[linux-2.6-block.git] / arch / arm / plat-mxc / 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.
 *
 * Derived from pxa PWM driver by eric miao <eric.miao@marvell.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pwm.h>
#include <mach/hardware.h>


/* i.MX1 and i.MX21 share the same PWM function block: */

#define MX1_PWMC    0x00   /* PWM Control Register */
#define MX1_PWMS    0x04   /* PWM Sample Register */
#define MX1_PWMP    0x08   /* PWM Period Register */


/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */

#define MX3_PWMCR                 0x00    /* PWM Control Register */
#define MX3_PWMSAR                0x0C    /* PWM Sample Register */
#define MX3_PWMPR                 0x10    /* PWM Period Register */
#define MX3_PWMCR_PRESCALER(x)    (((x - 1) & 0xFFF) << 4)
#define MX3_PWMCR_DOZEEN                (1 << 24)
#define MX3_PWMCR_WAITEN                (1 << 23)
#define MX3_PWMCR_DBGEN			(1 << 22)
#define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16)
#define MX3_PWMCR_CLKSRC_IPG      (1 << 16)
#define MX3_PWMCR_EN              (1 << 0)


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;
};

int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
	if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
		return -EINVAL;

	if (!(cpu_is_mx1() || cpu_is_mx21())) {
		unsigned long long c;
		unsigned long period_cycles, duty_cycles, prescale;
		u32 cr;

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

		prescale = period_cycles / 0x10000 + 1;

		period_cycles /= prescale;
		c = (unsigned long long)period_cycles * duty_ns;
		do_div(c, period_ns);
		duty_cycles = c;

		/*
		 * according to imx pwm RM, the real period value should be
		 * PERIOD value in PWMPR plus 2.
		 */
		if (period_cycles > 2)
			period_cycles -= 2;
		else
			period_cycles = 0;

		writel(duty_cycles, pwm->mmio_base + MX3_PWMSAR);
		writel(period_cycles, pwm->mmio_base + MX3_PWMPR);

		cr = MX3_PWMCR_PRESCALER(prescale) |
			MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
			MX3_PWMCR_DBGEN | MX3_PWMCR_EN;

		if (cpu_is_mx25())
			cr |= MX3_PWMCR_CLKSRC_IPG;
		else
			cr |= MX3_PWMCR_CLKSRC_IPG_HIGH;

		writel(cr, pwm->mmio_base + MX3_PWMCR);
	} else if (cpu_is_mx1() || cpu_is_mx21()) {
		/* The PWM subsystem allows for exact frequencies. However,
		 * I cannot connect a scope on my device to the PWM line and
		 * thus cannot provide the program the PWM controller
		 * exactly. Instead, I'm relying on the fact that the
		 * Bootloader (u-boot or WinCE+haret) has programmed the PWM
		 * function group already. So I'll just modify the PWM sample
		 * register to follow the ratio of duty_ns vs. period_ns
		 * accordingly.
		 *
		 * This is good enough for programming the brightness of
		 * the LCD backlight.
		 *
		 * The real implementation would divide PERCLK[0] first by
		 * both the prescaler (/1 .. /128) and then by CLKSEL
		 * (/2 .. /16).
		 */
		u32 max = readl(pwm->mmio_base + MX1_PWMP);
		u32 p = max * duty_ns / period_ns;
		writel(max - p, pwm->mmio_base + MX1_PWMS);
	} else {
		BUG();
	}

	return 0;
}
EXPORT_SYMBOL(pwm_config);

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

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

void pwm_disable(struct pwm_device *pwm)
{
	writel(0, pwm->mmio_base + MX3_PWMCR);

	if (pwm->clk_enabled) {
		clk_disable_unprepare(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 int __devinit mxc_pwm_probe(struct platform_device *pdev)
{
	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 -ENOMEM;
	}

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

	if (IS_ERR(pwm->clk)) {
		ret = PTR_ERR(pwm->clk);
		goto err_free;
	}

	pwm->clk_enabled = 0;

	pwm->use_count = 0;
	pwm->pwm_id = 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;
	}

