/* linux/drivers/mmc/host/sdhci-s3c.c
 *
 * Copyright 2008 Openmoko Inc.
 * Copyright 2008 Simtec Electronics
 *      Ben Dooks <ben@simtec.co.uk>
 *      http://armlinux.simtec.co.uk/
 *
 * SDHCI (HSMMC) support for Samsung SoC
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/platform_data/mmc-sdhci-s3c.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>

#include <linux/mmc/host.h>

#include "sdhci-s3c-regs.h"
#include "sdhci.h"

#define MAX_BUS_CLK     (4)

/* Number of gpio's used is max data bus width + command and clock lines */
#define NUM_GPIOS(x)    (x + 2)

/**
 * struct sdhci_s3c - S3C SDHCI instance
 * @host: The SDHCI host created
 * @pdev: The platform device we where created from.
 * @ioarea: The resource created when we claimed the IO area.
 * @pdata: The platform data for this controller.
 * @cur_clk: The index of the current bus clock.
 * @clk_io: The clock for the internal bus interface.
 * @clk_bus: The clocks that are available for the SD/MMC bus clock.
 */
struct sdhci_s3c {
        struct sdhci_host       *host;
        struct platform_device  *pdev;
        struct resource         *ioarea;
        struct s3c_sdhci_platdata *pdata;
        unsigned int            cur_clk;
        int                     ext_cd_irq;
        int                     ext_cd_gpio;

        struct clk              *clk_io;
        struct clk              *clk_bus[MAX_BUS_CLK];
};

/**
 * struct sdhci_s3c_driver_data - S3C SDHCI platform specific driver data
 * @sdhci_quirks: sdhci host specific quirks.
 *
 * Specifies platform specific configuration of sdhci controller.
 * Note: A structure for driver specific platform data is used for future
 * expansion of its usage.
 */
struct sdhci_s3c_drv_data {
        unsigned int    sdhci_quirks;
};

static inline struct sdhci_s3c *to_s3c(struct sdhci_host *host)
{
        return sdhci_priv(host);
}

/**
 * get_curclk - convert ctrl2 register to clock source number
 * @ctrl2: Control2 register value.
 */
static u32 get_curclk(u32 ctrl2)
{
        ctrl2 &= S3C_SDHCI_CTRL2_SELBASECLK_MASK;
        ctrl2 >>= S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;

        return ctrl2;
}

static void sdhci_s3c_check_sclk(struct sdhci_host *host)
{
        struct sdhci_s3c *ourhost = to_s3c(host);
        u32 tmp = readl(host->ioaddr + S3C_SDHCI_CONTROL2);

        if (get_curclk(tmp) != ourhost->cur_clk) {
                dev_dbg(&ourhost->pdev->dev, "restored ctrl2 clock setting\n");

                tmp &= ~S3C_SDHCI_CTRL2_SELBASECLK_MASK;
                tmp |= ourhost->cur_clk << S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
                writel(tmp, host->ioaddr + S3C_SDHCI_CONTROL2);
        }
}

/**
 * sdhci_s3c_get_max_clk - callback to get maximum clock frequency.
 * @host: The SDHCI host instance.
 *
 * Callback to return the maximum clock rate acheivable by the controller.
*/
static unsigned int sdhci_s3c_get_max_clk(struct sdhci_host *host)
{
        struct sdhci_s3c *ourhost = to_s3c(host);
        struct clk *busclk;
        unsigned int rate, max;
        int clk;

        /* note, a reset will reset the clock source */

        sdhci_s3c_check_sclk(host);

        for (max = 0, clk = 0; clk < MAX_BUS_CLK; clk++) {
                busclk = ourhost->clk_bus[clk];
                if (!busclk)
                        continue;

                rate = clk_get_rate(busclk);
                if (rate > max)
                        max = rate;
        }

        return max;
}

/**
 * sdhci_s3c_consider_clock - consider one the bus clocks for current setting
 * @ourhost: Our SDHCI instance.
 * @src: The source clock index.
 * @wanted: The clock frequency wanted.
 */
static unsigned int sdhci_s3c_consider_clock(struct sdhci_s3c *ourhost,
                                             unsigned int src,
                                             unsigned int wanted)
{
        unsigned long rate;
        struct clk *clksrc = ourhost->clk_bus[src];
        int div;

        if (!clksrc)
                return UINT_MAX;

