leds: Add rb532 LED driver for the User LED

Mikrotik built six LEDs into the Routerboard 532, from which one is
destined for custom use, the so called "User LED". This patch adds a
driver for it, based on the LEDs class.

Signed-off-by: Phil Sutter <n0-1@freewrt.org>
Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

drivers/leds/leds-rb532.c

@@ -0,0 +1,77 @@
+/*
+ * LEDs driver for the "User LED" on Routerboard532
+ *
+ * Copyright (C) 2009 Phil Sutter <n0-1@freewrt.org>
+ *
+ * Based on leds-cobalt-qube.c by Florian Fainelly and
+ * rb-diag.c (my own standalone driver for both LED and
+ * button of Routerboard532).
+ */
+
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <asm/mach-rc32434/gpio.h>
+#include <asm/mach-rc32434/rb.h>
+
+static void rb532_led_set(struct led_classdev *cdev,
+                          enum led_brightness brightness)
+{
+	if (brightness)
+		set_latch_u5(LO_ULED, 0);
+
+	else
+		set_latch_u5(0, LO_ULED);
+}
+
+static enum led_brightness rb532_led_get(struct led_classdev *cdev)
+{
+	return (get_latch_u5() & LO_ULED) ? LED_FULL : LED_OFF;
+}
+
+static struct led_classdev rb532_uled = {
+	.name = "uled",
+	.brightness_set = rb532_led_set,
+	.brightness_get = rb532_led_get,
+	.default_trigger = "nand-disk",
+};
+
+static int __devinit rb532_led_probe(struct platform_device *pdev)
+{
+	return led_classdev_register(&pdev->dev, &rb532_uled);
+}
+
+static int __devexit rb532_led_remove(struct platform_device *pdev)
+{
+	led_classdev_unregister(&rb532_uled);
+	return 0;
+}
+
+static struct platform_driver rb532_led_driver = {
+	.probe = rb532_led_probe,
+	.remove = __devexit_p(rb532_led_remove),
+	.driver = {
+		.name = "rb532-led",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init rb532_led_init(void)
+{
+	return platform_driver_register(&rb532_led_driver);
+}
+
+static void __exit rb532_led_exit(void)
+{
+	platform_driver_unregister(&rb532_led_driver);
+}
+
+module_init(rb532_led_init);
+module_exit(rb532_led_exit);
+
+MODULE_ALIAS("platform:rb532-led");
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("User LED support for Routerboard532");
+MODULE_AUTHOR("Phil Sutter <n0-1@freewrt.org>");