176 lines
3.5 KiB
C
176 lines
3.5 KiB
C
/*
|
|
* 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>
|
|
|
|
/* 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, 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",
|
|
.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");
|