[deliverable/linux.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/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_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_mx27() || cpu_is_mx3() || cpu_is_mx25()) {
		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;

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

		cr = MX3_PWMCR_PRESCALER(prescale) | 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_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(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, 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;
	}

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

	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>
	14	#include <linux/err.h>
	15	#include <linux/clk.h>
	16	#include <linux/io.h>
	17	#include <linux/pwm.h>
c010dba8 HS	18	#include <mach/hardware.h>
	19
	20
	21	/* i.MX1 and i.MX21 share the same PWM function block: */
	22
	23	#define MX1_PWMC 0x00 /* PWM Control Register */
	24	#define MX1_PWMS 0x04 /* PWM Sample Register */
	25	#define MX1_PWMP 0x08 /* PWM Period Register */
	26
	27
	28	/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */
	29
	30	#define MX3_PWMCR 0x00 /* PWM Control Register */
	31	#define MX3_PWMSAR 0x0C /* PWM Sample Register */
	32	#define MX3_PWMPR 0x10 /* PWM Period Register */
	33	#define MX3_PWMCR_PRESCALER(x) (((x - 1) & 0xFFF) << 4)
	34	#define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16)
a058cbc1	35	#define MX3_PWMCR_CLKSRC_IPG (1 << 16)
c010dba8 HS	36	#define MX3_PWMCR_EN (1 << 0)
c010dba8 HS	37
166091b1	38
166091b1 SH	39
	40	struct pwm_device {
	41	struct list_head node;
	42	struct platform_device *pdev;
	43
	44	const char *label;
	45	struct clk *clk;
	46
	47	int clk_enabled;
	48	void __iomem *mmio_base;
	49
	50	unsigned int use_count;
	51	unsigned int pwm_id;
	52	};
	53
	54	int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
	55	{
166091b1 SH	56	if (pwm == NULL \|\| period_ns == 0 \|\| duty_ns > period_ns)
	57	return -EINVAL;
	58
a058cbc1	59	if (cpu_is_mx27() \|\| cpu_is_mx3() \|\| cpu_is_mx25()) {
c010dba8 HS	60	unsigned long long c;
c010dba8 HS	61	unsigned long period_cycles, duty_cycles, prescale;
a058cbc1 SH	62	u32 cr;
a058cbc1 SH	63
c010dba8 HS	64	c = clk_get_rate(pwm->clk);
	65	c = c * period_ns;
	66	do_div(c, 1000000000);
	67	period_cycles = c;
	68
	69	prescale = period_cycles / 0x10000 + 1;
	70
	71	period_cycles /= prescale;
	72	c = (unsigned long long)period_cycles * duty_ns;
	73	do_div(c, period_ns);
	74	duty_cycles = c;
	75
	76	writel(duty_cycles, pwm->mmio_base + MX3_PWMSAR);
	77	writel(period_cycles, pwm->mmio_base + MX3_PWMPR);
a058cbc1 SH	78
	79	cr = MX3_PWMCR_PRESCALER(prescale) \| MX3_PWMCR_EN;
	80
	81	if (cpu_is_mx25())
	82	cr \|= MX3_PWMCR_CLKSRC_IPG;
	83	else
	84	cr \|= MX3_PWMCR_CLKSRC_IPG_HIGH;
	85
	86	writel(cr, pwm->mmio_base + MX3_PWMCR);
c010dba8 HS	87	} else if (cpu_is_mx1() \|\| cpu_is_mx21()) {
	88	/* The PWM subsystem allows for exact frequencies. However,
	89	* I cannot connect a scope on my device to the PWM line and
	90	* thus cannot provide the program the PWM controller
	91	* exactly. Instead, I'm relying on the fact that the
	92	* Bootloader (u-boot or WinCE+haret) has programmed the PWM
	93	* function group already. So I'll just modify the PWM sample
	94	* register to follow the ratio of duty_ns vs. period_ns
	95	* accordingly.
	96	*
af901ca1	97	* This is good enough for programming the brightness of
c010dba8 HS	98	* the LCD backlight.
	99	*
	100	* The real implementation would divide PERCLK[0] first by
	101	* both the prescaler (/1 .. /128) and then by CLKSEL
	102	* (/2 .. /16).
	103	*/
	104	u32 max = readl(pwm->mmio_base + MX1_PWMP);
	105	u32 p = max * duty_ns / period_ns;
	106	writel(max - p, pwm->mmio_base + MX1_PWMS);
	107	} else {
	108	BUG();
	109	}
166091b1 SH	110
	111	return 0;
	112	}
	113	EXPORT_SYMBOL(pwm_config);
	114
	115	int pwm_enable(struct pwm_device *pwm)
	116	{
	117	int rc = 0;
