[deliverable/linux.git] / arch / arm / plat-s3c24xx / pwm.c

/* arch/arm/plat-s3c24xx/pwm.c
 *
 * Copyright (c) 2007 Ben Dooks
 * Copyright (c) 2008 Simtec Electronics
 *	Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
 *
 * S3C24XX PWM 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/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pwm.h>

#include <asm/plat-s3c/regs-timer.h>

struct pwm_device {
	struct list_head	 list;
	struct platform_device	*pdev;

	struct clk		*clk_div;
	struct clk		*clk;
	const char		*label;

	unsigned int		 period_ns;
	unsigned int		 duty_ns;

	unsigned char		 tcon_base;
	unsigned char		 running;
	unsigned char		 use_count;
	unsigned char		 pwm_id;
};

#define pwm_dbg(_pwm, msg...) dev_info(&(_pwm)->pdev->dev, msg)

static struct clk *clk_scaler[2];

/* Standard setup for a timer block. */

#define TIMER_RESOURCE_SIZE (1)

#define TIMER_RESOURCE(_tmr, _irq)			\
	(struct resource [TIMER_RESOURCE_SIZE]) {	\
		[0] = {					\
			.start	= _irq,			\
			.end	= _irq,			\
			.flags	= IORESOURCE_IRQ	\
		}					\
	}

#define DEFINE_TIMER(_tmr_no, _irq)			\
	.name		= "s3c24xx-pwm",		\
	.id		= _tmr_no,			\
	.num_resources	= TIMER_RESOURCE_SIZE,		\
	.resource	= TIMER_RESOURCE(_tmr_no, _irq),	\

/* since we already have an static mapping for the timer, we do not
 * bother setting any IO resource for the base.
 */

struct platform_device s3c_device_timer[] = {
	[0] = { DEFINE_TIMER(0, IRQ_TIMER0) },
	[1] = { DEFINE_TIMER(1, IRQ_TIMER1) },
	[2] = { DEFINE_TIMER(2, IRQ_TIMER2) },
	[3] = { DEFINE_TIMER(3, IRQ_TIMER3) },
	[4] = { DEFINE_TIMER(4, IRQ_TIMER4) },
};

static inline int pwm_is_tdiv(struct pwm_device *pwm)
{
	return clk_get_parent(pwm->clk) == pwm->clk_div;
}

static DEFINE_MUTEX(pwm_lock);
static LIST_HEAD(pwm_list);

struct pwm_device *pwm_request(int pwm_id, const char *label)
{
	struct pwm_device *pwm;
	int found = 0;

	mutex_lock(&pwm_lock);

	list_for_each_entry(pwm, &pwm_list, list) {
		if (pwm->pwm_id == pwm_id) {
			found = 1;
			break;
		}
	}

	if (found) {
		if (pwm->use_count == 0) {
			pwm->use_count = 1;
			pwm->label = label;
		} else
			pwm = ERR_PTR(-EBUSY);
	} else
		pwm = ERR_PTR(-ENOENT);

	mutex_unlock(&pwm_lock);
	return pwm;
}

EXPORT_SYMBOL(pwm_request);


void pwm_free(struct pwm_device *pwm)
{
	mutex_lock(&pwm_lock);

	if (pwm->use_count) {
		pwm->use_count--;
		pwm->label = NULL;
	} else
		printk(KERN_ERR "PWM%d device already freed\n", pwm->pwm_id);

	mutex_unlock(&pwm_lock);
}

EXPORT_SYMBOL(pwm_free);

