/*
 * A hwmon driver for the as7712_32x_cpld
 *
 * Copyright (C) 2013 Accton Technology Corporation.
 * Brandon Chuang <brandon_chuang@accton.com.tw>
 *
 * Based on ad7414.c
 * Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/list.h>

static LIST_HEAD(cpld_client_list);
static struct mutex	 list_lock;

struct cpld_client_node {
	struct i2c_client *client;
	struct list_head   list;
};

#define I2C_RW_RETRY_COUNT				10
#define I2C_RW_RETRY_INTERVAL			60 /* ms */

static ssize_t show_present(struct device *dev, struct device_attribute *da,
             char *buf);
static ssize_t show_present_all(struct device *dev, struct device_attribute *da,
             char *buf);
static ssize_t access(struct device *dev, struct device_attribute *da,
			const char *buf, size_t count);
static ssize_t show_version(struct device *dev, struct device_attribute *da,
             char *buf);
static int as7712_32x_cpld_read_internal(struct i2c_client *client, u8 reg);
static int as7712_32x_cpld_write_internal(struct i2c_client *client, u8 reg, u8 value);

struct as7712_32x_cpld_data {
    struct device      *hwmon_dev;
    struct mutex        update_lock;
};

/* Addresses scanned for as7712_32x_cpld
 */
static const unsigned short normal_i2c[] = { I2C_CLIENT_END };

#define TRANSCEIVER_PRESENT_ATTR_ID(index)   MODULE_PRESENT_##index

enum as7712_32x_cpld_sysfs_attributes {
	CPLD_VERSION,
	ACCESS,
	MODULE_PRESENT_ALL,
	/* transceiver attributes */
	TRANSCEIVER_PRESENT_ATTR_ID(1),
	TRANSCEIVER_PRESENT_ATTR_ID(2),
	TRANSCEIVER_PRESENT_ATTR_ID(3),
	TRANSCEIVER_PRESENT_ATTR_ID(4),
	TRANSCEIVER_PRESENT_ATTR_ID(5),
	TRANSCEIVER_PRESENT_ATTR_ID(6),
	TRANSCEIVER_PRESENT_ATTR_ID(7),
	TRANSCEIVER_PRESENT_ATTR_ID(8),
	TRANSCEIVER_PRESENT_ATTR_ID(9),
	TRANSCEIVER_PRESENT_ATTR_ID(10),
	TRANSCEIVER_PRESENT_ATTR_ID(11),
	TRANSCEIVER_PRESENT_ATTR_ID(12),
	TRANSCEIVER_PRESENT_ATTR_ID(13),
	TRANSCEIVER_PRESENT_ATTR_ID(14),
	TRANSCEIVER_PRESENT_ATTR_ID(15),
	TRANSCEIVER_PRESENT_ATTR_ID(16),
	TRANSCEIVER_PRESENT_ATTR_ID(17),
	TRANSCEIVER_PRESENT_ATTR_ID(18),
	TRANSCEIVER_PRESENT_ATTR_ID(19),
	TRANSCEIVER_PRESENT_ATTR_ID(20),
	TRANSCEIVER_PRESENT_ATTR_ID(21),
	TRANSCEIVER_PRESENT_ATTR_ID(22),
	TRANSCEIVER_PRESENT_ATTR_ID(23),
	TRANSCEIVER_PRESENT_ATTR_ID(24),
	TRANSCEIVER_PRESENT_ATTR_ID(25),
	TRANSCEIVER_PRESENT_ATTR_ID(26),
	TRANSCEIVER_PRESENT_ATTR_ID(27),
	TRANSCEIVER_PRESENT_ATTR_ID(28),
	TRANSCEIVER_PRESENT_ATTR_ID(29),
	TRANSCEIVER_PRESENT_ATTR_ID(30),
	TRANSCEIVER_PRESENT_ATTR_ID(31),
	TRANSCEIVER_PRESENT_ATTR_ID(32),
};

