/*
 *   This file is provided under a GPLv2 license.  When using or
 *   redistributing this file, you may do so under that license.
 *
 *   GPL LICENSE SUMMARY
 *
 *   Copyright (C) 2016 T-Platforms. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or modify it
 *   under the terms and conditions of the GNU General Public License,
 *   version 2, as published by the Free Software Foundation.
 *
 *   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, it can be found <http://www.gnu.org/licenses/>.
 *
 *   The full GNU General Public License is included in this distribution in
 *   the file called "COPYING".
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * IDT PCIe-switch NTB Linux driver
 *
 * Contact Information:
 * Serge Semin <fancer.lancer@gmail.com>, <Sergey.Semin@t-platforms.ru>
 */
/*
 *           NOTE of the IDT 89HPESx SMBus-slave interface driver
 *    This driver primarily is developed to have an access to EEPROM device of
 * IDT PCIe-switches. IDT provides a simple SMBus interface to perform IO-
 * operations from/to EEPROM, which is located at private (so called Master)
 * SMBus of switches. Using that interface this the driver creates a simple
 * binary sysfs-file in the device directory:
 * /sys/bus/i2c/devices/<bus>-<devaddr>/eeprom
 * In case if read-only flag is specified in the dts-node of device desription,
 * User-space applications won't be able to write to the EEPROM sysfs-node.
 *    Additionally IDT 89HPESx SMBus interface has an ability to write/read
 * data of device CSRs. This driver exposes debugf-file to perform simple IO
 * operations using that ability for just basic debug purpose. Particularly
 * next file is created in the specific debugfs-directory:
 * /sys/kernel/debug/idt_csr/
 * Format of the debugfs-node is:
 * $ cat /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>;
 * <CSR address>:<CSR value>
 * So reading the content of the file gives current CSR address and it value.
 * If User-space application wishes to change current CSR address,
 * it can just write a proper value to the sysfs-file:
 * $ echo "<CSR address>" > /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>
 * If it wants to change the CSR value as well, the format of the write
 * operation is:
 * $ echo "<CSR address>:<CSR value>" > \
 *        /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>;
 * CSR address and value can be any of hexadecimal, decimal or octal format.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include <linux/debugfs.h>
#include <linux/mod_devicetable.h>
#include <linux/property.h>
#include <linux/i2c.h>
#include <linux/pci_ids.h>
#include <linux/delay.h>

#define IDT_NAME                "89hpesx"
#define IDT_89HPESX_DESC        "IDT 89HPESx SMBus-slave interface driver"
#define IDT_89HPESX_VER         "1.0"

MODULE_DESCRIPTION(IDT_89HPESX_DESC);
MODULE_VERSION(IDT_89HPESX_VER);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("T-platforms");

/*
 * csr_dbgdir - CSR read/write operations Debugfs directory
 */
static struct dentry *csr_dbgdir;

/*
 * struct idt_89hpesx_dev - IDT 89HPESx device data structure
 * @eesize:     Size of EEPROM in bytes (calculated from "idt,eecompatible")
 * @eero:       EEPROM Read-only flag
 * @eeaddr:     EEPROM custom address
 *
 * @inieecmd:   Initial cmd value for EEPROM read/write operations
 * @inicsrcmd:  Initial cmd value for CSR read/write operations
 * @iniccode:   Initialial command code value for IO-operations
 *
 * @csr:        CSR address to perform read operation
 *
 * @smb_write:  SMBus write method
 * @smb_read:   SMBus read method
 * @smb_mtx:    SMBus mutex
 *
 * @client:     i2c client used to perform IO operations
 *
 * @ee_file:    EEPROM read/write sysfs-file
 * @csr_file:   CSR read/write debugfs-node
 */
struct idt_smb_seq;
struct idt_89hpesx_dev {
        u32 eesize;
        bool eero;
        u8 eeaddr;

        u8 inieecmd;
        u8 inicsrcmd;
        u8 iniccode;

        u16 csr;

        int (*smb_write)(struct idt_89hpesx_dev *, const struct idt_smb_seq *);
        int (*smb_read)(struct idt_89hpesx_dev *, struct idt_smb_seq *);
        struct mutex smb_mtx;

        struct i2c_client *client;

        struct bin_attribute *ee_file;
        struct dentry *csr_dir;
        struct dentry *csr_file;
};

/*
 * struct idt_smb_seq - sequence of data to be read/written from/to IDT 89HPESx
 * @ccode:      SMBus command code
 * @bytecnt:    Byte count of operation
 * @data:       Data to by written
 */
struct idt_smb_seq {
        u8 ccode;
        u8 bytecnt;
        u8 *data;
};

