drm/nouveau: fix kernel-doc comments

[drm/drm-misc.git] / 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/io.h>
#include <linux/module.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/string.h>

#include <linux/gpio/consumer.h>
#include <linux/gpio/machine.h>

#include "gpiolib.h"
#include "gpiolib-of.h"

/*
 * This is Linux-specific flags. By default controllers' and Linux' mapping
 * match, but GPIO controllers are free to translate their own flags to
 * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
 */
enum of_gpio_flags {
        OF_GPIO_ACTIVE_LOW = 0x1,
        OF_GPIO_SINGLE_ENDED = 0x2,
        OF_GPIO_OPEN_DRAIN = 0x4,
        OF_GPIO_TRANSITORY = 0x8,
        OF_GPIO_PULL_UP = 0x10,
        OF_GPIO_PULL_DOWN = 0x20,
        OF_GPIO_PULL_DISABLE = 0x40,
};

/**
 * of_gpio_named_count() - Count GPIOs for a device
 * @np:         device node to count GPIOs for
 * @propname:   property name containing gpio specifier(s)
 *
 * The function returns the count of GPIOs specified for a node.
 * NOTE: The empty GPIO specifiers count too.
 *
 * Returns:
 * Either number of GPIOs defined in the property, or
 * *  %-EINVAL for an incorrectly formed "gpios" property, or
 * *  %-ENOENT for a missing "gpios" property.
 *
 * Example::
 *
 *     gpios = <0
 *              &gpio1 1 2
 *              0
 *              &gpio2 3 4>;
 *
 * The above example defines four GPIOs, two of which are not specified.
 * This function will return '4'
 */
static int of_gpio_named_count(const struct device_node *np,
                               const char *propname)
{
        return of_count_phandle_with_args(np, propname, "#gpio-cells");
}

/**
 * of_gpio_spi_cs_get_count() - special GPIO counting for SPI
 * @np:    Consuming device node
 * @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.
 *
 * Returns:
 * Either number of GPIOs defined in the property, or
 * *  %-EINVAL for an incorrectly formed "gpios" property, or
 * *  %-ENOENT for a missing "gpios" property.
 */
static int of_gpio_spi_cs_get_count(const struct device_node *np,
                                    const char *con_id)
{
        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");
}

int of_gpio_count(const struct fwnode_handle *fwnode, const char *con_id)
{
        const struct device_node *np = to_of_node(fwnode);
        int ret;
        char propname[32];

        ret = of_gpio_spi_cs_get_count(np, con_id);
        if (ret > 0)
                return ret;

        for_each_gpio_property_name(propname, con_id) {
                ret = of_gpio_named_count(np, propname);
                if (ret > 0)
                        break;
        }
        return ret ? ret : -ENOENT;
}

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

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

static struct gpio_device *
of_find_gpio_device_by_xlate(const struct of_phandle_args *gpiospec)
{
        return gpio_device_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);
}

/*
 * Overrides stated polarity of a gpio line and warns when there is a
 * discrepancy.
 */
static void of_gpio_quirk_polarity(const struct device_node *np,
                                   bool active_high,
                                   enum of_gpio_flags *flags)
{
        if (active_high) {
                if (*flags & OF_GPIO_ACTIVE_LOW) {
                        pr_warn("%s GPIO handle specifies active low - ignored\n",
                                of_node_full_name(np));
                        *flags &= ~OF_GPIO_ACTIVE_LOW;
                }
        } else {
                if (!(*flags & OF_GPIO_ACTIVE_LOW))
                        pr_info("%s enforce active low on GPIO handle\n",
                                of_node_full_name(np));
                *flags |= OF_GPIO_ACTIVE_LOW;
        }
}