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

	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 mxc_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, resource_size(r));

	clk_put(pwm->clk);

	kfree(pwm);
	return 0;
}

static struct platform_driver mxc_pwm_driver = {
	.driver		= {
		.name	= "mxc_pwm",
	},
	.probe		= mxc_pwm_probe,
	.remove		= __devexit_p(mxc_pwm_remove),
};

static int __init mxc_pwm_init(void)
{
	return platform_driver_register(&mxc_pwm_driver);
}
arch_initcall(mxc_pwm_init);

static void __exit mxc_pwm_exit(void)
{
	platform_driver_unregister(&mxc_pwm_driver);
}
module_exit(mxc_pwm_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
Commit	Line	Data
166091b1 SH	1	/*
	2	* simple driver for PWM (Pulse Width Modulator) controller
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* Derived from pxa PWM driver by eric miao <eric.miao@marvell.com>
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/kernel.h>
	13	#include <linux/platform_device.h>
5a0e3ad6	14	#include <linux/slab.h>
166091b1 SH	15	#include <linux/err.h>
	16	#include <linux/clk.h>
	17	#include <linux/io.h>
	18	#include <linux/pwm.h>
c010dba8 HS	19	#include <mach/hardware.h>
	20
	21
	22	/* i.MX1 and i.MX21 share the same PWM function block: */
	23
	24	#define MX1_PWMC 0x00 /* PWM Control Register */
	25	#define MX1_PWMS 0x04 /* PWM Sample Register */
	26	#define MX1_PWMP 0x08 /* PWM Period Register */
	27
	28
	29	/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */
	30
	31	#define MX3_PWMCR 0x00 /* PWM Control Register */
	32	#define MX3_PWMSAR 0x0C /* PWM Sample Register */
	33	#define MX3_PWMPR 0x10 /* PWM Period Register */
	34	#define MX3_PWMCR_PRESCALER(x) (((x - 1) & 0xFFF) << 4)
c0d96aed JC	35	#define MX3_PWMCR_DOZEEN (1 << 24)
	36	#define MX3_PWMCR_WAITEN (1 << 23)
	37	#define MX3_PWMCR_DBGEN (1 << 22)
c010dba8	38	#define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16)
a058cbc1	39	#define MX3_PWMCR_CLKSRC_IPG (1 << 16)
c010dba8 HS	40	#define MX3_PWMCR_EN (1 << 0)
c010dba8 HS	41
166091b1	42
166091b1 SH	43
	44	struct pwm_device {
	45	struct list_head node;
	46	struct platform_device *pdev;
	47
	48	const char *label;
	49	struct clk *clk;
	50
	51	int clk_enabled;
	52	void __iomem *mmio_base;
	53
	54	unsigned int use_count;
	55	unsigned int pwm_id;
	56	};
	57
	58	int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
	59	{
166091b1 SH	60	if (pwm == NULL \|\| period_ns == 0 \|\| duty_ns > period_ns)
	61	return -EINVAL;
	62
97f45313	63	if (!(cpu_is_mx1() \|\| cpu_is_mx21())) {
c010dba8 HS	64	unsigned long long c;
c010dba8 HS	65	unsigned long period_cycles, duty_cycles, prescale;
a058cbc1 SH	66	u32 cr;
a058cbc1 SH	67
c010dba8 HS	68	c = clk_get_rate(pwm->clk);
	69	c = c * period_ns;
	70	do_div(c, 1000000000);
	71	period_cycles = c;
	72
	73	prescale = period_cycles / 0x10000 + 1;
	74
	75	period_cycles /= prescale;
	76	c = (unsigned long long)period_cycles * duty_ns;
	77	do_div(c, period_ns);