/*
 * struct idt_eeprom_seq - sequence of data to be read/written from/to EEPROM
 * @cmd:        Transaction CMD
 * @eeaddr:     EEPROM custom address
 * @memaddr:    Internal memory address of EEPROM
 * @data:       Data to be written at the memory address
 */
struct idt_eeprom_seq {
        u8 cmd;
        u8 eeaddr;
        u16 memaddr;
        u8 data;
} __packed;

/*
 * struct idt_csr_seq - sequence of data to be read/written from/to CSR
 * @cmd:        Transaction CMD
 * @csraddr:    Internal IDT device CSR address
 * @data:       Data to be read/written from/to the CSR address
 */
struct idt_csr_seq {
        u8 cmd;
        u16 csraddr;
        u32 data;
} __packed;

/*
 * SMBus command code macros
 * @CCODE_END:          Indicates the end of transaction
 * @CCODE_START:        Indicates the start of transaction
 * @CCODE_CSR:          CSR read/write transaction
 * @CCODE_EEPROM:       EEPROM read/write transaction
 * @CCODE_BYTE:         Supplied data has BYTE length
 * @CCODE_WORD:         Supplied data has WORD length
 * @CCODE_BLOCK:        Supplied data has variable length passed in bytecnt
 *                      byte right following CCODE byte
 */
#define CCODE_END       ((u8)0x01)
#define CCODE_START     ((u8)0x02)
#define CCODE_CSR       ((u8)0x00)
#define CCODE_EEPROM    ((u8)0x04)
#define CCODE_BYTE      ((u8)0x00)
#define CCODE_WORD      ((u8)0x20)
#define CCODE_BLOCK     ((u8)0x40)
#define CCODE_PEC       ((u8)0x80)

/*
 * EEPROM command macros
 * @EEPROM_OP_WRITE:    EEPROM write operation
 * @EEPROM_OP_READ:     EEPROM read operation
 * @EEPROM_USA:         Use specified address of EEPROM
 * @EEPROM_NAERR:       EEPROM device is not ready to respond
 * @EEPROM_LAERR:       EEPROM arbitration loss error
 * @EEPROM_MSS:         EEPROM misplace start & stop bits error
 * @EEPROM_WR_CNT:      Bytes count to perform write operation
 * @EEPROM_WRRD_CNT:    Bytes count to write before reading
 * @EEPROM_RD_CNT:      Bytes count to perform read operation
 * @EEPROM_DEF_SIZE:    Fall back size of EEPROM
 * @EEPROM_DEF_ADDR:    Defatul EEPROM address
 * @EEPROM_TOUT:        Timeout before retry read operation if eeprom is busy
 */
#define EEPROM_OP_WRITE ((u8)0x00)
#define EEPROM_OP_READ  ((u8)0x01)
#define EEPROM_USA      ((u8)0x02)
#define EEPROM_NAERR    ((u8)0x08)
#define EEPROM_LAERR    ((u8)0x10)
#define EEPROM_MSS      ((u8)0x20)
#define EEPROM_WR_CNT   ((u8)5)
#define EEPROM_WRRD_CNT ((u8)4)
#define EEPROM_RD_CNT   ((u8)5)
#define EEPROM_DEF_SIZE ((u16)4096)
#define EEPROM_DEF_ADDR ((u8)0x50)
#define EEPROM_TOUT     (100)

/*
 * CSR command macros
 * @CSR_DWE:            Enable all four bytes of the operation
 * @CSR_OP_WRITE:       CSR write operation
 * @CSR_OP_READ:        CSR read operation
 * @CSR_RERR:           Read operation error
 * @CSR_WERR:           Write operation error
 * @CSR_WR_CNT:         Bytes count to perform write operation
 * @CSR_WRRD_CNT:       Bytes count to write before reading
 * @CSR_RD_CNT:         Bytes count to perform read operation
 * @CSR_MAX:            Maximum CSR address
 * @CSR_DEF:            Default CSR address
 * @CSR_REAL_ADDR:      CSR real unshifted address
 */
#define CSR_DWE                 ((u8)0x0F)
#define CSR_OP_WRITE            ((u8)0x00)
#define CSR_OP_READ             ((u8)0x10)
#define CSR_RERR                ((u8)0x40)
#define CSR_WERR                ((u8)0x80)
#define CSR_WR_CNT              ((u8)7)
#define CSR_WRRD_CNT            ((u8)3)
#define CSR_RD_CNT              ((u8)7)
#define CSR_MAX                 ((u32)0x3FFFF)
#define CSR_DEF                 ((u16)0x0000)
#define CSR_REAL_ADDR(val)      ((unsigned int)val << 2)

