// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic GPIO card-detect helper
 *
 * Copyright (C) 2011, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 */

#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/mmc/host.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "slot-gpio.h"

struct mmc_gpio {
        struct gpio_desc *ro_gpio;
        struct gpio_desc *cd_gpio;
        irqreturn_t (*cd_gpio_isr)(int irq, void *dev_id);
        char *ro_label;
        char *cd_label;
        u32 cd_debounce_delay_ms;
};

static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
{
        /* Schedule a card detection after a debounce timeout */
        struct mmc_host *host = dev_id;
        struct mmc_gpio *ctx = host->slot.handler_priv;

        host->trigger_card_event = true;
        mmc_detect_change(host, msecs_to_jiffies(ctx->cd_debounce_delay_ms));

        return IRQ_HANDLED;
}

int mmc_gpio_alloc(struct mmc_host *host)
{
        struct mmc_gpio *ctx = devm_kzalloc(host->parent,
                                            sizeof(*ctx), GFP_KERNEL);

        if (ctx) {
                ctx->cd_debounce_delay_ms = 200;
                ctx->cd_label = devm_kasprintf(host->parent, GFP_KERNEL,
                                "%s cd", dev_name(host->parent));
                if (!ctx->cd_label)
                        return -ENOMEM;
                ctx->ro_label = devm_kasprintf(host->parent, GFP_KERNEL,
                                "%s ro", dev_name(host->parent));
                if (!ctx->ro_label)
                        return -ENOMEM;
                host->slot.handler_priv = ctx;
                host->slot.cd_irq = -EINVAL;
        }

        return ctx ? 0 : -ENOMEM;
}

int mmc_gpio_get_ro(struct mmc_host *host)
{
        struct mmc_gpio *ctx = host->slot.handler_priv;

        if (!ctx || !ctx->ro_gpio)
                return -ENOSYS;

        return gpiod_get_value_cansleep(ctx->ro_gpio);
}
EXPORT_SYMBOL(mmc_gpio_get_ro);

int mmc_gpio_get_cd(struct mmc_host *host)
{
        struct mmc_gpio *ctx = host->slot.handler_priv;
        int cansleep;

        if (!ctx || !ctx->cd_gpio)
                return -ENOSYS;

        cansleep = gpiod_cansleep(ctx->cd_gpio);
        return cansleep ?
                gpiod_get_value_cansleep(ctx->cd_gpio) :
                gpiod_get_value(ctx->cd_gpio);
}
EXPORT_SYMBOL(mmc_gpio_get_cd);

void mmc_gpiod_request_cd_irq(struct mmc_host *host)
{
        struct mmc_gpio *ctx = host->slot.handler_priv;
        int irq = -EINVAL;
        int ret;

        if (host->slot.cd_irq >= 0 || !ctx || !ctx->cd_gpio)
                return;

        /*
         * Do not use IRQ if the platform prefers to poll, e.g., because that
         * IRQ number is already used by another unit and cannot be shared.
         */
        if (!(host->caps & MMC_CAP_NEEDS_POLL))
                irq = gpiod_to_irq(ctx->cd_gpio);

        if (irq >= 0) {
                if (!ctx->cd_gpio_isr)
                        ctx->cd_gpio_isr = mmc_gpio_cd_irqt;
                ret = devm_request_threaded_irq(host->parent, irq,
                        NULL, ctx->cd_gpio_isr,
                        IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                        ctx->cd_label, host);
                if (ret < 0)
                        irq = ret;
        }

        host->slot.cd_irq = irq;

        if (irq < 0)
                host->caps |= MMC_CAP_NEEDS_POLL;
}
EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);

int mmc_gpio_set_cd_wake(struct mmc_host *host, bool on)
{
        int ret = 0;

        if (!(host->caps & MMC_CAP_CD_WAKE) ||
            host->slot.cd_irq < 0 ||
            on == host->slot.cd_wake_enabled)
                return 0;

        if (on) {
                ret = enable_irq_wake(host->slot.cd_irq);
                host->slot.cd_wake_enabled = !ret;
        } else {
                disable_irq_wake(host->slot.cd_irq);
                host->slot.cd_wake_enabled = false;
        }

        return ret;
}
EXPORT_SYMBOL(mmc_gpio_set_cd_wake);

/* Register an alternate interrupt service routine for
 * the card-detect GPIO.
 */
void mmc_gpio_set_cd_isr(struct mmc_host *host,
                         irqreturn_t (*isr)(int irq, void *dev_id))
{
        struct mmc_gpio *ctx = host->slot.handler_priv;

        WARN_ON(ctx->cd_gpio_isr);
        ctx->cd_gpio_isr = isr;
}
EXPORT_SYMBOL(mmc_gpio_set_cd_isr);

/**
 * mmc_gpiod_request_cd - request a gpio descriptor for card-detection
 * @host: mmc host
 * @con_id: function within the GPIO consumer
 * @idx: index of the GPIO to obtain in the consumer
 * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
 * @debounce: debounce time in microseconds
 *
 * Note that this must be called prior to mmc_add_host()
 * otherwise the caller must also call mmc_gpiod_request_cd_irq().
 *
 * Returns zero on success, else an error.
 */
int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
                         unsigned int idx, bool override_active_level,
                         unsigned int debounce)
{
        struct mmc_gpio *ctx = host->slot.handler_priv;
        struct gpio_desc *desc;
        int ret;

        desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
        if (IS_ERR(desc))
                return PTR_ERR(desc);

        if (debounce) {
                ret = gpiod_set_debounce(desc, debounce);
                if (ret < 0)
                        ctx->cd_debounce_delay_ms = debounce / 1000;
        }

        /* override forces default (active-low) polarity ... */
        if (override_active_level && !gpiod_is_active_low(desc))
                gpiod_toggle_active_low(desc);

        /* ... or active-high */
        if (host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
                gpiod_toggle_active_low(desc);

        ctx->cd_gpio = desc;

        return 0;
}
EXPORT_SYMBOL(mmc_gpiod_request_cd);

bool mmc_can_gpio_cd(struct mmc_host *host)
{
        struct mmc_gpio *ctx = host->slot.handler_priv;

        return ctx->cd_gpio ? true : false;
}
EXPORT_SYMBOL(mmc_can_gpio_cd);

/**
 * mmc_gpiod_request_ro - request a gpio descriptor for write protection
 * @host: mmc host
 * @con_id: function within the GPIO consumer
 * @idx: index of the GPIO to obtain in the consumer
 * @debounce: debounce time in microseconds
 *
 * Returns zero on success, else an error.
 */
int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id,
                         unsigned int idx, unsigned int debounce)
{
        struct mmc_gpio *ctx = host->slot.handler_priv;
        struct gpio_desc *desc;
        int ret;

        desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
        if (IS_ERR(desc))
                return PTR_ERR(desc);

        if (debounce) {
                ret = gpiod_set_debounce(desc, debounce);
                if (ret < 0)
                        return ret;
        }

        if (host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH)
                gpiod_toggle_active_low(desc);

        ctx->ro_gpio = desc;

        return 0;
}
EXPORT_SYMBOL(mmc_gpiod_request_ro);

bool mmc_can_gpio_ro(struct mmc_host *host)
{
        struct mmc_gpio *ctx = host->slot.handler_priv;

        return ctx->ro_gpio ? true : false;
}
EXPORT_SYMBOL(mmc_can_gpio_ro);