/* sysfs attributes for hwmon 
 */

/* transceiver attributes */
#define DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(index) \
	static SENSOR_DEVICE_ATTR(module_present_##index, S_IRUGO, show_present, NULL, MODULE_PRESENT_##index)
#define DECLARE_TRANSCEIVER_ATTR(index)  &sensor_dev_attr_module_present_##index.dev_attr.attr

static SENSOR_DEVICE_ATTR(version, S_IRUGO, show_version, NULL, CPLD_VERSION);
static SENSOR_DEVICE_ATTR(access, S_IWUSR, NULL, access, ACCESS);
/* transceiver attributes */
static SENSOR_DEVICE_ATTR(module_present_all, S_IRUGO, show_present_all, NULL, MODULE_PRESENT_ALL);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(1);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(2);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(3);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(4);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(5);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(6);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(7);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(8);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(9);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(10);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(11);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(12);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(13);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(14);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(15);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(16);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(17);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(18);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(19);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(20);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(21);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(22);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(23);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(24);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(25);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(26);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(27);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(28);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(29);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(30);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(31);
DECLARE_TRANSCEIVER_SENSOR_DEVICE_ATTR(32);

static struct attribute *as7712_32x_cpld_attributes[] = {
    &sensor_dev_attr_version.dev_attr.attr,
    &sensor_dev_attr_access.dev_attr.attr,
	/* transceiver attributes */
	&sensor_dev_attr_module_present_all.dev_attr.attr,
	DECLARE_TRANSCEIVER_ATTR(1),
	DECLARE_TRANSCEIVER_ATTR(2),
	DECLARE_TRANSCEIVER_ATTR(3),
	DECLARE_TRANSCEIVER_ATTR(4),
	DECLARE_TRANSCEIVER_ATTR(5),
	DECLARE_TRANSCEIVER_ATTR(6),
	DECLARE_TRANSCEIVER_ATTR(7),
	DECLARE_TRANSCEIVER_ATTR(8),
	DECLARE_TRANSCEIVER_ATTR(9),
	DECLARE_TRANSCEIVER_ATTR(10),
	DECLARE_TRANSCEIVER_ATTR(11),
	DECLARE_TRANSCEIVER_ATTR(12),
	DECLARE_TRANSCEIVER_ATTR(13),
	DECLARE_TRANSCEIVER_ATTR(14),
	DECLARE_TRANSCEIVER_ATTR(15),
	DECLARE_TRANSCEIVER_ATTR(16),
	DECLARE_TRANSCEIVER_ATTR(17),
	DECLARE_TRANSCEIVER_ATTR(18),
	DECLARE_TRANSCEIVER_ATTR(19),
	DECLARE_TRANSCEIVER_ATTR(20),
	DECLARE_TRANSCEIVER_ATTR(21),
	DECLARE_TRANSCEIVER_ATTR(22),
	DECLARE_TRANSCEIVER_ATTR(23),
	DECLARE_TRANSCEIVER_ATTR(24),
	DECLARE_TRANSCEIVER_ATTR(25),
	DECLARE_TRANSCEIVER_ATTR(26),
	DECLARE_TRANSCEIVER_ATTR(27),
	DECLARE_TRANSCEIVER_ATTR(28),
	DECLARE_TRANSCEIVER_ATTR(29),
	DECLARE_TRANSCEIVER_ATTR(30),
	DECLARE_TRANSCEIVER_ATTR(31),
	DECLARE_TRANSCEIVER_ATTR(32),
	NULL
};

static const struct attribute_group as7712_32x_cpld_group = {
	.attrs = as7712_32x_cpld_attributes,
};

static ssize_t show_present_all(struct device *dev, struct device_attribute *da,
             char *buf)
{
	int i, status;
	u8 values[4]  = {0};
	u8 regs[] = {0x30, 0x31, 0x32, 0x33};
	struct i2c_client *client = to_i2c_client(dev);
	struct as7712_32x_cpld_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->update_lock);

    for (i = 0; i < ARRAY_SIZE(regs); i++) {
        status = as7712_32x_cpld_read_internal(client, regs[i]);
        
        if (status < 0) {
            goto exit;
        }

        values[i] = ~(u8)status;
    }

	mutex_unlock(&data->update_lock);

    /* Return values 1 -> 32 in order */
    return sprintf(buf, "%.2x %.2x %.2x %.2x\n",
                   values[0], values[1], values[2],
                   values[3]);

exit:
	mutex_unlock(&data->update_lock);
	return status;
}

static ssize_t show_present(struct device *dev, struct device_attribute *da,
             char *buf)
{
    struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
    struct i2c_client *client = to_i2c_client(dev);
    struct as7712_32x_cpld_data *data = i2c_get_clientdata(client);
	int status = 0;
	u8 reg = 0, mask = 0;