#define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0))
#define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2))
#define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3))
#define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1))

int pwm_enable(struct pwm_device *pwm)
{
	unsigned long flags;
	unsigned long tcon;

	local_irq_save(flags);

	tcon = __raw_readl(S3C2410_TCON);
	tcon |= pwm_tcon_start(pwm);
	__raw_writel(tcon, S3C2410_TCON);

	local_irq_restore(flags);

	pwm->running = 1;
	return 0;
}

EXPORT_SYMBOL(pwm_enable);

void pwm_disable(struct pwm_device *pwm)
{
	unsigned long flags;
	unsigned long tcon;

	local_irq_save(flags);

	tcon = __raw_readl(S3C2410_TCON);
	tcon &= ~pwm_tcon_start(pwm);
	__raw_writel(tcon, S3C2410_TCON);

	local_irq_restore(flags);

	pwm->running = 0;
}

EXPORT_SYMBOL(pwm_disable);

unsigned long pwm_calc_tin(struct pwm_device *pwm, unsigned long freq)
{
	unsigned long tin_parent_rate;
	unsigned int div;

	tin_parent_rate = clk_get_rate(clk_get_parent(pwm->clk_div));
	pwm_dbg(pwm, "tin parent at %lu\n", tin_parent_rate);

	for (div = 2; div <= 16; div *= 2) {
		if ((tin_parent_rate / (div << 16)) < freq)
			return tin_parent_rate / div;
	}

	return tin_parent_rate / 16;
}

#define NS_IN_HZ (1000000000UL)

int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
	unsigned long tin_rate;
	unsigned long tin_ns;
	unsigned long period;
	unsigned long flags;
	unsigned long tcon;
	unsigned long tcnt;
	long tcmp;

	/* We currently avoid using 64bit arithmetic by using the
	 * fact that anything faster than 1Hz is easily representable
	 * by 32bits. */

	if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ)
		return -ERANGE;

	if (duty_ns > period_ns)
		return -EINVAL;

	if (period_ns == pwm->period_ns &&
	    duty_ns == pwm->duty_ns)
		return 0;

	/* The TCMP and TCNT can be read without a lock, they're not
	 * shared between the timers. */

	tcmp = __raw_readl(S3C2410_TCMPB(pwm->pwm_id));
	tcnt = __raw_readl(S3C2410_TCNTB(pwm->pwm_id));

	period = NS_IN_HZ / period_ns;

	pwm_dbg(pwm, "duty_ns=%d, period_ns=%d (%lu)\n",
		duty_ns, period_ns, period);

	/* Check to see if we are changing the clock rate of the PWM */

	if (pwm->period_ns != period_ns) {
		if (pwm_is_tdiv(pwm)) {
			tin_rate = pwm_calc_tin(pwm, period);
			clk_set_rate(pwm->clk_div, tin_rate);
		} else
			tin_rate = clk_get_rate(pwm->clk);

		pwm->period_ns = period_ns;

		pwm_dbg(pwm, "tin_rate=%lu\n", tin_rate);

		tin_ns = NS_IN_HZ / tin_rate;
		tcnt = period_ns / tin_ns;
	} else
		tin_ns = NS_IN_HZ / clk_get_rate(pwm->clk);

	/* Note, counters count down */

	tcmp = duty_ns / tin_ns;
	tcmp = tcnt - tcmp;

	pwm_dbg(pwm, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt);

	if (tcmp < 0)
		tcmp = 0;

	/* Update the PWM register block. */

	local_irq_save(flags);

	__raw_writel(tcmp, S3C2410_TCMPB(pwm->pwm_id));
	__raw_writel(tcnt, S3C2410_TCNTB(pwm->pwm_id));

	tcon = __raw_readl(S3C2410_TCON);
	tcon |= pwm_tcon_manulupdate(pwm);
	tcon |= pwm_tcon_autoreload(pwm);
	__raw_writel(tcon, S3C2410_TCON);

	tcon &= ~pwm_tcon_manulupdate(pwm);
	__raw_writel(tcon, S3C2410_TCON);

	local_irq_restore(flags);

	return 0;
}

EXPORT_SYMBOL(pwm_config);

static int pwm_register(struct pwm_device *pwm)
{
	pwm->duty_ns = -1;
	pwm->period_ns = -1;

	mutex_lock(&pwm_lock);
	list_add_tail(&pwm->list, &pwm_list);
	mutex_unlock(&pwm_lock);

	return 0;
}

static int s3c_pwm_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct pwm_device *pwm;
	unsigned long flags;
	unsigned long tcon;
	unsigned int id = pdev->id;
	int ret;

	if (id == 4) {
		dev_err(dev, "TIMER4 is currently not supported\n");
		return -ENXIO;
	}

