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led: Add pwm-led driver 

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Sascha Hauer 2014-02-28 13:29:57 +01:00
parent e390a8e2b4
commit 70e2d85096
3 changed files with 98 additions and 0 deletions
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4
drivers/led/Kconfig
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@ -7,6 +7,10 @@ config LED_GPIO
bool "gpio LED support"
depends on GENERIC_GPIO
config LED_PWM
bool "PWM LED support"
depends on PWM
config LED_GPIO_OF
bool "support parsing gpio LEDs from device tree"
depends on LED_GPIO && OFTREE

1
drivers/led/Makefile
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@ -1,3 +1,4 @@
obj-$(CONFIG_LED) += core.o
obj-$(CONFIG_LED_GPIO) += led-gpio.o
obj-$(CONFIG_LED_PWM) += led-pwm.o
obj-$(CONFIG_LED_TRIGGERS) += led-triggers.o

93
drivers/led/led-pwm.c Normal file
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@ -0,0 +1,93 @@
/*
* pwm LED support for barebox
*
* (C) Copyright 2010 Sascha Hauer, Pengutronix
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <common.h>
#include <malloc.h>
#include <init.h>
#include <led.h>
#include <pwm.h>
#include <of.h>
#include <asm-generic/div64.h>
struct pwmled {
bool active_low;
struct led led;
struct pwm_device *pwm;
uint32_t period;
};
static void led_pwm_set(struct led *led, unsigned int brightness)
{
struct pwmled *pwmled = container_of(led, struct pwmled, led);
unsigned long long duty = pwmled->period;
unsigned int max = pwmled->led.max_value;
duty *= brightness;
do_div(duty, max);
pwm_config(pwmled->pwm, duty, pwmled->period);
}
static int led_pwm_of_probe(struct device_d *dev)
{
struct device_node *child;
int ret;
for_each_child_of_node(dev->device_node, child) {
struct pwmled *pwmled;
struct pwm_device *pwm;
pwm = of_pwm_request(child, NULL);
if (pwm < 0)
continue;
pwmled = xzalloc(sizeof(*pwmled));
pwmled->led.name = xstrdup(child->name);
pwmled->pwm = pwm;
of_property_read_u32(child, "max-brightness", &pwmled->led.max_value);
pwmled->period = pwm_get_period(pwmled->pwm);
pwmled->led.set = led_pwm_set;
pwm_config(pwmled->pwm, 0, pwmled->period);
pwm_enable(pwmled->pwm);
ret = led_register(&pwmled->led);
if (ret)
return ret;
led_of_parse_trigger(&pwmled->led, child);
}
return 0;
}
static struct of_device_id led_pwm_of_ids[] = {
{ .compatible = "pwm-leds", },
{ }
};
static struct driver_d led_pwm_of_driver = {
.name = "pwm-leds",
.probe = led_pwm_of_probe,
.of_compatible = DRV_OF_COMPAT(led_pwm_of_ids),
};
device_platform_driver(led_pwm_of_driver);