/*
 * SFP driver for accton as7816_64x sfp
 *
 * Copyright (C)  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>

#define DRIVER_NAME 	"as7816_64x_sfp" /* Platform dependent */

#define DEBUG_MODE 0

#if (DEBUG_MODE == 1)
	#define DEBUG_PRINT(fmt, args...)										 \
		printk (KERN_INFO "%s:%s[%d]: " fmt "\r\n", __FILE__, __FUNCTION__, __LINE__, ##args)
#else
	#define DEBUG_PRINT(fmt, args...)
#endif

#define NUM_OF_SFP_PORT			24
#define EEPROM_NAME				"sfp_eeprom"
#define EEPROM_SIZE				256	/*	256 byte eeprom */
#define BIT_INDEX(i)			(1ULL << (i))
#define USE_I2C_BLOCK_READ 		1 /* Platform dependent */
#define I2C_RW_RETRY_COUNT		10
#define I2C_RW_RETRY_INTERVAL	60 /* ms */

#define SFP_EEPROM_A0_I2C_ADDR (0xA0 >> 1)

#define SFF8024_PHYSICAL_DEVICE_ID_ADDR		0x0
#define SFF8024_DEVICE_ID_SFP				0x3
#define SFF8024_DEVICE_ID_QSFP				0xC
#define SFF8024_DEVICE_ID_QSFP_PLUS			0xD
#define SFF8024_DEVICE_ID_QSFP28			0x11

#define SFF8436_RX_LOS_ADDR					3
#define SFF8436_TX_FAULT_ADDR				4
#define SFF8436_TX_DISABLE_ADDR				86

#define MULTIPAGE_SUPPORT		1

#if (MULTIPAGE_SUPPORT == 1)
/* fundamental unit of addressing for SFF_8472/SFF_8436 */
#define SFF_8436_PAGE_SIZE 128
/* 
 * The current 8436 (QSFP) spec provides for only 4 supported
 * pages (pages 0-3).  
 * This driver is prepared to support more, but needs a register in the 
 * EEPROM to indicate how many pages are supported before it is safe
 * to implement more pages in the driver.
 */
#define SFF_8436_SPECED_PAGES 4
#define SFF_8436_EEPROM_SIZE ((1 + SFF_8436_SPECED_PAGES) * SFF_8436_PAGE_SIZE)
#define SFF_8436_EEPROM_UNPAGED_SIZE (2 * SFF_8436_PAGE_SIZE)
/* 
 * The current 8472 (SFP) spec provides for only 3 supported 
 * pages (pages 0-2).
 * This driver is prepared to support more, but needs a register in the 
 * EEPROM to indicate how many pages are supported before it is safe
 * to implement more pages in the driver.
 */
#define SFF_8472_SPECED_PAGES 3
#define SFF_8472_EEPROM_SIZE ((3 + SFF_8472_SPECED_PAGES) * SFF_8436_PAGE_SIZE)
#define SFF_8472_EEPROM_UNPAGED_SIZE (4 * SFF_8436_PAGE_SIZE)

/* a few constants to find our way around the EEPROM */
#define SFF_8436_PAGE_SELECT_REG   0x7F
#define SFF_8436_PAGEABLE_REG 0x02
#define SFF_8436_NOT_PAGEABLE (1<<2)
#define SFF_8472_PAGEABLE_REG 0x40
#define SFF_8472_PAGEABLE (1<<4)

/*
 * This parameter is to help this driver avoid blocking other drivers out
 * of I2C for potentially troublesome amounts of time. With a 100 kHz I2C
 * clock, one 256 byte read takes about 1/43 second which is excessive;
 * but the 1/170 second it takes at 400 kHz may be quite reasonable; and
 * at 1 MHz (Fm+) a 1/430 second delay could easily be invisible.
 *
 * This value is forced to be a power of two so that writes align on pages.
 */
static unsigned io_limit = SFF_8436_PAGE_SIZE;

/*
 * specs often allow 5 msec for a page write, sometimes 20 msec;
 * it's important to recover from write timeouts.
 */
static unsigned write_timeout = 25;

typedef enum qsfp_opcode {
	QSFP_READ_OP = 0,
	QSFP_WRITE_OP = 1
} qsfp_opcode_e;
#endif

static ssize_t show_port_number(struct device *dev, struct device_attribute *da, char *buf);
static ssize_t show_present(struct device *dev, struct device_attribute *da, char *buf);
static ssize_t qsfp_show_tx_rx_status(struct device *dev, struct device_attribute *da, char *buf);
static ssize_t qsfp_set_tx_disable(struct device *dev, struct device_attribute *da, const char *buf, size_t count);;
static ssize_t sfp_eeprom_read(struct i2c_client *, u8, u8 *,int);
static ssize_t sfp_eeprom_write(struct i2c_client *, u8 , const char *,int);
extern int accton_i2c_cpld_read (u8 cpld_addr, u8 reg);

enum sfp_sysfs_attributes {
	PRESENT,
	PRESENT_ALL,
	PORT_NUMBER,
	PORT_TYPE,
	DDM_IMPLEMENTED,
	TX_FAULT,
	TX_FAULT1,
	TX_FAULT2,
	TX_FAULT3,
	TX_FAULT4,
	TX_DISABLE,
	TX_DISABLE1,
	TX_DISABLE2,
	TX_DISABLE3,
	TX_DISABLE4,
	RX_LOS,
	RX_LOS1,
	RX_LOS2,
	RX_LOS3,
	RX_LOS4,
	RX_LOS_ALL
};

/* SFP/QSFP common attributes for sysfs */
static SENSOR_DEVICE_ATTR(sfp_port_number, S_IRUGO, show_port_number, NULL, PORT_NUMBER);
static SENSOR_DEVICE_ATTR(sfp_is_present,  S_IRUGO, show_present, NULL, PRESENT);
static SENSOR_DEVICE_ATTR(sfp_is_present_all,  S_IRUGO, show_present, NULL, PRESENT_ALL);
static SENSOR_DEVICE_ATTR(sfp_tx_disable,  S_IWUSR | S_IRUGO, qsfp_show_tx_rx_status, qsfp_set_tx_disable, TX_DISABLE);
static SENSOR_DEVICE_ATTR(sfp_tx_fault,	 S_IRUGO, qsfp_show_tx_rx_status, NULL, TX_FAULT);

