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authorSascha Hauer <s.hauer@pengutronix.de>2014-02-28 13:29:57 +0100
committerSascha Hauer <s.hauer@pengutronix.de>2014-03-03 08:05:19 +0100
commit70e2d85096c6358321b67d4313228d73855dd38f (patch)
treec6d8b753c32092bd6e09b1d0874ec328704dc0dc /drivers
parente390a8e2b42b2063760ce127f2eacacb2e3a962f (diff)
downloadbarebox-70e2d85096c6358321b67d4313228d73855dd38f.tar.gz
barebox-70e2d85096c6358321b67d4313228d73855dd38f.tar.xz
led: Add pwm-led driver
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/led/Kconfig4
-rw-r--r--drivers/led/Makefile1
-rw-r--r--drivers/led/led-pwm.c93
3 files changed, 98 insertions, 0 deletions
diff --git a/drivers/led/Kconfig b/drivers/led/Kconfig
index 3ead82e031..155a78a7df 100644
--- a/drivers/led/Kconfig
+++ b/drivers/led/Kconfig
@@ -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
diff --git a/drivers/led/Makefile b/drivers/led/Makefile
index 6aafa6df05..619bbcf5ca 100644
--- a/drivers/led/Makefile
+++ b/drivers/led/Makefile
@@ -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
diff --git a/drivers/led/led-pwm.c b/drivers/led/led-pwm.c
new file mode 100644
index 0000000000..16d22b5569
--- /dev/null
+++ b/drivers/led/led-pwm.c
@@ -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);