	switch (attr->index) {
	case MODULE_PRESENT_1 ... MODULE_PRESENT_8:
		reg  = 0x30;
		mask = 0x1 << (attr->index - MODULE_PRESENT_1);
		break;
	case MODULE_PRESENT_9 ... MODULE_PRESENT_16:
		reg  = 0x31;
		mask = 0x1 << (attr->index - MODULE_PRESENT_9);
		break;
	case MODULE_PRESENT_17 ... MODULE_PRESENT_24:
		reg  = 0x32;
		mask = 0x1 << (attr->index - MODULE_PRESENT_17);
		break;
	case MODULE_PRESENT_25 ... MODULE_PRESENT_32:
		reg  = 0x33;
		mask = 0x1 << (attr->index - MODULE_PRESENT_25);
		break;
	default:
		return 0;
	}


    mutex_lock(&data->update_lock);
	status = as7712_32x_cpld_read_internal(client, reg);
	if (unlikely(status < 0)) {
		goto exit;
	}
	mutex_unlock(&data->update_lock);

	return sprintf(buf, "%d\n", !(status & mask));

exit:
	mutex_unlock(&data->update_lock);
	return status;
}

static ssize_t show_version(struct device *dev, struct device_attribute *da,
             char *buf)
{
	u8 reg = 0, mask = 0;
    struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
    struct i2c_client *client = to_i2c_client(dev);
    struct as7712_32x_cpld_data *data = i2c_get_clientdata(client);
	int status = 0;

	switch (attr->index) {
	case CPLD_VERSION:
		reg  = 0x1;
		mask = 0xFF;
		break;
	default:
		break;
	}

    mutex_lock(&data->update_lock);
	status = as7712_32x_cpld_read_internal(client, reg);
	if (unlikely(status < 0)) {
		goto exit;
	}
	mutex_unlock(&data->update_lock);
	return sprintf(buf, "%d\n", (status & mask));

exit:
	mutex_unlock(&data->update_lock);
	return status;
}

static ssize_t access(struct device *dev, struct device_attribute *da,
			const char *buf, size_t count)
{
	int status;
	u32 addr, val;
    struct i2c_client *client = to_i2c_client(dev);
    struct as7712_32x_cpld_data *data = i2c_get_clientdata(client);

	if (sscanf(buf, "0x%x 0x%x", &addr, &val) != 2) {
		return -EINVAL;
	}

	if (addr > 0xFF || val > 0xFF) {
		return -EINVAL;
	}

	mutex_lock(&data->update_lock);
	status = as7712_32x_cpld_write_internal(client, addr, val);
	if (unlikely(status < 0)) {
		goto exit;
	}
	mutex_unlock(&data->update_lock);
	return count;

exit:
	mutex_unlock(&data->update_lock);
	return status;
}

static int as7712_32x_cpld_read_internal(struct i2c_client *client, u8 reg)
{
	int status = 0, retry = I2C_RW_RETRY_COUNT;

	while (retry) {
		status = i2c_smbus_read_byte_data(client, reg);
		if (unlikely(status < 0)) {
			msleep(I2C_RW_RETRY_INTERVAL);
			retry--;
			continue;
		}

		break;
	}

    return status;
}

static int as7712_32x_cpld_write_internal(struct i2c_client *client, u8 reg, u8 value)
{
	int status = 0, retry = I2C_RW_RETRY_COUNT;

	while (retry) {
		status = i2c_smbus_write_byte_data(client, reg, value);
		if (unlikely(status < 0)) {
			msleep(I2C_RW_RETRY_INTERVAL);
			retry--;
			continue;
		}

		break;
	}

    return status;
}

static void as7712_32x_cpld_add_client(struct i2c_client *client)
{
	struct cpld_client_node *node = kzalloc(sizeof(struct cpld_client_node), GFP_KERNEL);
	
	if (!node) {
		dev_dbg(&client->dev, "Can't allocate cpld_client_node (0x%x)\n", client->addr);
		return;
	}
	
	node->client = client;
	
	mutex_lock(&list_lock);
	list_add(&node->list, &cpld_client_list);
	mutex_unlock(&list_lock);
}

static void as7712_32x_cpld_remove_client(struct i2c_client *client)
{
	struct list_head		*list_node = NULL;
	struct cpld_client_node *cpld_node = NULL;
	int found = 0;
	
	mutex_lock(&list_lock);

	list_for_each(list_node, &cpld_client_list)
	{
		cpld_node = list_entry(list_node, struct cpld_client_node, list);
		
