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/*

 * Atmel SSC driver

 *

 * Copyright (C) 2007 Atmel Corporation

 *

 * 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/platform_device.h>

#include <linux/list.h>

#include <linux/clk.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/list.h>

#include <linux/spinlock.h>

#include <linux/atmel-ssc.h>

/* Serialize access to ssc_list and user count */

static DEFINE_SPINLOCK(user_lock);

static LIST_HEAD(ssc_list);

struct ssc_device *ssc_request(unsigned int ssc_num)

{

        int ssc_valid = 0;

        struct ssc_device *ssc;

        spin_lock(&user_lock);

        list_for_each_entry(ssc, &ssc_list, list) {

                if (ssc->pdev->id == ssc_num) {

                        ssc_valid = 1;

                        break;

                }

        }

        if (!ssc_valid) {

                spin_unlock(&user_lock);

                dev_dbg(&ssc->pdev->dev, "could not find requested device\n");

                return ERR_PTR(-ENODEV);

        }

        if (ssc->user) {

                spin_unlock(&user_lock);

                dev_dbg(&ssc->pdev->dev, "module busy\n");

                return ERR_PTR(-EBUSY);

        }

        ssc->user++;

        spin_unlock(&user_lock);

        clk_enable(ssc->clk);

        return ssc;

}

EXPORT_SYMBOL(ssc_request);

void ssc_free(struct ssc_device *ssc)

{

        spin_lock(&user_lock);

        if (ssc->user) {

                ssc->user--;

                clk_disable(ssc->clk);

        } else {

                dev_dbg(&ssc->pdev->dev, "device already free\n");

        }

        spin_unlock(&user_lock);

}

EXPORT_SYMBOL(ssc_free);

static int __init ssc_probe(struct platform_device *pdev)

{

        int retval = 0;

        struct resource *regs;

        struct ssc_device *ssc;

        ssc = kzalloc(sizeof(struct ssc_device), GFP_KERNEL);

        if (!ssc) {

                dev_dbg(&pdev->dev, "out of memory\n");

                retval = -ENOMEM;

                goto out;

        }

        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);

        if (!regs) {

                dev_dbg(&pdev->dev, "no mmio resource defined\n");

                retval = -ENXIO;

                goto out_free;

        }

        ssc->clk = clk_get(&pdev->dev, "pclk");

        if (IS_ERR(ssc->clk)) {

                dev_dbg(&pdev->dev, "no pclk clock defined\n");

                retval = -ENXIO;

                goto out_free;

        }

        ssc->pdev = pdev;

        ssc->regs = ioremap(regs->start, regs->end - regs->start + 1);

        if (!ssc->regs) {

                dev_dbg(&pdev->dev, "ioremap failed\n");

                retval = -EINVAL;

                goto out_clk;

        }

        /* disable all interrupts */

        clk_enable(ssc->clk);

        ssc_writel(ssc->regs, IDR, ~0UL);

        ssc_readl(ssc->regs, SR);

        clk_disable(ssc->clk);

        ssc->irq = platform_get_irq(pdev, 0);

        if (!ssc->irq) {

                dev_dbg(&pdev->dev, "could not get irq\n");

                retval = -ENXIO;

                goto out_unmap;

        }

        spin_lock(&user_lock);

        list_add_tail(&ssc->list, &ssc_list);

        spin_unlock(&user_lock);

        platform_set_drvdata(pdev, ssc);

        dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",

                        ssc->regs, ssc->irq);

        goto out;

out_unmap:

        iounmap(ssc->regs);

out_clk:

        clk_put(ssc->clk);

out_free:

        kfree(ssc);

out:

        return retval;

}

static int __devexit ssc_remove(struct platform_device *pdev)

{

        struct ssc_device *ssc = platform_get_drvdata(pdev);

        spin_lock(&user_lock);

        iounmap(ssc->regs);

        clk_put(ssc->clk);

        list_del(&ssc->list);

        kfree(ssc);

        spin_unlock(&user_lock);

        return 0;

}

static struct platform_driver ssc_driver = {

        .remove         = __devexit_p(ssc_remove),

        .driver         = {

                .name           = "ssc",

        },

};

static int __init ssc_init(void)

{

        return platform_driver_probe(&ssc_driver, ssc_probe);

}

module_init(ssc_init);

static void __exit ssc_exit(void)

{

        platform_driver_unregister(&ssc_driver);

}

module_exit(ssc_exit);

MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");

MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");

MODULE_LICENSE("GPL");