arch/arm/plat-s3c24xx/adc.c - kernel/prism - Git at Google

 /* arch/arm/plat-s3c24xx/adc.c
  *
  * Copyright (c) 2008 Simtec Electronics
  *	http://armlinux.simtec.co.uk/
  *	Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
  *
  * S3C24XX ADC device core
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License.
 */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 #include <linux/sched.h>
 #include <linux/list.h>
 #include <linux/err.h>
 #include <linux/clk.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>

 #include <plat/regs-adc.h>
 #include <plat/adc.h>

 /* This driver is designed to control the usage of the ADC block between
  * the touchscreen and any other drivers that may need to use it, such as
  * the hwmon driver.
  *
  * Priority will be given to the touchscreen driver, but as this itself is
  * rate limited it should not starve other requests which are processed in
  * order that they are received.
  *
  * Each user registers to get a client block which uniquely identifies it
  * and stores information such as the necessary functions to callback when
  * action is required.
  */

 struct s3c_adc_client {
 	struct platform_device	*pdev;
 	struct list_head	 pend;
 	wait_queue_head_t	*wait;

 	unsigned int		 nr_samples;
 	int			 result;
 	unsigned char		 is_ts;
 	unsigned char		 channel;

 	void	(*select_cb)(struct s3c_adc_client *c, unsigned selected);
 	void	(*convert_cb)(struct s3c_adc_client *c,
 			      unsigned val1, unsigned val2,
 			      unsigned *samples_left);
 };

 struct adc_device {
 	struct platform_device	*pdev;
 	struct platform_device	*owner;
 	struct clk		*clk;
 	struct s3c_adc_client	*cur;
 	struct s3c_adc_client	*ts_pend;
 	void __iomem		*regs;

 	unsigned int		 prescale;

 	int			 irq;
 };

 static struct adc_device *adc_dev;

 static LIST_HEAD(adc_pending);

 #define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)

 static inline void s3c_adc_convert(struct adc_device *adc)
 {
 	unsigned con = readl(adc->regs + S3C2410_ADCCON);

 	con |= S3C2410_ADCCON_ENABLE_START;
 	writel(con, adc->regs + S3C2410_ADCCON);
 }

 static inline void s3c_adc_select(struct adc_device *adc,
 				  struct s3c_adc_client *client)
 {
 	unsigned con = readl(adc->regs + S3C2410_ADCCON);

 	client->select_cb(client, 1);

 	con &= ~S3C2410_ADCCON_MUXMASK;
 	con &= ~S3C2410_ADCCON_STDBM;
 	con &= ~S3C2410_ADCCON_STARTMASK;

 	if (!client->is_ts)
 		con |= S3C2410_ADCCON_SELMUX(client->channel);

 	writel(con, adc->regs + S3C2410_ADCCON);
 }

 static void s3c_adc_dbgshow(struct adc_device *adc)
 {
 	adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
 		readl(adc->regs + S3C2410_ADCCON),
 		readl(adc->regs + S3C2410_ADCTSC),
 		readl(adc->regs + S3C2410_ADCDLY));
 }

 static void s3c_adc_try(struct adc_device *adc)
 {
 	struct s3c_adc_client *next = adc->ts_pend;

 	if (!next && !list_empty(&adc_pending)) {
 		next = list_first_entry(&adc_pending,
 					struct s3c_adc_client, pend);
 		list_del(&next->pend);
 	} else
 		adc->ts_pend = NULL;

 	if (next) {
 		adc_dbg(adc, "new client is %p\n", next);
 		adc->cur = next;
 		s3c_adc_select(adc, next);
 		s3c_adc_convert(adc);
 		s3c_adc_dbgshow(adc);
 	}
 }

 int s3c_adc_start(struct s3c_adc_client *client,
 		  unsigned int channel, unsigned int nr_samples)
 {
 	struct adc_device *adc = adc_dev;
 	unsigned long flags;

 	if (!adc) {
 		printk(KERN_ERR "%s: failed to find adc\n", __func__);
 		return -EINVAL;
 	}

 	if (client->is_ts && adc->ts_pend)
 		return -EAGAIN;

 	local_irq_save(flags);

 	client->channel = channel;
 	client->nr_samples = nr_samples;

 	if (client->is_ts)
 		adc->ts_pend = client;
 	else
 		list_add_tail(&client->pend, &adc_pending);

 	if (!adc->cur)
 		s3c_adc_try(adc);
 	local_irq_restore(flags);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(s3c_adc_start);

 static void s3c_convert_done(struct s3c_adc_client *client,
 			     unsigned v, unsigned u, unsigned *left)
 {
 	client->result = v;
 	wake_up(client->wait);
 }

 int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
 {
 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
 	int ret;

 	client->convert_cb = s3c_convert_done;
 	client->wait = &wake;
 	client->result = -1;

 	ret = s3c_adc_start(client, ch, 1);
 	if (ret < 0)
 		goto err;

