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/*
* Freescale MXS PWM LED driver
*
* Author: Drew Benedetti <drewb@embeddedalley.com>
*
* Copyright 2008-2010 Freescale Semiconductor, Inc.
* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
*/
/*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/leds.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <mach/hardware.h>
#include <mach/system.h>
#include <mach/device.h>
#include <mach/regs-pwm.h>
/*
* PWM enables are the lowest bits of HW_PWM_CTRL register
*/
#define BM_PWM_CTRL_PWM_ENABLE ((1<<(CONFIG_MXS_PWM_CHANNELS)) - 1)
#define BF_PWM_CTRL_PWM_ENABLE(n) ((1<<(n)) & BM_PWM_CTRL_PWM_ENABLE)
#define BF_PWM_PERIODn_SETTINGS \
(BF_PWM_PERIODn_CDIV(5) | /* divide by 64 */ \
BF_PWM_PERIODn_INACTIVE_STATE(3) | /* low */ \
BF_PWM_PERIODn_ACTIVE_STATE(2) | /* high */ \
BF_PWM_PERIODn_PERIOD(LED_FULL)) /* 255 cycles */
struct mxs_pwm_leds {
struct clk *pwm_clk;
unsigned int base;
unsigned int led_num;
struct mxs_pwm_led *leds;
};
static struct mxs_pwm_leds leds;
static void mxs_pwm_led_brightness_set(struct led_classdev *pled,
enum led_brightness value)
{
struct mxs_pwm_led *pwm_led;
pwm_led = container_of(pled, struct mxs_pwm_led, dev);
if (pwm_led->pwm < CONFIG_MXS_PWM_CHANNELS) {
__raw_writel(BF_PWM_CTRL_PWM_ENABLE(pwm_led->pwm),
leds.base + HW_PWM_CTRL_CLR);
__raw_writel(BF_PWM_ACTIVEn_INACTIVE(LED_FULL) |
BF_PWM_ACTIVEn_ACTIVE(value),
leds.base + HW_PWM_ACTIVEn(pwm_led->pwm));
__raw_writel(BF_PWM_PERIODn_SETTINGS,
leds.base + HW_PWM_PERIODn(pwm_led->pwm));
__raw_writel(BF_PWM_CTRL_PWM_ENABLE(pwm_led->pwm),
leds.base + HW_PWM_CTRL_SET);
}
}
static int __devinit mxs_pwm_led_probe(struct platform_device *pdev)
{
struct mxs_pwm_leds_plat_data *plat_data;
struct resource *res;
struct led_classdev *led;
unsigned int pwmn;
int leds_in_use = 0, rc = 0;
int i;
plat_data = (struct mxs_pwm_leds_plat_data *)pdev->dev.platform_data;
if (plat_data == NULL)
return -ENODEV;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL)
return -ENODEV;
leds.base = (unsigned int)IO_ADDRESS(res->start);
mxs_reset_block((void __iomem *)leds.base, 1);
leds.led_num = plat_data->num;
if (leds.led_num <= 0 || leds.led_num > CONFIG_MXS_PWM_CHANNELS)
return -EFAULT;
leds.leds = plat_data->leds;
if (leds.leds == NULL)
return -EFAULT;
leds.pwm_clk = clk_get(&pdev->dev, "pwm");
if (IS_ERR(leds.pwm_clk)) {
rc = PTR_ERR(leds.pwm_clk);
return rc;
}
clk_enable(leds.pwm_clk);
for (i = 0; i < leds.led_num; i++) {
pwmn = leds.leds[i].pwm;
if (pwmn >= CONFIG_MXS_PWM_CHANNELS) {
dev_err(&pdev->dev,
"[led-pwm%d]:PWM %d doesn't exist\n",
i, pwmn);
continue;
}
led = &(leds.leds[i].dev);
led->name = leds.leds[i].name;
led->brightness = LED_HALF;
led->flags = 0;
led->brightness_set = mxs_pwm_led_brightness_set;
led->default_trigger = 0;
rc = led_classdev_register(&pdev->dev, led);
if (rc < 0) {
dev_err(&pdev->dev,
"Unable to register LED device %d (err=%d)\n",
i, rc);
continue;
}
leds_in_use++;
/* Set default brightness */
mxs_pwm_led_brightness_set(led, LED_HALF);
}
if (leds_in_use == 0) {
dev_info(&pdev->dev, "No PWM LEDs available\n");
clk_disable(leds.pwm_clk);
clk_put(leds.pwm_clk);
return -ENODEV;
}
return 0;
}
static int __devexit mxs_pwm_led_remove(struct platform_device *pdev)
{
int i;
unsigned int pwm;
for (i = 0; i < leds.led_num; i++) {
pwm = leds.leds[i].pwm;
__raw_writel(BF_PWM_CTRL_PWM_ENABLE(pwm),
leds.base + HW_PWM_CTRL_CLR);
__raw_writel(BF_PWM_ACTIVEn_INACTIVE(0) |
BF_PWM_ACTIVEn_ACTIVE(0),
leds.base + HW_PWM_ACTIVEn(pwm));
__raw_writel(BF_PWM_PERIODn_SETTINGS,
leds.base + HW_PWM_PERIODn(pwm));
led_classdev_unregister(&leds.leds[i].dev);
}
clk_disable(leds.pwm_clk);
clk_put(leds.pwm_clk);
return 0;
}
static struct platform_driver mxs_pwm_led_driver = {
.probe = mxs_pwm_led_probe,
.remove = __devexit_p(mxs_pwm_led_remove),
.driver = {
.name = "mxs-leds",
},
};
static int __init mxs_pwm_led_init(void)
{
return platform_driver_register(&mxs_pwm_led_driver);
}
static void __exit mxs_pwm_led_exit(void)
{
platform_driver_unregister(&mxs_pwm_led_driver);
}
module_init(mxs_pwm_led_init);
module_exit(mxs_pwm_led_exit);
MODULE_AUTHOR("Drew Benedetti <drewb@embeddedalley.com>");
MODULE_DESCRIPTION("mxs PWM LED driver");
MODULE_LICENSE("GPL");
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