/*
 * IDT 89HPESx basic register
 * @IDT_VIDDID_CSR:     PCIe VID and DID of IDT 89HPESx
 * @IDT_VID_MASK:       Mask of VID
 */
#define IDT_VIDDID_CSR  ((u32)0x0000)
#define IDT_VID_MASK    ((u32)0xFFFF)

/*
 * IDT 89HPESx can send NACK when new command is sent before previous one
 * fininshed execution. In this case driver retries operation
 * certain times.
 * @RETRY_CNT:          Number of retries before giving up and fail
 * @idt_smb_safe:       Generate a retry loop on corresponding SMBus method
 */
#define RETRY_CNT (128)
#define idt_smb_safe(ops, args...) ({ \
        int __retry = RETRY_CNT; \
        s32 __sts; \
        do { \
                __sts = i2c_smbus_ ## ops ## _data(args); \
        } while (__retry-- && __sts < 0); \
        __sts; \
})

/*===========================================================================
 *                         i2c bus level IO-operations
 *===========================================================================
 */

/*
 * idt_smb_write_byte() - SMBus write method when I2C_SMBUS_BYTE_DATA operation
 *                        is only available
 * @pdev:       Pointer to the driver data
 * @seq:        Sequence of data to be written
 */
static int idt_smb_write_byte(struct idt_89hpesx_dev *pdev,
                              const struct idt_smb_seq *seq)
{
        s32 sts;
        u8 ccode;
        int idx;

        /* Loop over the supplied data sending byte one-by-one */
        for (idx = 0; idx < seq->bytecnt; idx++) {
                /* Collect the command code byte */
                ccode = seq->ccode | CCODE_BYTE;
                if (idx == 0)
                        ccode |= CCODE_START;
                if (idx == seq->bytecnt - 1)
                        ccode |= CCODE_END;

                /* Send data to the device */
                sts = idt_smb_safe(write_byte, pdev->client, ccode,
                        seq->data[idx]);
                if (sts != 0)
                        return (int)sts;
        }

        return 0;
}

/*
 * idt_smb_read_byte() - SMBus read method when I2C_SMBUS_BYTE_DATA operation
 *                        is only available
 * @pdev:       Pointer to the driver data
 * @seq:        Buffer to read data to
 */
static int idt_smb_read_byte(struct idt_89hpesx_dev *pdev,
                             struct idt_smb_seq *seq)
{
        s32 sts;
        u8 ccode;
        int idx;

        /* Loop over the supplied buffer receiving byte one-by-one */
        for (idx = 0; idx < seq->bytecnt; idx++) {
                /* Collect the command code byte */
                ccode = seq->ccode | CCODE_BYTE;
                if (idx == 0)
                        ccode |= CCODE_START;
                if (idx == seq->bytecnt - 1)
                        ccode |= CCODE_END;

                /* Read data from the device */
                sts = idt_smb_safe(read_byte, pdev->client, ccode);
                if (sts < 0)
                        return (int)sts;

                seq->data[idx] = (u8)sts;
        }

        return 0;
}

/*
 * idt_smb_write_word() - SMBus write method when I2C_SMBUS_BYTE_DATA and
 *                        I2C_FUNC_SMBUS_WORD_DATA operations are available
 * @pdev:       Pointer to the driver data
 * @seq:        Sequence of data to be written
 */
static int idt_smb_write_word(struct idt_89hpesx_dev *pdev,
                              const struct idt_smb_seq *seq)
{
        s32 sts;
        u8 ccode;
        int idx, evencnt;

        /* Calculate the even count of data to send */
        evencnt = seq->bytecnt - (seq->bytecnt % 2);

        /* Loop over the supplied data sending two bytes at a time */
        for (idx = 0; idx < evencnt; idx += 2) {
                /* Collect the command code byte */
                ccode = seq->ccode | CCODE_WORD;
                if (idx == 0)
                        ccode |= CCODE_START;
                if (idx == evencnt - 2)
                        ccode |= CCODE_END;

                /* Send word data to the device */
                sts = idt_smb_safe(write_word, pdev->client, ccode,
                        *(u16 *)&seq->data[idx]);
                if (sts != 0)
                        return (int)sts;
        }