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

	pwm->pdev = pdev;
	pwm->pwm_id = id;

	/* calculate base of control bits in TCON */
	pwm->tcon_base = id == 0 ? 0 : (id * 4) + 4;

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

	pwm->clk_div = clk_get(dev, "pwm-tdiv");
	if (IS_ERR(pwm->clk_div)) {
		dev_err(dev, "failed to get pwm tdiv clk\n");
		ret = PTR_ERR(pwm->clk_div);
		goto err_clk_tin;
	}

	local_irq_save(flags);

	tcon = __raw_readl(S3C2410_TCON);
	tcon |= pwm_tcon_invert(pwm);
	__raw_writel(tcon, S3C2410_TCON);

	local_irq_restore(flags);


	ret = pwm_register(pwm);
	if (ret) {
		dev_err(dev, "failed to register pwm\n");
		goto err_clk_tdiv;
	}

	pwm_dbg(pwm, "config bits %02x\n",
		(__raw_readl(S3C2410_TCON) >> pwm->tcon_base) & 0x0f);

	dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n",
		 clk_get_rate(pwm->clk),
		 clk_get_rate(pwm->clk_div),
		 pwm_is_tdiv(pwm) ? "div" : "ext", pwm->tcon_base);

	platform_set_drvdata(pdev, pwm);
	return 0;

 err_clk_tdiv:
	clk_put(pwm->clk_div);

 err_clk_tin:
	clk_put(pwm->clk);

 err_alloc:
	kfree(pwm);
	return ret;
}

static int s3c_pwm_remove(struct platform_device *pdev)
{
	struct pwm_device *pwm = platform_get_drvdata(pdev);

	clk_put(pwm->clk_div);
	clk_put(pwm->clk);
	kfree(pwm);

	return 0;
}

static struct platform_driver s3c_pwm_driver = {
	.driver		= {
		.name	= "s3c24xx-pwm",
		.owner	= THIS_MODULE,
	},
	.probe		= s3c_pwm_probe,
	.remove		= __devexit_p(s3c_pwm_remove),
};

static int __init pwm_init(void)
{
	int ret;

	clk_scaler[0] = clk_get(NULL, "pwm-scaler0");
	clk_scaler[1] = clk_get(NULL, "pwm-scaler1");

	if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) {
		printk(KERN_ERR "%s: failed to get scaler clocks\n", __func__);
		return -EINVAL;
	}

	ret = platform_driver_register(&s3c_pwm_driver);
	if (ret)
		printk(KERN_ERR "%s: failed to add pwm driver\n", __func__);

