leds: Add generic GPIO LED driver

This patch adds support for GPIO connected leds via the new GPIO framework.

Information about leds (gpio, polarity, name, default trigger) is passed
to the driver via platform_data.

Signed-off-by: Raphael Assenat <raph@8d.com>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>

drivers/leds/Kconfig

@@ -95,6 +95,14 @@ config LEDS_COBALT
 	help
 	  This option enables support for the front LED on Cobalt Server
 
+config LEDS_GPIO
+	tristate "LED Support for GPIO connected LEDs"
+	depends on LEDS_CLASS && GENERIC_GPIO
+	help
+	  This option enables support for the LEDs connected to GPIO
+	  outputs. To be useful the particular board must have LEDs
+	  and they must be connected to the GPIO lines.
+
 comment "LED Triggers"
 
 config LEDS_TRIGGERS

drivers/leds/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_LEDS_NET48XX)		+= leds-net48xx.o
 obj-$(CONFIG_LEDS_WRAP)			+= leds-wrap.o
 obj-$(CONFIG_LEDS_H1940)		+= leds-h1940.o
 obj-$(CONFIG_LEDS_COBALT)		+= leds-cobalt.o
+obj-$(CONFIG_LEDS_GPIO)			+= leds-gpio.o
 
 # LED Triggers
 obj-$(CONFIG_LEDS_TRIGGER_TIMER)	+= ledtrig-timer.o

drivers/leds/leds-gpio.c

@@ -0,0 +1,174 @@
+/*
+ * LEDs driver for GPIOs
+ *
+ * Copyright (C) 2007 8D Technologies inc.
+ * Raphael Assenat <raph@8d.com>
+ *
+ * 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.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/leds.h>
+#include <asm/gpio.h>
+
+struct gpio_led_data {
+	struct led_classdev cdev;
+	unsigned gpio;
+	u8 active_low;
+};
+
+
+static void gpio_led_set(struct led_classdev *led_cdev,
+	enum led_brightness value)
+{
+	struct gpio_led_data *led_dat =
+		container_of(led_cdev, struct gpio_led_data, cdev);
+	int level;
+
+	if (value == LED_OFF)
+		level = 0;
+	else
+		level = 1;
+
+	if (led_dat->active_low)
+		level = !level;
+
+	gpio_set_value(led_dat->gpio, level);
+}
+
+static int __init gpio_led_probe(struct platform_device *pdev)
+{
+	struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
+	struct gpio_led *cur_led;
+	struct gpio_led_data *leds_data, *led_dat;
+	int i, ret = 0;
+
+	if (!pdata)
+		return -EBUSY;
+
+	leds_data = kzalloc(sizeof(struct gpio_led_data) * pdata->num_leds,
+				GFP_KERNEL);
+	if (!leds_data)
+		return -ENOMEM;
+
+	for (i = 0; i < pdata->num_leds; i++) {
+		cur_led = &pdata->leds[i];
+		led_dat = &leds_data[i];
+
+		led_dat->cdev.name = cur_led->name;
+		led_dat->cdev.default_trigger = cur_led->default_trigger;
+		led_dat->gpio = cur_led->gpio;
+		led_dat->active_low = cur_led->active_low;
+		led_dat->cdev.brightness_set = gpio_led_set;
+		led_dat->cdev.brightness = cur_led->active_low ? LED_FULL : LED_OFF;
+
+		ret = gpio_request(led_dat->gpio, led_dat->cdev.name);
+		if (ret < 0)
+			goto err;
+
+		gpio_direction_output(led_dat->gpio, led_dat->active_low);
+
+		ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
+		if (ret < 0) {
+			gpio_free(led_dat->gpio);
+			goto err;
+		}
+	}
+
+	platform_set_drvdata(pdev, leds_data);
+
+	return 0;
+
+err:
+	if (i > 0) {
+		for (i = i - 1; i >= 0; i--) {
+			led_classdev_unregister(&leds_data[i].cdev);
+			gpio_free(leds_data[i].gpio);
+		}
+	}
+	kfree(leds_data);
+
+	return ret;
+}
+
+static int __exit gpio_led_remove(struct platform_device *pdev)
+{
+	int i;
+	struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
+	struct gpio_led_data *leds_data;
+
+	leds_data = platform_get_drvdata(pdev);
+
+	for (i = 0; i < pdata->num_leds; i++) {
+		led_classdev_unregister(&leds_data[i].cdev);
+		gpio_free(leds_data[i].gpio);
+	}
+	
+	kfree(leds_data);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int gpio_led_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
+	struct gpio_led_data *leds_data;
+	int i;
+	
+	leds_data = platform_get_drvdata(pdev);
+
+	for (i = 0; i < pdata->num_leds; i++)
+		led_classdev_suspend(&leds_data[i].cdev);
+
+	return 0;
+}
+
+static int gpio_led_resume(struct platform_device *pdev)
+{
+	struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
+	struct gpio_led_data *leds_data;
+	int i;
+
+	leds_data = platform_get_drvdata(pdev);
+
+	for (i = 0; i < pdata->num_leds; i++)
+		led_classdev_resume(&leds_data[i].cdev);
+
+	return 0;
+}
+#else
+#define gpio_led_suspend NULL
+#define gpio_led_resume NULL
+#endif
+
+static struct platform_driver gpio_led_driver = {
+	.remove		= __exit_p(gpio_led_remove),
+	.suspend	= gpio_led_suspend,
+	.resume		= gpio_led_resume,
+	.driver		= {
+		.name	= "leds-gpio",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init gpio_led_init(void)
+{
+	return platform_driver_probe(&gpio_led_driver, gpio_led_probe);
+}
+
+static void __exit gpio_led_exit(void)
+{
+	platform_driver_unregister(&gpio_led_driver);
+}
+
+module_init(gpio_led_init);
+module_exit(gpio_led_exit);
+
+MODULE_AUTHOR("Raphael Assenat <raph@8d.com>");
+MODULE_DESCRIPTION("GPIO LED driver");
+MODULE_LICENSE("GPL");

include/linux/leds.h

@@ -110,4 +110,18 @@ extern void ledtrig_ide_activity(void);
 #define ledtrig_ide_activity() do {} while(0)
 #endif
 
+/* For the leds-gpio driver */
+struct gpio_led {
+	const char *name;
+	char *default_trigger;
+	unsigned 	gpio;
+	u8 		active_low;
+};
+
+struct gpio_led_platform_data {
+	int 		num_leds;
+	struct gpio_led *leds;
+};
+
+
 #endif		/* __LINUX_LEDS_H_INCLUDED */