/* QSFP attributes for sysfs */
static SENSOR_DEVICE_ATTR(sfp_rx_los,  S_IRUGO, qsfp_show_tx_rx_status, NULL, RX_LOS);
static SENSOR_DEVICE_ATTR(sfp_rx_los1, S_IRUGO, qsfp_show_tx_rx_status, NULL, RX_LOS1);
static SENSOR_DEVICE_ATTR(sfp_rx_los2, S_IRUGO, qsfp_show_tx_rx_status, NULL, RX_LOS2);
static SENSOR_DEVICE_ATTR(sfp_rx_los3, S_IRUGO, qsfp_show_tx_rx_status, NULL, RX_LOS3);
static SENSOR_DEVICE_ATTR(sfp_rx_los4, S_IRUGO, qsfp_show_tx_rx_status, NULL, RX_LOS4);
static SENSOR_DEVICE_ATTR(sfp_tx_disable1, S_IWUSR | S_IRUGO, qsfp_show_tx_rx_status, qsfp_set_tx_disable, TX_DISABLE1);
static SENSOR_DEVICE_ATTR(sfp_tx_disable2, S_IWUSR | S_IRUGO, qsfp_show_tx_rx_status, qsfp_set_tx_disable, TX_DISABLE2);
static SENSOR_DEVICE_ATTR(sfp_tx_disable3, S_IWUSR | S_IRUGO, qsfp_show_tx_rx_status, qsfp_set_tx_disable, TX_DISABLE3);
static SENSOR_DEVICE_ATTR(sfp_tx_disable4, S_IWUSR | S_IRUGO, qsfp_show_tx_rx_status, qsfp_set_tx_disable, TX_DISABLE4);
static SENSOR_DEVICE_ATTR(sfp_tx_fault1, S_IRUGO, qsfp_show_tx_rx_status, NULL, TX_FAULT1);
static SENSOR_DEVICE_ATTR(sfp_tx_fault2, S_IRUGO, qsfp_show_tx_rx_status, NULL, TX_FAULT2);
static SENSOR_DEVICE_ATTR(sfp_tx_fault3, S_IRUGO, qsfp_show_tx_rx_status, NULL, TX_FAULT3);
static SENSOR_DEVICE_ATTR(sfp_tx_fault4, S_IRUGO, qsfp_show_tx_rx_status, NULL, TX_FAULT4);
static struct attribute *qsfp_attributes[] = {
	&sensor_dev_attr_sfp_port_number.dev_attr.attr,
	&sensor_dev_attr_sfp_is_present.dev_attr.attr,
	&sensor_dev_attr_sfp_is_present_all.dev_attr.attr,
	&sensor_dev_attr_sfp_rx_los.dev_attr.attr,
	&sensor_dev_attr_sfp_rx_los1.dev_attr.attr,
	&sensor_dev_attr_sfp_rx_los2.dev_attr.attr,
	&sensor_dev_attr_sfp_rx_los3.dev_attr.attr,
	&sensor_dev_attr_sfp_rx_los4.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_disable.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_disable1.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_disable2.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_disable3.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_disable4.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_fault.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_fault1.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_fault2.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_fault3.dev_attr.attr,
	&sensor_dev_attr_sfp_tx_fault4.dev_attr.attr,
	NULL
};

/* Platform dependent +++ */
#define CPLD_PORT_TO_FRONT_PORT(port)  (port+1)

enum port_numbers {
as7816_64x_port1,  as7816_64x_port2,  as7816_64x_port3,  as7816_64x_port4,  
as7816_64x_port5,  as7816_64x_port6,  as7816_64x_port7,  as7816_64x_port8, 
as7816_64x_port9,  as7816_64x_port10, as7816_64x_port11, as7816_64x_port12, 
as7816_64x_port13, as7816_64x_port14, as7816_64x_port15, as7816_64x_port16,
as7816_64x_port17, as7816_64x_port18, as7816_64x_port19, as7816_64x_port20,
as7816_64x_port21, as7816_64x_port22, as7816_64x_port23, as7816_64x_port24, 
as7816_64x_port25, as7816_64x_port26, as7816_64x_port27, as7816_64x_port28, 
as7816_64x_port29, as7816_64x_port30, as7816_64x_port31, as7816_64x_port32, 
as7816_64x_port33, as7816_64x_port34, as7816_64x_port35, as7816_64x_port36,
as7816_64x_port37, as7816_64x_port38, as7816_64x_port39, as7816_64x_port40,
as7816_64x_port41, as7816_64x_port42, as7816_64x_port43, as7816_64x_port44,
as7816_64x_port45, as7816_64x_port46, as7816_64x_port47, as7816_64x_port48, 
as7816_64x_port49, as7816_64x_port50, as7816_64x_port51, as7816_64x_port52, 
as7816_64x_port53, as7816_64x_port54, as7816_64x_port55, as7816_64x_port56,
as7816_64x_port57, as7816_64x_port58, as7816_64x_port59, as7816_64x_port60,
as7816_64x_port61, as7816_64x_port62, as7816_64x_port63, as7816_64x_port64
};

#define I2C_DEV_ID(x) { #x, x}

static const struct i2c_device_id sfp_device_id[] = {
I2C_DEV_ID(as7816_64x_port1),
I2C_DEV_ID(as7816_64x_port2),
I2C_DEV_ID(as7816_64x_port3),
I2C_DEV_ID(as7816_64x_port4),
I2C_DEV_ID(as7816_64x_port5),
I2C_DEV_ID(as7816_64x_port6),
I2C_DEV_ID(as7816_64x_port7),
I2C_DEV_ID(as7816_64x_port8),
I2C_DEV_ID(as7816_64x_port9),
I2C_DEV_ID(as7816_64x_port10),
I2C_DEV_ID(as7816_64x_port11),
I2C_DEV_ID(as7816_64x_port12),
I2C_DEV_ID(as7816_64x_port13),
I2C_DEV_ID(as7816_64x_port14),
I2C_DEV_ID(as7816_64x_port15),
I2C_DEV_ID(as7816_64x_port16),
I2C_DEV_ID(as7816_64x_port17),
I2C_DEV_ID(as7816_64x_port18),
I2C_DEV_ID(as7816_64x_port19),
I2C_DEV_ID(as7816_64x_port20),
I2C_DEV_ID(as7816_64x_port21),
I2C_DEV_ID(as7816_64x_port22),
I2C_DEV_ID(as7816_64x_port23),
I2C_DEV_ID(as7816_64x_port24),
I2C_DEV_ID(as7816_64x_port25),
I2C_DEV_ID(as7816_64x_port26),
I2C_DEV_ID(as7816_64x_port27),
I2C_DEV_ID(as7816_64x_port28),
I2C_DEV_ID(as7816_64x_port29),
I2C_DEV_ID(as7816_64x_port30),
I2C_DEV_ID(as7816_64x_port31),
I2C_DEV_ID(as7816_64x_port32),
I2C_DEV_ID(as7816_64x_port33),
I2C_DEV_ID(as7816_64x_port34),
I2C_DEV_ID(as7816_64x_port35),
I2C_DEV_ID(as7816_64x_port36),
I2C_DEV_ID(as7816_64x_port37),
I2C_DEV_ID(as7816_64x_port38),
I2C_DEV_ID(as7816_64x_port39),
I2C_DEV_ID(as7816_64x_port40),
I2C_DEV_ID(as7816_64x_port41),
I2C_DEV_ID(as7816_64x_port42),
I2C_DEV_ID(as7816_64x_port43),
I2C_DEV_ID(as7816_64x_port44),
I2C_DEV_ID(as7816_64x_port45),
I2C_DEV_ID(as7816_64x_port46),
I2C_DEV_ID(as7816_64x_port47),
I2C_DEV_ID(as7816_64x_port48),
I2C_DEV_ID(as7816_64x_port49),
I2C_DEV_ID(as7816_64x_port50),
I2C_DEV_ID(as7816_64x_port51),
I2C_DEV_ID(as7816_64x_port52),
I2C_DEV_ID(as7816_64x_port53),
I2C_DEV_ID(as7816_64x_port54),
I2C_DEV_ID(as7816_64x_port55),
I2C_DEV_ID(as7816_64x_port56),
I2C_DEV_ID(as7816_64x_port57),
I2C_DEV_ID(as7816_64x_port58),
I2C_DEV_ID(as7816_64x_port59),
I2C_DEV_ID(as7816_64x_port60),
I2C_DEV_ID(as7816_64x_port61),
I2C_DEV_ID(as7816_64x_port62),
I2C_DEV_ID(as7816_64x_port63),
I2C_DEV_ID(as7816_64x_port64),
{ /* LIST END */ }
};
MODULE_DEVICE_TABLE(i2c, sfp_device_id);
/* Platform dependent --- */