		if (cpld_node->client == client) {
			found = 1;
			break;
		}
	}
	
	if (found) {
		list_del(list_node);
		kfree(cpld_node);
	}
	
	mutex_unlock(&list_lock);
}

static int as7712_32x_cpld_probe(struct i2c_client *client,
            const struct i2c_device_id *dev_id)
{
    int status;
	struct as7712_32x_cpld_data *data = NULL;

    if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
        dev_dbg(&client->dev, "i2c_check_functionality failed (0x%x)\n", client->addr);
        status = -EIO;
        goto exit;
    }

    data = kzalloc(sizeof(struct as7712_32x_cpld_data), GFP_KERNEL);
    if (!data) {
        status = -ENOMEM;
        goto exit;
    }

    i2c_set_clientdata(client, data);
    mutex_init(&data->update_lock);
    dev_info(&client->dev, "chip found\n");

	/* Register sysfs hooks */
	status = sysfs_create_group(&client->dev.kobj, &as7712_32x_cpld_group);
	if (status) {
		goto exit_free;
	}

    data->hwmon_dev = hwmon_device_register_with_info(&client->dev, "as7712_32x_cpld",
                                                      NULL, NULL, NULL);
	if (IS_ERR(data->hwmon_dev)) {
		status = PTR_ERR(data->hwmon_dev);
		goto exit_remove;
	}

	as7712_32x_cpld_add_client(client);

	dev_info(&client->dev, "%s: cpld '%s'\n",
		 dev_name(data->hwmon_dev), client->name);

    return 0;

exit_remove:
    sysfs_remove_group(&client->dev.kobj, &as7712_32x_cpld_group);
exit_free:
    kfree(data);
exit:
    
    return status;
}

static int as7712_32x_cpld_remove(struct i2c_client *client)
{
    struct as7712_32x_cpld_data *data = i2c_get_clientdata(client);

    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &as7712_32x_cpld_group);
    kfree(data);
	as7712_32x_cpld_remove_client(client);

    return 0;
}

int as7712_32x_cpld_read(unsigned short cpld_addr, u8 reg)
{
	struct list_head   *list_node = NULL;
	struct cpld_client_node *cpld_node = NULL;
	int ret = -EPERM;
	
	mutex_lock(&list_lock);

	list_for_each(list_node, &cpld_client_list)
	{
		cpld_node = list_entry(list_node, struct cpld_client_node, list);
		
		if (cpld_node->client->addr == cpld_addr) {
			ret = i2c_smbus_read_byte_data(cpld_node->client, reg);
			break;
		}
	}
	
	mutex_unlock(&list_lock);

	return ret;
}
EXPORT_SYMBOL(as7712_32x_cpld_read);

int as7712_32x_cpld_write(unsigned short cpld_addr, u8 reg, u8 value)
{
	struct list_head   *list_node = NULL;
	struct cpld_client_node *cpld_node = NULL;
	int ret = -EIO;
	
	mutex_lock(&list_lock);

	list_for_each(list_node, &cpld_client_list)
	{
		cpld_node = list_entry(list_node, struct cpld_client_node, list);
		
		if (cpld_node->client->addr == cpld_addr) {
			ret = i2c_smbus_write_byte_data(cpld_node->client, reg, value);
			break;
		}
	}
	
	mutex_unlock(&list_lock);

	return ret;
}
EXPORT_SYMBOL(as7712_32x_cpld_write);

static const struct i2c_device_id as7712_32x_cpld_id[] = {
    { "as7712_32x_cpld1", 0 },
    {}
};
MODULE_DEVICE_TABLE(i2c, as7712_32x_cpld_id);

static struct i2c_driver as7712_32x_cpld_driver = {
    .class        = I2C_CLASS_HWMON,
    .driver = {
        .name     = "as7712_32x_cpld1",
    },
    .probe        = as7712_32x_cpld_probe,
    .remove       = as7712_32x_cpld_remove,
    .id_table     = as7712_32x_cpld_id,
    .address_list = normal_i2c,
};

static int __init as7712_32x_cpld_init(void)
{
	mutex_init(&list_lock);
	return i2c_add_driver(&as7712_32x_cpld_driver);
}

static void __exit as7712_32x_cpld_exit(void)
{
	i2c_del_driver(&as7712_32x_cpld_driver);
}

module_init(as7712_32x_cpld_init);
module_exit(as7712_32x_cpld_exit);

MODULE_AUTHOR("Brandon Chuang <brandon_chuang@accton.com.tw>");
MODULE_DESCRIPTION("as7712_32x_cpld driver");
MODULE_LICENSE("GPL");

