arch/arm/mach-pxa/pwm.c - maze/linux - Git at Google

 /*
  * 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 < 0)
 		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");
	/*
	* 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 < 0)
	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");