        /* If there is odd number of bytes then send just one last byte */
        if (seq->bytecnt != evencnt) {
                /* Collect the command code byte */
                ccode = seq->ccode | CCODE_BYTE | CCODE_END;
                if (idx == 0)
                        ccode |= CCODE_START;

                /* Send byte data to the device */
                sts = idt_smb_safe(write_byte, pdev->client, ccode,
                        seq->data[idx]);
                if (sts != 0)
                        return (int)sts;
        }

        return 0;
}

/*
 * idt_smb_read_word() - SMBus read method when I2C_SMBUS_BYTE_DATA and
 *                       I2C_FUNC_SMBUS_WORD_DATA operations are available
 * @pdev:       Pointer to the driver data
 * @seq:        Buffer to read data to
 */
static int idt_smb_read_word(struct idt_89hpesx_dev *pdev,
                             struct idt_smb_seq *seq)
{
        s32 sts;
        u8 ccode;
        int idx, evencnt;

        /* Calculate the even count of data to send */
        evencnt = seq->bytecnt - (seq->bytecnt % 2);

        /* Loop over the supplied data reading two bytes at a time */
        for (idx = 0; idx < evencnt; idx += 2) {
                /* Collect the command code byte */
                ccode = seq->ccode | CCODE_WORD;
                if (idx == 0)
                        ccode |= CCODE_START;
                if (idx == evencnt - 2)
                        ccode |= CCODE_END;

                /* Read word data from the device */
                sts = idt_smb_safe(read_word, pdev->client, ccode);
                if (sts < 0)
                        return (int)sts;

                *(u16 *)&seq->data[idx] = (u16)sts;
        }

        /* If there is odd number of bytes then receive just one last byte */
        if (seq->bytecnt != evencnt) {
                /* Collect the command code byte */
                ccode = seq->ccode | CCODE_BYTE | CCODE_END;
                if (idx == 0)
                        ccode |= CCODE_START;

                /* Read last data byte from the device */
                sts = idt_smb_safe(read_byte, pdev->client, ccode);
                if (sts < 0)
                        return (int)sts;

                seq->data[idx] = (u8)sts;
        }

        return 0;
}

/*
 * idt_smb_write_block() - SMBus write method when I2C_SMBUS_BLOCK_DATA
 *                         operation is available
 * @pdev:       Pointer to the driver data
 * @seq:        Sequence of data to be written
 */
static int idt_smb_write_block(struct idt_89hpesx_dev *pdev,
                               const struct idt_smb_seq *seq)
{
        u8 ccode;

        /* Return error if too much data passed to send */
        if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
                return -EINVAL;

        /* Collect the command code byte */
        ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;

        /* Send block of data to the device */
        return idt_smb_safe(write_block, pdev->client, ccode, seq->bytecnt,
                seq->data);
}

/*
 * idt_smb_read_block() - SMBus read method when I2C_SMBUS_BLOCK_DATA
 *                        operation is available
 * @pdev:       Pointer to the driver data
 * @seq:        Buffer to read data to
 */
static int idt_smb_read_block(struct idt_89hpesx_dev *pdev,
                              struct idt_smb_seq *seq)
{
        s32 sts;
        u8 ccode;

        /* Return error if too much data passed to send */
        if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
                return -EINVAL;

        /* Collect the command code byte */
        ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;

        /* Read block of data from the device */
        sts = idt_smb_safe(read_block, pdev->client, ccode, seq->data);
        if (sts != seq->bytecnt)
                return (sts < 0 ? sts : -ENODATA);

        return 0;
}

/*
 * idt_smb_write_i2c_block() - SMBus write method when I2C_SMBUS_I2C_BLOCK_DATA
 *                             operation is available
 * @pdev:       Pointer to the driver data
 * @seq:        Sequence of data to be written
 *
 * NOTE It's usual SMBus write block operation, except the actual data length is
 * sent as first byte of data
 */
static int idt_smb_write_i2c_block(struct idt_89hpesx_dev *pdev,
                                   const struct idt_smb_seq *seq)
{
        u8 ccode, buf[I2C_SMBUS_BLOCK_MAX + 1];

        /* Return error if too much data passed to send */
        if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
                return -EINVAL;

        /* Collect the data to send. Length byte must be added prior the data */
        buf[0] = seq->bytecnt;
        memcpy(&buf[1], seq->data, seq->bytecnt);

        /* Collect the command code byte */
        ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;

        /* Send length and block of data to the device */
        return idt_smb_safe(write_i2c_block, pdev->client, ccode,
                seq->bytecnt + 1, buf);
}

