/*
 * I2C multiplexer for accton as6812 CPLD
 *
 * Copyright (C) 2015 Accton Technology Corporation.
 * Brandon Chuang <brandon_chuang@accton.com.tw>
 *
 * This module supports the accton cpld that hold the channel select
 * mechanism for other i2c slave devices, such as SFP.
 * This includes the:
 *	 Accton as6812_32x CPLD1/CPLD2/CPLD3
 *
 * Based on:
 *	pca954x.c from Kumar Gala <galak@kernel.crashing.org>
 * Copyright (C) 2006
 *
 * Based on:
 *	pca954x.c from Ken Harrenstien
 * Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
 *
 * Based on:
 *	i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
 * and
 *	pca9540.c from Jean Delvare <khali@linux-fr.org>.
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/version.h>
#include <linux/stat.h>
#include <linux/hwmon-sysfs.h>
#include <linux/delay.h>

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

#define NUM_OF_CPLD1_CHANS 0x0
#define NUM_OF_CPLD2_CHANS 0x10
#define NUM_OF_CPLD3_CHANS 0x10
#define CPLD_CHANNEL_SELECT_REG 0x2

static LIST_HEAD(cpld_client_list);
static struct mutex     list_lock;

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

enum cpld_mux_type {
	as6812_32x_cpld2,
	as6812_32x_cpld3,
	as6812_32x_cpld1
};

struct as6812_32x_cpld_data {
    enum cpld_mux_type type;
    struct i2c_client *client;
    u8 last_chan;  /* last register value */

    struct device      *hwmon_dev;
    struct mutex        update_lock;
};

struct chip_desc {
	u8	 nchans;
	u8	 deselectChan;
};

/* Provide specs for the PCA954x types we know about */
static const struct chip_desc chips[] = {
	[as6812_32x_cpld1] = {
	.nchans		   = NUM_OF_CPLD1_CHANS,
	.deselectChan  = NUM_OF_CPLD1_CHANS,
	},
	[as6812_32x_cpld2] = {
	.nchans		   = NUM_OF_CPLD2_CHANS,
	.deselectChan  = NUM_OF_CPLD2_CHANS,
	},
	[as6812_32x_cpld3] = {
	.nchans		   = NUM_OF_CPLD3_CHANS,
	.deselectChan  = NUM_OF_CPLD3_CHANS,
	}
};

static const struct i2c_device_id as6812_32x_cpld_mux_id[] = {
	{ "as6812_32x_cpld1", as6812_32x_cpld1 },
	{ "as6812_32x_cpld2", as6812_32x_cpld2 },
	{ "as6812_32x_cpld3", as6812_32x_cpld3 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, as6812_32x_cpld_mux_id);

#define TRANSCEIVER_PRESENT_ATTR_ID(index)   	MODULE_PRESENT_##index
#define TRANSCEIVER_TXDISABLE_ATTR_ID(index)   	MODULE_TXDISABLE_##index
#define TRANSCEIVER_RXLOS_ATTR_ID(index)   		MODULE_RXLOS_##index
#define TRANSCEIVER_TXFAULT_ATTR_ID(index)   	MODULE_TXFAULT_##index

enum as6812_32x_cpld_sysfs_attributes {
	CPLD_VERSION,
	ACCESS,
	MODULE_PRESENT_ALL,
	MODULE_RXLOS_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 
 */
static ssize_t show_status(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 as6812_32x_cpld_read_internal(struct i2c_client *client, u8 reg);
static int as6812_32x_cpld_write_internal(struct i2c_client *client, u8 reg, u8 value);

/* transceiver attributes */
#define DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(index) \
	static SENSOR_DEVICE_ATTR(module_present_##index, S_IRUGO, show_status, NULL, MODULE_PRESENT_##index)
#define DECLARE_TRANSCEIVER_PRESENT_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_PRESENT_SENSOR_DEVICE_ATTR(1);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(2);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(3);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(4);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(5);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(6);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(7);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(8);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(9);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(10);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(11);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(12);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(13);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(14);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(15);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(16);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(17);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(18);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(19);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(20);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(21);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(22);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(23);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(24);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(25);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(26);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(27);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(28);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(29);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(30);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(31);
DECLARE_TRANSCEIVER_PRESENT_SENSOR_DEVICE_ATTR(32);

static struct attribute *as6812_32x_cpld1_attributes[] = {
    &sensor_dev_attr_version.dev_attr.attr,
    &sensor_dev_attr_access.dev_attr.attr,
	NULL
};

static const struct attribute_group as6812_32x_cpld1_group = {
	.attrs = as6812_32x_cpld1_attributes,
};