        /*
         * If controller uses a non-standard clock division, find the best clock
         * speed possible with selected clock source and skip the division.
         */
        if (ourhost->host->quirks & SDHCI_QUIRK_NONSTANDARD_CLOCK) {
                rate = clk_round_rate(clksrc, wanted);
                return wanted - rate;
        }

        rate = clk_get_rate(clksrc);

        for (div = 1; div < 256; div *= 2) {
                if ((rate / div) <= wanted)
                        break;
        }

        dev_dbg(&ourhost->pdev->dev, "clk %d: rate %ld, want %d, got %ld\n",
                src, rate, wanted, rate / div);

        return wanted - (rate / div);
}

/**
 * sdhci_s3c_set_clock - callback on clock change
 * @host: The SDHCI host being changed
 * @clock: The clock rate being requested.
 *
 * When the card's clock is going to be changed, look at the new frequency
 * and find the best clock source to go with it.
*/
static void sdhci_s3c_set_clock(struct sdhci_host *host, unsigned int clock)
{
        struct sdhci_s3c *ourhost = to_s3c(host);
        unsigned int best = UINT_MAX;
        unsigned int delta;
        int best_src = 0;
        int src;
        u32 ctrl;

        /* don't bother if the clock is going off. */
        if (clock == 0)
                return;

        for (src = 0; src < MAX_BUS_CLK; src++) {
                delta = sdhci_s3c_consider_clock(ourhost, src, clock);
                if (delta < best) {
                        best = delta;
                        best_src = src;
                }
        }

        dev_dbg(&ourhost->pdev->dev,
                "selected source %d, clock %d, delta %d\n",
                 best_src, clock, best);

        /* select the new clock source */
        if (ourhost->cur_clk != best_src) {
                struct clk *clk = ourhost->clk_bus[best_src];

                clk_prepare_enable(clk);
                clk_disable_unprepare(ourhost->clk_bus[ourhost->cur_clk]);

                /* turn clock off to card before changing clock source */
                writew(0, host->ioaddr + SDHCI_CLOCK_CONTROL);

                ourhost->cur_clk = best_src;
                host->max_clk = clk_get_rate(clk);

                ctrl = readl(host->ioaddr + S3C_SDHCI_CONTROL2);
                ctrl &= ~S3C_SDHCI_CTRL2_SELBASECLK_MASK;
                ctrl |= best_src << S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
                writel(ctrl, host->ioaddr + S3C_SDHCI_CONTROL2);
        }

        /* reprogram default hardware configuration */
        writel(S3C64XX_SDHCI_CONTROL4_DRIVE_9mA,
                host->ioaddr + S3C64XX_SDHCI_CONTROL4);

        ctrl = readl(host->ioaddr + S3C_SDHCI_CONTROL2);
        ctrl |= (S3C64XX_SDHCI_CTRL2_ENSTAASYNCCLR |
                  S3C64XX_SDHCI_CTRL2_ENCMDCNFMSK |
                  S3C_SDHCI_CTRL2_ENFBCLKRX |
                  S3C_SDHCI_CTRL2_DFCNT_NONE |
                  S3C_SDHCI_CTRL2_ENCLKOUTHOLD);
        writel(ctrl, host->ioaddr + S3C_SDHCI_CONTROL2);

        /* reconfigure the controller for new clock rate */
        ctrl = (S3C_SDHCI_CTRL3_FCSEL1 | S3C_SDHCI_CTRL3_FCSEL0);
        if (clock < 25 * 1000000)
                ctrl |= (S3C_SDHCI_CTRL3_FCSEL3 | S3C_SDHCI_CTRL3_FCSEL2);
        writel(ctrl, host->ioaddr + S3C_SDHCI_CONTROL3);
}

/**
 * sdhci_s3c_get_min_clock - callback to get minimal supported clock value
 * @host: The SDHCI host being queried
 *
 * To init mmc host properly a minimal clock value is needed. For high system
 * bus clock's values the standard formula gives values out of allowed range.
 * The clock still can be set to lower values, if clock source other then
 * system bus is selected.
*/
static unsigned int sdhci_s3c_get_min_clock(struct sdhci_host *host)
{
        struct sdhci_s3c *ourhost = to_s3c(host);
        unsigned int delta, min = UINT_MAX;
        int src;

        for (src = 0; src < MAX_BUS_CLK; src++) {
                delta = sdhci_s3c_consider_clock(ourhost, src, 0);
                if (delta == UINT_MAX)
                        continue;
                /* delta is a negative value in this case */
                if (-delta < min)
                        min = -delta;
        }
        return min;
}

