[net-next-2.6.git] / drivers / misc / atmel-ssc.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>
#include <linux/slab.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");
Commit	Line	Data
eb1f2930 HCE	1	/*
	2	* Atmel SSC driver
	3	*
	4	* Copyright (C) 2007 Atmel Corporation
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*/
	10
	11	#include <linux/platform_device.h>
	12	#include <linux/list.h>
	13	#include <linux/clk.h>
	14	#include <linux/err.h>
	15	#include <linux/io.h>
eb1f2930 HCE	16	#include <linux/spinlock.h>
eb1f2930 HCE	17	#include <linux/atmel-ssc.h>
5a0e3ad6	18	#include <linux/slab.h>
eb1f2930 HCE	19
	20	/* Serialize access to ssc_list and user count */
	21	static DEFINE_SPINLOCK(user_lock);
	22	static LIST_HEAD(ssc_list);
	23
	24	struct ssc_device *ssc_request(unsigned int ssc_num)
	25	{
	26	int ssc_valid = 0;
	27	struct ssc_device *ssc;
	28
	29	spin_lock(&user_lock);
	30	list_for_each_entry(ssc, &ssc_list, list) {
	31	if (ssc->pdev->id == ssc_num) {
	32	ssc_valid = 1;
	33	break;
	34	}
	35	}
	36
	37	if (!ssc_valid) {
	38	spin_unlock(&user_lock);
dfecb716	39	pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
eb1f2930 HCE	40	return ERR_PTR(-ENODEV);
	41	}
	42
	43	if (ssc->user) {
	44	spin_unlock(&user_lock);
	45	dev_dbg(&ssc->pdev->dev, "module busy\n");
	46	return ERR_PTR(-EBUSY);
	47	}
	48	ssc->user++;
	49	spin_unlock(&user_lock);
	50
	51	clk_enable(ssc->clk);
	52
	53	return ssc;
	54	}
	55	EXPORT_SYMBOL(ssc_request);
	56
	57	void ssc_free(struct ssc_device *ssc)
	58	{
	59	spin_lock(&user_lock);
	60	if (ssc->user) {
	61	ssc->user--;
	62	clk_disable(ssc->clk);
	63	} else {
	64	dev_dbg(&ssc->pdev->dev, "device already free\n");
	65	}
	66	spin_unlock(&user_lock);
	67	}
	68	EXPORT_SYMBOL(ssc_free);
	69
	70	static int __init ssc_probe(struct platform_device *pdev)
	71	{
	72	int retval = 0;
	73	struct resource *regs;
	74	struct ssc_device *ssc;
	75
	76	ssc = kzalloc(sizeof(struct ssc_device), GFP_KERNEL);
	77	if (!ssc) {
	78	dev_dbg(&pdev->dev, "out of memory\n");
	79	retval = -ENOMEM;
	80	goto out;
	81	}
	82
	83	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	84	if (!regs) {
	85	dev_dbg(&pdev->dev, "no mmio resource defined\n");
	86	retval = -ENXIO;
	87	goto out_free;
	88	}
	89
	90	ssc->clk = clk_get(&pdev->dev, "pclk");
	91	if (IS_ERR(ssc->clk)) {
	92	dev_dbg(&pdev->dev, "no pclk clock defined\n");
	93	retval = -ENXIO;
	94	goto out_free;
	95	}
	96
	97	ssc->pdev = pdev;
	98	ssc->regs = ioremap(regs->start, regs->end - regs->start + 1);
	99	if (!ssc->regs) {
	100	dev_dbg(&pdev->dev, "ioremap failed\n");
	101	retval = -EINVAL;
	102	goto out_clk;
	103	}
104
105	/* disable all interrupts */
106	clk_enable(ssc->clk);
107	ssc_writel(ssc->regs, IDR, ~0UL);
108	ssc_readl(ssc->regs, SR);
109	clk_disable(ssc->clk);
110
111	ssc->irq = platform_get_irq(pdev, 0);
112	if (!ssc->irq) {
113	dev_dbg(&pdev->dev, "could not get irq\n");
114	retval = -ENXIO;
115	goto out_unmap;
116	}
117
118	spin_lock(&user_lock);
119	list_add_tail(&ssc->list, &ssc_list);
120	spin_unlock(&user_lock);
121
122	platform_set_drvdata(pdev, ssc);
123
124	dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
125	ssc->regs, ssc->irq);
126
127	goto out;
128
129	out_unmap:
130	iounmap(ssc->regs);
131	out_clk:
132	clk_put(ssc->clk);
133	out_free:
134	kfree(ssc);
135	out:
136	return retval;
137	}
138
139	static int __devexit ssc_remove(struct platform_device *pdev)
140	{
141	struct ssc_device *ssc = platform_get_drvdata(pdev);
142
143	spin_lock(&user_lock);
144	iounmap(ssc->regs);
145	clk_put(ssc->clk);
146	list_del(&ssc->list);
147	kfree(ssc);
148	spin_unlock(&user_lock);
149
150	return 0;
151	}
152
153	static struct platform_driver ssc_driver = {
154	.remove = __devexit_p(ssc_remove),
155	.driver = {
156	.name = "ssc",
d6c23850	157	.owner = THIS_MODULE,
eb1f2930 HCE	158	},
	159	};
	160
	161	static int __init ssc_init(void)
	162	{
	163	return platform_driver_probe(&ssc_driver, ssc_probe);
	164	}
	165	module_init(ssc_init);
	166
	167	static void __exit ssc_exit(void)
	168	{
	169	platform_driver_unregister(&ssc_driver);
	170	}
	171	module_exit(ssc_exit);
	172
	173	MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
	174	MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
	175	MODULE_LICENSE("GPL");
d6c23850	176	MODULE_ALIAS("platform:ssc");