enum driver_type_e {
	DRIVER_TYPE_SFP_MSA,
	DRIVER_TYPE_SFP_DDM,
	DRIVER_TYPE_QSFP,
	DRIVER_TYPE_XFP
};

/* Each client has this additional data
 */
struct eeprom_data {
	char				 valid;			/* !=0 if registers are valid */
	unsigned long		 last_updated;	/* In jiffies */
	struct bin_attribute bin;			/* eeprom data */
};

struct qsfp_data {
	char			valid;			/* !=0 if registers are valid */
	unsigned long	last_updated;	/* In jiffies */
	u8				status[3];		/* bit0:port0, bit1:port1 and so on */
									/* index 0 => tx_fail
											 1 => tx_disable
											 2 => rx_loss */
	u8					device_id;
	struct eeprom_data	eeprom;
};

struct sfp_port_data {
	struct mutex		   update_lock;
	enum driver_type_e	   driver_type;
	int					   port;		/* CPLD port index */
	u64					   present;		/* present status, bit0:port0, bit1:port1 and so on */

	struct qsfp_data	  *qsfp;

	struct i2c_client	  *client;
#if (MULTIPAGE_SUPPORT == 1)
	int use_smbus;
	u8 *writebuf;
	unsigned write_max;
#endif
};

#if (MULTIPAGE_SUPPORT == 1)
static ssize_t sfp_port_read_write(struct sfp_port_data *port_data,
		char *buf, loff_t off, size_t len, qsfp_opcode_e opcode);
#endif
static ssize_t show_port_number(struct device *dev, struct device_attribute *da,
			 char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct sfp_port_data *data = i2c_get_clientdata(client);
	return sprintf(buf, "%d\n", CPLD_PORT_TO_FRONT_PORT(data->port));
}

/* Platform dependent +++ */
static struct sfp_port_data *sfp_update_present(struct i2c_client *client)
{
	struct sfp_port_data *data = i2c_get_clientdata(client);
	int i = 0;
	int status = -1;
	u8 regs[] = {0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77};

	DEBUG_PRINT("Starting sfp present status update");
	mutex_lock(&data->update_lock);

	/* Read present status of port 1~64 */
    data->present = 0;
	
    for (i = 0; i < ARRAY_SIZE(regs); i++) {
        status = accton_i2c_cpld_read(0x60, regs[i]);
        
        if (status < 0) {
            DEBUG_PRINT("cpld(0x60) reg(0x%x) err %d", regs[i], status);
            goto exit;
        }
        
		DEBUG_PRINT("Present status = 0x%lx", data->present);		
        data->present |= (u64)status << (i*8);
    }

	DEBUG_PRINT("Present status = 0x%lx", data->present);
exit:
	mutex_unlock(&data->update_lock);
	return (status < 0) ? ERR_PTR(status) : data;
}

/* Platform dependent --- */

static int sfp_is_port_present(struct i2c_client *client, int port)
{
	struct sfp_port_data *data = i2c_get_clientdata(client);

	data = sfp_update_present(client);
	if (IS_ERR(data)) {
		return PTR_ERR(data);
	}

	return (data->present & BIT_INDEX(data->port)) ? 0 : 1; /* Platform dependent */
}

/* Platform dependent +++ */
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);

	if (PRESENT_ALL == attr->index) {
		int i;
		u8 values[8]  = {0};
		struct sfp_port_data *data = sfp_update_present(client);
		
		if (IS_ERR(data)) {
			return PTR_ERR(data);
		}

		for (i = 0; i < ARRAY_SIZE(values); i++) {
			values[i] = ~(u8)(data->present >> (i * 8));
		}

        /* Return values 1 -> 64 in order */
        return sprintf(buf, "%.2x %.2x %.2x %.2x %.2x %.2x %.2x %.2x\n",
                       values[0], values[1], values[2], values[3],
                       values[4], values[5], values[6], values[7]);
	}
	else {
		struct sfp_port_data *data = i2c_get_clientdata(client);
		int present = sfp_is_port_present(client, data->port);

		if (IS_ERR_VALUE(present)) {
			return present;
		}

		/* PRESENT */
		return sprintf(buf, "%d\n", present);
	}
}
/* Platform dependent --- */

static struct sfp_port_data *qsfp_update_tx_rx_status(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct sfp_port_data *data = i2c_get_clientdata(client);
	int i, status = -1;
	u8 buf = 0;
	u8 reg[] = {SFF8436_TX_FAULT_ADDR, SFF8436_TX_DISABLE_ADDR, SFF8436_RX_LOS_ADDR};

	if (time_before(jiffies, data->qsfp->last_updated + HZ + HZ / 2) && data->qsfp->valid) {
		return data;
	}

	DEBUG_PRINT("Starting sfp tx rx status update");
	mutex_lock(&data->update_lock);
	data->qsfp->valid = 0;
	memset(data->qsfp->status, 0, sizeof(data->qsfp->status));