 	ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
 	if (client->result < 0) {
 		ret = -ETIMEDOUT;
 		goto err;
 	}

 	client->convert_cb = NULL;
 	return client->result;

 err:
 	return ret;
 }
 EXPORT_SYMBOL_GPL(s3c_adc_read);

 static void s3c_adc_default_select(struct s3c_adc_client *client,
 				   unsigned select)
 {
 }

 struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
 					void (*select)(struct s3c_adc_client *client,
 						       unsigned int selected),
 					void (*conv)(struct s3c_adc_client *client,
 						     unsigned d0, unsigned d1,
 						     unsigned *samples_left),
 					unsigned int is_ts)
 {
 	struct s3c_adc_client *client;

 	WARN_ON(!pdev);

 	if (!select)
 		select = s3c_adc_default_select;

 	if (!pdev)
 		return ERR_PTR(-EINVAL);

 	client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
 	if (!client) {
 		dev_err(&pdev->dev, "no memory for adc client\n");
 		return ERR_PTR(-ENOMEM);
 	}

 	client->pdev = pdev;
 	client->is_ts = is_ts;
 	client->select_cb = select;
 	client->convert_cb = conv;

 	return client;
 }
 EXPORT_SYMBOL_GPL(s3c_adc_register);

 void s3c_adc_release(struct s3c_adc_client *client)
 {
 	/* We should really check that nothing is in progress. */
 	if (adc_dev->cur == client)
 		adc_dev->cur = NULL;
 	if (adc_dev->ts_pend == client)
 		adc_dev->ts_pend = NULL;
 	else {
 		struct list_head *p, *n;
 		struct s3c_adc_client *tmp;

 		list_for_each_safe(p, n, &adc_pending) {
 			tmp = list_entry(p, struct s3c_adc_client, pend);
 			if (tmp == client)
 				list_del(&tmp->pend);
 		}
 	}

 	if (adc_dev->cur == NULL)
 		s3c_adc_try(adc_dev);
 	kfree(client);
 }
 EXPORT_SYMBOL_GPL(s3c_adc_release);

 static irqreturn_t s3c_adc_irq(int irq, void *pw)
 {
 	struct adc_device *adc = pw;
 	struct s3c_adc_client *client = adc->cur;
 	unsigned long flags;
 	unsigned data0, data1;

 	if (!client) {
 		dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
 		return IRQ_HANDLED;
 	}

 	data0 = readl(adc->regs + S3C2410_ADCDAT0);
 	data1 = readl(adc->regs + S3C2410_ADCDAT1);
 	adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);

 	client->nr_samples--;

 	if (client->convert_cb)
 		(client->convert_cb)(client, data0 & 0x3ff, data1 & 0x3ff,
 				     &client->nr_samples);

 	if (client->nr_samples > 0) {
 		/* fire another conversion for this */

 		client->select_cb(client, 1);
 		s3c_adc_convert(adc);
 	} else {
 		local_irq_save(flags);
 		(client->select_cb)(client, 0);
 		adc->cur = NULL;

 		s3c_adc_try(adc);
 		local_irq_restore(flags);
 	}

 	return IRQ_HANDLED;
 }

 static int s3c_adc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct adc_device *adc;
 	struct resource *regs;
 	int ret;

 	adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
 	if (adc == NULL) {
 		dev_err(dev, "failed to allocate adc_device\n");
 		return -ENOMEM;
 	}

 	adc->pdev = pdev;
 	adc->prescale = S3C2410_ADCCON_PRSCVL(49);

 	adc->irq = platform_get_irq(pdev, 1);
 	if (adc->irq <= 0) {
 		dev_err(dev, "failed to get adc irq\n");
 		ret = -ENOENT;
 		goto err_alloc;
 	}

 	ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc);
 	if (ret < 0) {
 		dev_err(dev, "failed to attach adc irq\n");
 		goto err_alloc;
 	}

 	adc->clk = clk_get(dev, "adc");
 	if (IS_ERR(adc->clk)) {
 		dev_err(dev, "failed to get adc clock\n");
 		ret = PTR_ERR(adc->clk);
 		goto err_irq;
 	}

