[net-next-2.6.git] / arch / arm / mach-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>
#include <mach/pxa-regs.h>

/* 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 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 struct pwm_device *pwm_probe(struct platform_device *pdev,
		unsigned int pwm_id, struct pwm_device *parent_pwm)
{
	struct pwm_device *pwm;
	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 ERR_PTR(-ENOMEM);
	}

	pwm->clk = clk_get(&pdev->dev, "PWMCLK");
	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;
	pwm->pdev = pdev;

	if (parent_pwm != NULL) {
		/* registers for the second PWM has offset of 0x10 */
		pwm->mmio_base = parent_pwm->mmio_base + 0x10;
		__add_pwm(pwm);
		return pwm;
	}

	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, r->end - r->start + 1, 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, r->end - r->start + 1);
	if (pwm->mmio_base == NULL) {
		dev_err(&pdev->dev, "failed to ioremap() registers\n");
		ret = -ENODEV;
		goto err_free_mem;
	}

	__add_pwm(pwm);
	platform_set_drvdata(pdev, pwm);
	return pwm;

err_free_mem:
	release_mem_region(r->start, r->end - r->start + 1);
err_free_clk:
	clk_put(pwm->clk);
err_free:
	kfree(pwm);
	return ERR_PTR(ret);
}

static int __devinit pxa25x_pwm_probe(struct platform_device *pdev)
{
	struct pwm_device *pwm = pwm_probe(pdev, pdev->id, NULL);

	if (IS_ERR(pwm))
		return PTR_ERR(pwm);

	return 0;
}

static int __devinit pxa27x_pwm_probe(struct platform_device *pdev)
{
	struct pwm_device *pwm;

	pwm = pwm_probe(pdev, pdev->id, NULL);
	if (IS_ERR(pwm))
		return PTR_ERR(pwm);

	pwm = pwm_probe(pdev, pdev->id + 2, pwm);
	if (IS_ERR(pwm))
		return PTR_ERR(pwm);

	return 0;
}

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);
	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, r->end - r->start + 1);

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

static struct platform_driver pxa25x_pwm_driver = {
	.driver		= {
		.name	= "pxa25x-pwm",
	},
	.probe		= pxa25x_pwm_probe,
	.remove		= __devexit_p(pwm_remove),
};

static struct platform_driver pxa27x_pwm_driver = {
	.driver		= {
		.name	= "pxa27x-pwm",
	},
	.probe		= pxa27x_pwm_probe,
	.remove		= __devexit_p(pwm_remove),
};

static int __init pwm_init(void)
{
	int ret = 0;

	ret = platform_driver_register(&pxa25x_pwm_driver);
	if (ret) {
		printk(KERN_ERR "failed to register pxa25x_pwm_driver\n");
		return ret;
	}

	ret = platform_driver_register(&pxa27x_pwm_driver);
	if (ret) {
		printk(KERN_ERR "failed to register pxa27x_pwm_driver\n");
		return ret;
	}

	return ret;
}
arch_initcall(pwm_init);