	/* Notify device to update tx fault/ tx disable/ rx los status */
	for (i = 0; i < ARRAY_SIZE(reg); i++) {
		status = sfp_eeprom_read(client, reg[i], &buf, sizeof(buf));
		if (unlikely(status < 0)) {
			goto exit;
		}
	}
	msleep(200);

	/* Read actual tx fault/ tx disable/ rx los status */
	for (i = 0; i < ARRAY_SIZE(reg); i++) {
		status = sfp_eeprom_read(client, reg[i], &buf, sizeof(buf));
		if (unlikely(status < 0)) {
			goto exit;
		}

		DEBUG_PRINT("qsfp reg(0x%x) status = (0x%x)", reg[i], data->qsfp->status[i]);
		data->qsfp->status[i] = (buf & 0xF);
	}

	data->qsfp->valid = 1;
	data->qsfp->last_updated = jiffies;

exit:
	mutex_unlock(&data->update_lock);
	return (status < 0) ? ERR_PTR(status) : data;
}

static ssize_t qsfp_show_tx_rx_status(struct device *dev, struct device_attribute *da,
			 char *buf)
{
	int present;
	u8 val = 0;
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct i2c_client *client = to_i2c_client(dev);
	struct sfp_port_data *data = i2c_get_clientdata(client);

	present = sfp_is_port_present(client, data->port);
	if (IS_ERR_VALUE(present)) {
		return present;
	}

	if (present == 0) {
		/* port is not present */
		return -ENXIO;
	}

	data = qsfp_update_tx_rx_status(dev);
	if (IS_ERR(data)) {
		return PTR_ERR(data);
	}

	switch (attr->index) {
	case TX_FAULT:
		val = !!(data->qsfp->status[2] & 0xF);
		break;
	case TX_FAULT1:
	case TX_FAULT2:
	case TX_FAULT3:
	case TX_FAULT4:
		val = !!(data->qsfp->status[2] & BIT_INDEX(attr->index - TX_FAULT1));
		break;
	case TX_DISABLE:
		val = data->qsfp->status[1] & 0xF;
		break;
	case TX_DISABLE1:
	case TX_DISABLE2:
	case TX_DISABLE3:
	case TX_DISABLE4:
		val = !!(data->qsfp->status[1] & BIT_INDEX(attr->index - TX_DISABLE1));
		break;
	case RX_LOS:
		val = !!(data->qsfp->status[0] & 0xF);
		break;
	case RX_LOS1:
	case RX_LOS2:
	case RX_LOS3:
	case RX_LOS4:
		val = !!(data->qsfp->status[0] & BIT_INDEX(attr->index - RX_LOS1));
		break;
	default:
		break;
	}

	return sprintf(buf, "%d\n", val);
}

static ssize_t qsfp_set_tx_disable(struct device *dev, struct device_attribute *da,
			const char *buf, size_t count)
{
	long disable;
	int status;
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct i2c_client *client = to_i2c_client(dev);
	struct sfp_port_data *data = i2c_get_clientdata(client);	

	status = sfp_is_port_present(client, data->port);
	if (IS_ERR_VALUE(status)) {
		return status;
	}

	if (!status) {
		/* port is not present */
		return -ENXIO;
	}

	status = kstrtol(buf, 10, &disable);
	if (status) {
		return status;
	}

	data = qsfp_update_tx_rx_status(dev);
	if (IS_ERR(data)) {
		return PTR_ERR(data);
	}

	mutex_lock(&data->update_lock);

	if (attr->index == TX_DISABLE) {
		if (disable) {
			data->qsfp->status[1] |= 0xF;
		}
		else {
			data->qsfp->status[1] &= ~0xF;
		}
	}
	else {/* TX_DISABLE1 ~ TX_DISABLE4*/
		if (disable) {
			data->qsfp->status[1] |= (1 << (attr->index - TX_DISABLE1));
		}
		else {
			data->qsfp->status[1] &= ~(1 << (attr->index - TX_DISABLE1));
		}
	}

	DEBUG_PRINT("index = (%d), status = (0x%x)", attr->index, data->qsfp->status[1]);
	status = sfp_eeprom_write(data->client, SFF8436_TX_DISABLE_ADDR, &data->qsfp->status[1], sizeof(data->qsfp->status[1]));
	if (unlikely(status < 0)) {
		count = status;
	}

	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t sfp_eeprom_write(struct i2c_client *client, u8 command, const char *data,
			  int data_len)
{
#if USE_I2C_BLOCK_READ
	int status, retry = I2C_RW_RETRY_COUNT;

	if (data_len > I2C_SMBUS_BLOCK_MAX) {
		data_len = I2C_SMBUS_BLOCK_MAX;
	}

	while (retry) {
		status = i2c_smbus_write_i2c_block_data(client, command, data_len, data);
		if (unlikely(status < 0)) {
			msleep(I2C_RW_RETRY_INTERVAL);
			retry--;
			continue;
		}

		break;
	}

	if (unlikely(status < 0)) {
		return status;
	}

	return data_len;
#else
	int status, retry = I2C_RW_RETRY_COUNT;

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

		break;
	}

	if (unlikely(status < 0)) {
		return status;
	}

	return 1;
#endif


}

#if (MULTIPAGE_SUPPORT == 0)
static ssize_t sfp_port_write(struct sfp_port_data *data,
						  const char *buf, loff_t off, size_t count)
{
	ssize_t retval = 0;

	if (unlikely(!count)) {
		return count;
	}

	/*
	 * Write data to chip, protecting against concurrent updates
	 * from this host, but not from other I2C masters.
	 */
	mutex_lock(&data->update_lock);

	while (count) {
		ssize_t status;

		status = sfp_eeprom_write(data->client, off, buf, count);
		if (status <= 0) {
			if (retval == 0) {
				retval = status;
			}
			break;
		}
		buf += status;
		off += status;
		count -= status;
		retval += status;
	}

	mutex_unlock(&data->update_lock);
	return retval;
}
#endif

static ssize_t sfp_bin_write(struct file *filp, struct kobject *kobj,
				struct bin_attribute *attr,
				char *buf, loff_t off, size_t count)
{
	int present;
	struct sfp_port_data *data;
	DEBUG_PRINT("%s(%d) offset = (%d), count = (%d)", off, count);
	data = dev_get_drvdata(container_of(kobj, struct device, kobj));

	present = sfp_is_port_present(data->client, data->port);
	if (IS_ERR_VALUE(present)) {
		return present;
	}

	if (present == 0) {
		/* port is not present */
		return -ENODEV;
	}

#if (MULTIPAGE_SUPPORT == 1)
	return sfp_port_read_write(data, buf, off, count, QSFP_WRITE_OP);
#else
	return sfp_port_write(data, buf, off, count);
#endif
}

static ssize_t sfp_eeprom_read(struct i2c_client *client, u8 command, u8 *data,
			  int data_len)
{
#if USE_I2C_BLOCK_READ
	int status, retry = I2C_RW_RETRY_COUNT;

	if (data_len > I2C_SMBUS_BLOCK_MAX) {
		data_len = I2C_SMBUS_BLOCK_MAX;
	}

	while (retry) {
		status = i2c_smbus_read_i2c_block_data(client, command, data_len, data);
		if (unlikely(status < 0)) {
			msleep(I2C_RW_RETRY_INTERVAL);
			retry--;
			continue;
		}

		break;
	}

	if (unlikely(status < 0)) {
		goto abort;
	}
	if (unlikely(status != data_len)) {
		status = -EIO;
		goto abort;
	}

