#define DRIVER_VERSION  "v2.0.0"
#define DRIVER_AUTHOR   "Multi-Tech"
#define DRIVER_DESC "MTS XDOT (LoRa) Accessory Card"
#define DRIVER_NAME "mtac-xdot"

#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/kmod.h>
#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/mtac.h>
#include <linux/mts_io.h>
#include <linux/gpio/consumer.h>

static struct gpio_pin gpio_pins_mtcdt_mtac_xdot[] = {
	// gpio pins for Accessory Card 1
	{
		.name = "AP1_NRESET",
		.pin = {
			.gpio = ~0U,
			.flags = GPIOD_OUT_HIGH,  // Only when not flashing
			.label = "ap1-reset",
		},
		.do_gpio_desc = 1,
	},


	// gpio pins for Accessory Card 2
	{
		.name = "AP2_NRESET",
		.pin = {
			.gpio = ~0U,
			.flags = GPIOD_OUT_HIGH,
			.label = "ap2-reset",
		},
		.do_gpio_desc = 1,
	},
	{ },
};

static int reset_state[NUM_AP];

static ssize_t xdot_show_reset(struct kobject *kobj,
                        struct kobj_attribute *attr,
                        char *buf)
{
    int value;
    int port;
    struct gpio_pin *pin;
        
    dev_dbg(&mts_io_platform_device->dev,"xdot_show_reset: enter\n");
    port = mtac_port_from_kobject(kobj);
    dev_dbg(&mts_io_platform_device->dev,"xdot_show_reset: %d\n",reset_state[port - 1]);
    if (port < 1) {
            dev_err(&mts_io_platform_device->dev,"mtac_port_from_kobject returned %d\n", port);
            return -EINVAL;
    }
    
    pin	= mtac_gpio_pin_by_attr_name(attr->attr.name, port);
    if (!pin) {
        return -ENODEV;
    }

    dev_dbg(&mts_io_platform_device->dev,"mtac_attr_show_ap_gpio_pin: State of mtac mutex is %s\n",
        mutex_is_locked(&mtac_mutex) ? "locked" : "unlocked");
    mutex_lock(&mtac_mutex);

    value = gpiod_get_value(pin->desc);
    if (value < 0) {
        mutex_unlock(&mtac_mutex);
        return -ENODEV;
    }
    if(reset_state[port - 1] < 0) {
        mutex_unlock(&mtac_mutex);
        return sprintf(buf, "Input state: %d\n", value);
    }

    mutex_unlock(&mtac_mutex);
    return sprintf(buf, "%d\n", value);
}

static ssize_t xdot_store_reset(struct kobject *kobj,
                struct kobj_attribute *attr, const char *buf, size_t count)
{
        int value, ret;
        int port, port_index;
        struct gpio_pin *pin;

        dev_dbg(&mts_io_platform_device->dev,"xdot_store_reset: store %s\n",buf);
        port = mtac_port_from_kobject(kobj);
        if (port < 1) {
                dev_err(&mts_io_platform_device->dev,"mtac_port_from_kobject returned %d\n", port);
                return -EINVAL;
        }
        port_index = port - 1;
        
        pin	= mtac_gpio_pin_by_attr_name(attr->attr.name, port);
        if (!pin) {
                return -ENODEV;
        }

        if (sscanf(buf, "%i", &value) != 1) {
                return -EINVAL;
        }
        if(value < -1 || value > 1)
                return EINVAL;
        
        dev_dbg(&mts_io_platform_device->dev,"xdot_store_reset: old %d new %d\n",reset_state[port_index],value);

        
        dev_dbg(&mts_io_platform_device->dev,"mtac_attr_store_ap_gpio_pin: State of mtac mutex is %s\n",
            mutex_is_locked(&mtac_mutex) ? "locked" : "unlocked");
        mutex_lock(&mtac_mutex);

        if (value == reset_state[port_index]) {
            mutex_unlock(&mtac_mutex);
            return count;  // No change
        }
        