static void __exit pwm_exit(void)
{
	platform_driver_unregister(&pxa25x_pwm_driver);
	platform_driver_unregister(&pxa27x_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>
a09e64fb	23	#include <mach/pxa-regs.h>
75540c1a	24
	25	/* PWM registers and bits definitions */
	26	#define PWMCR (0x00)
	27	#define PWMDCR (0x04)
	28	#define PWMPCR (0x08)
	29
	30	#define PWMCR_SD (1 << 6)
	31	#define PWMDCR_FD (1 << 10)
	32
	33	struct pwm_device {
	34	struct list_head node;
	35	struct platform_device *pdev;
	36
	37	const char *label;
	38	struct clk *clk;
c860d701	39	int clk_enabled;
75540c1a	40	void __iomem *mmio_base;
	41
	42	unsigned int use_count;
	43	unsigned int pwm_id;
	44	};
	45
	46	/*
	47	* period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
	48	* duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
	49	*/
	50	int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
	51	{
	52	unsigned long long c;
	53	unsigned long period_cycles, prescale, pv, dc;
	54
	55	if (pwm == NULL \|\| period_ns == 0 \|\| duty_ns > period_ns)
	56	return -EINVAL;
	57
	58	c = clk_get_rate(pwm->clk);
	59	c = c * period_ns;
	60	do_div(c, 1000000000);
	61	period_cycles = c;
	62
71a35d75	63	if (period_cycles < 1)
75540c1a	64	period_cycles = 1;
	65	prescale = (period_cycles - 1) / 1024;
	66	pv = period_cycles / (prescale + 1) - 1;
	67
	68	if (prescale > 63)
	69	return -EINVAL;
	70
	71	if (duty_ns == period_ns)
	72	dc = PWMDCR_FD;
	73	else
	74	dc = (pv + 1) * duty_ns / period_ns;
	75
	76	/* NOTE: the clock to PWM has to be enabled first
	77	* before writing to the registers
	78	*/
	79	clk_enable(pwm->clk);
	80	__raw_writel(prescale, pwm->mmio_base + PWMCR);
	81	__raw_writel(dc, pwm->mmio_base + PWMDCR);
	82	__raw_writel(pv, pwm->mmio_base + PWMPCR);
	83	clk_disable(pwm->clk);
	84
	85	return 0;
	86	}
	87	EXPORT_SYMBOL(pwm_config);
	88
	89	int pwm_enable(struct pwm_device *pwm)
	90	{
c860d701 RJ	91	int rc = 0;
	92
	93	if (!pwm->clk_enabled) {
	94	rc = clk_enable(pwm->clk);
	95	if (!rc)
	96	pwm->clk_enabled = 1;
	97	}
	98	return rc;
75540c1a	99	}
	100	EXPORT_SYMBOL(pwm_enable);
	101
	102	void pwm_disable(struct pwm_device *pwm)
	103	{
c860d701 RJ	104	if (pwm->clk_enabled) {
	105	clk_disable(pwm->clk);
	106	pwm->clk_enabled = 0;
	107	}
75540c1a	108	}
	109	EXPORT_SYMBOL(pwm_disable);
	110
	111	static DEFINE_MUTEX(pwm_lock);
	112	static LIST_HEAD(pwm_list);
	113
	114	struct pwm_device pwm_request(int pwm_id, const char label)
	115	{
	116	struct pwm_device *pwm;
	117	int found = 0;
	118
	119	mutex_lock(&pwm_lock);
	120
	121	list_for_each_entry(pwm, &pwm_list, node) {
43bda1a6	122	if (pwm->pwm_id == pwm_id) {
75540c1a	123	found = 1;
	124	break;
	125	}
	126	}
	127
43bda1a6 BD	128	if (found) {
	129	if (pwm->use_count == 0) {
	130	pwm->use_count++;
	131	pwm->label = label;
	132	} else
	133	pwm = ERR_PTR(-EBUSY);
	134	} else
	135	pwm = ERR_PTR(-ENOENT);
75540c1a	136
43bda1a6 BD	137	mutex_unlock(&pwm_lock);
43bda1a6 BD	138	return pwm;
75540c1a	139	}
	140	EXPORT_SYMBOL(pwm_request);
	141
	142	void pwm_free(struct pwm_device *pwm)
	143	{
	144	mutex_lock(&pwm_lock);
	145
	146	if (pwm->use_count) {
	147	pwm->use_count--;
	148	pwm->label = NULL;
	149	} else
	150	pr_warning("PWM device already freed\n");
	151
	152	mutex_unlock(&pwm_lock);
	153	}
	154	EXPORT_SYMBOL(pwm_free);
	155
	156	static inline void __add_pwm(struct pwm_device *pwm)
	157	{
	158	mutex_lock(&pwm_lock);
	159	list_add_tail(&pwm->node, &pwm_list);
	160	mutex_unlock(&pwm_lock);
	161	}
	162
	163	static struct pwm_device pwm_probe(struct platform_device pdev,
	164	unsigned int pwm_id, struct pwm_device *parent_pwm)
	165	{
	166	struct pwm_device *pwm;
	167	struct resource *r;
	168	int ret = 0;
	169
	170	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
