Use PWM Subsystem to drive LED

diff -Narub linux.orig/arch/arm/plat-omap/include/plat/board.h linux/arch/arm/plat-omap/include/plat/board.h
--- linux.orig/arch/arm/plat-omap/include/plat/board.h	2012-07-19 22:21:31.000000000 +0200
+++ linux/arch/arm/plat-omap/include/plat/board.h	2012-09-26 13:00:17.288764186 +0200
@@ -119,6 +119,14 @@
 	int intensity_timer;
 	int blink_timer;
 	void (*set_power)(struct omap_pwm_led_platform_data *self, int on_off);
+#ifdef CONFIG_LEDS_OMAP_PWM
+	void (*set_pad)(struct omap_pwm_led_platform_data *Self, int on_off);
+	const char *default_trigger;
+	unsigned int bkl_freq;
+	unsigned char bkl_max;
+	unsigned char bkl_min;
+	unsigned invert;
+#endif
 };
 
 struct omap_uart_config {
diff -Narub linux.orig/drivers/leds/Kconfig linux/drivers/leds/Kconfig
--- linux.orig/drivers/leds/Kconfig	2012-09-20 21:25:14.771827238 +0200
+++ linux/drivers/leds/Kconfig	2012-09-26 12:57:43.247140169 +0200
@@ -344,6 +344,13 @@
 	  This option enable support for on-chip LED drivers found
 	  on Freescale Semiconductor MC13783 PMIC.
 
+config LEDS_OMAP_PWM
+	tristate "LED Support for OMAP PWM-controlled LEDs"
+	depends on LEDS_CLASS && ARCH_OMAP && OMAP_DM_TIMER
+	help
+	  This options enables support for LEDs connected to GPIO lines
+	  controlled by a PWM timer on OMAP CPUs.
+
 config LEDS_NS2
 	tristate "LED support for Network Space v2 GPIO LEDs"
 	depends on LEDS_CLASS
diff -Narub linux.orig/drivers/leds/leds-omap-pwm.c linux/drivers/leds/leds-omap-pwm.c
--- linux.orig/drivers/leds/leds-omap-pwm.c	1970-01-01 01:00:00.000000000 +0100
+++ linux/drivers/leds/leds-omap-pwm.c	2012-09-26 13:02:05.075795659 +0200
@@ -0,0 +1,454 @@
+/* drivers/leds/leds-omap_pwm.c
+ *
+ * Driver to blink LEDs using OMAP PWM timers
+ *
+ * Copyright (C) 2006 Nokia Corporation
+ * Author: Timo Teras
+ *
+ * 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.
+*/
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/leds.h>
+#include <linux/ctype.h>
+#include <linux/sched.h>
+#include <linux/clk.h>
+#include <asm/delay.h>
+#include <plat/board.h>
+#include <plat/dmtimer.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+
+#define MAX_GPTIMER_ID		12
+
+struct omap_pwm_led {
+	struct led_classdev cdev;
+	struct omap_pwm_led_platform_data *pdata;
+	struct omap_dm_timer *intensity_timer;
+	struct omap_dm_timer *blink_timer;
+	int powered;
+	unsigned int on_period, off_period;
+	enum led_brightness brightness;
+};
+
+static inline struct omap_pwm_led *pdev_to_omap_pwm_led(struct platform_device *pdev)
+{
+	return platform_get_drvdata(pdev);
+}
+
+static inline struct omap_pwm_led *cdev_to_omap_pwm_led(struct led_classdev *led_cdev)
+{
+	return container_of(led_cdev, struct omap_pwm_led, cdev);
+}
+
+static void omap_pwm_led_set_blink(struct omap_pwm_led *led)
+{
+	if (!led->powered)
+		return;
+
+	if (led->on_period != 0 && led->off_period != 0) {
+		unsigned long load_reg, cmp_reg;
+
+		load_reg = 32768 * (led->on_period + led->off_period) / 1000;
+		cmp_reg = 32768 * led->on_period / 1000;
+
+		omap_dm_timer_stop(led->blink_timer);
+		omap_dm_timer_set_load(led->blink_timer, 1, -load_reg);
+		omap_dm_timer_set_match(led->blink_timer, 1, -cmp_reg);
+		omap_dm_timer_set_pwm(led->blink_timer, 1, 1,
+				      OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE);
+		omap_dm_timer_write_counter(led->blink_timer, -2);
