[mirror_ubuntu-bionic-kernel.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>
#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 __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>
eb12a679	19	#include <linux/module.h>
eb1f2930 HCE	20
	21	/* Serialize access to ssc_list and user count */
	22	static DEFINE_SPINLOCK(user_lock);
	23	static LIST_HEAD(ssc_list);
	24
	25	struct ssc_device *ssc_request(unsigned int ssc_num)
	26	{
	27	int ssc_valid = 0;
	28	struct ssc_device *ssc;
	29
	30	spin_lock(&user_lock);
	31	list_for_each_entry(ssc, &ssc_list, list) {
	32	if (ssc->pdev->id == ssc_num) {
	33	ssc_valid = 1;
	34	break;
	35	}
	36	}
	37
	38	if (!ssc_valid) {
	39	spin_unlock(&user_lock);
dfecb716	40	pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
eb1f2930 HCE	41	return ERR_PTR(-ENODEV);
	42	}
	43
	44	if (ssc->user) {
	45	spin_unlock(&user_lock);
	46	dev_dbg(&ssc->pdev->dev, "module busy\n");
	47	return ERR_PTR(-EBUSY);
	48	}
	49	ssc->user++;
	50	spin_unlock(&user_lock);
	51
	52	clk_enable(ssc->clk);
	53
	54	return ssc;
	55	}
	56	EXPORT_SYMBOL(ssc_request);
	57
	58	void ssc_free(struct ssc_device *ssc)
	59	{
	60	spin_lock(&user_lock);
	61	if (ssc->user) {
	62	ssc->user--;
	63	clk_disable(ssc->clk);
	64	} else {
	65	dev_dbg(&ssc->pdev->dev, "device already free\n");
	66	}
	67	spin_unlock(&user_lock);
	68	}
	69	EXPORT_SYMBOL(ssc_free);
	70
	71	static int __init ssc_probe(struct platform_device *pdev)
	72	{
	73	int retval = 0;
	74	struct resource *regs;
	75	struct ssc_device *ssc;
	76
	77	ssc = kzalloc(sizeof(struct ssc_device), GFP_KERNEL);
	78	if (!ssc) {
	79	dev_dbg(&pdev->dev, "out of memory\n");
	80	retval = -ENOMEM;
	81	goto out;
	82	}
	83
	84	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	85	if (!regs) {
	86	dev_dbg(&pdev->dev, "no mmio resource defined\n");
	87	retval = -ENXIO;
	88	goto out_free;
	89	}
	90
	91	ssc->clk = clk_get(&pdev->dev, "pclk");
	92	if (IS_ERR(ssc->clk)) {
	93	dev_dbg(&pdev->dev, "no pclk clock defined\n");
	94	retval = -ENXIO;
	95	goto out_free;
	96	}
	97
	98	ssc->pdev = pdev;
28f65c11	99	ssc->regs = ioremap(regs->start, resource_size(regs));
eb1f2930 HCE	100	if (!ssc->regs) {
	101	dev_dbg(&pdev->dev, "ioremap failed\n");
	102	retval = -EINVAL;
	103	goto out_clk;
	104	}
	105
	106	/* disable all interrupts */
	107	clk_enable(ssc->clk);
	108	ssc_writel(ssc->regs, IDR, ~0UL);
	109	ssc_readl(ssc->regs, SR);
	110	clk_disable(ssc->clk);
	111
	112	ssc->irq = platform_get_irq(pdev, 0);
	113	if (!ssc->irq) {
	114	dev_dbg(&pdev->dev, "could not get irq\n");
	115	retval = -ENXIO;
	116	goto out_unmap;
	117	}
	118
	119	spin_lock(&user_lock);
	120	list_add_tail(&ssc->list, &ssc_list);
	121	spin_unlock(&user_lock);
	122
	123	platform_set_drvdata(pdev, ssc);
	124
	125	dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
	126	ssc->regs, ssc->irq);
	127
	128	goto out;
	129
	130	out_unmap:
	131	iounmap(ssc->regs);
	132	out_clk:
	133	clk_put(ssc->clk);
	134	out_free:
	135	kfree(ssc);
	136	out:
	137	return retval;
	138	}
	139
	140	static int __devexit ssc_remove(struct platform_device *pdev)
	141	{
	142	struct ssc_device *ssc = platform_get_drvdata(pdev);
	143
	144	spin_lock(&user_lock);
	145	iounmap(ssc->regs);
	146	clk_put(ssc->clk);
	147	list_del(&ssc->list);
	148	kfree(ssc);
	149	spin_unlock(&user_lock);
	150
	151	return 0;
	152	}
	153
	154	static struct platform_driver ssc_driver = {
	155	.remove = __devexit_p(ssc_remove),
	156	.driver = {
	157	.name = "ssc",
d6c23850	158	.owner = THIS_MODULE,
eb1f2930 HCE	159	},
	160	};
	161
	162	static int __init ssc_init(void)
	163	{
	164	return platform_driver_probe(&ssc_driver, ssc_probe);
	165	}
	166	module_init(ssc_init);
	167
	168	static void __exit ssc_exit(void)
	169	{
	170	platform_driver_unregister(&ssc_driver);
	171	}
	172	module_exit(ssc_exit);
	173
	174	MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
	175	MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
	176	MODULE_LICENSE("GPL");
d6c23850	177	MODULE_ALIAS("platform:ssc");