[linux-2.6-block.git] / arch / arm / plat-pxa / pwm.c

/*
 * linux/arch/arm/mach-pxa/pwm.c
 *
 * simple driver for PWM (Pulse Width Modulator) controller
 *
 * 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.
 *
 * 2008-02-13	initial version
 * 		eric miao <eric.miao@marvell.com>
 */

#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/div64.h>

#define HAS_SECONDARY_PWM	0x10
#define PWM_ID_BASE(d)		((d) & 0xf)

static const struct platform_device_id pwm_id_table[] = {
	/*   PWM    has_secondary_pwm? */
	{ "pxa25x-pwm", 0 },
	{ "pxa27x-pwm", 0 | HAS_SECONDARY_PWM },
	{ "pxa168-pwm", 1 },
	{ "pxa910-pwm", 1 },
	{ },
};
MODULE_DEVICE_TABLE(platform, pwm_id_table);

/* PWM registers and bits definitions */
#define PWMCR		(0x00)
#define PWMDCR		(0x04)
#define PWMPCR		(0x08)

#define PWMCR_SD	(1 << 6)
#define PWMDCR_FD	(1 << 10)

struct pwm_device {
	struct list_head	node;
	struct pwm_device	*secondary;
	struct platform_device	*pdev;

	const char	*label;
	struct clk	*clk;
	int		clk_enabled;
	void __iomem	*mmio_base;

	unsigned int	use_count;
	unsigned int	pwm_id;
};

/*
 * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
 * duty_ns   = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
 */
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
	unsigned long long c;
	unsigned long period_cycles, prescale, pv, dc;

	if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
		return -EINVAL;

	c = clk_get_rate(pwm->clk);
	c = c * period_ns;
	do_div(c, 1000000000);
	period_cycles = c;

	if (period_cycles < 1)
		period_cycles = 1;
	prescale = (period_cycles - 1) / 1024;
	pv = period_cycles / (prescale + 1) - 1;

	if (prescale > 63)
		return -EINVAL;

	if (duty_ns == period_ns)
		dc = PWMDCR_FD;
	else
		dc = (pv + 1) * duty_ns / period_ns;

	/* NOTE: the clock to PWM has to be enabled first
	 * before writing to the registers
	 */
	clk_enable(pwm->clk);
	__raw_writel(prescale, pwm->mmio_base + PWMCR);
	__raw_writel(dc, pwm->mmio_base + PWMDCR);
	__raw_writel(pv, pwm->mmio_base + PWMPCR);
	clk_disable(pwm->clk);

	return 0;
}
EXPORT_SYMBOL(pwm_config);

int pwm_enable(struct pwm_device *pwm)
{
	int rc = 0;

	if (!pwm->clk_enabled) {
		rc = clk_enable(pwm->clk);
		if (!rc)
			pwm->clk_enabled = 1;
	}
	return rc;
}
EXPORT_SYMBOL(pwm_enable);

void pwm_disable(struct pwm_device *pwm)
{
	if (pwm->clk_enabled) {
		clk_disable(pwm->clk);
		pwm->clk_enabled = 0;
	}
}
EXPORT_SYMBOL(pwm_disable);

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, node) {
		if (pwm->pwm_id == pwm_id) {
			found = 1;
			break;
		}
	}

	if (found) {
		if (pwm->use_count == 0) {
			pwm->use_count++;
			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
		pr_warning("PWM device already freed\n");

	mutex_unlock(&pwm_lock);
}
EXPORT_SYMBOL(pwm_free);

static inline void __add_pwm(struct pwm_device *pwm)
{
	mutex_lock(&pwm_lock);
	list_add_tail(&pwm->node, &pwm_list);
	mutex_unlock(&pwm_lock);
}

static int __devinit pwm_probe(struct platform_device *pdev)
{
	struct platform_device_id *id = platform_get_device_id(pdev);
	struct pwm_device *pwm, *secondary = NULL;
	struct resource *r;
	int ret = 0;