	return ret;
}

arch_initcall(pwm_init);
Commit	Line	Data
6fc601e3 BD	1	/* arch/arm/plat-s3c24xx/pwm.c
	2	*
	3	* Copyright (c) 2007 Ben Dooks
	4	* Copyright (c) 2008 Simtec Electronics
	5	* Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
	6	*
	7	* S3C24XX PWM device core
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation; either version 2 of the License.
	12	*/
	13
	14	#include <linux/module.h>
	15	#include <linux/kernel.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/err.h>
	18	#include <linux/clk.h>
	19	#include <linux/io.h>
	20	#include <linux/pwm.h>
	21
	22	#include <asm/plat-s3c/regs-timer.h>
	23
	24	struct pwm_device {
	25	struct list_head list;
	26	struct platform_device *pdev;
	27
	28	struct clk *clk_div;
	29	struct clk *clk;
	30	const char *label;
	31
	32	unsigned int period_ns;
	33	unsigned int duty_ns;
	34
	35	unsigned char tcon_base;
	36	unsigned char running;
	37	unsigned char use_count;
	38	unsigned char pwm_id;
	39	};
	40
	41	#define pwm_dbg(_pwm, msg...) dev_info(&(_pwm)->pdev->dev, msg)
	42
	43	static struct clk *clk_scaler[2];
	44
	45	/* Standard setup for a timer block. */
	46
	47	#define TIMER_RESOURCE_SIZE (1)
	48
	49	#define TIMER_RESOURCE(_tmr, _irq) \
	50	(struct resource [TIMER_RESOURCE_SIZE]) { \
	51	[0] = { \
	52	.start = _irq, \
	53	.end = _irq, \
	54	.flags = IORESOURCE_IRQ \
	55	} \
	56	}
	57
	58	#define DEFINE_TIMER(_tmr_no, _irq) \
	59	.name = "s3c24xx-pwm", \
	60	.id = _tmr_no, \
	61	.num_resources = TIMER_RESOURCE_SIZE, \
	62	.resource = TIMER_RESOURCE(_tmr_no, _irq), \
	63
	64	/* since we already have an static mapping for the timer, we do not
65	* bother setting any IO resource for the base.
66	*/
67
68	struct platform_device s3c_device_timer[] = {
69	[0] = { DEFINE_TIMER(0, IRQ_TIMER0) },
70	[1] = { DEFINE_TIMER(1, IRQ_TIMER1) },
71	[2] = { DEFINE_TIMER(2, IRQ_TIMER2) },
72	[3] = { DEFINE_TIMER(3, IRQ_TIMER3) },
73	[4] = { DEFINE_TIMER(4, IRQ_TIMER4) },
74	};
75
76	static inline int pwm_is_tdiv(struct pwm_device *pwm)
77	{
78	return clk_get_parent(pwm->clk) == pwm->clk_div;
79	}
80
81	static DEFINE_MUTEX(pwm_lock);
82	static LIST_HEAD(pwm_list);
83
84	struct pwm_device pwm_request(int pwm_id, const char label)
85	{
86	struct pwm_device *pwm;
87	int found = 0;
88
89	mutex_lock(&pwm_lock);
90
91	list_for_each_entry(pwm, &pwm_list, list) {
92	if (pwm->pwm_id == pwm_id) {
93	found = 1;
94	break;
95	}
96	}
97
98	if (found) {
99	if (pwm->use_count == 0) {
100	pwm->use_count = 1;
101	pwm->label = label;
102	} else
103	pwm = ERR_PTR(-EBUSY);
104	} else
105	pwm = ERR_PTR(-ENOENT);
106
107	mutex_unlock(&pwm_lock);
108	return pwm;
109	}
110
111	EXPORT_SYMBOL(pwm_request);
112
113
114	void pwm_free(struct pwm_device *pwm)
115	{
116	mutex_lock(&pwm_lock);
117
118	if (pwm->use_count) {
119	pwm->use_count--;
120	pwm->label = NULL;
121	} else
122	printk(KERN_ERR "PWM%d device already freed\n", pwm->pwm_id);
123
124	mutex_unlock(&pwm_lock);
125	}
126
127	EXPORT_SYMBOL(pwm_free);
128
129	#define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0))
130	#define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2))
131	#define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3))