	//result = data_len;

abort:
	return status;
#else
	int status, retry = I2C_RW_RETRY_COUNT;

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

		break;
	}

	if (unlikely(status < 0)) {
		dev_dbg(&client->dev, "sfp read byte data failed, command(0x%2x), data(0x%2x)\r\n", command, status);
		goto abort;
	}

	*data  = (u8)status;
	status = 1;

abort:
	return status;
#endif
}

#if (MULTIPAGE_SUPPORT == 1)
/*-------------------------------------------------------------------------*/
/*
 * This routine computes the addressing information to be used for
 * a given r/w request.
 *
 * Task is to calculate the client (0 = i2c addr 50, 1 = i2c addr 51),
 * the page, and the offset.
 *
 * Handles both SFP and QSFP.  
 *     For SFP, offset 0-255 are on client[0], >255 is on client[1]
 *     Offset 256-383 are on the lower half of client[1]
 *     Pages are accessible on the upper half of client[1].
 *     Offset >383 are in 128 byte pages mapped into the upper half
 *
 *     For QSFP, all offsets are on client[0]
 *     offset 0-127 are on the lower half of client[0] (no paging)
 *     Pages are accessible on the upper half of client[1].
 *     Offset >127 are in 128 byte pages mapped into the upper half
 *
 *     Callers must not read/write beyond the end of a client or a page
 *     without recomputing the client/page.  Hence offset (within page)
 *     plus length must be less than or equal to 128.  (Note that this
 *     routine does not have access to the length of the call, hence 
 *     cannot do the validity check.)
 *
 * Offset within Lower Page 00h and Upper Page 00h are not recomputed
 */
static uint8_t sff_8436_translate_offset(struct sfp_port_data *port_data,
		loff_t *offset, struct i2c_client **client)
{
	unsigned page = 0;

	*client = port_data->client;

	/*
	 * if offset is in the range 0-128...
	 * page doesn't matter (using lower half), return 0.
	 * offset is already correct (don't add 128 to get to paged area)
	 */
	if (*offset < SFF_8436_PAGE_SIZE)
		return page;

	/* note, page will always be positive since *offset >= 128 */
	page = (*offset >> 7)-1;
	/* 0x80 places the offset in the top half, offset is last 7 bits */
	*offset = SFF_8436_PAGE_SIZE + (*offset & 0x7f);

	return page;  /* note also returning client and offset */
}

static ssize_t sff_8436_eeprom_read(struct sfp_port_data *port_data,
		    struct i2c_client *client,
		    char *buf, unsigned offset, size_t count)
{
	struct i2c_msg msg[2];
	u8 msgbuf[2];
	unsigned long timeout, read_time;
	int status, i;

	memset(msg, 0, sizeof(msg));

	switch (port_data->use_smbus) {
	case I2C_SMBUS_I2C_BLOCK_DATA:
		/*smaller eeproms can work given some SMBus extension calls */
		if (count > I2C_SMBUS_BLOCK_MAX)
			count = I2C_SMBUS_BLOCK_MAX;
		break;
	case I2C_SMBUS_WORD_DATA:
		/* Check for odd length transaction */
		count = (count == 1) ? 1 : 2;
		break;
	case I2C_SMBUS_BYTE_DATA:
		count = 1;
		break;
	default:
		/*
		 * When we have a better choice than SMBus calls, use a
		 * combined I2C message. Write address; then read up to
		 * io_limit data bytes.  msgbuf is u8 and will cast to our
		 * needs.
		 */
		i = 0;
		msgbuf[i++] = offset;

		msg[0].addr = client->addr;
		msg[0].buf = msgbuf;
		msg[0].len = i;

		msg[1].addr = client->addr;
		msg[1].flags = I2C_M_RD;
		msg[1].buf = buf;
		msg[1].len = count;
	}

	/*
	 * Reads fail if the previous write didn't complete yet. We may
	 * loop a few times until this one succeeds, waiting at least
	 * long enough for one entire page write to work.
	 */
	timeout = jiffies + msecs_to_jiffies(write_timeout);
	do {
		read_time = jiffies;

		switch (port_data->use_smbus) {
		case I2C_SMBUS_I2C_BLOCK_DATA:
			status = i2c_smbus_read_i2c_block_data(client, offset,
					count, buf);
			break;
		case I2C_SMBUS_WORD_DATA:
			status = i2c_smbus_read_word_data(client, offset);
			if (status >= 0) {
				buf[0] = status & 0xff;
				if (count == 2)
					buf[1] = status >> 8;
				status = count;
			}
			break;
		case I2C_SMBUS_BYTE_DATA:
			status = i2c_smbus_read_byte_data(client, offset);
			if (status >= 0) {
				buf[0] = status;
				status = count;
			}
			break;
		default:
			status = i2c_transfer(client->adapter, msg, 2);
			if (status == 2)
				status = count;
		}

		dev_dbg(&client->dev, "eeprom read %zu@%d --> %d (%ld)\n",
				count, offset, status, jiffies);

		if (status == count)  /* happy path */
			return count;

		if (status == -ENXIO) /* no module present */
			return status;

		/* REVISIT: at HZ=100, this is sloooow */
		msleep(1);
	} while (time_before(read_time, timeout));

	return -ETIMEDOUT;
}

static ssize_t sff_8436_eeprom_write(struct sfp_port_data *port_data,
		    		struct i2c_client *client,
				const char *buf,
				unsigned offset, size_t count)
{
	struct i2c_msg msg;
	ssize_t status;
	unsigned long timeout, write_time;
	unsigned next_page_start;
	int i = 0;

	/* write max is at most a page
	 * (In this driver, write_max is actually one byte!)
	 */
	if (count > port_data->write_max)
		count = port_data->write_max;