/*
 * idt_smb_read_i2c_block() - SMBus read method when I2C_SMBUS_I2C_BLOCK_DATA
 *                            operation is available
 * @pdev:       Pointer to the driver data
 * @seq:        Buffer to read data to
 *
 * NOTE It's usual SMBus read block operation, except the actual data length is
 * retrieved as first byte of data
 */
static int idt_smb_read_i2c_block(struct idt_89hpesx_dev *pdev,
                                  struct idt_smb_seq *seq)
{
        u8 ccode, buf[I2C_SMBUS_BLOCK_MAX + 1];
        s32 sts;

        /* Return error if too much data passed to send */
        if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
                return -EINVAL;

        /* Collect the command code byte */
        ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;

        /* Read length and block of data from the device */
        sts = idt_smb_safe(read_i2c_block, pdev->client, ccode,
                seq->bytecnt + 1, buf);
        if (sts != seq->bytecnt + 1)
                return (sts < 0 ? sts : -ENODATA);
        if (buf[0] != seq->bytecnt)
                return -ENODATA;

        /* Copy retrieved data to the output data buffer */
        memcpy(seq->data, &buf[1], seq->bytecnt);

        return 0;
}

/*===========================================================================
 *                          EEPROM IO-operations
 *===========================================================================
 */

/*
 * idt_eeprom_read_byte() - read just one byte from EEPROM
 * @pdev:       Pointer to the driver data
 * @memaddr:    Start EEPROM memory address
 * @data:       Data to be written to EEPROM
 */
static int idt_eeprom_read_byte(struct idt_89hpesx_dev *pdev, u16 memaddr,
                                u8 *data)
{
        struct device *dev = &pdev->client->dev;
        struct idt_eeprom_seq eeseq;
        struct idt_smb_seq smbseq;
        int ret, retry;

        /* Initialize SMBus sequence fields */
        smbseq.ccode = pdev->iniccode | CCODE_EEPROM;
        smbseq.data = (u8 *)&eeseq;

        /*
         * Sometimes EEPROM may respond with NACK if it's busy with previous
         * operation, so we need to perform a few attempts of read cycle
         */
        retry = RETRY_CNT;
        do {
                /* Send EEPROM memory address to read data from */
                smbseq.bytecnt = EEPROM_WRRD_CNT;
                eeseq.cmd = pdev->inieecmd | EEPROM_OP_READ;
                eeseq.eeaddr = pdev->eeaddr;
                eeseq.memaddr = cpu_to_le16(memaddr);
                ret = pdev->smb_write(pdev, &smbseq);
                if (ret != 0) {
                        dev_err(dev, "Failed to init eeprom addr 0x%02hhx",
                                memaddr);
                        break;
                }

                /* Perform read operation */
                smbseq.bytecnt = EEPROM_RD_CNT;
                ret = pdev->smb_read(pdev, &smbseq);
                if (ret != 0) {
                        dev_err(dev, "Failed to read eeprom data 0x%02hhx",
                                memaddr);
                        break;
                }

                /* Restart read operation if the device is busy */
                if (retry && (eeseq.cmd & EEPROM_NAERR)) {
                        dev_dbg(dev, "EEPROM busy, retry reading after %d ms",
                                EEPROM_TOUT);
                        msleep(EEPROM_TOUT);
                        continue;
                }

                /* Check whether IDT successfully read data from EEPROM */
                if (eeseq.cmd & (EEPROM_NAERR | EEPROM_LAERR | EEPROM_MSS)) {
                        dev_err(dev,
                                "Communication with eeprom failed, cmd 0x%hhx",
                                eeseq.cmd);
                        ret = -EREMOTEIO;
                        break;
                }

                /* Save retrieved data and exit the loop */
                *data = eeseq.data;
                break;
        } while (retry--);

        /* Return the status of operation */
        return ret;
}

/*
 * idt_eeprom_write() - EEPROM write operation
 * @pdev:       Pointer to the driver data
 * @memaddr:    Start EEPROM memory address
 * @len:        Length of data to be written
 * @data:       Data to be written to EEPROM
 */
static int idt_eeprom_write(struct idt_89hpesx_dev *pdev, u16 memaddr, u16 len,
                            const u8 *data)
{
        struct device *dev = &pdev->client->dev;
        struct idt_eeprom_seq eeseq;
        struct idt_smb_seq smbseq;
        int ret;
        u16 idx;

        /* Initialize SMBus sequence fields */
        smbseq.ccode = pdev->iniccode | CCODE_EEPROM;
        smbseq.data = (u8 *)&eeseq;

