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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/spinlock.h>
#include <linux/atmel-ssc.h>
#include <linux/slab.h>
#include <linux/module.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);
pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
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, resource_size(regs));
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 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 = ssc_remove,
.driver = {
.name = "ssc",
.owner = THIS_MODULE,
},
};
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");
MODULE_ALIAS("platform:ssc");
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