/*
 * This quirk does static polarity overrides in cases where existing
 * DTS specified incorrect polarity.
 */
static void of_gpio_try_fixup_polarity(const struct device_node *np,
                                       const char *propname,
                                       enum of_gpio_flags *flags)
{
        static const struct {
                const char *compatible;
                const char *propname;
                bool active_high;
        } gpios[] = {
#if IS_ENABLED(CONFIG_LCD_HX8357)
                /*
                 * Himax LCD controllers used incorrectly named
                 * "gpios-reset" property and also specified wrong
                 * polarity.
                 */
                { "himax,hx8357",       "gpios-reset",  false },
                { "himax,hx8369",       "gpios-reset",  false },
                /*
                 * The rb-gpios semantics was undocumented and qi,lb60 (along with
                 * the ingenic driver) got it wrong. The active state encodes the
                 * NAND ready state, which is high level. Since there's no signal
                 * inverter on this board, it should be active-high. Let's fix that
                 * here for older DTs so we can re-use the generic nand_gpio_waitrdy()
                 * helper, and be consistent with what other drivers do.
                 */
                { "qi,lb60",            "rb-gpios",     true },
#endif
#if IS_ENABLED(CONFIG_PCI_LANTIQ)
                /*
                 * According to the PCI specification, the RST# pin is an
                 * active-low signal. However, most of the device trees that
                 * have been widely used for a long time incorrectly describe
                 * reset GPIO as active-high, and were also using wrong name
                 * for the property.
                 */
                { "lantiq,pci-xway",    "gpio-reset",   false },
#endif
#if IS_ENABLED(CONFIG_TOUCHSCREEN_TSC2005)
                /*
                 * DTS for Nokia N900 incorrectly specified "active high"
                 * polarity for the reset line, while the chip actually
                 * treats it as "active low".
                 */
                { "ti,tsc2005",         "reset-gpios",  false },
#endif
        };
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(gpios); i++) {
                if (of_device_is_compatible(np, gpios[i].compatible) &&
                    !strcmp(propname, gpios[i].propname)) {
                        of_gpio_quirk_polarity(np, gpios[i].active_high, flags);
                        break;
                }
        }
}

static void of_gpio_set_polarity_by_property(const struct device_node *np,
                                             const char *propname,
                                             enum of_gpio_flags *flags)
{
        const struct device_node *np_compat = np;
        const struct device_node *np_propname = np;
        static const struct {
                const char *compatible;
                const char *gpio_propname;
                const char *polarity_propname;
        } gpios[] = {
#if IS_ENABLED(CONFIG_FEC)
                /* Freescale Fast Ethernet Controller */
                { "fsl,imx25-fec",   "phy-reset-gpios", "phy-reset-active-high" },
                { "fsl,imx27-fec",   "phy-reset-gpios", "phy-reset-active-high" },
                { "fsl,imx28-fec",   "phy-reset-gpios", "phy-reset-active-high" },
                { "fsl,imx6q-fec",   "phy-reset-gpios", "phy-reset-active-high" },
                { "fsl,mvf600-fec",  "phy-reset-gpios", "phy-reset-active-high" },
                { "fsl,imx6sx-fec",  "phy-reset-gpios", "phy-reset-active-high" },
                { "fsl,imx6ul-fec",  "phy-reset-gpios", "phy-reset-active-high" },
                { "fsl,imx8mq-fec",  "phy-reset-gpios", "phy-reset-active-high" },
                { "fsl,imx8qm-fec",  "phy-reset-gpios", "phy-reset-active-high" },
                { "fsl,s32v234-fec", "phy-reset-gpios", "phy-reset-active-high" },
#endif
#if IS_ENABLED(CONFIG_PCI_IMX6)
                { "fsl,imx6q-pcie",  "reset-gpio", "reset-gpio-active-high" },
                { "fsl,imx6sx-pcie", "reset-gpio", "reset-gpio-active-high" },
                { "fsl,imx6qp-pcie", "reset-gpio", "reset-gpio-active-high" },
                { "fsl,imx7d-pcie",  "reset-gpio", "reset-gpio-active-high" },
                { "fsl,imx8mq-pcie", "reset-gpio", "reset-gpio-active-high" },
                { "fsl,imx8mm-pcie", "reset-gpio", "reset-gpio-active-high" },
                { "fsl,imx8mp-pcie", "reset-gpio", "reset-gpio-active-high" },
#endif

                /*
                 * 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 IS_ENABLED(CONFIG_REGULATOR_FIXED_VOLTAGE)
                { "regulator-fixed",   "gpios",        "enable-active-high" },
                { "regulator-fixed",   "gpio",         "enable-active-high" },
                { "reg-fixed-voltage", "gpios",        "enable-active-high" },
                { "reg-fixed-voltage", "gpio",         "enable-active-high" },
#endif
#if IS_ENABLED(CONFIG_REGULATOR_GPIO)
                { "regulator-gpio",    "enable-gpio",  "enable-active-high" },
                { "regulator-gpio",    "enable-gpios", "enable-active-high" },
#endif
#if IS_ENABLED(CONFIG_MMC_ATMELMCI)
                { "atmel,hsmci",       "cd-gpios",     "cd-inverted" },
#endif
        };
        unsigned int i;
        bool active_high;