        /* Send data byte-by-byte, checking if it is successfully written */
        for (idx = 0; idx < len; idx++, memaddr++) {
                /* Lock IDT SMBus device */
                mutex_lock(&pdev->smb_mtx);

                /* Perform write operation */
                smbseq.bytecnt = EEPROM_WR_CNT;
                eeseq.cmd = pdev->inieecmd | EEPROM_OP_WRITE;
                eeseq.eeaddr = pdev->eeaddr;
                eeseq.memaddr = cpu_to_le16(memaddr);
                eeseq.data = data[idx];
                ret = pdev->smb_write(pdev, &smbseq);
                if (ret != 0) {
                        dev_err(dev,
                                "Failed to write 0x%04hx:0x%02hhx to eeprom",
                                memaddr, data[idx]);
                        goto err_mutex_unlock;
                }

                /*
                 * Check whether the data is successfully written by reading
                 * from the same EEPROM memory address.
                 */
                eeseq.data = ~data[idx];
                ret = idt_eeprom_read_byte(pdev, memaddr, &eeseq.data);
                if (ret != 0)
                        goto err_mutex_unlock;

                /* Check whether the read byte is the same as written one */
                if (eeseq.data != data[idx]) {
                        dev_err(dev, "Values don't match 0x%02hhx != 0x%02hhx",
                                eeseq.data, data[idx]);
                        ret = -EREMOTEIO;
                        goto err_mutex_unlock;
                }

                /* Unlock IDT SMBus device */
err_mutex_unlock:
                mutex_unlock(&pdev->smb_mtx);
                if (ret != 0)
                        return ret;
        }

        return 0;
}

/*
 * idt_eeprom_read() - EEPROM read operation
 * @pdev:       Pointer to the driver data
 * @memaddr:    Start EEPROM memory address
 * @len:        Length of data to read
 * @buf:        Buffer to read data to
 */
static int idt_eeprom_read(struct idt_89hpesx_dev *pdev, u16 memaddr, u16 len,
                           u8 *buf)
{
        int ret;
        u16 idx;

        /* Read data byte-by-byte, retrying if it wasn't successful */
        for (idx = 0; idx < len; idx++, memaddr++) {
                /* Lock IDT SMBus device */
                mutex_lock(&pdev->smb_mtx);

                /* Just read the byte to the buffer */
                ret = idt_eeprom_read_byte(pdev, memaddr, &buf[idx]);

                /* Unlock IDT SMBus device */
                mutex_unlock(&pdev->smb_mtx);

                /* Return error if read operation failed */
                if (ret != 0)
                        return ret;
        }

        return 0;
}

/*===========================================================================
 *                          CSR IO-operations
 *===========================================================================
 */

/*
 * idt_csr_write() - CSR write operation
 * @pdev:       Pointer to the driver data
 * @csraddr:    CSR address (with no two LS bits)
 * @data:       Data to be written to CSR
 */
static int idt_csr_write(struct idt_89hpesx_dev *pdev, u16 csraddr,
                         const u32 data)
{
        struct device *dev = &pdev->client->dev;
        struct idt_csr_seq csrseq;
        struct idt_smb_seq smbseq;
        int ret;

        /* Initialize SMBus sequence fields */
        smbseq.ccode = pdev->iniccode | CCODE_CSR;
        smbseq.data = (u8 *)&csrseq;

        /* Lock IDT SMBus device */
        mutex_lock(&pdev->smb_mtx);

        /* Perform write operation */
        smbseq.bytecnt = CSR_WR_CNT;
        csrseq.cmd = pdev->inicsrcmd | CSR_OP_WRITE;
        csrseq.csraddr = cpu_to_le16(csraddr);
        csrseq.data = cpu_to_le32(data);
        ret = pdev->smb_write(pdev, &smbseq);
        if (ret != 0) {
                dev_err(dev, "Failed to write 0x%04x: 0x%04x to csr",
                        CSR_REAL_ADDR(csraddr), data);
                goto err_mutex_unlock;
        }

        /* Send CSR address to read data from */
        smbseq.bytecnt = CSR_WRRD_CNT;
        csrseq.cmd = pdev->inicsrcmd | CSR_OP_READ;
        ret = pdev->smb_write(pdev, &smbseq);
        if (ret != 0) {
                dev_err(dev, "Failed to init csr address 0x%04x",
                        CSR_REAL_ADDR(csraddr));
                goto err_mutex_unlock;
        }

