leds: add led driver for Bachmann's ot200

Add support for leds on Bachmann's ot200 visualisation device.  The
device has three leds on the back panel (led_err, led_init and led_run)
and can handle up to seven leds on the front panel.

The driver was written by Linutronix on behalf of Bachmann electronic
GmbH.  It incorporates feedback from Lars-Peter Clausen

[akpm@linux-foundation.org: add dependency on HAS_IOMEM]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 179 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index c957c344233f..9ca28fced2b9 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -403,6 +403,13 @@ config LEDS_MAX8997
           This option enables support for on-chip LED drivers on
           MAXIM MAX8997 PMIC.
 
+config LEDS_OT200
+        tristate "LED support for the Bachmann OT200"
+        depends on LEDS_CLASS && HAS_IOMEM
+        help
+          This option enables support for the LEDs on the Bachmann OT200.
+          Say Y to enable LEDs on the Bachmann OT200.
+
 config LEDS_TRIGGERS
         bool "LED Trigger support"
         depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index b8a9723477f0..1fc6875a8b20 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_LEDS_LP5523)		+= leds-lp5523.o
 obj-$(CONFIG_LEDS_TCA6507)              += leds-tca6507.o
 obj-$(CONFIG_LEDS_CLEVO_MAIL)           += leds-clevo-mail.o
 obj-$(CONFIG_LEDS_HP6XX)                += leds-hp6xx.o
+obj-$(CONFIG_LEDS_OT200)                += leds-ot200.o
 obj-$(CONFIG_LEDS_FSG)                  += leds-fsg.o
 obj-$(CONFIG_LEDS_PCA955X)              += leds-pca955x.o
 obj-$(CONFIG_LEDS_DA903X)               += leds-da903x.o
diff --git a/drivers/leds/leds-ot200.c b/drivers/leds/leds-ot200.c
new file mode 100644
index 000000000000..c4646825a620
--- /dev/null
+++ b/drivers/leds/leds-ot200.c
@@ -0,0 +1,171 @@
+/*
+ * Bachmann ot200 leds driver.
+ *
+ * Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+ *         Christian Gmeiner <christian.gmeiner@gmail.com>
+ *
+ * License: GPL as published by the FSF.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+#include <linux/io.h>
+#include <linux/module.h>
+
+
+struct ot200_led {
+        struct led_classdev cdev;
+        const char *name;
+        unsigned long port;
+        u8 mask;
+};
+
+/*
+ * The device has three leds on the back panel (led_err, led_init and led_run)
+ * and can handle up to seven leds on the front panel.
+ */
+
+static struct ot200_led leds[] = {
+        {
+                .name = "led_run",
+                .port = 0x5a,
+                .mask = BIT(0),
+        },
+        {
+                .name = "led_init",
+                .port = 0x5a,
+                .mask = BIT(1),
+        },
+        {
+                .name = "led_err",
+                .port = 0x5a,
+                .mask = BIT(2),
+        },
+        {
+                .name = "led_1",
+                .port = 0x49,
+                .mask = BIT(7),
+        },
+        {
+                .name = "led_2",
+                .port = 0x49,
+                .mask = BIT(6),
+        },
+        {
+                .name = "led_3",
+                .port = 0x49,
+                .mask = BIT(5),
+        },
+        {
+                .name = "led_4",
+                .port = 0x49,
+                .mask = BIT(4),
+        },
+        {
+                .name = "led_5",
+                .port = 0x49,
+                .mask = BIT(3),
+        },
+        {
+                .name = "led_6",
+                .port = 0x49,
+                .mask = BIT(2),
+        },
+        {
+                .name = "led_7",
+                .port = 0x49,
+                .mask = BIT(1),
+        }
+};
+
+static DEFINE_SPINLOCK(value_lock);
+
+/*
+ * we need to store the current led states, as it is not
+ * possible to read the current led state via inb().
+ */
+static u8 leds_back;
+static u8 leds_front;
+
+static void ot200_led_brightness_set(struct led_classdev *led_cdev,
+                enum led_brightness value)
+{
+        struct ot200_led *led = container_of(led_cdev, struct ot200_led, cdev);
+        u8 *val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&value_lock, flags);
+
+        if (led->port == 0x49)
+                val = &leds_front;
+        else if (led->port == 0x5a)
+                val = &leds_back;
+        else
+                BUG();
+
+        if (value == LED_OFF)
+                *val &= ~led->mask;
+        else
+                *val |= led->mask;
+
+        outb(*val, led->port);
+        spin_unlock_irqrestore(&value_lock, flags);
+}
+
+static int __devinit ot200_led_probe(struct platform_device *pdev)
+{
+        int i;
+        int ret;
+
+        for (i = 0; i < ARRAY_SIZE(leds); i++) {
+
+                leds[i].cdev.name = leds[i].name;
+                leds[i].cdev.brightness_set = ot200_led_brightness_set;
+
+                ret = led_classdev_register(&pdev->dev, &leds[i].cdev);
+                if (ret < 0)
+                        goto err;
+        }
+
+        leds_front = 0;         /* turn off all front leds */
+        leds_back = BIT(1);     /* turn on init led */
+        outb(leds_front, 0x49);
+        outb(leds_back, 0x5a);
+
+        return 0;
+
+err:
+        for (i = i - 1; i >= 0; i--)
+                led_classdev_unregister(&leds[i].cdev);
+
+        return ret;
+}
+
+static int __devexit ot200_led_remove(struct platform_device *pdev)
+{
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(leds); i++)
+                led_classdev_unregister(&leds[i].cdev);
+
+        return 0;
+}
+
+static struct platform_driver ot200_led_driver = {
+        .probe          = ot200_led_probe,
+        .remove         = __devexit_p(ot200_led_remove),
+        .driver         = {
+                .name   = "leds-ot200",
+                .owner  = THIS_MODULE,
+        },
+};
+
+module_platform_driver(ot200_led_driver);
+
+MODULE_AUTHOR("Sebastian A. Siewior <bigeasy@linutronix.de>");
+MODULE_DESCRIPTION("ot200 LED driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:leds-ot200");