static struct attribute *as6812_32x_cpld2_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_PRESENT_ATTR(1),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(2),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(3),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(4),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(5),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(6),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(7),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(8),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(9),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(10),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(11),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(12),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(13),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(14),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(15),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(16),
	NULL
};

static const struct attribute_group as6812_32x_cpld2_group = {
	.attrs = as6812_32x_cpld2_attributes,
};

static struct attribute *as6812_32x_cpld3_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_PRESENT_ATTR(17),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(18),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(19),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(20),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(21),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(22),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(23),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(24),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(25),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(26),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(27),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(28),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(29),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(30),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(31),
	DECLARE_TRANSCEIVER_PRESENT_ATTR(32),
	NULL
};

static const struct attribute_group as6812_32x_cpld3_group = {
	.attrs = as6812_32x_cpld3_attributes,
};

static ssize_t show_present_all(struct device *dev, struct device_attribute *da,
             char *buf)
{
	int i, status;
	u8 values[2] = {0};
	u8 regs[] = {0xA, 0xB};
    struct i2c_client *client = to_i2c_client(dev);
    struct i2c_mux_core *muxc = i2c_get_clientdata(client);
    struct as6812_32x_cpld_data *data = i2c_mux_priv(muxc);

	mutex_lock(&data->update_lock);

    for (i = 0; i < ARRAY_SIZE(regs); i++) {
        status = as6812_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\n", values[0], values[1]);

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

static ssize_t show_status(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 i2c_mux_core *muxc = i2c_get_clientdata(client);
    struct as6812_32x_cpld_data *data = i2c_mux_priv(muxc);
	int status = 0;
	u8 reg = 0, mask = 0;

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

    mutex_lock(&data->update_lock);
	status = as6812_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)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct i2c_mux_core *muxc = i2c_get_clientdata(client);
    struct as6812_32x_cpld_data *data = i2c_mux_priv(muxc);
	int status;
	u32 addr, val;

	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 = as6812_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;
}

/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
   for this as they will try to lock adapter a second time */
static int as6812_32x_cpld_mux_reg_write(struct i2c_adapter *adap,
			     struct i2c_client *client, u8 val)
{
	unsigned long orig_jiffies;
	unsigned short flags;
	union i2c_smbus_data data;
	int try;
	s32 res = -EIO;

	data.byte = val;
	flags = client->flags;
	flags &= I2C_M_TEN | I2C_CLIENT_PEC;

	if (adap->algo->smbus_xfer) {
		/* Retry automatically on arbitration loss */
		orig_jiffies = jiffies;
		for (res = 0, try = 0; try <= adap->retries; try++) {
			res = adap->algo->smbus_xfer(adap, client->addr, flags,
                             I2C_SMBUS_WRITE, CPLD_CHANNEL_SELECT_REG,
                             I2C_SMBUS_BYTE_DATA, &data);
			if (res != -EAGAIN)
				break;
			if (time_after(jiffies,
					orig_jiffies + adap->timeout))
				break;
		}
	}

	return res;
}

static int as6812_32x_cpld_mux_select_chan(struct i2c_mux_core *muxc, 
    u32 chan)
{
    struct as6812_32x_cpld_data *data = i2c_mux_priv(muxc);
	struct i2c_client *client = data->client;
	u8 regval;
	int ret = 0;
	regval = chan;

	/* Only select the channel if its different from the last channel */
	if (data->last_chan != regval) {
		ret = as6812_32x_cpld_mux_reg_write(muxc->parent, client, regval);
		data->last_chan = regval;
	}

	return ret;
}

static int as6812_32x_cpld_mux_deselect_mux(struct i2c_mux_core *muxc,
    u32 chan)
{
	struct as6812_32x_cpld_data *data = i2c_mux_priv(muxc);
	struct i2c_client *client = data->client;

	/* Deselect active channel */
	data->last_chan = chips[data->type].deselectChan;

	return as6812_32x_cpld_mux_reg_write(muxc->parent, client, data->last_chan);
}

static void as6812_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 as6812_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 ssize_t show_version(struct device *dev, struct device_attribute *attr, char *buf)
{
    int val = 0;
    struct i2c_client *client = to_i2c_client(dev);
	
	val = i2c_smbus_read_byte_data(client, 0x1);

    if (val < 0) {
        dev_dbg(&client->dev, "cpld(0x%x) reg(0x1) err %d\n", client->addr, val);
    }
	
    return sprintf(buf, "%d", val);
}

/*
 * I2C init/probing/exit functions
 */
static int as6812_32x_cpld_mux_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
    struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
	int num, force, class;
	struct i2c_mux_core *muxc;
	struct as6812_32x_cpld_data *data;
    int ret = 0;
    const struct attribute_group *group = NULL;