 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!regs) {
 		dev_err(dev, "failed to find registers\n");
 		ret = -ENXIO;
 		goto err_clk;
 	}

 	adc->regs = ioremap(regs->start, resource_size(regs));
 	if (!adc->regs) {
 		dev_err(dev, "failed to map registers\n");
 		ret = -ENXIO;
 		goto err_clk;
 	}

 	clk_enable(adc->clk);

 	writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
 	       adc->regs + S3C2410_ADCCON);

 	dev_info(dev, "attached adc driver\n");

 	platform_set_drvdata(pdev, adc);
 	adc_dev = adc;

 	return 0;

  err_clk:
 	clk_put(adc->clk);

  err_irq:
 	free_irq(adc->irq, adc);

  err_alloc:
 	kfree(adc);
 	return ret;
 }

 static int s3c_adc_remove(struct platform_device *pdev)
 {
 	struct adc_device *adc = platform_get_drvdata(pdev);

 	iounmap(adc->regs);
 	free_irq(adc->irq, adc);
 	clk_disable(adc->clk);
 	clk_put(adc->clk);
 	kfree(adc);

 	return 0;
 }

 #ifdef CONFIG_PM
 static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state)
 {
 	struct adc_device *adc = platform_get_drvdata(pdev);
 	u32 con;

 	con = readl(adc->regs + S3C2410_ADCCON);
 	con |= S3C2410_ADCCON_STDBM;
 	writel(con, adc->regs + S3C2410_ADCCON);

 	clk_disable(adc->clk);

 	return 0;
 }

 static int s3c_adc_resume(struct platform_device *pdev)
 {
 	struct adc_device *adc = platform_get_drvdata(pdev);

 	clk_enable(adc->clk);

 	writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
 	       adc->regs + S3C2410_ADCCON);

 	return 0;
 }

 #else
 #define s3c_adc_suspend NULL
 #define s3c_adc_resume NULL
 #endif

 static struct platform_driver s3c_adc_driver = {
 	.driver		= {
 		.name	= "s3c24xx-adc",
 		.owner	= THIS_MODULE,
 	},
 	.probe		= s3c_adc_probe,
 	.remove		= __devexit_p(s3c_adc_remove),
 	.suspend	= s3c_adc_suspend,
 	.resume		= s3c_adc_resume,
 };

 static int __init adc_init(void)
 {
 	int ret;

 	ret = platform_driver_register(&s3c_adc_driver);
 	if (ret)
 		printk(KERN_ERR "%s: failed to add adc driver\n", __func__);

 	return ret;
 }

 arch_initcall(adc_init);
	/* arch/arm/plat-s3c24xx/adc.c
	*
	* Copyright (c) 2008 Simtec Electronics
	* http://armlinux.simtec.co.uk/
	* Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
	*
	* S3C24XX ADC device core
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License.
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/platform_device.h>
	#include <linux/sched.h>
	#include <linux/list.h>
	#include <linux/err.h>
	#include <linux/clk.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>

	#include <plat/regs-adc.h>
	#include <plat/adc.h>

	/* This driver is designed to control the usage of the ADC block between
	* the touchscreen and any other drivers that may need to use it, such as
	* the hwmon driver.
	*
	* Priority will be given to the touchscreen driver, but as this itself is
	* rate limited it should not starve other requests which are processed in
	* order that they are received.
	*
	* Each user registers to get a client block which uniquely identifies it
	* and stores information such as the necessary functions to callback when
	* action is required.
	*/

	struct s3c_adc_client {
	struct platform_device *pdev;
	struct list_head pend;
	wait_queue_head_t *wait;

	unsigned int nr_samples;
	int result;
	unsigned char is_ts;
	unsigned char channel;

	void (select_cb)(struct s3c_adc_client c, unsigned selected);
	void (convert_cb)(struct s3c_adc_client c,
	unsigned val1, unsigned val2,
	unsigned *samples_left);
	};

	struct adc_device {
	struct platform_device *pdev;
	struct platform_device *owner;
	struct clk *clk;
	struct s3c_adc_client *cur;
	struct s3c_adc_client *ts_pend;
	void __iomem *regs;

	unsigned int prescale;

	int irq;
	};

	static struct adc_device *adc_dev;

	static LIST_HEAD(adc_pending);

