320 строки
6.4 KiB
C
320 строки
6.4 KiB
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, 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;
|
|
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");
|