	/* shorten count if necessary to avoid crossing page boundary */
	next_page_start = roundup(offset + 1, SFF_8436_PAGE_SIZE);
	if (offset + count > next_page_start)
		count = next_page_start - offset;

	switch (port_data->use_smbus) {
	case I2C_SMBUS_I2C_BLOCK_DATA:
		/*smaller eeproms can work given some SMBus extension calls */
		if (count > I2C_SMBUS_BLOCK_MAX)
			count = I2C_SMBUS_BLOCK_MAX;
		break;
	case I2C_SMBUS_WORD_DATA:
		/* Check for odd length transaction */
		count = (count == 1) ? 1 : 2;
		break;
	case I2C_SMBUS_BYTE_DATA:
		count = 1;
		break;
	default:
		/* If we'll use I2C calls for I/O, set up the message */
		msg.addr = client->addr;
		msg.flags = 0;

		/* msg.buf is u8 and casts will mask the values */
		msg.buf = port_data->writebuf;

		msg.buf[i++] = offset;
		memcpy(&msg.buf[i], buf, count);
		msg.len = i + count;
		break;
	}

	/*
	 * Reads fail if the previous write didn't complete yet. We may
	 * loop a few times until this one succeeds, waiting at least
	 * long enough for one entire page write to work.
	 */
	timeout = jiffies + msecs_to_jiffies(write_timeout);
	do {
		write_time = jiffies;

		switch (port_data->use_smbus) {
		case I2C_SMBUS_I2C_BLOCK_DATA:
			status = i2c_smbus_write_i2c_block_data(client,
						offset, count, buf);
			if (status == 0)
				status = count;
			break;
		case I2C_SMBUS_WORD_DATA:
			if (count == 2) {
				status = i2c_smbus_write_word_data(client,
					offset, (u16)((buf[0])|(buf[1] << 8)));
			} else {
				/* count = 1 */
				status = i2c_smbus_write_byte_data(client,
					offset, buf[0]);
			}
			if (status == 0)
				status = count;
			break;
		case I2C_SMBUS_BYTE_DATA:
			status = i2c_smbus_write_byte_data(client, offset,
						buf[0]);
			if (status == 0)
				status = count;
			break;
		default:
			status = i2c_transfer(client->adapter, &msg, 1);
			if (status == 1)
				status = count;
			break;
		}

		dev_dbg(&client->dev, "eeprom write %zu@%d --> %ld (%lu)\n",
				count, offset, (long int) status, jiffies);

		if (status == count)
			return count;

		/* REVISIT: at HZ=100, this is sloooow */
		msleep(1);
	} while (time_before(write_time, timeout));

	return -ETIMEDOUT;
}


static ssize_t sff_8436_eeprom_update_client(struct sfp_port_data *port_data,
				char *buf, loff_t off, 
				size_t count, qsfp_opcode_e opcode)
{
	struct i2c_client *client;
	ssize_t retval = 0;
	u8 page = 0;
	loff_t phy_offset = off;
	int ret = 0;

	page = sff_8436_translate_offset(port_data, &phy_offset, &client);

	dev_dbg(&client->dev,
			"sff_8436_eeprom_update_client off %lld  page:%d phy_offset:%lld, count:%ld, opcode:%d\n",
			off, page, phy_offset, (long int) count, opcode);
	if (page > 0) {
		ret = sff_8436_eeprom_write(port_data, client, &page, 
			SFF_8436_PAGE_SELECT_REG, 1);
		if (ret < 0) {
			dev_dbg(&client->dev,
				"Write page register for page %d failed ret:%d!\n",
					page, ret);
			return ret;
		}
	}

	while (count) {
		ssize_t	status;

		if (opcode == QSFP_READ_OP) {
			status =  sff_8436_eeprom_read(port_data, client,
				buf, phy_offset, count);
		} else {
			status =  sff_8436_eeprom_write(port_data, client,
				buf, phy_offset, count);
		}
		if (status <= 0) {
			if (retval == 0)
				retval = status;
			break;
		}
		buf += status;
		phy_offset += status;
		count -= status;
		retval += status;
	}


	if (page > 0) {
		/* return the page register to page 0 (why?) */
		page = 0;
		ret = sff_8436_eeprom_write(port_data, client, &page, 
			SFF_8436_PAGE_SELECT_REG, 1);
		if (ret < 0) {
			dev_err(&client->dev,
				"Restore page register to page %d failed ret:%d!\n",
					page, ret);
			return ret;
		}
	}
	return retval;
}


/*
 * Figure out if this access is within the range of supported pages.
 * Note this is called on every access because we don't know if the
 * module has been replaced since the last call.
 * If/when modules support more pages, this is the routine to update
 * to validate and allow access to additional pages.
 *
 * Returns updated len for this access:
 *     - entire access is legal, original len is returned.
 *     - access begins legal but is too long, len is truncated to fit.
 *     - initial offset exceeds supported pages, return -EINVAL
 */
static ssize_t sff_8436_page_legal(struct sfp_port_data *port_data, 
		loff_t off, size_t len)
{
	struct i2c_client *client = port_data->client;
	u8 regval;
	int status;
	size_t maxlen;

	if (off < 0) return -EINVAL;
	if (port_data->driver_type == DRIVER_TYPE_SFP_MSA) {
		/* SFP case */
		/* if no pages needed, we're good */
		if ((off + len) <= SFF_8472_EEPROM_UNPAGED_SIZE) return len;
		/* if offset exceeds possible pages, we're not good */
		if (off >= SFF_8472_EEPROM_SIZE) return -EINVAL;
		/* in between, are pages supported? */
		status = sff_8436_eeprom_read(port_data, client, &regval, 
				SFF_8472_PAGEABLE_REG, 1);
		if (status < 0) return status;  /* error out (no module?) */
		if (regval & SFF_8472_PAGEABLE) {
			/* Pages supported, trim len to the end of pages */
			maxlen = SFF_8472_EEPROM_SIZE - off;
		} else {
			/* pages not supported, trim len to unpaged size */
			maxlen = SFF_8472_EEPROM_UNPAGED_SIZE - off;
		}
		len = (len > maxlen) ? maxlen : len;
		dev_dbg(&client->dev,
			"page_legal, SFP, off %lld len %ld\n",
			off, (long int) len);
	} 
	else if (port_data->driver_type == DRIVER_TYPE_QSFP ||
		     port_data->driver_type == DRIVER_TYPE_XFP) {
		/* QSFP case */
		/* if no pages needed, we're good */
		if ((off + len) <= SFF_8436_EEPROM_UNPAGED_SIZE) return len;
		/* if offset exceeds possible pages, we're not good */
		if (off >= SFF_8436_EEPROM_SIZE) return -EINVAL;
		/* in between, are pages supported? */
		status = sff_8436_eeprom_read(port_data, client, &regval, 
				SFF_8436_PAGEABLE_REG, 1);
		if (status < 0) return status;  /* error out (no module?) */
		if (regval & SFF_8436_NOT_PAGEABLE) {
			/* pages not supported, trim len to unpaged size */
			maxlen = SFF_8436_EEPROM_UNPAGED_SIZE - off;
		} else {
			/* Pages supported, trim len to the end of pages */
			maxlen = SFF_8436_EEPROM_SIZE - off;
		}
		len = (len > maxlen) ? maxlen : len;
		dev_dbg(&client->dev,
			"page_legal, QSFP, off %lld len %ld\n",
			off, (long int) len);
	}
	else {
		return -EINVAL;
	}
	return len;
}


