }

    if (!chip->of_xlate) {
        chip->of_gpio_n_cells = 0x2;
        chip->of_xlate = of_gpio_simple_xlate;
    }

    if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS) {
        return -EINVAL;
    }

    of_gpiochip_init_valid_mask(chip);

    ret = of_gpiochip_add_pin_range(chip);
    if (ret) {
        return ret;
    }

    of_node_get(chip->of_node);

    ret = of_gpiochip_scan_gpios(chip);
    if (ret) {
        of_node_put(chip->of_node);
    }

    return ret;
}

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

void of_gpio_dev_init(struct gpio_chip *gc, struct gpio_device *gdev)
{
    /* If the gpiochip has an assigned OF node this takes precedence */
    if (gc->of_node) {
        gdev->dev.of_node = gc->of_node;
    } else {
        gc->of_node = gdev->dev.of_node;
    }
    if (gdev->dev.of_node) {
        gdev->dev.fwnode = of_fwnode_handle(gdev->dev.of_node);
    }
}