#if IS_ENABLED(CONFIG_MMC_ATMELMCI)
        /*
         * The Atmel HSMCI has compatible property in the parent node and
         * gpio property in a child node
         */
        if (of_device_is_compatible(np->parent, "atmel,hsmci")) {
                np_compat = np->parent;
                np_propname = np;
        }
#endif

        for (i = 0; i < ARRAY_SIZE(gpios); i++) {
                if (of_device_is_compatible(np_compat, gpios[i].compatible) &&
                    !strcmp(propname, gpios[i].gpio_propname)) {
                        active_high = of_property_read_bool(np_propname,
                                                gpios[i].polarity_propname);
                        of_gpio_quirk_polarity(np, active_high, flags);
                        break;
                }
        }
}

static void of_gpio_flags_quirks(const struct device_node *np,
                                 const char *propname,
                                 enum of_gpio_flags *flags,
                                 int index)
{
        of_gpio_try_fixup_polarity(np, propname, flags);
        of_gpio_set_polarity_by_property(np, propname, flags);

        /*
         * 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_present(np, "cs-gpios")) {
                u32 cs;
                int ret;

                for_each_child_of_node_scoped(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.
                                 */
                                bool active_high = of_property_read_bool(child,
                                                                "spi-cs-high");
                                of_gpio_quirk_polarity(child, active_high,
                                                       flags);
                                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(const struct device_node *np,
                     const char *propname, int index, enum of_gpio_flags *flags)
{
        struct of_phandle_args gpiospec;
        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);
        }

        struct gpio_device *gdev __free(gpio_device_put) =
                                of_find_gpio_device_by_xlate(&gpiospec);
        if (!gdev) {
                desc = ERR_PTR(-EPROBE_DEFER);
                goto out;
        }

        desc = of_xlate_and_get_gpiod_flags(gpio_device_get_chip(gdev),
                                            &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;
}

/**
 * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 * @np:         device node to get GPIO from
 * @propname:   Name of property containing gpio specifier(s)
 * @index:      index of the GPIO
 *
 * **DEPRECATED** This function is deprecated and must not be used in new code.
 *
 * Returns:
 * GPIO number to use with Linux generic GPIO API, or one of the errno
 * value on the error condition.
 */
int of_get_named_gpio(const struct device_node *np, const char *propname,
                      int index)
{
        struct gpio_desc *desc;

        desc = of_get_named_gpiod_flags(np, propname, index, NULL);

        if (IS_ERR(desc))
                return PTR_ERR(desc);
        else
                return desc_to_gpio(desc);
}
EXPORT_SYMBOL_GPL(of_get_named_gpio);

/* Converts gpio_lookup_flags into bitmask of GPIO_* values */
static unsigned long of_convert_gpio_flags(enum of_gpio_flags flags)
{
        unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;

        if (flags & OF_GPIO_ACTIVE_LOW)
                lflags |= GPIO_ACTIVE_LOW;

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

        if (flags & OF_GPIO_TRANSITORY)
                lflags |= GPIO_TRANSITORY;

        if (flags & OF_GPIO_PULL_UP)
                lflags |= GPIO_PULL_UP;

        if (flags & OF_GPIO_PULL_DOWN)
                lflags |= GPIO_PULL_DOWN;

        if (flags & OF_GPIO_PULL_DISABLE)
                lflags |= GPIO_PULL_DISABLE;