	#define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)

	static inline void s3c_adc_convert(struct adc_device *adc)
	{
	unsigned con = readl(adc->regs + S3C2410_ADCCON);

	con \|= S3C2410_ADCCON_ENABLE_START;
	writel(con, adc->regs + S3C2410_ADCCON);
	}

	static inline void s3c_adc_select(struct adc_device *adc,
	struct s3c_adc_client *client)
	{
	unsigned con = readl(adc->regs + S3C2410_ADCCON);

	client->select_cb(client, 1);

	con &= ~S3C2410_ADCCON_MUXMASK;
	con &= ~S3C2410_ADCCON_STDBM;
	con &= ~S3C2410_ADCCON_STARTMASK;

	if (!client->is_ts)
	con \|= S3C2410_ADCCON_SELMUX(client->channel);

	writel(con, adc->regs + S3C2410_ADCCON);
	}

	static void s3c_adc_dbgshow(struct adc_device *adc)
	{
	adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
	readl(adc->regs + S3C2410_ADCCON),
	readl(adc->regs + S3C2410_ADCTSC),
	readl(adc->regs + S3C2410_ADCDLY));
	}

	static void s3c_adc_try(struct adc_device *adc)
	{
	struct s3c_adc_client *next = adc->ts_pend;

	if (!next && !list_empty(&adc_pending)) {
	next = list_first_entry(&adc_pending,
	struct s3c_adc_client, pend);
	list_del(&next->pend);
	} else
	adc->ts_pend = NULL;

	if (next) {
	adc_dbg(adc, "new client is %p\n", next);
	adc->cur = next;
	s3c_adc_select(adc, next);
	s3c_adc_convert(adc);
	s3c_adc_dbgshow(adc);
	}
	}

	int s3c_adc_start(struct s3c_adc_client *client,
	unsigned int channel, unsigned int nr_samples)
	{
	struct adc_device *adc = adc_dev;
	unsigned long flags;

	if (!adc) {
	printk(KERN_ERR "%s: failed to find adc\n", __func__);
	return -EINVAL;
	}

	if (client->is_ts && adc->ts_pend)
	return -EAGAIN;

	local_irq_save(flags);

	client->channel = channel;
	client->nr_samples = nr_samples;

	if (client->is_ts)
	adc->ts_pend = client;
	else
	list_add_tail(&client->pend, &adc_pending);

	if (!adc->cur)
	s3c_adc_try(adc);
	local_irq_restore(flags);

	return 0;
	}
	EXPORT_SYMBOL_GPL(s3c_adc_start);

	static void s3c_convert_done(struct s3c_adc_client *client,
	unsigned v, unsigned u, unsigned *left)
	{
	client->result = v;
	wake_up(client->wait);
	}

	int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
	{
	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
	int ret;

	client->convert_cb = s3c_convert_done;
	client->wait = &wake;
	client->result = -1;

	ret = s3c_adc_start(client, ch, 1);
	if (ret < 0)
	goto err;

	ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
	if (client->result < 0) {
	ret = -ETIMEDOUT;
	goto err;
	}

	client->convert_cb = NULL;
	return client->result;

	err:
	return ret;
	}
	EXPORT_SYMBOL_GPL(s3c_adc_read);

	static void s3c_adc_default_select(struct s3c_adc_client *client,
	unsigned select)
	{
	}

	struct s3c_adc_client s3c_adc_register(struct platform_device pdev,
	void (select)(struct s3c_adc_client client,
	unsigned int selected),
	void (conv)(struct s3c_adc_client client,
	unsigned d0, unsigned d1,
	unsigned *samples_left),
	unsigned int is_ts)
	{
	struct s3c_adc_client *client;

	WARN_ON(!pdev);

	if (!select)
	select = s3c_adc_default_select;

	if (!pdev)
	return ERR_PTR(-EINVAL);

	client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
	if (!client) {
	dev_err(&pdev->dev, "no memory for adc client\n");
	return ERR_PTR(-ENOMEM);
	}

	client->pdev = pdev;
	client->is_ts = is_ts;
	client->select_cb = select;
	client->convert_cb = conv;

	return client;
	}
	EXPORT_SYMBOL_GPL(s3c_adc_register);

	void s3c_adc_release(struct s3c_adc_client *client)
	{
	/* We should really check that nothing is in progress. */
	if (adc_dev->cur == client)
	adc_dev->cur = NULL;
	if (adc_dev->ts_pend == client)
	adc_dev->ts_pend = NULL;
	else {
	struct list_head p, n;
	struct s3c_adc_client *tmp;

	list_for_each_safe(p, n, &adc_pending) {
	tmp = list_entry(p, struct s3c_adc_client, pend);
	if (tmp == client)
	list_del(&tmp->pend);
	}
	}

	if (adc_dev->cur == NULL)
	s3c_adc_try(adc_dev);
	kfree(client);
	}
	EXPORT_SYMBOL_GPL(s3c_adc_release);