/* sdhci_cmu_get_max_clk - callback to get maximum clock frequency.*/
static unsigned int sdhci_cmu_get_max_clock(struct sdhci_host *host)
{
        struct sdhci_s3c *ourhost = to_s3c(host);

        return clk_round_rate(ourhost->clk_bus[ourhost->cur_clk], UINT_MAX);
}

/* sdhci_cmu_get_min_clock - callback to get minimal supported clock value. */
static unsigned int sdhci_cmu_get_min_clock(struct sdhci_host *host)
{
        struct sdhci_s3c *ourhost = to_s3c(host);

        /*
         * initial clock can be in the frequency range of
         * 100KHz-400KHz, so we set it as max value.
         */
        return clk_round_rate(ourhost->clk_bus[ourhost->cur_clk], 400000);
}

/* sdhci_cmu_set_clock - callback on clock change.*/
static void sdhci_cmu_set_clock(struct sdhci_host *host, unsigned int clock)
{
        struct sdhci_s3c *ourhost = to_s3c(host);
        struct device *dev = &ourhost->pdev->dev;
        unsigned long timeout;
        u16 clk = 0;

        /* If the clock is going off, set to 0 at clock control register */
        if (clock == 0) {
                sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
                host->clock = clock;
                return;
        }

        sdhci_s3c_set_clock(host, clock);

        clk_set_rate(ourhost->clk_bus[ourhost->cur_clk], clock);

        host->clock = clock;

        clk = SDHCI_CLOCK_INT_EN;
        sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);

        /* Wait max 20 ms */
        timeout = 20;
        while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
                & SDHCI_CLOCK_INT_STABLE)) {
                if (timeout == 0) {
                        dev_err(dev, "%s: Internal clock never stabilised.\n",
                                mmc_hostname(host->mmc));
                        return;
                }
                timeout--;
                mdelay(1);
        }

        clk |= SDHCI_CLOCK_CARD_EN;
        sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
}

/**
 * sdhci_s3c_platform_bus_width - support 8bit buswidth
 * @host: The SDHCI host being queried
 * @width: MMC_BUS_WIDTH_ macro for the bus width being requested
 *
 * We have 8-bit width support but is not a v3 controller.
 * So we add platform_bus_width() and support 8bit width.
 */
static int sdhci_s3c_platform_bus_width(struct sdhci_host *host, int width)
{
        u8 ctrl;

        ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);

        switch (width) {
        case MMC_BUS_WIDTH_8:
                ctrl |= SDHCI_CTRL_8BITBUS;
                ctrl &= ~SDHCI_CTRL_4BITBUS;
                break;
        case MMC_BUS_WIDTH_4:
                ctrl |= SDHCI_CTRL_4BITBUS;
                ctrl &= ~SDHCI_CTRL_8BITBUS;
                break;
        default:
                ctrl &= ~SDHCI_CTRL_4BITBUS;
                ctrl &= ~SDHCI_CTRL_8BITBUS;
                break;
        }

        sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);

        return 0;
}

static struct sdhci_ops sdhci_s3c_ops = {
        .get_max_clock          = sdhci_s3c_get_max_clk,
        .set_clock              = sdhci_s3c_set_clock,
        .get_min_clock          = sdhci_s3c_get_min_clock,
        .platform_bus_width     = sdhci_s3c_platform_bus_width,
};

static void sdhci_s3c_notify_change(struct platform_device *dev, int state)
{
        struct sdhci_host *host = platform_get_drvdata(dev);
#ifdef CONFIG_PM_RUNTIME
        struct sdhci_s3c *sc = sdhci_priv(host);
#endif
        unsigned long flags;

