/*
 * 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/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(6),
        },
        {
                .name = "led_2",
                .port = 0x49,
                .mask = BIT(5),
        },
        {
                .name = "led_3",
                .port = 0x49,
                .mask = BIT(4),
        },
        {
                .name = "led_4",
                .port = 0x49,
                .mask = BIT(3),
        },
        {
                .name = "led_5",
                .port = 0x49,
                .mask = BIT(2),
        },
        {
                .name = "led_6",
                .port = 0x49,
                .mask = BIT(1),
        },
        {
                .name = "led_7",
                .port = 0x49,
                .mask = BIT(0),
        }
};

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 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 = devm_led_classdev_register(&pdev->dev, &leds[i].cdev);
                if (ret < 0)
                        return ret;
        }

        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;
}

static struct platform_driver ot200_led_driver = {
        .probe          = ot200_led_probe,
        .driver         = {
                .name   = "leds-ot200",
        },
};

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");