        return lflags;
}

static struct gpio_desc *of_find_gpio_rename(struct device_node *np,
                                             const char *con_id,
                                             unsigned int idx,
                                             enum of_gpio_flags *of_flags)
{
        static const struct of_rename_gpio {
                const char *con_id;
                const char *legacy_id;  /* NULL - same as con_id */
                /*
                 * Compatible string can be set to NULL in case where
                 * matching to a particular compatible is not practical,
                 * but it should only be done for gpio names that have
                 * vendor prefix to reduce risk of false positives.
                 * Addition of such entries is strongly discouraged.
                 */
                const char *compatible;
        } gpios[] = {
#if IS_ENABLED(CONFIG_LCD_HX8357)
                /* Himax LCD controllers used "gpios-reset" */
                { "reset",      "gpios-reset",  "himax,hx8357" },
                { "reset",      "gpios-reset",  "himax,hx8369" },
#endif
#if IS_ENABLED(CONFIG_MFD_ARIZONA)
                { "wlf,reset",  NULL,           NULL },
#endif
#if IS_ENABLED(CONFIG_RTC_DRV_MOXART)
                { "rtc-data",   "gpio-rtc-data",        "moxa,moxart-rtc" },
                { "rtc-sclk",   "gpio-rtc-sclk",        "moxa,moxart-rtc" },
                { "rtc-reset",  "gpio-rtc-reset",       "moxa,moxart-rtc" },
#endif
#if IS_ENABLED(CONFIG_NFC_MRVL_I2C)
                { "reset",      "reset-n-io",   "marvell,nfc-i2c" },
#endif
#if IS_ENABLED(CONFIG_NFC_MRVL_SPI)
                { "reset",      "reset-n-io",   "marvell,nfc-spi" },
#endif
#if IS_ENABLED(CONFIG_NFC_MRVL_UART)
                { "reset",      "reset-n-io",   "marvell,nfc-uart" },
                { "reset",      "reset-n-io",   "mrvl,nfc-uart" },
#endif
#if IS_ENABLED(CONFIG_PCI_LANTIQ)
                /* MIPS Lantiq PCI */
                { "reset",      "gpio-reset",   "lantiq,pci-xway" },
#endif

                /*
                 * 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.
                 */
#if IS_ENABLED(CONFIG_REGULATOR_ARIZONA_LDO1)
                { "wlf,ldoena",  NULL,          NULL }, /* Arizona */
#endif
#if IS_ENABLED(CONFIG_REGULATOR_WM8994)
                { "wlf,ldo1ena", NULL,          NULL }, /* WM8994 */
                { "wlf,ldo2ena", NULL,          NULL }, /* WM8994 */
#endif

#if IS_ENABLED(CONFIG_SND_SOC_CS42L56)
                { "reset",      "cirrus,gpio-nreset",   "cirrus,cs42l56" },
#endif
#if IS_ENABLED(CONFIG_SND_SOC_MT2701_CS42448)
                { "i2s1-in-sel-gpio1",  NULL,   "mediatek,mt2701-cs42448-machine" },
                { "i2s1-in-sel-gpio2",  NULL,   "mediatek,mt2701-cs42448-machine" },
#endif
#if IS_ENABLED(CONFIG_SND_SOC_TLV320AIC3X)
                { "reset",      "gpio-reset",   "ti,tlv320aic3x" },
                { "reset",      "gpio-reset",   "ti,tlv320aic33" },
                { "reset",      "gpio-reset",   "ti,tlv320aic3007" },
                { "reset",      "gpio-reset",   "ti,tlv320aic3104" },
                { "reset",      "gpio-reset",   "ti,tlv320aic3106" },
#endif
#if IS_ENABLED(CONFIG_SPI_GPIO)
                /*
                 * 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.
                 */
                { "miso",       "gpio-miso",    "spi-gpio" },
                { "mosi",       "gpio-mosi",    "spi-gpio" },
                { "sck",        "gpio-sck",     "spi-gpio" },
#endif

                /*
                 * The old Freescale bindings use simply "gpios" as name
                 * for the chip select lines rather than "cs-gpios" like
                 * all other SPI hardware. Allow this specifically for
                 * Freescale and PPC devices.
                 */
#if IS_ENABLED(CONFIG_SPI_FSL_SPI)
                { "cs",         "gpios",        "fsl,spi" },
                { "cs",         "gpios",        "aeroflexgaisler,spictrl" },
#endif
#if IS_ENABLED(CONFIG_SPI_PPC4xx)
                { "cs",         "gpios",        "ibm,ppc4xx-spi" },
#endif

#if IS_ENABLED(CONFIG_TYPEC_FUSB302)
                /*
                 * Fairchild FUSB302 host is using undocumented "fcs,int_n"
                 * property without the compulsory "-gpios" suffix.
                 */
                { "fcs,int_n",  NULL,           "fcs,fusb302" },
#endif
        };
        struct gpio_desc *desc;
        const char *legacy_id;
        unsigned int i;