        if (host) {
                spin_lock_irqsave(&host->lock, flags);
                if (state) {
                        dev_dbg(&dev->dev, "card inserted.\n");
#ifdef CONFIG_PM_RUNTIME
                        clk_prepare_enable(sc->clk_io);
#endif
                        host->flags &= ~SDHCI_DEVICE_DEAD;
                        host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
                } else {
                        dev_dbg(&dev->dev, "card removed.\n");
                        host->flags |= SDHCI_DEVICE_DEAD;
                        host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
#ifdef CONFIG_PM_RUNTIME
                        clk_disable_unprepare(sc->clk_io);
#endif
                }
                tasklet_schedule(&host->card_tasklet);
                spin_unlock_irqrestore(&host->lock, flags);
        }
}

static irqreturn_t sdhci_s3c_gpio_card_detect_thread(int irq, void *dev_id)
{
        struct sdhci_s3c *sc = dev_id;
        int status = gpio_get_value(sc->ext_cd_gpio);
        if (sc->pdata->ext_cd_gpio_invert)
                status = !status;
        sdhci_s3c_notify_change(sc->pdev, status);
        return IRQ_HANDLED;
}

static void sdhci_s3c_setup_card_detect_gpio(struct sdhci_s3c *sc)
{
        struct s3c_sdhci_platdata *pdata = sc->pdata;
        struct device *dev = &sc->pdev->dev;

        if (devm_gpio_request(dev, pdata->ext_cd_gpio, "SDHCI EXT CD") == 0) {
                sc->ext_cd_gpio = pdata->ext_cd_gpio;
                sc->ext_cd_irq = gpio_to_irq(pdata->ext_cd_gpio);
                if (sc->ext_cd_irq &&
                    request_threaded_irq(sc->ext_cd_irq, NULL,
                                         sdhci_s3c_gpio_card_detect_thread,
                                         IRQF_TRIGGER_RISING |
                                         IRQF_TRIGGER_FALLING |
                                         IRQF_ONESHOT,
                                         dev_name(dev), sc) == 0) {
                        int status = gpio_get_value(sc->ext_cd_gpio);
                        if (pdata->ext_cd_gpio_invert)
                                status = !status;
                        sdhci_s3c_notify_change(sc->pdev, status);
                } else {
                        dev_warn(dev, "cannot request irq for card detect\n");
                        sc->ext_cd_irq = 0;
                }
        } else {
                dev_err(dev, "cannot request gpio for card detect\n");
        }
}

#ifdef CONFIG_OF
static int sdhci_s3c_parse_dt(struct device *dev,
                struct sdhci_host *host, struct s3c_sdhci_platdata *pdata)
{
        struct device_node *node = dev->of_node;
        struct sdhci_s3c *ourhost = to_s3c(host);
        u32 max_width;
        int gpio;

        /* if the bus-width property is not specified, assume width as 1 */
        if (of_property_read_u32(node, "bus-width", &max_width))
                max_width = 1;
        pdata->max_width = max_width;

        /* get the card detection method */
        if (of_get_property(node, "broken-cd", NULL)) {
                pdata->cd_type = S3C_SDHCI_CD_NONE;
                return 0;
        }

        if (of_get_property(node, "non-removable", NULL)) {
                pdata->cd_type = S3C_SDHCI_CD_PERMANENT;
                return 0;
        }

        gpio = of_get_named_gpio(node, "cd-gpios", 0);
        if (gpio_is_valid(gpio)) {
                pdata->cd_type = S3C_SDHCI_CD_GPIO;
                pdata->ext_cd_gpio = gpio;
                ourhost->ext_cd_gpio = -1;
                if (of_get_property(node, "cd-inverted", NULL))
                        pdata->ext_cd_gpio_invert = 1;
                return 0;
        } else if (gpio != -ENOENT) {
                dev_err(dev, "invalid card detect gpio specified\n");
                return -EINVAL;
        }

        /* assuming internal card detect that will be configured by pinctrl */
        pdata->cd_type = S3C_SDHCI_CD_INTERNAL;
        return 0;
}
#else
static int sdhci_s3c_parse_dt(struct device *dev,
                struct sdhci_host *host, struct s3c_sdhci_platdata *pdata)
{
        return -EINVAL;
}
#endif

static const struct of_device_id sdhci_s3c_dt_match[];