	78	duty_cycles = c;
	79
5776ac2e JC	80	/*
	81	* according to imx pwm RM, the real period value should be
	82	* PERIOD value in PWMPR plus 2.
	83	*/
	84	if (period_cycles > 2)
	85	period_cycles -= 2;
	86	else
	87	period_cycles = 0;
	88
c010dba8 HS	89	writel(duty_cycles, pwm->mmio_base + MX3_PWMSAR);
c010dba8 HS	90	writel(period_cycles, pwm->mmio_base + MX3_PWMPR);
a058cbc1	91
c0d96aed JC	92	cr = MX3_PWMCR_PRESCALER(prescale) \|
	93	MX3_PWMCR_DOZEEN \| MX3_PWMCR_WAITEN \|
	94	MX3_PWMCR_DBGEN \| MX3_PWMCR_EN;
a058cbc1 SH	95
	96	if (cpu_is_mx25())
	97	cr \|= MX3_PWMCR_CLKSRC_IPG;
	98	else
	99	cr \|= MX3_PWMCR_CLKSRC_IPG_HIGH;
	100
	101	writel(cr, pwm->mmio_base + MX3_PWMCR);
c010dba8 HS	102	} else if (cpu_is_mx1() \|\| cpu_is_mx21()) {
	103	/* The PWM subsystem allows for exact frequencies. However,
	104	* I cannot connect a scope on my device to the PWM line and
	105	* thus cannot provide the program the PWM controller
	106	* exactly. Instead, I'm relying on the fact that the
	107	* Bootloader (u-boot or WinCE+haret) has programmed the PWM
	108	* function group already. So I'll just modify the PWM sample
	109	* register to follow the ratio of duty_ns vs. period_ns
	110	* accordingly.
	111	*
af901ca1	112	* This is good enough for programming the brightness of
c010dba8 HS	113	* the LCD backlight.
	114	*
	115	* The real implementation would divide PERCLK[0] first by
	116	* both the prescaler (/1 .. /128) and then by CLKSEL
	117	* (/2 .. /16).
	118	*/
	119	u32 max = readl(pwm->mmio_base + MX1_PWMP);
	120	u32 p = max * duty_ns / period_ns;
	121	writel(max - p, pwm->mmio_base + MX1_PWMS);
	122	} else {
	123	BUG();
	124	}
166091b1 SH	125
	126	return 0;
	127	}
	128	EXPORT_SYMBOL(pwm_config);
	129
	130	int pwm_enable(struct pwm_device *pwm)
	131	{
	132	int rc = 0;
	133
	134	if (!pwm->clk_enabled) {
c23c081a	135	rc = clk_prepare_enable(pwm->clk);
166091b1 SH	136	if (!rc)
	137	pwm->clk_enabled = 1;
	138	}
	139	return rc;
	140	}
	141	EXPORT_SYMBOL(pwm_enable);
	142
	143	void pwm_disable(struct pwm_device *pwm)
	144	{
5ef881bb SH	145	writel(0, pwm->mmio_base + MX3_PWMCR);
5ef881bb SH	146
166091b1	147	if (pwm->clk_enabled) {
c23c081a	148	clk_disable_unprepare(pwm->clk);
166091b1 SH	149	pwm->clk_enabled = 0;
	150	}
	151	}
	152	EXPORT_SYMBOL(pwm_disable);
	153
	154	static DEFINE_MUTEX(pwm_lock);
	155	static LIST_HEAD(pwm_list);
	156
	157	struct pwm_device pwm_request(int pwm_id, const char label)
	158	{
	159	struct pwm_device *pwm;
	160	int found = 0;
	161
	162	mutex_lock(&pwm_lock);
	163
	164	list_for_each_entry(pwm, &pwm_list, node) {
	165	if (pwm->pwm_id == pwm_id) {
	166	found = 1;
	167	break;
	168	}
	169	}
	170
	171	if (found) {
	172	if (pwm->use_count == 0) {
	173	pwm->use_count++;
	174	pwm->label = label;
	175	} else
	176	pwm = ERR_PTR(-EBUSY);
	177	} else
	178	pwm = ERR_PTR(-ENOENT);
	179
	180	mutex_unlock(&pwm_lock);
	181	return pwm;
	182	}
	183	EXPORT_SYMBOL(pwm_request);
	184
	185	void pwm_free(struct pwm_device *pwm)
