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/*
* Freescale STMP378X PWM LED driver
*
* Author: Drew Benedetti <drewb@embeddedalley.com>
*
* Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
* 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/clk.h>
#include <mach/hardware.h>
#include <mach/regs-pwm.h>
#include <mach/regs-clkctrl.h>
#include <mach/pwm-led.h>
#include <mach/stmp3xxx.h>
/* Up to 5 PWM lines are available. */
#define PWM_MAX 5
/* PWM enables are the lowest PWM_MAX bits of HW_PWM_CTRL register */
#define BM_PWM_CTRL_PWM_ENABLE(n) ((1<<(n)) & ((1<<(PWM_MAX))-1))
#define BF_PWM_PERIODn_SETTINGS \
(BF_PWM_PERIODn_CDIV(5) | /* divide by 64 */ \
BF_PWM_PERIODn_INACTIVE_STATE(2) | /* low */ \
BF_PWM_PERIODn_ACTIVE_STATE(3) | /* high */ \
BF_PWM_PERIODn_PERIOD(LED_FULL)) /* 255 cycles */
struct stmp378x_led {
struct led_classdev led_dev;
int in_use;
};
static struct stmp378x_led leds[PWM_MAX];
static struct clk *pwm_clk;
static void stmp378x_pwm_led_brightness_set(struct led_classdev *pled,
enum led_brightness value)
{
unsigned int pwmn;
pwmn = container_of(pled, struct stmp378x_led, led_dev) - leds;
if (pwmn < PWM_MAX && leds[pwmn].in_use) {
HW_PWM_CTRL_CLR(BM_PWM_CTRL_PWM_ENABLE(pwmn));
HW_PWM_ACTIVEn_WR(pwmn, BF_PWM_ACTIVEn_INACTIVE(value) |
BF_PWM_ACTIVEn_ACTIVE(0));
HW_PWM_PERIODn_WR(pwmn, BF_PWM_PERIODn_SETTINGS);
HW_PWM_CTRL_SET(BM_PWM_CTRL_PWM_ENABLE(pwmn));
}
}
static int stmp378x_pwm_led_probe(struct platform_device *pdev)
{
struct led_classdev *led;
unsigned int pwmn;
int leds_in_use = 0, rc = 0;
int i;
stmp3xxx_reset_block(REGS_PWM_BASE, 1);
pwm_clk = clk_get(&pdev->dev, "pwm");
if (IS_ERR(pwm_clk)) {
rc = PTR_ERR(pwm_clk);
return rc;
}
clk_enable(pwm_clk);
for (i = 0; i < pdev->num_resources; i++) {
if (pdev->resource[i].flags & IORESOURCE_DISABLED)
continue;
pwmn = pdev->resource[i].start;
if (pwmn >= PWM_MAX) {
dev_err(&pdev->dev, "PWM %d doesn't exist\n", pwmn);
continue;
}
rc = pwm_led_pinmux_request(pwmn, "stmp378x_pwm_led");
if (rc) {
dev_err(&pdev->dev,
"PWM %d is not available (err=%d)\n",
pwmn, rc);
continue;
}
led = &leds[pwmn].led_dev;
led->flags = pdev->resource[i].flags;
led->name = pdev->resource[i].name;
led->brightness = LED_HALF;
led->flags = 0;
led->brightness_set = stmp378x_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",
pwmn, rc);
pwm_led_pinmux_free(pwmn, "stmp378x_pwm_led");
continue;
}
/* PWM LED is available now */
leds[pwmn].in_use = !0;
leds_in_use++;
/* Set default brightness */
stmp378x_pwm_led_brightness_set(led, LED_HALF);
}
if (leds_in_use == 0) {
dev_info(&pdev->dev, "No PWM LEDs available\n");
clk_disable(pwm_clk);
clk_put(pwm_clk);
return -ENODEV;
}
return 0;
}
static int stmp378x_pwm_led_remove(struct platform_device *pdev)
{
unsigned int pwmn;
for (pwmn = 0; pwmn < PWM_MAX; pwmn++) {
if (!leds[pwmn].in_use)
continue;
/* Disable LED */
HW_PWM_CTRL_CLR(BM_PWM_CTRL_PWM_ENABLE(pwmn));
HW_PWM_ACTIVEn_WR(pwmn, BF_PWM_ACTIVEn_INACTIVE(0) |
BF_PWM_ACTIVEn_ACTIVE(0));
HW_PWM_PERIODn_WR(pwmn, BF_PWM_PERIODn_SETTINGS);
led_classdev_unregister(&leds[pwmn].led_dev);
pwm_led_pinmux_free(pwmn, "stmp378x_pwm_led");
leds[pwmn].led_dev.name = 0;
leds[pwmn].in_use = 0;
}
clk_disable(pwm_clk);
clk_put(pwm_clk);
return 0;
}
static struct platform_driver stmp378x_pwm_led_driver = {
.probe = stmp378x_pwm_led_probe,
.remove = stmp378x_pwm_led_remove,
.driver = {
.name = "stmp378x-pwm-led",
},
};
static int __init stmp378x_pwm_led_init(void)
{
return platform_driver_register(&stmp378x_pwm_led_driver);
}
static void __exit stmp378x_pwm_led_exit(void)
{
platform_driver_unregister(&stmp378x_pwm_led_driver);
}
module_init(stmp378x_pwm_led_init);
module_exit(stmp378x_pwm_led_exit);
MODULE_AUTHOR("Drew Benedetti <drewb@embeddedalley.com>");
MODULE_DESCRIPTION("STMP378X PWM LED driver");
MODULE_LICENSE("GPL");
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