static inline struct sdhci_s3c_drv_data *sdhci_s3c_get_driver_data(
                        struct platform_device *pdev)
{
#ifdef CONFIG_OF
        if (pdev->dev.of_node) {
                const struct of_device_id *match;
                match = of_match_node(sdhci_s3c_dt_match, pdev->dev.of_node);
                return (struct sdhci_s3c_drv_data *)match->data;
        }
#endif
        return (struct sdhci_s3c_drv_data *)
                        platform_get_device_id(pdev)->driver_data;
}

static int sdhci_s3c_probe(struct platform_device *pdev)
{
        struct s3c_sdhci_platdata *pdata;
        struct sdhci_s3c_drv_data *drv_data;
        struct device *dev = &pdev->dev;
        struct sdhci_host *host;
        struct sdhci_s3c *sc;
        struct resource *res;
        int ret, irq, ptr, clks;

        if (!pdev->dev.platform_data && !pdev->dev.of_node) {
                dev_err(dev, "no device data specified\n");
                return -ENOENT;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                dev_err(dev, "no irq specified\n");
                return irq;
        }

        host = sdhci_alloc_host(dev, sizeof(struct sdhci_s3c));
        if (IS_ERR(host)) {
                dev_err(dev, "sdhci_alloc_host() failed\n");
                return PTR_ERR(host);
        }
        sc = sdhci_priv(host);

        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata) {
                ret = -ENOMEM;
                goto err_pdata_io_clk;
        }

        if (pdev->dev.of_node) {
                ret = sdhci_s3c_parse_dt(&pdev->dev, host, pdata);
                if (ret)
                        goto err_pdata_io_clk;
        } else {
                memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
                sc->ext_cd_gpio = -1; /* invalid gpio number */
        }

        drv_data = sdhci_s3c_get_driver_data(pdev);

        sc->host = host;
        sc->pdev = pdev;
        sc->pdata = pdata;

        platform_set_drvdata(pdev, host);

        sc->clk_io = devm_clk_get(dev, "hsmmc");
        if (IS_ERR(sc->clk_io)) {
                dev_err(dev, "failed to get io clock\n");
                ret = PTR_ERR(sc->clk_io);
                goto err_pdata_io_clk;
        }

        /* enable the local io clock and keep it running for the moment. */
        clk_prepare_enable(sc->clk_io);

        for (clks = 0, ptr = 0; ptr < MAX_BUS_CLK; ptr++) {
                struct clk *clk;
                char name[14];

                snprintf(name, 14, "mmc_busclk.%d", ptr);
                clk = devm_clk_get(dev, name);
                if (IS_ERR(clk))
                        continue;

                clks++;
                sc->clk_bus[ptr] = clk;

                /*
                 * save current clock index to know which clock bus
                 * is used later in overriding functions.
                 */
                sc->cur_clk = ptr;

                dev_info(dev, "clock source %d: %s (%ld Hz)\n",
                         ptr, name, clk_get_rate(clk));
        }

        if (clks == 0) {
                dev_err(dev, "failed to find any bus clocks\n");
                ret = -ENOENT;
                goto err_no_busclks;
        }

#ifndef CONFIG_PM_RUNTIME
        clk_prepare_enable(sc->clk_bus[sc->cur_clk]);
#endif

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        host->ioaddr = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(host->ioaddr)) {
                ret = PTR_ERR(host->ioaddr);
                goto err_req_regs;
        }

        /* Ensure we have minimal gpio selected CMD/CLK/Detect */
        if (pdata->cfg_gpio)
                pdata->cfg_gpio(pdev, pdata->max_width);

        host->hw_name = "samsung-hsmmc";
        host->ops = &sdhci_s3c_ops;
        host->quirks = 0;
        host->quirks2 = 0;
        host->irq = irq;

        /* Setup quirks for the controller */
        host->quirks |= SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC;
        host->quirks |= SDHCI_QUIRK_NO_HISPD_BIT;
        if (drv_data)
                host->quirks |= drv_data->sdhci_quirks;

#ifndef CONFIG_MMC_SDHCI_S3C_DMA

        /* we currently see overruns on errors, so disable the SDMA
         * support as well. */
        host->quirks |= SDHCI_QUIRK_BROKEN_DMA;

#endif /* CONFIG_MMC_SDHCI_S3C_DMA */

        /* It seems we do not get an DATA transfer complete on non-busy
         * transfers, not sure if this is a problem with this specific
         * SDHCI block, or a missing configuration that needs to be set. */
        host->quirks |= SDHCI_QUIRK_NO_BUSY_IRQ;