	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
		return -ENODEV;

	muxc = i2c_mux_alloc(adap, &client->dev,
			     chips[id->driver_data].nchans, sizeof(*data), 0,
			     as6812_32x_cpld_mux_select_chan, as6812_32x_cpld_mux_deselect_mux);
	if (!muxc)
		return -ENOMEM;

    i2c_set_clientdata(client, muxc);
	data = i2c_mux_priv(muxc);
	data->client = client;
    data->type = id->driver_data;
    data->last_chan = chips[data->type].deselectChan;	/* force the first selection */
    mutex_init(&data->update_lock);

	/* Now create an adapter for each channel */
	for (num = 0; num < chips[data->type].nchans; num++) {
		force = 0;			  /* dynamic adap number */
		class = 0;			  /* no class by default */

		ret = i2c_mux_add_adapter(muxc, force, num, class);

		if (ret) {
			dev_err(&client->dev,
				"failed to register multiplexed adapter"
				" %d as bus %d\n", num, force);
			goto add_mux_failed;
		}
	}

    /* Register sysfs hooks */
    switch (data->type) {
    case as6812_32x_cpld1:
        group = &as6812_32x_cpld1_group;
        break;
    case as6812_32x_cpld2:
        group = &as6812_32x_cpld2_group;
        break;
	case as6812_32x_cpld3:
        group = &as6812_32x_cpld3_group;
        break;
    default:
        break;
    }

	
    if (group) {
        ret = sysfs_create_group(&client->dev.kobj, group);
        if (ret) {
            goto add_mux_failed;
        }
    }

    if (chips[data->type].nchans) {
    	dev_info(&client->dev,
    		 "registered %d multiplexed busses for I2C %s\n",
    		 num, client->name);
    }
    else {
    	dev_info(&client->dev,
    		 "device %s registered\n", client->name);
    }

    as6812_32x_cpld_add_client(client);

    return 0;

add_mux_failed:
	i2c_mux_del_adapters(muxc);
	return ret;
} 

static int as6812_32x_cpld_mux_remove(struct i2c_client *client)
{
    struct i2c_mux_core *muxc = i2c_get_clientdata(client);
    struct as6812_32x_cpld_data *data = i2c_mux_priv(muxc);
    const struct attribute_group *group = NULL;

    as6812_32x_cpld_remove_client(client);

    /* Remove sysfs hooks */
    switch (data->type) {
    case as6812_32x_cpld1:
        group = &as6812_32x_cpld1_group;
        break;
    case as6812_32x_cpld2:
        group = &as6812_32x_cpld2_group;
        break;
	case as6812_32x_cpld3:
        group = &as6812_32x_cpld3_group;
        break;
    default:
        break;
    }

    if (group) {
        sysfs_remove_group(&client->dev.kobj, group);
    }

	i2c_mux_del_adapters(muxc);

    return 0;
}

static int as6812_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 as6812_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;
}

int as6812_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 = as6812_32x_cpld_read_internal(cpld_node->client, reg);
    		break;
        }
    }

	mutex_unlock(&list_lock);

    return ret;
}
EXPORT_SYMBOL(as6812_32x_cpld_read);

int as6812_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 = as6812_32x_cpld_write_internal(cpld_node->client, reg, value);
            break;
        }
    }

	mutex_unlock(&list_lock);

    return ret;
}
EXPORT_SYMBOL(as6812_32x_cpld_write);

static struct i2c_driver as6812_32x_cpld_mux_driver = {
	.driver		= {
		.name	= "as6812_32x_cpld",
		.owner	= THIS_MODULE,
	},
	.probe		= as6812_32x_cpld_mux_probe,
	.remove		= as6812_32x_cpld_mux_remove,
	.id_table	= as6812_32x_cpld_mux_id,
};

static int __init as6812_32x_cpld_mux_init(void)
{
    mutex_init(&list_lock);
    return i2c_add_driver(&as6812_32x_cpld_mux_driver);
}

static void __exit as6812_32x_cpld_mux_exit(void)
{
    i2c_del_driver(&as6812_32x_cpld_mux_driver);
}

MODULE_AUTHOR("Brandon Chuang <brandon_chuang@accton.com.tw>");
MODULE_DESCRIPTION("Accton I2C CPLD mux driver");
MODULE_LICENSE("GPL");

module_init(as6812_32x_cpld_mux_init);
module_exit(as6812_32x_cpld_mux_exit);

