/*
 * drivers/mmc/host/sdhci-spear.c
 *
 * Support of SDHCI platform devices for spear soc family
 *
 * Copyright (C) 2010 ST Microelectronics
 * Viresh Kumar <vireshk@kernel.org>
 *
 * Inspired by sdhci-pltfm.c
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/mmc/host.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/io.h>
#include "sdhci.h"

struct spear_sdhci {
        struct clk *clk;
};

/* sdhci ops */
static const struct sdhci_ops sdhci_pltfm_ops = {
        .set_clock = sdhci_set_clock,
        .set_bus_width = sdhci_set_bus_width,
        .reset = sdhci_reset,
        .set_uhs_signaling = sdhci_set_uhs_signaling,
};

static int sdhci_probe(struct platform_device *pdev)
{
        struct sdhci_host *host;
        struct spear_sdhci *sdhci;
        struct device *dev;
        int ret;

        dev = pdev->dev.parent ? pdev->dev.parent : &pdev->dev;
        host = sdhci_alloc_host(dev, sizeof(*sdhci));
        if (IS_ERR(host)) {
                ret = PTR_ERR(host);
                dev_dbg(&pdev->dev, "cannot allocate memory for sdhci\n");
                goto err;
        }

        host->ioaddr = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(host->ioaddr)) {
                ret = PTR_ERR(host->ioaddr);
                dev_dbg(&pdev->dev, "unable to map iomem: %d\n", ret);
                goto err;
        }

        host->hw_name = "sdhci";
        host->ops = &sdhci_pltfm_ops;
        host->irq = platform_get_irq(pdev, 0);
        if (host->irq < 0) {
                ret = host->irq;
                goto err;
        }
        host->quirks = SDHCI_QUIRK_BROKEN_ADMA;

        sdhci = sdhci_priv(host);

        /* clk enable */
        sdhci->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(sdhci->clk)) {
                ret = PTR_ERR(sdhci->clk);
                dev_dbg(&pdev->dev, "Error getting clock\n");
                goto err;
        }

        ret = clk_prepare_enable(sdhci->clk);
        if (ret) {
                dev_dbg(&pdev->dev, "Error enabling clock\n");
                goto err;
        }

        ret = clk_set_rate(sdhci->clk, 50000000);
        if (ret)
                dev_dbg(&pdev->dev, "Error setting desired clk, clk=%lu\n",
                                clk_get_rate(sdhci->clk));

        /*
         * It is optional to use GPIOs for sdhci card detection. If we
         * find a descriptor using slot GPIO, we use it.
         */
        ret = mmc_gpiod_request_cd(host->mmc, "cd", 0, false, 0);
        if (ret == -EPROBE_DEFER)
                goto disable_clk;

        ret = sdhci_add_host(host);
        if (ret)
                goto disable_clk;

        platform_set_drvdata(pdev, host);

        return 0;

disable_clk:
        clk_disable_unprepare(sdhci->clk);
err:
        dev_err(&pdev->dev, "spear-sdhci probe failed: %d\n", ret);
        return ret;
}

static void sdhci_remove(struct platform_device *pdev)
{
        struct sdhci_host *host = platform_get_drvdata(pdev);
        struct spear_sdhci *sdhci = sdhci_priv(host);
        int dead = 0;
        u32 scratch;

        scratch = readl(host->ioaddr + SDHCI_INT_STATUS);
        if (scratch == (u32)-1)
                dead = 1;

        sdhci_remove_host(host, dead);
        clk_disable_unprepare(sdhci->clk);
}

static int sdhci_suspend(struct device *dev)
{
        struct sdhci_host *host = dev_get_drvdata(dev);
        struct spear_sdhci *sdhci = sdhci_priv(host);
        int ret;

        if (host->tuning_mode != SDHCI_TUNING_MODE_3)
                mmc_retune_needed(host->mmc);

        ret = sdhci_suspend_host(host);
        if (!ret)
                clk_disable(sdhci->clk);

        return ret;
}

static int sdhci_resume(struct device *dev)
{
        struct sdhci_host *host = dev_get_drvdata(dev);
        struct spear_sdhci *sdhci = sdhci_priv(host);
        int ret;

        ret = clk_enable(sdhci->clk);
        if (ret) {
                dev_dbg(dev, "Resume: Error enabling clock\n");
                return ret;
        }

        return sdhci_resume_host(host);
}

static DEFINE_SIMPLE_DEV_PM_OPS(sdhci_pm_ops, sdhci_suspend, sdhci_resume);

static const struct of_device_id sdhci_spear_id_table[] = {
        { .compatible = "st,spear300-sdhci" },
        {}
};
MODULE_DEVICE_TABLE(of, sdhci_spear_id_table);

static struct platform_driver sdhci_driver = {
        .driver = {
                .name   = "sdhci",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .pm     = pm_sleep_ptr(&sdhci_pm_ops),
                .of_match_table = sdhci_spear_id_table,
        },
        .probe          = sdhci_probe,
        .remove         = sdhci_remove,
};

module_platform_driver(sdhci_driver);

MODULE_DESCRIPTION("SPEAr Secure Digital Host Controller Interface driver");
MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
MODULE_LICENSE("GPL v2");