        // reset_state does not match value
        
        if (value == -1) {
            // Wrong GPIO flags, so change to input
            gpiod_put(pin->desc);
	    pin->desc = devm_gpiod_get_optional(&mts_io_platform_device->dev, pin->name, GPIOD_IN);
            if (IS_ERR(pin->desc)) {
                dev_err(&mts_io_platform_device->dev,"Could not request pin %s (%d)\n", pin->name, ret);
                reset_state[port_index] = -2;  // Invalid state
                mutex_unlock(&mtac_mutex);
                return PTR_ERR(pin->desc);
            }
            reset_state[port_index] = -1;
            mutex_unlock(&mtac_mutex);
            return count;  // Pin is now an input
        }
        
        if (reset_state[port_index] == -1) {
            // Wrong GPIO flags, so change to output pin type
            gpiod_put(pin->desc);
            pin->desc = devm_gpiod_get_optional(&mts_io_platform_device->dev, pin->name, GPIOD_IN);
            if (IS_ERR(pin->desc)) {
                dev_err(&mts_io_platform_device->dev,"Could not request pin %s (%d)\n", pin->name, ret);
                reset_state[port_index] = -2;  // Invalid state
                mutex_unlock(&mtac_mutex);
                return PTR_ERR(pin->desc);
            }
        }
        
        if (value >= 0) {
            // Change the value
            gpiod_set_value(pin->desc, value);
            reset_state[port_index] = value;
        }

        mutex_unlock(&mtac_mutex);

        return count;
}


ssize_t xdot_show_eui(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	int retval = -1;
	int port;
	int port_index;
	struct mts_ap_eeprom_layout *app;


	port = mtac_port_from_kobject(kobj);
	if (port < 1) {
		dev_err(&mts_io_platform_device->dev,"mtac_port_from_kobject returned %d\n", port);
		return -1;
	}
	port_index = port - 1;

	app = (struct mts_ap_eeprom_layout *)mts_ap_eeprom[port_index];
	if (! strcmp(attr->attr.name, "eui")) {
		retval = sprintf(buf, "%02X:%02X:%02X:%02X:%02X:%02X:%02X:%02X\n",
			app->eui[0],
			app->eui[1],
			app->eui[2],
			app->eui[3],
			app->eui[4],
			app->eui[5],
			app->eui[6],
			app->eui[7]);
	}
	return retval;
}

static char* xdot_gpio_pin_name_by_attr_name(const char* name, int port) {
	switch (port) {
		case port_1:
			if (! strcmp(name, "reset")) {
				return "ap1-reset";
			} else {
				dev_err(&mts_io_platform_device->dev,"attribute name [%s] is invalid for XDOT in port %d\n", name, port);
				return "";
			}

		case port_2:
			if (! strcmp(name, "reset")) {
				return "ap2-reset";
			} else {
				dev_err(&mts_io_platform_device->dev,"attribute name [%s] is invalid for XDOT in port %d\n", name, port);
				return "";
			}
	}
	return "";
}

// 1 eui
// 1 reset
// 1 vendor-id
// 1 product-id
// 1 device-id
// 1 hw-version
// NULL
static size_t ap_xdot_attrs_size = 7;

static bool xdot_setup(enum ap port) {
	int i;
	int port_index = port - 1;
	int index = 0;
	int count = 0;
	int ret;
	char buf[32];
	struct kobj_attribute* attr;
	struct attribute **attrs;
	struct kobject *subdir;

	dev_info(&mts_io_platform_device->dev,"loading XDOT accessory card in port %d\n", port);

	sprintf(buf, "ap%d", port);
	subdir = kobject_create_and_add(buf, &mts_io_platform_device->dev.kobj);
	if (! subdir) {
		dev_err(&mts_io_platform_device->dev,"kobject_create_and_add for XDOT in port %d failed\n", port);
		return false;
	}

	mtac_set_port_pins(port_index,gpio_pins_mtcdt_mtac_xdot,subdir);