+		omap_dm_timer_start(led->blink_timer);
+	} else {
+		omap_dm_timer_set_pwm(led->blink_timer, 1, 1,
+				      OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE);
+		omap_dm_timer_stop(led->blink_timer);
+	}
+}
+
+static void omap_pwm_led_pad_enable(struct omap_pwm_led *led)
+{
+	if (led->pdata->set_pad)
+		led->pdata->set_pad(led->pdata, 1);
+}
+
+static void omap_pwm_led_pad_disable(struct omap_pwm_led *led)
+{
+	if (led->pdata->set_pad)
+		led->pdata->set_pad(led->pdata, 0);
+}
+
+static void omap_pwm_led_power_on(struct omap_pwm_led *led)
+{
+	if (led->powered)
+		return;
+	led->powered = 1;
+
+	pr_debug("%s: brightness: %i\n", 
+			__func__, led->brightness);
+	
+	/* Select clock */
+	omap_dm_timer_set_source(led->intensity_timer, OMAP_TIMER_SRC_SYS_CLK);
+
+	/* Turn voltage on */
+	if (led->pdata->set_power != NULL)
+		led->pdata->set_power(led->pdata, 1);
+
+	/* explicitly enable the timer, saves some SAR later */
+	omap_dm_timer_enable(led->intensity_timer);
+	
+	/* Enable PWM timers */
+	if (led->blink_timer != NULL) {
+		omap_dm_timer_set_source(led->blink_timer,
+					 OMAP_TIMER_SRC_32_KHZ);
+		omap_pwm_led_set_blink(led);
+	}
+}
+
+static void omap_pwm_led_power_off(struct omap_pwm_led *led)
+{
+	if (!led->powered)
+		return;
+	led->powered = 0;
+
+	pr_debug("%s: brightness: %i\n", 
+			__func__, led->brightness);
+	
+	if (led->pdata->set_power != NULL)
+		led->pdata->set_power(led->pdata, 0);
+
+	/* Everything off */
+	omap_dm_timer_stop(led->intensity_timer);
+
+	if (led->blink_timer != NULL)
+		omap_dm_timer_stop(led->blink_timer);
+}
+
+static void pwm_set_speed(struct omap_dm_timer *gpt,
+		int frequency, int duty_cycle)
+{
+	u32 val;
+	u32 period;
+	struct clk *timer_fclk;
+
+	/* and you will have an overflow in 1 sec         */
+	/* so,                              */
+	/* freq_timer     -> 1s             */
+	/* carrier_period -> 1/carrier_freq */
+	/* => carrier_period = freq_timer/carrier_freq */
+
+	timer_fclk = omap_dm_timer_get_fclk(gpt);
+	period = clk_get_rate(timer_fclk) / frequency;
+
+	val = 0xFFFFFFFF+1-period;
+	omap_dm_timer_set_load(gpt, 1, val);
+
+	val = 0xFFFFFFFF+1-(period*duty_cycle/256);
+	omap_dm_timer_set_match(gpt, 1, val);
+
+	/* assume overflow first: no toogle if first trig is match */
+	omap_dm_timer_write_counter(gpt, 0xFFFFFFFE);
+}
+
+static void omap_pwm_led_set_pwm_cycle(struct omap_pwm_led *led, int cycle)
+{
+	int pwm_frequency = 10000;
+	int def_on;
+	
+	pr_debug("%s: cycle: %i\n", 
+			__func__, cycle);
+	
+	if (led->pdata->bkl_max)
+		cycle = ( (cycle * led->pdata->bkl_max ) / 255);
+	
+	if (cycle < led->pdata->bkl_min)
+		cycle = led->pdata->bkl_min;
+
+	if (led->pdata->bkl_freq)
+		pwm_frequency = led->pdata->bkl_freq;
+
+	if (cycle != LED_FULL)
+		def_on = led->pdata->invert ? 1:0;
+	else
+		def_on = led->pdata->invert ? 0:1;
+	
+	omap_dm_timer_set_pwm(led->intensity_timer, def_on, 1,
+		      OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE);
+
+	if (cycle != LED_FULL) {
+		pwm_set_speed(led->intensity_timer, pwm_frequency, 256-cycle);
+		omap_dm_timer_start(led->intensity_timer);
+	} else
+		omap_dm_timer_stop(led->intensity_timer);
+}
+
+static void omap_pwm_led_set(struct led_classdev *led_cdev,
+			     enum led_brightness value)
+{
+	struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
+