        /* Perform read operation */
        smbseq.bytecnt = CSR_RD_CNT;
        ret = pdev->smb_read(pdev, &smbseq);
        if (ret != 0) {
                dev_err(dev, "Failed to read csr 0x%04x",
                        CSR_REAL_ADDR(csraddr));
                goto err_mutex_unlock;
        }

        /* Check whether IDT successfully retrieved CSR data */
        if (csrseq.cmd & (CSR_RERR | CSR_WERR)) {
                dev_err(dev, "IDT failed to perform CSR r/w");
                ret = -EREMOTEIO;
                goto err_mutex_unlock;
        }

        /* Unlock IDT SMBus device */
err_mutex_unlock:
        mutex_unlock(&pdev->smb_mtx);

        return ret;
}

/*
 * idt_csr_read() - CSR read operation
 * @pdev:       Pointer to the driver data
 * @csraddr:    CSR address (with no two LS bits)
 * @data:       Data to be written to CSR
 */
static int idt_csr_read(struct idt_89hpesx_dev *pdev, u16 csraddr, u32 *data)
{
        struct device *dev = &pdev->client->dev;
        struct idt_csr_seq csrseq;
        struct idt_smb_seq smbseq;
        int ret;

        /* Initialize SMBus sequence fields */
        smbseq.ccode = pdev->iniccode | CCODE_CSR;
        smbseq.data = (u8 *)&csrseq;

        /* Lock IDT SMBus device */
        mutex_lock(&pdev->smb_mtx);

        /* Send CSR register address before reading it */
        smbseq.bytecnt = CSR_WRRD_CNT;
        csrseq.cmd = pdev->inicsrcmd | CSR_OP_READ;
        csrseq.csraddr = cpu_to_le16(csraddr);
        ret = pdev->smb_write(pdev, &smbseq);
        if (ret != 0) {
                dev_err(dev, "Failed to init csr address 0x%04x",
                        CSR_REAL_ADDR(csraddr));
                goto err_mutex_unlock;
        }

        /* Perform read operation */
        smbseq.bytecnt = CSR_RD_CNT;
        ret = pdev->smb_read(pdev, &smbseq);
        if (ret != 0) {
                dev_err(dev, "Failed to read csr 0x%04hx",
                        CSR_REAL_ADDR(csraddr));
                goto err_mutex_unlock;
        }

        /* Check whether IDT successfully retrieved CSR data */
        if (csrseq.cmd & (CSR_RERR | CSR_WERR)) {
                dev_err(dev, "IDT failed to perform CSR r/w");
                ret = -EREMOTEIO;
                goto err_mutex_unlock;
        }

        /* Save data retrieved from IDT */
        *data = le32_to_cpu(csrseq.data);

        /* Unlock IDT SMBus device */
err_mutex_unlock:
        mutex_unlock(&pdev->smb_mtx);

        return ret;
}

/*===========================================================================
 *                          Sysfs/debugfs-nodes IO-operations
 *===========================================================================
 */

/*
 * eeprom_write() - EEPROM sysfs-node write callback
 * @filep:      Pointer to the file system node
 * @kobj:       Pointer to the kernel object related to the sysfs-node
 * @attr:       Attributes of the file
 * @buf:        Buffer to write data to
 * @off:        Offset at which data should be written to
 * @count:      Number of bytes to write
 */
static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
                            struct bin_attribute *attr,
                            char *buf, loff_t off, size_t count)
{
        struct idt_89hpesx_dev *pdev;
        int ret;

        /* Retrieve driver data */
        pdev = dev_get_drvdata(kobj_to_dev(kobj));

        /* Perform EEPROM write operation */
        ret = idt_eeprom_write(pdev, (u16)off, (u16)count, (u8 *)buf);
        return (ret != 0 ? ret : count);
}

/*
 * eeprom_read() - EEPROM sysfs-node read callback
 * @filep:      Pointer to the file system node
 * @kobj:       Pointer to the kernel object related to the sysfs-node
 * @attr:       Attributes of the file
 * @buf:        Buffer to write data to
 * @off:        Offset at which data should be written to
 * @count:      Number of bytes to write
 */
static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
                           struct bin_attribute *attr,
                           char *buf, loff_t off, size_t count)
{
        struct idt_89hpesx_dev *pdev;
        int ret;

        /* Retrieve driver data */
        pdev = dev_get_drvdata(kobj_to_dev(kobj));

        /* Perform EEPROM read operation */
        ret = idt_eeprom_read(pdev, (u16)off, (u16)count, (u8 *)buf);
        return (ret != 0 ? ret : count);
}