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

        for (i = 0; i < ARRAY_SIZE(gpios); i++) {
                if (strcmp(con_id, gpios[i].con_id))
                        continue;

                if (gpios[i].compatible &&
                    !of_device_is_compatible(np, gpios[i].compatible))
                        continue;

                legacy_id = gpios[i].legacy_id ?: gpios[i].con_id;
                desc = of_get_named_gpiod_flags(np, legacy_id, idx, of_flags);
                if (!gpiod_not_found(desc)) {
                        pr_info("%s uses legacy gpio name '%s' instead of '%s-gpios'\n",
                                of_node_full_name(np), legacy_id, con_id);
                        return desc;
                }
        }

        return ERR_PTR(-ENOENT);
}

static struct gpio_desc *of_find_mt2701_gpio(struct device_node *np,
                                             const char *con_id,
                                             unsigned int idx,
                                             enum of_gpio_flags *of_flags)
{
        struct gpio_desc *desc;
        const char *legacy_id;

        if (!IS_ENABLED(CONFIG_SND_SOC_MT2701_CS42448))
                return ERR_PTR(-ENOENT);

        if (!of_device_is_compatible(np, "mediatek,mt2701-cs42448-machine"))
                return ERR_PTR(-ENOENT);

        if (!con_id || strcmp(con_id, "i2s1-in-sel"))
                return ERR_PTR(-ENOENT);

        if (idx == 0)
                legacy_id = "i2s1-in-sel-gpio1";
        else if (idx == 1)
                legacy_id = "i2s1-in-sel-gpio2";
        else
                return ERR_PTR(-ENOENT);

        desc = of_get_named_gpiod_flags(np, legacy_id, 0, of_flags);
        if (!gpiod_not_found(desc))
                pr_info("%s is using legacy gpio name '%s' instead of '%s-gpios'\n",
                        of_node_full_name(np), legacy_id, con_id);

        return desc;
}

/*
 * Trigger sources are special, they allow us to use any GPIO as a LED trigger
 * and have the name "trigger-sources" no matter which kind of phandle it is
 * pointing to, whether to a GPIO, a USB host, a network PHY etc. So in this case
 * we allow looking something up that is not named "foo-gpios".
 */
static struct gpio_desc *of_find_trigger_gpio(struct device_node *np,
                                              const char *con_id,
                                              unsigned int idx,
                                              enum of_gpio_flags *of_flags)
{
        struct gpio_desc *desc;

        if (!IS_ENABLED(CONFIG_LEDS_TRIGGER_GPIO))
                return ERR_PTR(-ENOENT);

        if (!con_id || strcmp(con_id, "trigger-sources"))
                return ERR_PTR(-ENOENT);

        desc = of_get_named_gpiod_flags(np, con_id, idx, of_flags);
        if (!gpiod_not_found(desc))
                pr_debug("%s is used as a trigger\n", of_node_full_name(np));

        return desc;
}


typedef struct gpio_desc *(*of_find_gpio_quirk)(struct device_node *np,
                                                const char *con_id,
                                                unsigned int idx,
                                                enum of_gpio_flags *of_flags);
static const of_find_gpio_quirk of_find_gpio_quirks[] = {
        of_find_gpio_rename,
        of_find_mt2701_gpio,
        of_find_trigger_gpio,
        NULL
};

struct gpio_desc *of_find_gpio(struct device_node *np, const char *con_id,
                               unsigned int idx, unsigned long *flags)
{
        char propname[32]; /* 32 is max size of property name */
        enum of_gpio_flags of_flags;
        const of_find_gpio_quirk *q;
        struct gpio_desc *desc;

        /* Try GPIO property "foo-gpios" and "foo-gpio" */
        for_each_gpio_property_name(propname, con_id) {
                desc = of_get_named_gpiod_flags(np, propname, idx, &of_flags);
                if (!gpiod_not_found(desc))
                        break;
        }

        /* Properly named GPIO was not found, try workarounds */
        for (q = of_find_gpio_quirks; gpiod_not_found(desc) && *q; q++)
                desc = (*q)(np, con_id, idx, &of_flags);

        if (IS_ERR(desc))
                return desc;

        *flags = of_convert_gpio_flags(of_flags);

        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 = dev_of_node(&chip->gpiodev->dev);
        if (!chip_np)
                return ERR_PTR(-EINVAL);

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

        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;

        *lflags = of_convert_gpio_flags(xlate_flags);