+	pr_debug("%s: brightness: %i\n", __func__, value);
+
+	if (led->brightness != value) {
+		if (led->brightness == LED_OFF ||
+			led_cdev->flags & LED_SUSPENDED) {
+			/* LED currently OFF */
+			omap_pwm_led_power_on(led);
+			if (value < led->pdata->bkl_min*2) {
+				// some backlight stepup can't start without medium value during variable time
+				omap_pwm_led_set_pwm_cycle(led, led->pdata->bkl_min*3);
+				omap_pwm_led_pad_enable(led);
+				msleep(50);
+				omap_pwm_led_set_pwm_cycle(led, value);
+			
+			} else {
+				omap_pwm_led_set_pwm_cycle(led, value);
+				omap_pwm_led_pad_enable(led);
+			}
+		} else
+			/* just set the new cycle */
+			omap_pwm_led_set_pwm_cycle(led, value);
+			
+		if (value == LED_OFF) {
+			/* LED now suspended */
+			omap_pwm_led_pad_disable(led);
+			omap_pwm_led_set_pwm_cycle(led, value);
+			omap_pwm_led_power_off(led);
+		}
+		led->brightness = value;
+	}
+}
+
+static ssize_t omap_pwm_led_on_period_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
+
+	return sprintf(buf, "%u\n", led->on_period) + 1;
+}
+
+static ssize_t omap_pwm_led_on_period_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
+	int ret = -EINVAL;
+	unsigned long val;
+	char *after;
+	size_t count;
+
+	val = simple_strtoul(buf, &after, 10);
+	count = after - buf;
+	if (*after && isspace(*after))
+		count++;
+
+	if (count == size) {
+		led->on_period = val;
+		omap_pwm_led_set_blink(led);
+		ret = count;
+	}
+
+	return ret;
+}
+
+static ssize_t omap_pwm_led_off_period_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
+
+	return sprintf(buf, "%u\n", led->off_period) + 1;
+}
+
+static ssize_t omap_pwm_led_off_period_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
+	int ret = -EINVAL;
+	unsigned long val;
+	char *after;
+	size_t count;
+
+	val = simple_strtoul(buf, &after, 10);
+	count = after - buf;
+	if (*after && isspace(*after))
+		count++;
+
+	if (count == size) {
+		led->off_period = val;
+		omap_pwm_led_set_blink(led);
+		ret = count;
+	}
+
+	return ret;
+}
+
+static DEVICE_ATTR(on_period, 0644, omap_pwm_led_on_period_show,
+				omap_pwm_led_on_period_store);
+static DEVICE_ATTR(off_period, 0644, omap_pwm_led_off_period_show,
+				omap_pwm_led_off_period_store);
+
+static int omap_pwm_led_probe(struct platform_device *pdev)
+{
+	struct omap_pwm_led_platform_data *pdata = pdev->dev.platform_data;
+	struct omap_pwm_led *led;
+	int ret;
+
+	if (pdata->intensity_timer < 1 || pdata->intensity_timer > MAX_GPTIMER_ID)
+		return -EINVAL;
+
+	if (pdata->blink_timer != 0 || pdata->blink_timer > MAX_GPTIMER_ID)
+		return -EINVAL;
+
+	led = kzalloc(sizeof(struct omap_pwm_led), GFP_KERNEL);
+	if (led == NULL) {
+		dev_err(&pdev->dev, "No memory for device\n");
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(pdev, led);
+	led->cdev.brightness_set = omap_pwm_led_set;
+	led->cdev.default_trigger = pdata->default_trigger;
+	led->cdev.name = pdata->name;
+	led->pdata = pdata;
+	led->brightness = LED_OFF;
+
+	dev_info(&pdev->dev, "OMAP PWM LED (%s) at GP timer %d/%d\n",
+		 pdata->name, pdata->intensity_timer, pdata->blink_timer);
+
+	/* register our new led device */
+	ret = led_classdev_register(&pdev->dev, &led->cdev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "led_classdev_register failed\n");
+		goto error_classdev;
+	}
+
+	/* get related dm timers */
+	led->intensity_timer = omap_dm_timer_request_specific(pdata->intensity_timer);