	171	if (pwm == NULL) {
	172	dev_err(&pdev->dev, "failed to allocate memory\n");
	173	return ERR_PTR(-ENOMEM);
	174	}
	175
	176	pwm->clk = clk_get(&pdev->dev, "PWMCLK");
	177	if (IS_ERR(pwm->clk)) {
	178	ret = PTR_ERR(pwm->clk);
	179	goto err_free;
	180	}
c860d701	181	pwm->clk_enabled = 0;
75540c1a	182
	183	pwm->use_count = 0;
	184	pwm->pwm_id = pwm_id;
	185	pwm->pdev = pdev;
	186
	187	if (parent_pwm != NULL) {
	188	/* registers for the second PWM has offset of 0x10 */
	189	pwm->mmio_base = parent_pwm->mmio_base + 0x10;
	190	__add_pwm(pwm);
	191	return pwm;
	192	}
	193
	194	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	195	if (r == NULL) {
	196	dev_err(&pdev->dev, "no memory resource defined\n");
	197	ret = -ENODEV;
	198	goto err_free_clk;
	199	}
	200
	201	r = request_mem_region(r->start, r->end - r->start + 1, pdev->name);
	202	if (r == NULL) {
	203	dev_err(&pdev->dev, "failed to request memory resource\n");
	204	ret = -EBUSY;
	205	goto err_free_clk;
	206	}
	207
	208	pwm->mmio_base = ioremap(r->start, r->end - r->start + 1);
	209	if (pwm->mmio_base == NULL) {
	210	dev_err(&pdev->dev, "failed to ioremap() registers\n");
	211	ret = -ENODEV;
	212	goto err_free_mem;
	213	}
	214
	215	__add_pwm(pwm);
	216	platform_set_drvdata(pdev, pwm);
	217	return pwm;
	218
	219	err_free_mem:
	220	release_mem_region(r->start, r->end - r->start + 1);
	221	err_free_clk:
	222	clk_put(pwm->clk);
	223	err_free:
	224	kfree(pwm);
	225	return ERR_PTR(ret);
	226	}
	227
	228	static int __devinit pxa25x_pwm_probe(struct platform_device *pdev)
	229	{
	230	struct pwm_device *pwm = pwm_probe(pdev, pdev->id, NULL);
	231
	232	if (IS_ERR(pwm))
	233	return PTR_ERR(pwm);
	234
	235	return 0;
	236	}
	237
	238	static int __devinit pxa27x_pwm_probe(struct platform_device *pdev)
	239	{
	240	struct pwm_device *pwm;
	241
0b1c25d2	242	pwm = pwm_probe(pdev, pdev->id, NULL);
75540c1a	243	if (IS_ERR(pwm))
	244	return PTR_ERR(pwm);
	245
0b1c25d2	246	pwm = pwm_probe(pdev, pdev->id + 2, pwm);
75540c1a	247	if (IS_ERR(pwm))
	248	return PTR_ERR(pwm);
	249
	250	return 0;
	251	}
	252
	253	static int __devexit pwm_remove(struct platform_device *pdev)
	254	{
	255	struct pwm_device *pwm;
	256	struct resource *r;
	257
	258	pwm = platform_get_drvdata(pdev);
	259	if (pwm == NULL)
	260	return -ENODEV;
	261
	262	mutex_lock(&pwm_lock);
	263	list_del(&pwm->node);
	264	mutex_unlock(&pwm_lock);
	265
	266	iounmap(pwm->mmio_base);
	267
	268	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	269	release_mem_region(r->start, r->end - r->start + 1);
	270
	271	clk_put(pwm->clk);
	272	kfree(pwm);
	273	return 0;
	274	}
	275
	276	static struct platform_driver pxa25x_pwm_driver = {
	277	.driver = {
	278	.name = "pxa25x-pwm",
	279	},
	280	.probe = pxa25x_pwm_probe,
	281	.remove = __devexit_p(pwm_remove),
	282	};
	283
	284	static struct platform_driver pxa27x_pwm_driver = {
	285	.driver = {
	286	.name = "pxa27x-pwm",
	287	},
	288	.probe = pxa27x_pwm_probe,
	289	.remove = __devexit_p(pwm_remove),
	290	};
	291
	292	static int __init pwm_init(void)
	293	{
	294	int ret = 0;
	295
	296	ret = platform_driver_register(&pxa25x_pwm_driver);
	297	if (ret) {
	298	printk(KERN_ERR "failed to register pxa25x_pwm_driver\n");
	299	return ret;
	300	}
	301
	302	ret = platform_driver_register(&pxa27x_pwm_driver);
	303	if (ret) {
	304	printk(KERN_ERR "failed to register pxa27x_pwm_driver\n");
	305	return ret;
	306	}
	307
	308	return ret;
	309	}
	310	arch_initcall(pwm_init);
311
312	static void __exit pwm_exit(void)
313	{
314	platform_driver_unregister(&pxa25x_pwm_driver);
315	platform_driver_unregister(&pxa27x_pwm_driver);
316	}
317	module_exit(pwm_exit);
b5f0228a GL	318
b5f0228a GL	319	MODULE_LICENSE("GPL v2");