	186	{
	187	mutex_lock(&pwm_lock);
	188
	189	if (pwm->use_count) {
	190	pwm->use_count--;
	191	pwm->label = NULL;
	192	} else
	193	pr_warning("PWM device already freed\n");
	194
	195	mutex_unlock(&pwm_lock);
	196	}
	197	EXPORT_SYMBOL(pwm_free);
	198
	199	static int __devinit mxc_pwm_probe(struct platform_device *pdev)
	200	{
	201	struct pwm_device *pwm;
	202	struct resource *r;
	203	int ret = 0;
	204
	205	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
	206	if (pwm == NULL) {
	207	dev_err(&pdev->dev, "failed to allocate memory\n");
	208	return -ENOMEM;
	209	}
	210
	211	pwm->clk = clk_get(&pdev->dev, "pwm");
	212
213	if (IS_ERR(pwm->clk)) {
214	ret = PTR_ERR(pwm->clk);
215	goto err_free;
216	}
217
218	pwm->clk_enabled = 0;
219
220	pwm->use_count = 0;
221	pwm->pwm_id = pdev->id;
222	pwm->pdev = pdev;
223
224	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
225	if (r == NULL) {
226	dev_err(&pdev->dev, "no memory resource defined\n");
227	ret = -ENODEV;
228	goto err_free_clk;
229	}
230
ae817266	231	r = request_mem_region(r->start, resource_size(r), pdev->name);
166091b1 SH	232	if (r == NULL) {
	233	dev_err(&pdev->dev, "failed to request memory resource\n");
	234	ret = -EBUSY;
	235	goto err_free_clk;
	236	}
	237
ae817266	238	pwm->mmio_base = ioremap(r->start, resource_size(r));
166091b1 SH	239	if (pwm->mmio_base == NULL) {
	240	dev_err(&pdev->dev, "failed to ioremap() registers\n");
	241	ret = -ENODEV;
	242	goto err_free_mem;
	243	}
	244
	245	mutex_lock(&pwm_lock);
	246	list_add_tail(&pwm->node, &pwm_list);
	247	mutex_unlock(&pwm_lock);
	248
	249	platform_set_drvdata(pdev, pwm);
	250	return 0;
	251
	252	err_free_mem:
ae817266	253	release_mem_region(r->start, resource_size(r));
166091b1 SH	254	err_free_clk:
	255	clk_put(pwm->clk);
	256	err_free:
	257	kfree(pwm);
	258	return ret;
	259	}
	260
	261	static int __devexit mxc_pwm_remove(struct platform_device *pdev)
	262	{
	263	struct pwm_device *pwm;
	264	struct resource *r;
	265
	266	pwm = platform_get_drvdata(pdev);
	267	if (pwm == NULL)
	268	return -ENODEV;
	269
	270	mutex_lock(&pwm_lock);
	271	list_del(&pwm->node);
	272	mutex_unlock(&pwm_lock);
	273
	274	iounmap(pwm->mmio_base);
	275
	276	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ae817266	277	release_mem_region(r->start, resource_size(r));
166091b1 SH	278
	279	clk_put(pwm->clk);
	280
	281	kfree(pwm);
	282	return 0;
	283	}
	284
	285	static struct platform_driver mxc_pwm_driver = {
	286	.driver = {
	287	.name = "mxc_pwm",
	288	},
	289	.probe = mxc_pwm_probe,
	290	.remove = __devexit_p(mxc_pwm_remove),
	291	};
	292
	293	static int __init mxc_pwm_init(void)
	294	{
	295	return platform_driver_register(&mxc_pwm_driver);
	296	}
	297	arch_initcall(mxc_pwm_init);
	298
	299	static void __exit mxc_pwm_exit(void)
	300	{
	301	platform_driver_unregister(&mxc_pwm_driver);
	302	}
	303	module_exit(mxc_pwm_exit);
	304
	305	MODULE_LICENSE("GPL v2");
	306	MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");