static ssize_t sfp_port_read_write(struct sfp_port_data *port_data,
		char *buf, loff_t off, size_t len, qsfp_opcode_e opcode)
{
	struct i2c_client *client = port_data->client;
	int chunk;
	int status = 0;
	ssize_t retval;
	size_t pending_len = 0, chunk_len = 0;
	loff_t chunk_offset = 0, chunk_start_offset = 0;

	if (unlikely(!len))
		return len;

	/*
	 * Read data from chip, protecting against concurrent updates
	 * from this host, but not from other I2C masters.
	 */
	mutex_lock(&port_data->update_lock);
	
	/*
	 * Confirm this access fits within the device suppored addr range 
	 */
	len = sff_8436_page_legal(port_data, off, len);
	if (len < 0) {
		status = len;
		goto err;
	}

	/*
	 * For each (128 byte) chunk involved in this request, issue a
	 * separate call to sff_eeprom_update_client(), to
	 * ensure that each access recalculates the client/page
	 * and writes the page register as needed.
	 * Note that chunk to page mapping is confusing, is different for 
	 * QSFP and SFP, and never needs to be done.  Don't try!
	 */
	pending_len = len; /* amount remaining to transfer */
	retval = 0;  /* amount transferred */
	for (chunk = off >> 7; chunk <= (off + len - 1) >> 7; chunk++) {

		/*
		 * Compute the offset and number of bytes to be read/write
		 *
		 * 1. start at offset 0 (within the chunk), and read/write
		 *    the entire chunk
		 * 2. start at offset 0 (within the chunk) and read/write less
		 *    than entire chunk
		 * 3. start at an offset not equal to 0 and read/write the rest
		 *    of the chunk
		 * 4. start at an offset not equal to 0 and read/write less than
		 *    (end of chunk - offset)
		 */
		chunk_start_offset = chunk * SFF_8436_PAGE_SIZE;

		if (chunk_start_offset < off) {
			chunk_offset = off;
			if ((off + pending_len) < (chunk_start_offset +
					SFF_8436_PAGE_SIZE))
				chunk_len = pending_len;
			else
				chunk_len = (chunk+1)*SFF_8436_PAGE_SIZE - off;/*SFF_8436_PAGE_SIZE - off;*/
		} else {
			chunk_offset = chunk_start_offset;
			if (pending_len > SFF_8436_PAGE_SIZE)
				chunk_len = SFF_8436_PAGE_SIZE;
			else
				chunk_len = pending_len;
		}

		dev_dbg(&client->dev,
			"sff_r/w: off %lld, len %ld, chunk_start_offset %lld, chunk_offset %lld, chunk_len %ld, pending_len %ld\n",
			off, (long int) len, chunk_start_offset, chunk_offset,
			(long int) chunk_len, (long int) pending_len);

		/* 
		 * note: chunk_offset is from the start of the EEPROM, 
		 * not the start of the chunk 
		 */
		status = sff_8436_eeprom_update_client(port_data, buf, 
				chunk_offset, chunk_len, opcode);
		if (status != chunk_len) {
			/* This is another 'no device present' path */
			dev_dbg(&client->dev, 
	"sff_8436_update_client for chunk %d chunk_offset %lld chunk_len %ld failed %d!\n",
				chunk, chunk_offset, (long int) chunk_len, status);
			goto err;
		}
		buf += status;
		pending_len -= status;
		retval += status;
	}
	mutex_unlock(&port_data->update_lock);

	return retval;

err:
	mutex_unlock(&port_data->update_lock);

	return status;
}

#else
static ssize_t sfp_port_read(struct sfp_port_data *data,
				char *buf, loff_t off, size_t count)
{
	ssize_t retval = 0;

	if (unlikely(!count)) {
		DEBUG_PRINT("Count = 0, return");
		return count;
	}

	/*
	 * Read data from chip, protecting against concurrent updates
	 * from this host, but not from other I2C masters.
	 */
	mutex_lock(&data->update_lock);

	while (count) {
		ssize_t status;

		status = sfp_eeprom_read(data->client, off, buf, count);
		if (status <= 0) {
			if (retval == 0) {
				retval = status;
			}
			break;
		}

		buf += status;
		off += status;
		count -= status;
		retval += status;
	}

	mutex_unlock(&data->update_lock);
	return retval;

}
#endif

static ssize_t sfp_bin_read(struct file *filp, struct kobject *kobj,
		struct bin_attribute *attr,
		char *buf, loff_t off, size_t count)
{
	int present;
	struct sfp_port_data *data;
	DEBUG_PRINT("offset = (%d), count = (%d)", off, count);
	
	data = dev_get_drvdata(container_of(kobj, struct device, kobj));
	present = sfp_is_port_present(data->client, data->port);
	if (IS_ERR_VALUE(present)) {
		return present;
	}

	if (present == 0) {
		/* port is not present */
		return -ENODEV;
	}

#if (MULTIPAGE_SUPPORT == 1)
	return sfp_port_read_write(data, buf, off, count, QSFP_READ_OP);
#else
	return sfp_port_read(data, buf, off, count);
#endif
}

#if (MULTIPAGE_SUPPORT == 1)
static int sfp_sysfs_eeprom_init(struct kobject *kobj, struct bin_attribute *eeprom, size_t size)
#else
static int sfp_sysfs_eeprom_init(struct kobject *kobj, struct bin_attribute *eeprom)
#endif
{
	int err;

	sysfs_bin_attr_init(eeprom);
	eeprom->attr.name = EEPROM_NAME;
	eeprom->attr.mode = S_IWUSR | S_IRUGO;
	eeprom->read	  = sfp_bin_read;
	eeprom->write	  = sfp_bin_write;
#if (MULTIPAGE_SUPPORT == 1)
	eeprom->size	  = size;
#else
	eeprom->size	  = EEPROM_SIZE;
#endif