        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:
 * 0 on success, or negative errno on failure.
 */
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
                WRITE_ONCE(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.
 *
 * Returns:
 * 0 on success, or negative errno on failure.
 */
static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
{
        int ret;

        for_each_available_child_of_node_scoped(dev_of_node(&chip->gpiodev->dev), np) {
                if (!of_property_read_bool(np, "gpio-hog"))
                        continue;

                ret = of_gpiochip_add_hog(chip, np);
                if (ret < 0)
                        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 *desc;

        for_each_gpio_desc_with_flag(chip, desc, FLAG_IS_HOGGED)
                if (READ_ONCE(desc->hog) == hog)
                        gpiochip_free_own_desc(desc);
}

static int of_gpiochip_match_node(struct gpio_chip *chip, const void *data)
{
        return device_match_of_node(&chip->gpiodev->dev, data);
}

static struct gpio_device *of_find_gpio_device_by_node(struct device_node *np)
{
        return gpio_device_find(np, of_gpiochip_match_node);
}

static int of_gpio_notify(struct notifier_block *nb, unsigned long action,
                          void *arg)
{
        struct gpio_device *gdev __free(gpio_device_put) = NULL;
        struct of_reconfig_data *rd = arg;
        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_DONE;     /* not for us */

                if (of_node_test_and_set_flag(rd->dn, OF_POPULATED))
                        return NOTIFY_DONE;

                gdev = of_find_gpio_device_by_node(rd->dn->parent);
                if (!gdev)
                        return NOTIFY_DONE;     /* not for us */

                ret = of_gpiochip_add_hog(gpio_device_get_chip(gdev), 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);
                }
                return NOTIFY_OK;

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

                gdev = of_find_gpio_device_by_node(rd->dn->parent);
                if (!gdev)
                        return NOTIFY_DONE;     /* not for us */

                of_gpiochip_remove_hog(gpio_device_get_chip(gdev), rd->dn);
                of_node_clear_flag(rd->dn, OF_POPULATED);
                return NOTIFY_OK;
        }

        return NOTIFY_DONE;
}

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).
 *
 * Returns:
 * GPIO number (>= 0) on success, negative errno on failure.
 */
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];
}

#if IS_ENABLED(CONFIG_OF_GPIO_MM_GPIOCHIP)
#include <linux/gpio/legacy-of-mm-gpiochip.h>
/**
 * 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.
 *
 * Returns:
 * 0 on success, or negative errno on failure.
 */
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);

        fwnode_handle_put(mm_gc->gc.fwnode);
        mm_gc->gc.fwnode = fwnode_handle_get(of_fwnode_handle(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;

        gpiochip_remove(gc);
        iounmap(mm_gc->regs);
        kfree(gc->label);
}
EXPORT_SYMBOL_GPL(of_mm_gpiochip_remove);
#endif

#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;
        int index = 0, ret, trim;
        const char *name;
        static const char group_names_propname[] = "gpio-ranges-group-names";
        bool has_group_names;

        np = dev_of_node(&chip->gpiodev->dev);
        if (!np)
                return 0;

        has_group_names = of_property_present(np, group_names_propname);

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

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

                /* Ignore ranges outside of this GPIO chip */
                if (pinspec.args[0] >= (chip->offset + chip->ngpio))
                        continue;
                if (pinspec.args[0] + pinspec.args[2] <= chip->offset)
                        continue;

                if (pinspec.args[2]) {
                        /* npins != 0: linear range */
                        if (has_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;
                                }
                        }

                        /* Trim the range to fit this GPIO chip */
                        if (chip->offset > pinspec.args[0]) {
                                trim = chip->offset - pinspec.args[0];
                                pinspec.args[2] -= trim;
                                pinspec.args[1] += trim;
                                pinspec.args[0] = 0;
                        } else {
                                pinspec.args[0] -= chip->offset;
                        }
                        if ((pinspec.args[0] + pinspec.args[2]) > chip->ngpio)
                                pinspec.args[2] = chip->ngpio - pinspec.args[0];

                        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("%pOF: Illegal gpio-range format.\n",
                                        np);
                                break;
                        }

                        if (!has_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)
{
        struct device_node *np;
        int ret;

        np = dev_of_node(&chip->gpiodev->dev);
        if (!np)
                return 0;

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

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

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

        of_node_get(np);

        ret = of_gpiochip_scan_gpios(chip);
        if (ret)
                of_node_put(np);

        return ret;
}

void of_gpiochip_remove(struct gpio_chip *chip)
{
        of_node_put(dev_of_node(&chip->gpiodev->dev));
}