132	#define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1))
133
134	int pwm_enable(struct pwm_device *pwm)
135	{
136	unsigned long flags;
137	unsigned long tcon;
138
139	local_irq_save(flags);
140
141	tcon = __raw_readl(S3C2410_TCON);
142	tcon \|= pwm_tcon_start(pwm);
143	__raw_writel(tcon, S3C2410_TCON);
144
145	local_irq_restore(flags);
146
147	pwm->running = 1;
148	return 0;
149	}
150
151	EXPORT_SYMBOL(pwm_enable);
152
153	void pwm_disable(struct pwm_device *pwm)
154	{
155	unsigned long flags;
156	unsigned long tcon;
157
158	local_irq_save(flags);
159
160	tcon = __raw_readl(S3C2410_TCON);
161	tcon &= ~pwm_tcon_start(pwm);
162	__raw_writel(tcon, S3C2410_TCON);
163
164	local_irq_restore(flags);
165
166	pwm->running = 0;
167	}
168
169	EXPORT_SYMBOL(pwm_disable);
170
171	unsigned long pwm_calc_tin(struct pwm_device *pwm, unsigned long freq)
172	{
173	unsigned long tin_parent_rate;
174	unsigned int div;
175
176	tin_parent_rate = clk_get_rate(clk_get_parent(pwm->clk_div));
177	pwm_dbg(pwm, "tin parent at %lu\n", tin_parent_rate);
178
179	for (div = 2; div <= 16; div *= 2) {
180	if ((tin_parent_rate / (div << 16)) < freq)
181	return tin_parent_rate / div;
182	}
183
184	return tin_parent_rate / 16;
185	}
186
187	#define NS_IN_HZ (1000000000UL)
188
189	int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
190	{
191	unsigned long tin_rate;
192	unsigned long tin_ns;
193	unsigned long period;
194	unsigned long flags;
195	unsigned long tcon;
196	unsigned long tcnt;
197	long tcmp;
198
199	/* We currently avoid using 64bit arithmetic by using the
200	* fact that anything faster than 1Hz is easily representable
201	* by 32bits. */
202
203	if (period_ns > NS_IN_HZ \|\| duty_ns > NS_IN_HZ)
204	return -ERANGE;
205
206	if (duty_ns > period_ns)
207	return -EINVAL;
208
209	if (period_ns == pwm->period_ns &&
210	duty_ns == pwm->duty_ns)
211	return 0;
212
213	/* The TCMP and TCNT can be read without a lock, they're not
214	* shared between the timers. */
215
216	tcmp = __raw_readl(S3C2410_TCMPB(pwm->pwm_id));
217	tcnt = __raw_readl(S3C2410_TCNTB(pwm->pwm_id));
218
219	period = NS_IN_HZ / period_ns;
220
221	pwm_dbg(pwm, "duty_ns=%d, period_ns=%d (%lu)\n",
222	duty_ns, period_ns, period);
223
224	/* Check to see if we are changing the clock rate of the PWM */
225
226	if (pwm->period_ns != period_ns) {
227	if (pwm_is_tdiv(pwm)) {
228	tin_rate = pwm_calc_tin(pwm, period);
229	clk_set_rate(pwm->clk_div, tin_rate);
230	} else
231	tin_rate = clk_get_rate(pwm->clk);
232
233	pwm->period_ns = period_ns;
234
235	pwm_dbg(pwm, "tin_rate=%lu\n", tin_rate);
236
237	tin_ns = NS_IN_HZ / tin_rate;
238	tcnt = period_ns / tin_ns;
239	} else
240	tin_ns = NS_IN_HZ / clk_get_rate(pwm->clk);
241
242	/* Note, counters count down */
243
244	tcmp = duty_ns / tin_ns;
245	tcmp = tcnt - tcmp;
246
247	pwm_dbg(pwm, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt);
248
249	if (tcmp < 0)
250	tcmp = 0;
251
252	/* Update the PWM register block. */
253
254	local_irq_save(flags);
255
256	__raw_writel(tcmp, S3C2410_TCMPB(pwm->pwm_id));
257	__raw_writel(tcnt, S3C2410_TCNTB(pwm->pwm_id));
258
259	tcon = __raw_readl(S3C2410_TCON);
260	tcon \|= pwm_tcon_manulupdate(pwm);
261	tcon \|= pwm_tcon_autoreload(pwm);