	/* Create eeprom file */
	err = sysfs_create_bin_file(kobj, eeprom);
	if (err) {
		return err;
	}

	return 0;
}

static int sfp_sysfs_eeprom_cleanup(struct kobject *kobj, struct bin_attribute *eeprom)
{
	sysfs_remove_bin_file(kobj, eeprom);
	return 0;
}


#if (MULTIPAGE_SUPPORT == 0)
static int sfp_i2c_check_functionality(struct i2c_client *client)
{
#if USE_I2C_BLOCK_READ
	return i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK);
#else
	return i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA);
#endif
}
#endif


static const struct attribute_group qsfp_group = {
	.attrs = qsfp_attributes,
};

static int qsfp_probe(struct i2c_client *client, const struct i2c_device_id *dev_id,
						  struct qsfp_data **data)
{
	int status;
	struct qsfp_data *qsfp;

#if (MULTIPAGE_SUPPORT == 0)
	if (!sfp_i2c_check_functionality(client)) {
		status = -EIO;
		goto exit;
	}
#endif

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

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

	/* init eeprom */
#if (MULTIPAGE_SUPPORT == 1)
	status = sfp_sysfs_eeprom_init(&client->dev.kobj, &qsfp->eeprom.bin, SFF_8436_EEPROM_SIZE);
#else
	status = sfp_sysfs_eeprom_init(&client->dev.kobj, &qsfp->eeprom.bin);
#endif
	if (status) {
		goto exit_remove;
	}

	*data = qsfp;
	dev_info(&client->dev, "qsfp '%s'\n", client->name);

	return 0;

exit_remove:
	sysfs_remove_group(&client->dev.kobj, &qsfp_group);
exit_free:
	kfree(qsfp);
exit:

	return status;
}

/* Platform dependent +++ */
static int sfp_device_probe(struct i2c_client *client,
			const struct i2c_device_id *dev_id)
{
	int ret = 0;
	struct sfp_port_data *data = NULL;

	if (client->addr != SFP_EEPROM_A0_I2C_ADDR) {
		return -ENODEV;
	}

	if (dev_id->driver_data < as7816_64x_port1 || dev_id->driver_data > as7816_64x_port64) {
		return -ENXIO;
	}

	data = kzalloc(sizeof(struct sfp_port_data), GFP_KERNEL);
	if (!data) {
		return -ENOMEM;
	}

#if (MULTIPAGE_SUPPORT == 1)
	data->use_smbus = 0;

	/* Use I2C operations unless we're stuck with SMBus extensions. */
	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
		if (i2c_check_functionality(client->adapter,
				I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
			data->use_smbus = I2C_SMBUS_I2C_BLOCK_DATA;
		} else if (i2c_check_functionality(client->adapter,
				I2C_FUNC_SMBUS_READ_WORD_DATA)) {
			data->use_smbus = I2C_SMBUS_WORD_DATA;
		} else if (i2c_check_functionality(client->adapter,
				I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
			data->use_smbus = I2C_SMBUS_BYTE_DATA;
		} else {
			ret = -EPFNOSUPPORT;
			goto exit_kfree;
		}
	}

	if (!data->use_smbus ||
			(i2c_check_functionality(client->adapter,
				I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) ||
			i2c_check_functionality(client->adapter,
				I2C_FUNC_SMBUS_WRITE_WORD_DATA) ||
			i2c_check_functionality(client->adapter,
				I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
		/*
		 * NOTE: AN-2079
		 * Finisar recommends that the host implement 1 byte writes
		 * only since this module only supports 32 byte page boundaries.
		 * 2 byte writes are acceptable for PE and Vout changes per
		 * Application Note AN-2071.
		 */
		unsigned write_max = 1;

		if (write_max > io_limit)
			write_max = io_limit;
		if (data->use_smbus && write_max > I2C_SMBUS_BLOCK_MAX)
			write_max = I2C_SMBUS_BLOCK_MAX;
		data->write_max = write_max;

		/* buffer (data + address at the beginning) */
		data->writebuf = kmalloc(write_max + 2, GFP_KERNEL);
		if (!data->writebuf) {
			ret = -ENOMEM;
			goto exit_kfree;
		}
	} else {
			dev_warn(&client->dev,
				"cannot write due to controller restrictions.");
	}

	if (data->use_smbus == I2C_SMBUS_WORD_DATA ||
	    data->use_smbus == I2C_SMBUS_BYTE_DATA) {
		dev_notice(&client->dev, "Falling back to %s reads, "
			   "performance will suffer\n", data->use_smbus ==
			   I2C_SMBUS_WORD_DATA ? "word" : "byte");
	}
#endif

	i2c_set_clientdata(client, data);
	mutex_init(&data->update_lock);
	data->port	 = dev_id->driver_data;
	data->client = client;
	data->driver_type = DRIVER_TYPE_QSFP;

	ret = qsfp_probe(client, dev_id, &data->qsfp);
	if (ret < 0) {
		goto exit_kfree_buf;
	}

	return ret;

exit_kfree_buf:
#if (MULTIPAGE_SUPPORT == 1)
	if (data->writebuf) kfree(data->writebuf);
#endif

exit_kfree:
	kfree(data);
	return ret;
}
/* Platform dependent --- */

static int qsfp_remove(struct i2c_client *client, struct qsfp_data *data)
{
	sfp_sysfs_eeprom_cleanup(&client->dev.kobj, &data->eeprom.bin);
	sysfs_remove_group(&client->dev.kobj, &qsfp_group);
	kfree(data);
	return 0;
}

static int sfp_device_remove(struct i2c_client *client)
{
	int ret = 0;
	struct sfp_port_data *data = i2c_get_clientdata(client);

	if (data->driver_type == DRIVER_TYPE_QSFP) {
		ret = qsfp_remove(client, data->qsfp);
	}

	kfree(data);
	return ret;
}

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

static struct i2c_driver sfp_driver = {
	.driver = {
		.name	  = DRIVER_NAME,
	},
	.probe		  = sfp_device_probe,
	.remove		  = sfp_device_remove,
	.id_table	  = sfp_device_id,
	.address_list = normal_i2c,
};

static int __init sfp_init(void)
{
	return i2c_add_driver(&sfp_driver);
}

static void __exit sfp_exit(void)
{
	i2c_del_driver(&sfp_driver);
}

MODULE_AUTHOR("Brandon Chuang <brandon_chuang@accton.com.tw>");
MODULE_DESCRIPTION("accton as7816_64x_sfp driver");
MODULE_LICENSE("GPL");

module_init(sfp_init);
module_exit(sfp_exit);