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

	pwm->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(pwm->clk)) {
		ret = PTR_ERR(pwm->clk);
		goto err_free;
	}
	pwm->clk_enabled = 0;

	pwm->use_count = 0;
	pwm->pwm_id = PWM_ID_BASE(id->driver_data) + pdev->id;
	pwm->pdev = pdev;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (r == NULL) {
		dev_err(&pdev->dev, "no memory resource defined\n");
		ret = -ENODEV;
		goto err_free_clk;
	}

	r = request_mem_region(r->start, resource_size(r), pdev->name);
	if (r == NULL) {
		dev_err(&pdev->dev, "failed to request memory resource\n");
		ret = -EBUSY;
		goto err_free_clk;
	}

	pwm->mmio_base = ioremap(r->start, resource_size(r));
	if (pwm->mmio_base == NULL) {
		dev_err(&pdev->dev, "failed to ioremap() registers\n");
		ret = -ENODEV;
		goto err_free_mem;
	}

	if (id->driver_data & HAS_SECONDARY_PWM) {
		secondary = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
		if (secondary == NULL) {
			ret = -ENOMEM;
			goto err_free_mem;
		}

		*secondary = *pwm;
		pwm->secondary = secondary;

		/* registers for the second PWM has offset of 0x10 */
		secondary->mmio_base = pwm->mmio_base + 0x10;
		secondary->pwm_id = pdev->id + 2;
	}

	__add_pwm(pwm);
	if (secondary)
		__add_pwm(secondary);

	platform_set_drvdata(pdev, pwm);
	return 0;

err_free_mem:
	release_mem_region(r->start, resource_size(r));
err_free_clk:
	clk_put(pwm->clk);
err_free:
	kfree(pwm);
	return ret;
}

static int __devexit pwm_remove(struct platform_device *pdev)
{
	struct pwm_device *pwm;
	struct resource *r;

	pwm = platform_get_drvdata(pdev);
	if (pwm == NULL)
		return -ENODEV;

	mutex_lock(&pwm_lock);

	if (pwm->secondary) {
		list_del(&pwm->secondary->node);
		kfree(pwm->secondary);
	}

	list_del(&pwm->node);
	mutex_unlock(&pwm_lock);

	iounmap(pwm->mmio_base);

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(r->start, resource_size(r));

	clk_put(pwm->clk);
	kfree(pwm);
	return 0;
}

static struct platform_driver pwm_driver = {
	.driver		= {
		.name	= "pxa25x-pwm",
		.owner	= THIS_MODULE,
	},
	.probe		= pwm_probe,
	.remove		= __devexit_p(pwm_remove),
	.id_table	= pwm_id_table,
};

static int __init pwm_init(void)
{
	return platform_driver_register(&pwm_driver);
}
arch_initcall(pwm_init);

static void __exit pwm_exit(void)
{
	platform_driver_unregister(&pwm_driver);
}
module_exit(pwm_exit);