262	__raw_writel(tcon, S3C2410_TCON);
263
264	tcon &= ~pwm_tcon_manulupdate(pwm);
265	__raw_writel(tcon, S3C2410_TCON);
266
267	local_irq_restore(flags);
268
269	return 0;
270	}
271
272	EXPORT_SYMBOL(pwm_config);
273
274	static int pwm_register(struct pwm_device *pwm)
275	{
276	pwm->duty_ns = -1;
277	pwm->period_ns = -1;
278
279	mutex_lock(&pwm_lock);
280	list_add_tail(&pwm->list, &pwm_list);
281	mutex_unlock(&pwm_lock);
282
283	return 0;
284	}
285
286	static int s3c_pwm_probe(struct platform_device *pdev)
287	{
288	struct device *dev = &pdev->dev;
289	struct pwm_device *pwm;
290	unsigned long flags;
291	unsigned long tcon;
292	unsigned int id = pdev->id;
293	int ret;
294
295	if (id == 4) {
296	dev_err(dev, "TIMER4 is currently not supported\n");
297	return -ENXIO;
298	}
299
300	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
301	if (pwm == NULL) {
302	dev_err(dev, "failed to allocate pwm_device\n");
303	return -ENOMEM;
304	}
305
306	pwm->pdev = pdev;
307	pwm->pwm_id = id;
308
309	/* calculate base of control bits in TCON */
310	pwm->tcon_base = id == 0 ? 0 : (id * 4) + 4;
311
312	pwm->clk = clk_get(dev, "pwm-tin");
313	if (IS_ERR(pwm->clk)) {
314	dev_err(dev, "failed to get pwm tin clk\n");
315	ret = PTR_ERR(pwm->clk);
316	goto err_alloc;
317	}
318
319	pwm->clk_div = clk_get(dev, "pwm-tdiv");
320	if (IS_ERR(pwm->clk_div)) {
321	dev_err(dev, "failed to get pwm tdiv clk\n");
322	ret = PTR_ERR(pwm->clk_div);
323	goto err_clk_tin;
324	}
325
326	local_irq_save(flags);
327
328	tcon = __raw_readl(S3C2410_TCON);
329	tcon \|= pwm_tcon_invert(pwm);
330	__raw_writel(tcon, S3C2410_TCON);
331
332	local_irq_restore(flags);
333
334
335	ret = pwm_register(pwm);
336	if (ret) {
337	dev_err(dev, "failed to register pwm\n");
338	goto err_clk_tdiv;
339	}
340
341	pwm_dbg(pwm, "config bits %02x\n",
342	(__raw_readl(S3C2410_TCON) >> pwm->tcon_base) & 0x0f);
343
344	dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n",
345	clk_get_rate(pwm->clk),
346	clk_get_rate(pwm->clk_div),
347	pwm_is_tdiv(pwm) ? "div" : "ext", pwm->tcon_base);
348
349	platform_set_drvdata(pdev, pwm);
350	return 0;
351
352	err_clk_tdiv:
353	clk_put(pwm->clk_div);
354
355	err_clk_tin:
356	clk_put(pwm->clk);
357
358	err_alloc:
359	kfree(pwm);
360	return ret;
361	}
362
363	static int s3c_pwm_remove(struct platform_device *pdev)
364	{
365	struct pwm_device *pwm = platform_get_drvdata(pdev);
366
367	clk_put(pwm->clk_div);
368	clk_put(pwm->clk);
369	kfree(pwm);
370
371	return 0;
372	}
373
374	static struct platform_driver s3c_pwm_driver = {
375	.driver = {
376	.name = "s3c24xx-pwm",
377	.owner = THIS_MODULE,
378	},
379	.probe = s3c_pwm_probe,
380	.remove = __devexit_p(s3c_pwm_remove),
381	};
382
383	static int __init pwm_init(void)
384	{
385	int ret;
386
387	clk_scaler[0] = clk_get(NULL, "pwm-scaler0");
388	clk_scaler[1] = clk_get(NULL, "pwm-scaler1");
389
390	if (IS_ERR(clk_scaler[0]) \|\| IS_ERR(clk_scaler[1])) {
391	printk(KERN_ERR "%s: failed to get scaler clocks\n", __func__);
392	return -EINVAL;
393	}
394
395	ret = platform_driver_register(&s3c_pwm_driver);
396	if (ret)
397	printk(KERN_ERR "%s: failed to add pwm driver\n", __func__);
398
399	return ret;
400	}
401
402	arch_initcall(pwm_init);