	static irqreturn_t s3c_adc_irq(int irq, void *pw)
	{
	struct adc_device *adc = pw;
	struct s3c_adc_client *client = adc->cur;
	unsigned long flags;
	unsigned data0, data1;

	if (!client) {
	dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
	return IRQ_HANDLED;
	}

	data0 = readl(adc->regs + S3C2410_ADCDAT0);
	data1 = readl(adc->regs + S3C2410_ADCDAT1);
	adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);

	client->nr_samples--;

	if (client->convert_cb)
	(client->convert_cb)(client, data0 & 0x3ff, data1 & 0x3ff,
	&client->nr_samples);

	if (client->nr_samples > 0) {
	/* fire another conversion for this */

	client->select_cb(client, 1);
	s3c_adc_convert(adc);
	} else {
	local_irq_save(flags);
	(client->select_cb)(client, 0);
	adc->cur = NULL;

	s3c_adc_try(adc);
	local_irq_restore(flags);
	}

	return IRQ_HANDLED;
	}

	static int s3c_adc_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct adc_device *adc;
	struct resource *regs;
	int ret;

	adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
	if (adc == NULL) {
	dev_err(dev, "failed to allocate adc_device\n");
	return -ENOMEM;
	}

	adc->pdev = pdev;
	adc->prescale = S3C2410_ADCCON_PRSCVL(49);

	adc->irq = platform_get_irq(pdev, 1);
	if (adc->irq <= 0) {
	dev_err(dev, "failed to get adc irq\n");
	ret = -ENOENT;
	goto err_alloc;
	}

	ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc);
	if (ret < 0) {
	dev_err(dev, "failed to attach adc irq\n");
	goto err_alloc;
	}

	adc->clk = clk_get(dev, "adc");
	if (IS_ERR(adc->clk)) {
	dev_err(dev, "failed to get adc clock\n");
	ret = PTR_ERR(adc->clk);
	goto err_irq;
	}

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!regs) {
	dev_err(dev, "failed to find registers\n");
	ret = -ENXIO;
	goto err_clk;
	}

	adc->regs = ioremap(regs->start, resource_size(regs));
	if (!adc->regs) {
	dev_err(dev, "failed to map registers\n");
	ret = -ENXIO;
	goto err_clk;
	}

	clk_enable(adc->clk);

	writel(adc->prescale \| S3C2410_ADCCON_PRSCEN,
	adc->regs + S3C2410_ADCCON);

	dev_info(dev, "attached adc driver\n");

	platform_set_drvdata(pdev, adc);
	adc_dev = adc;

	return 0;

	err_clk:
	clk_put(adc->clk);

	err_irq:
	free_irq(adc->irq, adc);

	err_alloc:
	kfree(adc);
	return ret;
	}

	static int s3c_adc_remove(struct platform_device *pdev)
	{
	struct adc_device *adc = platform_get_drvdata(pdev);

	iounmap(adc->regs);
	free_irq(adc->irq, adc);
	clk_disable(adc->clk);
	clk_put(adc->clk);
	kfree(adc);

	return 0;
	}

	#ifdef CONFIG_PM
	static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state)
	{
	struct adc_device *adc = platform_get_drvdata(pdev);
	u32 con;

	con = readl(adc->regs + S3C2410_ADCCON);
	con \|= S3C2410_ADCCON_STDBM;
	writel(con, adc->regs + S3C2410_ADCCON);

	clk_disable(adc->clk);

	return 0;
	}

	static int s3c_adc_resume(struct platform_device *pdev)
	{
	struct adc_device *adc = platform_get_drvdata(pdev);

	clk_enable(adc->clk);

	writel(adc->prescale \| S3C2410_ADCCON_PRSCEN,
	adc->regs + S3C2410_ADCCON);

	return 0;
	}

	#else
	#define s3c_adc_suspend NULL
	#define s3c_adc_resume NULL
	#endif

	static struct platform_driver s3c_adc_driver = {
	.driver = {
	.name = "s3c24xx-adc",
	.owner = THIS_MODULE,
	},
	.probe = s3c_adc_probe,
	.remove = __devexit_p(s3c_adc_remove),
	.suspend = s3c_adc_suspend,
	.resume = s3c_adc_resume,
	};

	static int __init adc_init(void)
	{
	int ret;

	ret = platform_driver_register(&s3c_adc_driver);
	if (ret)
	printk(KERN_ERR "%s: failed to add adc driver\n", __func__);

	return ret;
	}

	arch_initcall(adc_init);