+	if (led->intensity_timer == NULL) {
+		dev_err(&pdev->dev, "failed to request intensity pwm timer\n");
+		ret = -ENODEV;
+		goto error_intensity;
+	}
+
+	if (led->pdata->invert)
+		omap_dm_timer_set_pwm(led->intensity_timer, 1, 1,
+				      OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE);
+
+	if (pdata->blink_timer != 0) {
+		led->blink_timer = omap_dm_timer_request_specific(pdata->blink_timer);
+		if (led->blink_timer == NULL) {
+			dev_err(&pdev->dev, "failed to request blinking pwm timer\n");
+			ret = -ENODEV;
+			goto error_blink1;
+		}
+		ret = device_create_file(led->cdev.dev,
+					       &dev_attr_on_period);
+		if(ret)
+			goto error_blink2;
+
+		ret = device_create_file(led->cdev.dev,
+					&dev_attr_off_period);
+		if(ret)
+			goto error_blink3;
+
+	}
+
+	return 0;
+
+error_blink3:
+	device_remove_file(led->cdev.dev,
+				 &dev_attr_on_period);
+error_blink2:
+	dev_err(&pdev->dev, "failed to create device file(s)\n");
+error_blink1:
+	omap_dm_timer_free(led->intensity_timer);
+error_intensity:
+	led_classdev_unregister(&led->cdev);
+error_classdev:
+	kfree(led);
+	return ret;
+}
+
+static int omap_pwm_led_remove(struct platform_device *pdev)
+{
+	struct omap_pwm_led *led = pdev_to_omap_pwm_led(pdev);
+
+	device_remove_file(led->cdev.dev,
+				 &dev_attr_on_period);
+	device_remove_file(led->cdev.dev,
+				 &dev_attr_off_period);
+	led_classdev_unregister(&led->cdev);
+
+	omap_pwm_led_set(&led->cdev, LED_OFF);
+	if (led->blink_timer != NULL)
+		omap_dm_timer_free(led->blink_timer);
+	omap_dm_timer_free(led->intensity_timer);
+	kfree(led);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int omap_pwm_led_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct omap_pwm_led *led = pdev_to_omap_pwm_led(pdev);
+
+	pr_debug("%s: brightness: %i\n", __func__,
+			led->brightness);
+	led_classdev_suspend(&led->cdev);
+	return 0;
+}
+
+static int omap_pwm_led_resume(struct platform_device *pdev)
+{
+	struct omap_pwm_led *led = pdev_to_omap_pwm_led(pdev);
+
+	pr_debug("%s: brightness: %i\n", __func__,
+			led->brightness);
+	led_classdev_resume(&led->cdev);
+	return 0;
+}
+#else
+#define omap_pwm_led_suspend NULL
+#define omap_pwm_led_resume NULL
+#endif
+
+static struct platform_driver omap_pwm_led_driver = {
+	.probe		= omap_pwm_led_probe,
+	.remove		= omap_pwm_led_remove,
+	.suspend	= omap_pwm_led_suspend,
+	.resume		= omap_pwm_led_resume,
+	.driver		= {
+		.name		= "omap_pwm_led",
+		.owner		= THIS_MODULE,
+	},
+};
+
+static int __init omap_pwm_led_init(void)
+{
+	return platform_driver_register(&omap_pwm_led_driver);
+}
+
+static void __exit omap_pwm_led_exit(void)
+{
+	platform_driver_unregister(&omap_pwm_led_driver);
+}
+
+module_init(omap_pwm_led_init);
+module_exit(omap_pwm_led_exit);
+
+MODULE_AUTHOR("Timo Teras");
+MODULE_DESCRIPTION("OMAP PWM LED driver");
+MODULE_LICENSE("GPL");
diff -Narub linux.orig/drivers/leds/Makefile linux/drivers/leds/Makefile
--- linux.orig/drivers/leds/Makefile	2012-09-20 21:25:14.780827655 +0200
+++ linux/drivers/leds/Makefile	2012-09-26 12:58:08.060604765 +0200
@@ -43,6 +43,7 @@
 obj-$(CONFIG_LEDS_NETXBIG)		+= leds-netxbig.o
 obj-$(CONFIG_LEDS_ASIC3)		+= leds-asic3.o
 obj-$(CONFIG_LEDS_RENESAS_TPU)		+= leds-renesas-tpu.o
+obj-$(CONFIG_LEDS_OMAP_PWM)		+= leds-omap-pwm.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o