        /* This host supports the Auto CMD12 */
        host->quirks |= SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12;

        /* Samsung SoCs need BROKEN_ADMA_ZEROLEN_DESC */
        host->quirks |= SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC;

        if (pdata->cd_type == S3C_SDHCI_CD_NONE ||
            pdata->cd_type == S3C_SDHCI_CD_PERMANENT)
                host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;

        if (pdata->cd_type == S3C_SDHCI_CD_PERMANENT)
                host->mmc->caps = MMC_CAP_NONREMOVABLE;

        switch (pdata->max_width) {
        case 8:
                host->mmc->caps |= MMC_CAP_8_BIT_DATA;
        case 4:
                host->mmc->caps |= MMC_CAP_4_BIT_DATA;
                break;
        }

        if (pdata->pm_caps)
                host->mmc->pm_caps |= pdata->pm_caps;

        host->quirks |= (SDHCI_QUIRK_32BIT_DMA_ADDR |
                         SDHCI_QUIRK_32BIT_DMA_SIZE);

        /* HSMMC on Samsung SoCs uses SDCLK as timeout clock */
        host->quirks |= SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK;

        /*
         * If controller does not have internal clock divider,
         * we can use overriding functions instead of default.
         */
        if (host->quirks & SDHCI_QUIRK_NONSTANDARD_CLOCK) {
                sdhci_s3c_ops.set_clock = sdhci_cmu_set_clock;
                sdhci_s3c_ops.get_min_clock = sdhci_cmu_get_min_clock;
                sdhci_s3c_ops.get_max_clock = sdhci_cmu_get_max_clock;
        }

        /* It supports additional host capabilities if needed */
        if (pdata->host_caps)
                host->mmc->caps |= pdata->host_caps;

        if (pdata->host_caps2)
                host->mmc->caps2 |= pdata->host_caps2;

        pm_runtime_enable(&pdev->dev);
        pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
        pm_runtime_use_autosuspend(&pdev->dev);
        pm_suspend_ignore_children(&pdev->dev, 1);

        ret = sdhci_add_host(host);
        if (ret) {
                dev_err(dev, "sdhci_add_host() failed\n");
                pm_runtime_forbid(&pdev->dev);
                pm_runtime_get_noresume(&pdev->dev);
                goto err_req_regs;
        }

        /* The following two methods of card detection might call
           sdhci_s3c_notify_change() immediately, so they can be called
           only after sdhci_add_host(). Setup errors are ignored. */
        if (pdata->cd_type == S3C_SDHCI_CD_EXTERNAL && pdata->ext_cd_init)
                pdata->ext_cd_init(&sdhci_s3c_notify_change);
        if (pdata->cd_type == S3C_SDHCI_CD_GPIO &&
            gpio_is_valid(pdata->ext_cd_gpio))
                sdhci_s3c_setup_card_detect_gpio(sc);

#ifdef CONFIG_PM_RUNTIME
        if (pdata->cd_type != S3C_SDHCI_CD_INTERNAL)
                clk_disable_unprepare(sc->clk_io);
#endif
        return 0;

 err_req_regs:
#ifndef CONFIG_PM_RUNTIME
        clk_disable_unprepare(sc->clk_bus[sc->cur_clk]);
#endif

 err_no_busclks:
        clk_disable_unprepare(sc->clk_io);

 err_pdata_io_clk:
        sdhci_free_host(host);

        return ret;
}

static int sdhci_s3c_remove(struct platform_device *pdev)
{
        struct sdhci_host *host =  platform_get_drvdata(pdev);
        struct sdhci_s3c *sc = sdhci_priv(host);
        struct s3c_sdhci_platdata *pdata = sc->pdata;

        if (pdata->cd_type == S3C_SDHCI_CD_EXTERNAL && pdata->ext_cd_cleanup)
                pdata->ext_cd_cleanup(&sdhci_s3c_notify_change);

        if (sc->ext_cd_irq)
                free_irq(sc->ext_cd_irq, sc);

#ifdef CONFIG_PM_RUNTIME
        if (pdata->cd_type != S3C_SDHCI_CD_INTERNAL)
                clk_prepare_enable(sc->clk_io);
#endif
        sdhci_remove_host(host, 1);

        pm_runtime_dont_use_autosuspend(&pdev->dev);
        pm_runtime_disable(&pdev->dev);