	// create the link to the apX directory this card is in
	// if we're in the first slot, we get plain "XDOT"
	// if we're in a different slot, we might need to use "XDOT-2" to differentiate
	if (port > 1) {
		for (i = 1; i < port; i++) {
			if (mtac_port_info[i - 1]) {
				if (strstr(mtac_port_info[i - 1]->product_id, PRODUCT_ID_MTAC_XDOT)) {
					count++;
				}
			}
		}
	}
	if (count > 0) {
		sprintf(buf, "xdot-%d", count);
	} else {
		sprintf(buf, "xdot");
	}
	ret = sysfs_create_link(mtac_port_info[port_index]->subdirs->parent, mtac_port_info[port_index]->subdirs, buf);
	if (ret) {
		dev_err(&mts_io_platform_device->dev,"Failed to link [%s] to [%s], %d\n", buf, mtac_port_info[port_index]->subdirs->name, ret);
	}

	attrs = kzalloc(sizeof(struct attribute*) * ap_xdot_attrs_size, GFP_KERNEL);
	if (! attrs) {
		dev_err(&mts_io_platform_device->dev,"Failed to allocate attribute space for port %d\n", port);
		return false;
	}
	
	sprintf(buf,"eui");
	attr = mtac_create_attribute("eui", MTS_ATTR_MODE_RO);
	if (! attr) {
		dev_err(&mts_io_platform_device->dev,"Failed to create attribute [%s] for XDOT in port %d\n", buf, port);
		attrs[index] = NULL;
		mtac_port_info[port_index]->attr_group.attrs = attrs;
		return false;
	}
	attr->show = xdot_show_eui;
	attrs[index++] = &attr->attr;

	sprintf(buf, "reset");
	attr = mtac_create_attribute(buf, MTS_ATTR_MODE_RW);
	if (! attr) {
		dev_err(&mts_io_platform_device->dev,"Failed to create attribute [%s] for ETH in port %d\n", buf, port);
		kfree(attrs);
		return false;
	}
	mtac_port_info[port_index]->attr_group.attrs = attrs;
	attr->show = xdot_show_reset;
	attr->store = xdot_store_reset;
	attrs[index++] = &attr->attr;

	// add attributes for eeprom contents
	if (! mtac_add_product_info_attributes(port, attrs, &index)) {
		dev_err(&mts_io_platform_device->dev,"Failed to add product info attributes for XDOT in port %d\n", port);
		return false;
	}

	attrs[index] = NULL;

	mtac_port_info[port_index]->attr_group.attrs = attrs;
	if (sysfs_create_group(mtac_port_info[port_index]->subdirs, &mtac_port_info[port_index]->attr_group)) {
		dev_err(&mts_io_platform_device->dev,"sysfs_create_group failed for XDOT in port %d\n", port);
		return false;
	}

	return true;
}

static bool xdot_teardown(enum ap port) {
	int i;
	int port_index = port - 1;
	struct attribute **attrs = mtac_port_info[port_index]->attr_group.attrs;

	dev_info(&mts_io_platform_device->dev,"unloading XDOT accessory card in port %d\n", port);

	// clean up allocated memory for attributes
	for (i = 0; i < ap_xdot_attrs_size; i++) {
            if (attrs[i]) {
                if (attrs[i]->name)
                    kfree(attrs[i]->name);
                kfree(attrs[i]);
            }
	}

	kfree(attrs);

	// clean up our "apX/" kobject if it exists
	if (mtac_port_info[port_index]->subdirs) {
		kobject_put(mtac_port_info[port_index]->subdirs);
	}

	mtac_clear_port_pins(port_index);

	return true;
}

void set_xdot_info(struct ap_info* info) {
	snprintf(info->product_id, 32, "%s", PRODUCT_ID_MTAC_XDOT);
	info->setup = &xdot_setup;
	info->teardown = &xdot_teardown;
	info->gpio_pin_name_by_attr_name = &xdot_gpio_pin_name_by_attr_name;
}

/*
 * Loop through all the slots, and set up the
 * mtac-xdot driver for all slots.
 */
static int __init mtac_xdot_init(void)
{
	int slot_count = 0;

	slot_count = mtac_find(set_xdot_info,PRODUCT_ID_MTAC_XDOT);

	if (slot_count < 1) {
		dev_dbg(&mts_io_platform_device->dev,"No MTAC XDOT found\n");
		if (slot_count < 0)
			return slot_count;
		else
			return -ENXIO;

	}

	return 0;
}
/* We can only tear down our own device */
static void __exit mtac_xdot_exit(void)
{
	mtac_free(PRODUCT_ID_MTAC_XDOT,xdot_setup,"xdot");
	dev_info(&mts_io_platform_device->dev,"exiting\n");
}

module_init(mtac_xdot_init);
module_exit(mtac_xdot_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL");