// SPDX-License-Identifier: GPL-2.0
/*
 * Siemens SIMATIC IPC driver for LEDs
 *
 * Copyright (c) Siemens AG, 2018-2021
 *
 * Authors:
 *  Henning Schild <henning.schild@siemens.com>
 *  Jan Kiszka <jan.kiszka@siemens.com>
 *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
 */

#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_data/x86/simatic-ipc-base.h>
#include <linux/platform_device.h>
#include <linux/sizes.h>
#include <linux/spinlock.h>

#define SIMATIC_IPC_LED_PORT_BASE       0x404E

struct simatic_ipc_led {
        unsigned int value; /* mask for io */
        char *name;
        struct led_classdev cdev;
};

static struct simatic_ipc_led simatic_ipc_leds_io[] = {
        {1 << 15, "green:" LED_FUNCTION_STATUS "-1" },
        {1 << 7,  "yellow:" LED_FUNCTION_STATUS "-1" },
        {1 << 14, "red:" LED_FUNCTION_STATUS "-2" },
        {1 << 6,  "yellow:" LED_FUNCTION_STATUS "-2" },
        {1 << 13, "red:" LED_FUNCTION_STATUS "-3" },
        {1 << 5,  "yellow:" LED_FUNCTION_STATUS "-3" },
        { }
};

static struct resource simatic_ipc_led_io_res =
        DEFINE_RES_IO_NAMED(SIMATIC_IPC_LED_PORT_BASE, SZ_2, KBUILD_MODNAME);

static DEFINE_SPINLOCK(reg_lock);

static inline struct simatic_ipc_led *cdev_to_led(struct led_classdev *led_cd)
{
        return container_of(led_cd, struct simatic_ipc_led, cdev);
}

static void simatic_ipc_led_set_io(struct led_classdev *led_cd,
                                   enum led_brightness brightness)
{
        struct simatic_ipc_led *led = cdev_to_led(led_cd);
        unsigned long flags;
        unsigned int val;

        spin_lock_irqsave(&reg_lock, flags);

        val = inw(SIMATIC_IPC_LED_PORT_BASE);
        if (brightness == LED_OFF)
                outw(val | led->value, SIMATIC_IPC_LED_PORT_BASE);
        else
                outw(val & ~led->value, SIMATIC_IPC_LED_PORT_BASE);

        spin_unlock_irqrestore(&reg_lock, flags);
}

static enum led_brightness simatic_ipc_led_get_io(struct led_classdev *led_cd)
{
        struct simatic_ipc_led *led = cdev_to_led(led_cd);

        return inw(SIMATIC_IPC_LED_PORT_BASE) & led->value ? LED_OFF : led_cd->max_brightness;
}

static int simatic_ipc_leds_probe(struct platform_device *pdev)
{
        const struct simatic_ipc_platform *plat = pdev->dev.platform_data;
        struct device *dev = &pdev->dev;
        struct simatic_ipc_led *ipcled;
        struct led_classdev *cdev;
        struct resource *res;
        int err;

        switch (plat->devmode) {
        case SIMATIC_IPC_DEVICE_227D:
        case SIMATIC_IPC_DEVICE_427E:
                res = &simatic_ipc_led_io_res;
                ipcled = simatic_ipc_leds_io;
                /* on 227D the two bytes work the other way araound */
                if (plat->devmode == SIMATIC_IPC_DEVICE_227D) {
                        while (ipcled->value) {
                                ipcled->value = swab16(ipcled->value);
                                ipcled++;
                        }
                        ipcled = simatic_ipc_leds_io;
                }
                if (!devm_request_region(dev, res->start, resource_size(res), KBUILD_MODNAME)) {
                        dev_err(dev, "Unable to register IO resource at %pR\n", res);
                        return -EBUSY;
                }
                break;
        default:
                return -ENODEV;
        }

        while (ipcled->value) {
                cdev = &ipcled->cdev;
                cdev->brightness_set = simatic_ipc_led_set_io;
                cdev->brightness_get = simatic_ipc_led_get_io;
                cdev->max_brightness = LED_ON;
                cdev->name = ipcled->name;

                err = devm_led_classdev_register(dev, cdev);
                if (err < 0)
                        return err;
                ipcled++;
        }

        return 0;
}

static struct platform_driver simatic_ipc_led_driver = {
        .probe = simatic_ipc_leds_probe,
        .driver = {
                .name = KBUILD_MODNAME,
        }
};
module_platform_driver(simatic_ipc_led_driver);

MODULE_DESCRIPTION("LED driver for Siemens Simatic IPCs");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" KBUILD_MODNAME);
MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");