#ifndef CONFIG_PM_RUNTIME
        clk_disable_unprepare(sc->clk_bus[sc->cur_clk]);
#endif
        clk_disable_unprepare(sc->clk_io);

        sdhci_free_host(host);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int sdhci_s3c_suspend(struct device *dev)
{
        struct sdhci_host *host = dev_get_drvdata(dev);

        return sdhci_suspend_host(host);
}

static int sdhci_s3c_resume(struct device *dev)
{
        struct sdhci_host *host = dev_get_drvdata(dev);

        return sdhci_resume_host(host);
}
#endif

#ifdef CONFIG_PM_RUNTIME
static int sdhci_s3c_runtime_suspend(struct device *dev)
{
        struct sdhci_host *host = dev_get_drvdata(dev);
        struct sdhci_s3c *ourhost = to_s3c(host);
        struct clk *busclk = ourhost->clk_io;
        int ret;

        ret = sdhci_runtime_suspend_host(host);

        clk_disable_unprepare(ourhost->clk_bus[ourhost->cur_clk]);
        clk_disable_unprepare(busclk);
        return ret;
}

static int sdhci_s3c_runtime_resume(struct device *dev)
{
        struct sdhci_host *host = dev_get_drvdata(dev);
        struct sdhci_s3c *ourhost = to_s3c(host);
        struct clk *busclk = ourhost->clk_io;
        int ret;

        clk_prepare_enable(busclk);
        clk_prepare_enable(ourhost->clk_bus[ourhost->cur_clk]);
        ret = sdhci_runtime_resume_host(host);
        return ret;
}
#endif

#ifdef CONFIG_PM
static const struct dev_pm_ops sdhci_s3c_pmops = {
        SET_SYSTEM_SLEEP_PM_OPS(sdhci_s3c_suspend, sdhci_s3c_resume)
        SET_RUNTIME_PM_OPS(sdhci_s3c_runtime_suspend, sdhci_s3c_runtime_resume,
                           NULL)
};

#define SDHCI_S3C_PMOPS (&sdhci_s3c_pmops)

#else
#define SDHCI_S3C_PMOPS NULL
#endif

#if defined(CONFIG_CPU_EXYNOS4210) || defined(CONFIG_SOC_EXYNOS4212)
static struct sdhci_s3c_drv_data exynos4_sdhci_drv_data = {
        .sdhci_quirks = SDHCI_QUIRK_NONSTANDARD_CLOCK,
};
#define EXYNOS4_SDHCI_DRV_DATA ((kernel_ulong_t)&exynos4_sdhci_drv_data)
#else
#define EXYNOS4_SDHCI_DRV_DATA ((kernel_ulong_t)NULL)
#endif

static struct platform_device_id sdhci_s3c_driver_ids[] = {
        {
                .name           = "s3c-sdhci",
                .driver_data    = (kernel_ulong_t)NULL,
        }, {
                .name           = "exynos4-sdhci",
                .driver_data    = EXYNOS4_SDHCI_DRV_DATA,
        },
        { }
};
MODULE_DEVICE_TABLE(platform, sdhci_s3c_driver_ids);

#ifdef CONFIG_OF
static const struct of_device_id sdhci_s3c_dt_match[] = {
        { .compatible = "samsung,s3c6410-sdhci", },
        { .compatible = "samsung,exynos4210-sdhci",
                .data = (void *)EXYNOS4_SDHCI_DRV_DATA },
        {},
};
MODULE_DEVICE_TABLE(of, sdhci_s3c_dt_match);
#endif

static struct platform_driver sdhci_s3c_driver = {
        .probe          = sdhci_s3c_probe,
        .remove         = sdhci_s3c_remove,
        .id_table       = sdhci_s3c_driver_ids,
        .driver         = {
                .owner  = THIS_MODULE,
                .name   = "s3c-sdhci",
                .of_match_table = of_match_ptr(sdhci_s3c_dt_match),
                .pm     = SDHCI_S3C_PMOPS,
        },
};

module_platform_driver(sdhci_s3c_driver);

MODULE_DESCRIPTION("Samsung SDHCI (HSMMC) glue");
MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:s3c-sdhci");