MODULE_LICENSE("GPL v2");
Commit	Line	Data
75540c1a	1	/*
	2	* linux/arch/arm/mach-pxa/pwm.c
	3	*
	4	* simple driver for PWM (Pulse Width Modulator) controller
	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	* 2008-02-13 initial version
	11	* eric miao <eric.miao@marvell.com>
	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/div64.h>
75540c1a	23
3d2a98cd	24	#define HAS_SECONDARY_PWM 0x10
a757ad8b	25	#define PWM_ID_BASE(d) ((d) & 0xf)
3d2a98cd EM	26
	27	static const struct platform_device_id pwm_id_table[] = {
	28	/* PWM has_secondary_pwm? */
	29	{ "pxa25x-pwm", 0 },
a757ad8b	30	{ "pxa27x-pwm", 0 \| HAS_SECONDARY_PWM },
a27ba768 EM	31	{ "pxa168-pwm", 1 },
a27ba768 EM	32	{ "pxa910-pwm", 1 },
3d2a98cd EM	33	{ },
	34	};
	35	MODULE_DEVICE_TABLE(platform, pwm_id_table);
	36
75540c1a	37	/* PWM registers and bits definitions */
	38	#define PWMCR (0x00)
	39	#define PWMDCR (0x04)
	40	#define PWMPCR (0x08)
	41
	42	#define PWMCR_SD (1 << 6)
	43	#define PWMDCR_FD (1 << 10)
	44
	45	struct pwm_device {
	46	struct list_head node;
3d2a98cd EM	47	struct pwm_device *secondary;
3d2a98cd EM	48	struct platform_device *pdev;
75540c1a	49
	50	const char *label;
	51	struct clk *clk;
c860d701	52	int clk_enabled;
75540c1a	53	void __iomem *mmio_base;
	54
	55	unsigned int use_count;
	56	unsigned int pwm_id;
	57	};
	58
	59	/*
	60	* period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
	61	* duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
	62	*/
	63	int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
	64	{
	65	unsigned long long c;
	66	unsigned long period_cycles, prescale, pv, dc;
	67
	68	if (pwm == NULL \|\| period_ns == 0 \|\| duty_ns > period_ns)
	69	return -EINVAL;
	70
	71	c = clk_get_rate(pwm->clk);
	72	c = c * period_ns;
	73	do_div(c, 1000000000);
	74	period_cycles = c;
	75
71a35d75	76	if (period_cycles < 1)
75540c1a	77	period_cycles = 1;
	78	prescale = (period_cycles - 1) / 1024;
	79	pv = period_cycles / (prescale + 1) - 1;
	80
	81	if (prescale > 63)
	82	return -EINVAL;
	83
	84	if (duty_ns == period_ns)
	85	dc = PWMDCR_FD;
	86	else
	87	dc = (pv + 1) * duty_ns / period_ns;
	88
	89	/* NOTE: the clock to PWM has to be enabled first
	90	* before writing to the registers
	91	*/
	92	clk_enable(pwm->clk);
	93	__raw_writel(prescale, pwm->mmio_base + PWMCR);
	94	__raw_writel(dc, pwm->mmio_base + PWMDCR);
	95	__raw_writel(pv, pwm->mmio_base + PWMPCR);
	96	clk_disable(pwm->clk);
	97
	98	return 0;
	99	}
	100	EXPORT_SYMBOL(pwm_config);
	101
	102	int pwm_enable(struct pwm_device *pwm)
	103	{
c860d701 RJ	104	int rc = 0;
	105
	106	if (!pwm->clk_enabled) {
	107	rc = clk_enable(pwm->clk);
	108	if (!rc)
	109	pwm->clk_enabled = 1;
	110	}
	111	return rc;
75540c1a	112	}
	113	EXPORT_SYMBOL(pwm_enable);
	114
	115	void pwm_disable(struct pwm_device *pwm)
	116	{
c860d701 RJ	117	if (pwm->clk_enabled) {
	118	clk_disable(pwm->clk);
	119	pwm->clk_enabled = 0;
	120	}
75540c1a	121	}
	122	EXPORT_SYMBOL(pwm_disable);
	123
	124	static DEFINE_MUTEX(pwm_lock);
	125	static LIST_HEAD(pwm_list);
	126
	127	struct pwm_device pwm_request(int pwm_id, const char label)
	128	{
	129	struct pwm_device *pwm;
	130	int found = 0;
	131
	132	mutex_lock(&pwm_lock);
	133
	134	list_for_each_entry(pwm, &pwm_list, node) {
43bda1a6	135	if (pwm->pwm_id == pwm_id) {
75540c1a	136	found = 1;
	137	break;
	138	}
	139	}
	140
43bda1a6 BD	141	if (found) {
	142	if (pwm->use_count == 0) {
	143	pwm->use_count++;
	144	pwm->label = label;
	145	} else
	146	pwm = ERR_PTR(-EBUSY);
	147	} else
	148	pwm = ERR_PTR(-ENOENT);
75540c1a	149
43bda1a6 BD	150	mutex_unlock(&pwm_lock);
43bda1a6 BD	151	return pwm;
75540c1a	152	}
	153	EXPORT_SYMBOL(pwm_request);
	154
	155	void pwm_free(struct pwm_device *pwm)
	156	{
	157	mutex_lock(&pwm_lock);
	158
	159	if (pwm->use_count) {
	160	pwm->use_count--;
	161	pwm->label = NULL;
	162	} else
	163	pr_warning("PWM device already freed\n");
	164