	118
	119	if (!pwm->clk_enabled) {
	120	rc = clk_enable(pwm->clk);
	121	if (!rc)
	122	pwm->clk_enabled = 1;
	123	}
	124	return rc;
	125	}
	126	EXPORT_SYMBOL(pwm_enable);
	127
	128	void pwm_disable(struct pwm_device *pwm)
	129	{
5ef881bb SH	130	writel(0, pwm->mmio_base + MX3_PWMCR);
5ef881bb SH	131
166091b1 SH	132	if (pwm->clk_enabled) {
	133	clk_disable(pwm->clk);
	134	pwm->clk_enabled = 0;
	135	}
	136	}
	137	EXPORT_SYMBOL(pwm_disable);
	138
	139	static DEFINE_MUTEX(pwm_lock);
	140	static LIST_HEAD(pwm_list);
	141
	142	struct pwm_device pwm_request(int pwm_id, const char label)
	143	{
	144	struct pwm_device *pwm;
	145	int found = 0;
	146
	147	mutex_lock(&pwm_lock);
	148
	149	list_for_each_entry(pwm, &pwm_list, node) {
	150	if (pwm->pwm_id == pwm_id) {
	151	found = 1;
	152	break;
	153	}
	154	}
	155
	156	if (found) {
	157	if (pwm->use_count == 0) {
	158	pwm->use_count++;
	159	pwm->label = label;
	160	} else
	161	pwm = ERR_PTR(-EBUSY);
	162	} else
	163	pwm = ERR_PTR(-ENOENT);
	164
	165	mutex_unlock(&pwm_lock);
	166	return pwm;
	167	}
	168	EXPORT_SYMBOL(pwm_request);
	169
	170	void pwm_free(struct pwm_device *pwm)
	171	{
	172	mutex_lock(&pwm_lock);
	173
	174	if (pwm->use_count) {
	175	pwm->use_count--;
	176	pwm->label = NULL;
	177	} else
	178	pr_warning("PWM device already freed\n");
	179
	180	mutex_unlock(&pwm_lock);
	181	}
	182	EXPORT_SYMBOL(pwm_free);
	183
	184	static int __devinit mxc_pwm_probe(struct platform_device *pdev)
	185	{
	186	struct pwm_device *pwm;
	187	struct resource *r;
	188	int ret = 0;
	189
	190	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
	191	if (pwm == NULL) {
	192	dev_err(&pdev->dev, "failed to allocate memory\n");
	193	return -ENOMEM;
	194	}
	195
196	pwm->clk = clk_get(&pdev->dev, "pwm");
197
198	if (IS_ERR(pwm->clk)) {
199	ret = PTR_ERR(pwm->clk);
200	goto err_free;
201	}
202
203	pwm->clk_enabled = 0;
204
205	pwm->use_count = 0;
206	pwm->pwm_id = pdev->id;
207	pwm->pdev = pdev;
208
209	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
210	if (r == NULL) {
211	dev_err(&pdev->dev, "no memory resource defined\n");
212	ret = -ENODEV;
213	goto err_free_clk;
214	}
215
216	r = request_mem_region(r->start, r->end - r->start + 1, pdev->name);
217	if (r == NULL) {
218	dev_err(&pdev->dev, "failed to request memory resource\n");
219	ret = -EBUSY;
220	goto err_free_clk;
221	}
222
223	pwm->mmio_base = ioremap(r->start, r->end - r->start + 1);
224	if (pwm->mmio_base == NULL) {
225	dev_err(&pdev->dev, "failed to ioremap() registers\n");
226	ret = -ENODEV;
227	goto err_free_mem;
228	}
229
230	mutex_lock(&pwm_lock);
231	list_add_tail(&pwm->node, &pwm_list);
232	mutex_unlock(&pwm_lock);
233
234	platform_set_drvdata(pdev, pwm);
235	return 0;
236
237	err_free_mem:
238	release_mem_region(r->start, r->end - r->start + 1);
239	err_free_clk:
240	clk_put(pwm->clk);
241	err_free:
242	kfree(pwm);
243	return ret;
244	}
245
246	static int __devexit mxc_pwm_remove(struct platform_device *pdev)
247	{
248	struct pwm_device *pwm;
249	struct resource *r;
250
251	pwm = platform_get_drvdata(pdev);
252	if (pwm == NULL)
253	return -ENODEV;
254
255	mutex_lock(&pwm_lock);
256	list_del(&pwm->node);
257	mutex_unlock(&pwm_lock);
258
259	iounmap(pwm->mmio_base);
260
261	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
262	release_mem_region(r->start, r->end - r->start + 1);
263
264	clk_put(pwm->clk);
265
266	kfree(pwm);
267	return 0;
268	}
269
270	static struct platform_driver mxc_pwm_driver = {
271	.driver = {
272	.name = "mxc_pwm",
273	},
274	.probe = mxc_pwm_probe,
275	.remove = __devexit_p(mxc_pwm_remove),
276	};
277
278	static int __init mxc_pwm_init(void)
279	{
280	return platform_driver_register(&mxc_pwm_driver);
281	}
282	arch_initcall(mxc_pwm_init);
283
284	static void __exit mxc_pwm_exit(void)
285	{
286	platform_driver_unregister(&mxc_pwm_driver);
287	}
288	module_exit(mxc_pwm_exit);
289
290	MODULE_LICENSE("GPL v2");
291	MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");