// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2016 National Instruments Corp.
 */

#include <linux/array_size.h>
#include <linux/bits.h>
#include <linux/container_of.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/leds.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/types.h>

#define NIC78BX_USER1_LED_MASK          0x3
#define NIC78BX_USER1_GREEN_LED         BIT(0)
#define NIC78BX_USER1_YELLOW_LED        BIT(1)

#define NIC78BX_USER2_LED_MASK          0xC
#define NIC78BX_USER2_GREEN_LED         BIT(2)
#define NIC78BX_USER2_YELLOW_LED        BIT(3)

#define NIC78BX_LOCK_REG_OFFSET         1
#define NIC78BX_LOCK_VALUE              0xA5
#define NIC78BX_UNLOCK_VALUE            0x5A

#define NIC78BX_USER_LED_IO_SIZE        2

struct nic78bx_led_data {
        u16 io_base;
        spinlock_t lock;
        struct platform_device *pdev;
};

struct nic78bx_led {
        u8 bit;
        u8 mask;
        struct nic78bx_led_data *data;
        struct led_classdev cdev;
};

static inline struct nic78bx_led *to_nic78bx_led(struct led_classdev *cdev)
{
        return container_of(cdev, struct nic78bx_led, cdev);
}

static void nic78bx_brightness_set(struct led_classdev *cdev,
                                  enum led_brightness brightness)
{
        struct nic78bx_led *nled = to_nic78bx_led(cdev);
        unsigned long flags;
        u8 value;

        spin_lock_irqsave(&nled->data->lock, flags);
        value = inb(nled->data->io_base);

        if (brightness) {
                value &= ~nled->mask;
                value |= nled->bit;
        } else {
                value &= ~nled->bit;
        }

        outb(value, nled->data->io_base);
        spin_unlock_irqrestore(&nled->data->lock, flags);
}

static enum led_brightness nic78bx_brightness_get(struct led_classdev *cdev)
{
        struct nic78bx_led *nled = to_nic78bx_led(cdev);
        unsigned long flags;
        u8 value;

        spin_lock_irqsave(&nled->data->lock, flags);
        value = inb(nled->data->io_base);
        spin_unlock_irqrestore(&nled->data->lock, flags);

        return (value & nled->bit) ? 1 : LED_OFF;
}

static struct nic78bx_led nic78bx_leds[] = {
        {
                .bit = NIC78BX_USER1_GREEN_LED,
                .mask = NIC78BX_USER1_LED_MASK,
                .cdev = {
                        .name = "nilrt:green:user1",
                        .max_brightness = 1,
                        .brightness_set = nic78bx_brightness_set,
                        .brightness_get = nic78bx_brightness_get,
                }
        },
        {
                .bit = NIC78BX_USER1_YELLOW_LED,
                .mask = NIC78BX_USER1_LED_MASK,
                .cdev = {
                        .name = "nilrt:yellow:user1",
                        .max_brightness = 1,
                        .brightness_set = nic78bx_brightness_set,
                        .brightness_get = nic78bx_brightness_get,
                }
        },
        {
                .bit = NIC78BX_USER2_GREEN_LED,
                .mask = NIC78BX_USER2_LED_MASK,
                .cdev = {
                        .name = "nilrt:green:user2",
                        .max_brightness = 1,
                        .brightness_set = nic78bx_brightness_set,
                        .brightness_get = nic78bx_brightness_get,
                }
        },
        {
                .bit = NIC78BX_USER2_YELLOW_LED,
                .mask = NIC78BX_USER2_LED_MASK,
                .cdev = {
                        .name = "nilrt:yellow:user2",
                        .max_brightness = 1,
                        .brightness_set = nic78bx_brightness_set,
                        .brightness_get = nic78bx_brightness_get,
                }
        }
};

static void lock_led_reg_action(void *data)
{
        struct nic78bx_led_data *led_data = data;

        /* Lock LED register */
        outb(NIC78BX_LOCK_VALUE,
             led_data->io_base + NIC78BX_LOCK_REG_OFFSET);
}

static int nic78bx_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct nic78bx_led_data *led_data;
        struct resource *io_rc;
        int ret, i;

        led_data = devm_kzalloc(dev, sizeof(*led_data), GFP_KERNEL);
        if (!led_data)
                return -ENOMEM;

        led_data->pdev = pdev;
        platform_set_drvdata(pdev, led_data);

        io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
        if (!io_rc) {
                dev_err(dev, "missing IO resources\n");
                return -EINVAL;
        }

        if (resource_size(io_rc) < NIC78BX_USER_LED_IO_SIZE) {
                dev_err(dev, "IO region too small\n");
                return -EINVAL;
        }

        if (!devm_request_region(dev, io_rc->start, resource_size(io_rc),
                                 KBUILD_MODNAME)) {
                dev_err(dev, "failed to get IO region\n");
                return -EBUSY;
        }

        led_data->io_base = io_rc->start;
        spin_lock_init(&led_data->lock);

        ret = devm_add_action(dev, lock_led_reg_action, led_data);
        if (ret)
                return ret;

        for (i = 0; i < ARRAY_SIZE(nic78bx_leds); i++) {
                nic78bx_leds[i].data = led_data;

                ret = devm_led_classdev_register(dev, &nic78bx_leds[i].cdev);
                if (ret)
                        return ret;
        }

        /* Unlock LED register */
        outb(NIC78BX_UNLOCK_VALUE,
             led_data->io_base + NIC78BX_LOCK_REG_OFFSET);

        return ret;
}

static const struct acpi_device_id led_device_ids[] = {
        { "NIC78B3" },
        { }
};
MODULE_DEVICE_TABLE(acpi, led_device_ids);

static struct platform_driver led_driver = {
        .probe = nic78bx_probe,
        .driver = {
                .name = KBUILD_MODNAME,
                .acpi_match_table = led_device_ids,
        },
};

module_platform_driver(led_driver);

MODULE_DESCRIPTION("National Instruments PXI User LEDs driver");
MODULE_AUTHOR("Hui Chun Ong <hui.chun.ong@ni.com>");
MODULE_LICENSE("GPL");