	165	mutex_unlock(&pwm_lock);
	166	}
	167	EXPORT_SYMBOL(pwm_free);
	168
	169	static inline void __add_pwm(struct pwm_device *pwm)
	170	{
	171	mutex_lock(&pwm_lock);
	172	list_add_tail(&pwm->node, &pwm_list);
	173	mutex_unlock(&pwm_lock);
	174	}
	175
3d2a98cd	176	static int __devinit pwm_probe(struct platform_device *pdev)
75540c1a	177	{
3d2a98cd EM	178	struct platform_device_id *id = platform_get_device_id(pdev);
3d2a98cd EM	179	struct pwm_device pwm, secondary = NULL;
75540c1a	180	struct resource *r;
	181	int ret = 0;
	182
	183	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
	184	if (pwm == NULL) {
	185	dev_err(&pdev->dev, "failed to allocate memory\n");
3d2a98cd	186	return -ENOMEM;
75540c1a	187	}
75540c1a	188
e0d8b13a	189	pwm->clk = clk_get(&pdev->dev, NULL);
75540c1a	190	if (IS_ERR(pwm->clk)) {
	191	ret = PTR_ERR(pwm->clk);
	192	goto err_free;
	193	}
c860d701	194	pwm->clk_enabled = 0;
75540c1a	195
75540c1a	196	pwm->use_count = 0;
a757ad8b	197	pwm->pwm_id = PWM_ID_BASE(id->driver_data) + pdev->id;
75540c1a	198	pwm->pdev = pdev;
75540c1a	199
75540c1a	200	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	201	if (r == NULL) {
	202	dev_err(&pdev->dev, "no memory resource defined\n");
	203	ret = -ENODEV;
	204	goto err_free_clk;
	205	}
	206
1692231c	207	r = request_mem_region(r->start, resource_size(r), pdev->name);
75540c1a	208	if (r == NULL) {
	209	dev_err(&pdev->dev, "failed to request memory resource\n");
	210	ret = -EBUSY;
	211	goto err_free_clk;
	212	}
	213
1692231c	214	pwm->mmio_base = ioremap(r->start, resource_size(r));
75540c1a	215	if (pwm->mmio_base == NULL) {
	216	dev_err(&pdev->dev, "failed to ioremap() registers\n");
	217	ret = -ENODEV;
	218	goto err_free_mem;
	219	}
	220
3d2a98cd EM	221	if (id->driver_data & HAS_SECONDARY_PWM) {
	222	secondary = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
	223	if (secondary == NULL) {
	224	ret = -ENOMEM;
	225	goto err_free_mem;
	226	}
	227
	228	secondary = pwm;
	229	pwm->secondary = secondary;
	230
	231	/* registers for the second PWM has offset of 0x10 */
	232	secondary->mmio_base = pwm->mmio_base + 0x10;
	233	secondary->pwm_id = pdev->id + 2;
	234	}
	235
75540c1a	236	__add_pwm(pwm);
3d2a98cd EM	237	if (secondary)
	238	__add_pwm(secondary);
	239
75540c1a	240	platform_set_drvdata(pdev, pwm);
3d2a98cd	241	return 0;
75540c1a	242
75540c1a	243	err_free_mem:
1692231c	244	release_mem_region(r->start, resource_size(r));
75540c1a	245	err_free_clk:
	246	clk_put(pwm->clk);
	247	err_free:
	248	kfree(pwm);
3d2a98cd	249	return ret;
75540c1a	250	}
	251
	252	static int __devexit pwm_remove(struct platform_device *pdev)
	253	{
	254	struct pwm_device *pwm;
	255	struct resource *r;
	256
	257	pwm = platform_get_drvdata(pdev);
	258	if (pwm == NULL)
	259	return -ENODEV;
	260
	261	mutex_lock(&pwm_lock);
3d2a98cd EM	262
	263	if (pwm->secondary) {
	264	list_del(&pwm->secondary->node);
	265	kfree(pwm->secondary);
	266	}
	267
75540c1a	268	list_del(&pwm->node);
	269	mutex_unlock(&pwm_lock);
	270
	271	iounmap(pwm->mmio_base);
	272
	273	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1692231c	274	release_mem_region(r->start, resource_size(r));
75540c1a	275
	276	clk_put(pwm->clk);
	277	kfree(pwm);
	278	return 0;
	279	}
	280
3d2a98cd	281	static struct platform_driver pwm_driver = {
75540c1a	282	.driver = {
75540c1a	283	.name = "pxa25x-pwm",
3d2a98cd	284	.owner = THIS_MODULE,
75540c1a	285	},
3d2a98cd	286	.probe = pwm_probe,
75540c1a	287	.remove = __devexit_p(pwm_remove),
3d2a98cd	288	.id_table = pwm_id_table,
75540c1a	289	};
	290
	291	static int __init pwm_init(void)
	292	{
3d2a98cd	293	return platform_driver_register(&pwm_driver);
75540c1a	294	}
	295	arch_initcall(pwm_init);
	296
	297	static void __exit pwm_exit(void)
	298	{
3d2a98cd	299	platform_driver_unregister(&pwm_driver);
75540c1a	300	}
75540c1a	301	module_exit(pwm_exit);
b5f0228a GL	302
b5f0228a GL	303	MODULE_LICENSE("GPL v2");