/*
 * idt_dbgfs_csr_write() - CSR debugfs-node write callback
 * @filep:      Pointer to the file system file descriptor
 * @buf:        Buffer to read data from
 * @count:      Size of the buffer
 * @offp:       Offset within the file
 *
 * It accepts either "0x<reg addr>:0x<value>" for saving register address
 * and writing value to specified DWORD register or "0x<reg addr>" for
 * just saving register address in order to perform next read operation.
 *
 * WARNING No spaces are allowed. Incoming string must be strictly formated as:
 * "<reg addr>:<value>". Register address must be aligned within 4 bytes
 * (one DWORD).
 */
static ssize_t idt_dbgfs_csr_write(struct file *filep, const char __user *ubuf,
                                   size_t count, loff_t *offp)
{
        struct idt_89hpesx_dev *pdev = filep->private_data;
        char *colon_ch, *csraddr_str, *csrval_str;
        int ret, csraddr_len, csrval_len;
        u32 csraddr, csrval;
        char *buf;

        /* Copy data from User-space */
        buf = kmalloc(count + 1, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        ret = simple_write_to_buffer(buf, count, offp, ubuf, count);
        if (ret < 0)
                goto free_buf;
        buf[count] = 0;

        /* Find position of colon in the buffer */
        colon_ch = strnchr(buf, count, ':');

        /*
         * If there is colon passed then new CSR value should be parsed as
         * well, so allocate buffer for CSR address substring.
         * If no colon is found, then string must have just one number with
         * no new CSR value
         */
        if (colon_ch != NULL) {
                csraddr_len = colon_ch - buf;
                csraddr_str =
                        kmalloc(csraddr_len + 1, GFP_KERNEL);
                if (csraddr_str == NULL) {
                        ret = -ENOMEM;
                        goto free_buf;
                }
                /* Copy the register address to the substring buffer */
                strncpy(csraddr_str, buf, csraddr_len);
                csraddr_str[csraddr_len] = '\0';
                /* Register value must follow the colon */
                csrval_str = colon_ch + 1;
                csrval_len = strnlen(csrval_str, count - csraddr_len);
        } else /* if (str_colon == NULL) */ {
                csraddr_str = (char *)buf; /* Just to shut warning up */
                csraddr_len = strnlen(csraddr_str, count);
                csrval_str = NULL;
                csrval_len = 0;
        }

        /* Convert CSR address to u32 value */
        ret = kstrtou32(csraddr_str, 0, &csraddr);
        if (ret != 0)
                goto free_csraddr_str;

        /* Check whether passed register address is valid */
        if (csraddr > CSR_MAX || !IS_ALIGNED(csraddr, SZ_4)) {
                ret = -EINVAL;
                goto free_csraddr_str;
        }

        /* Shift register address to the right so to have u16 address */
        pdev->csr = (csraddr >> 2);

        /* Parse new CSR value and send it to IDT, if colon has been found */
        if (colon_ch != NULL) {

                ret = kstrtou32(csrval_str, 0, &csrval);
                if (ret != 0)
                        goto free_csraddr_str;

                ret = idt_csr_write(pdev, pdev->csr, csrval);
                if (ret != 0)
                        goto free_csraddr_str;
        }

        /* Free memory only if colon has been found */
free_csraddr_str:
        if (colon_ch != NULL)
                kfree(csraddr_str);

        /* Free buffer allocated for data retrieved from User-space */
free_buf:
        kfree(buf);

        return (ret != 0 ? ret : count);
}

/*
 * idt_dbgfs_csr_read() - CSR debugfs-node read callback
 * @filep:      Pointer to the file system file descriptor
 * @buf:        Buffer to write data to
 * @count:      Size of the buffer
 * @offp:       Offset within the file
 *
 * It just prints the pair "0x<reg addr>:0x<value>" to passed buffer.
 */
#define CSRBUF_SIZE     ((size_t)32)
static ssize_t idt_dbgfs_csr_read(struct file *filep, char __user *ubuf,
                                  size_t count, loff_t *offp)
{
        struct idt_89hpesx_dev *pdev = filep->private_data;
        u32 csraddr, csrval;
        char buf[CSRBUF_SIZE];
        int ret, size;

        /* Perform CSR read operation */
        ret = idt_csr_read(pdev, pdev->csr, &csrval);
        if (ret != 0)
                return ret;

        /* Shift register address to the left so to have real address */
        csraddr = ((u32)pdev->csr << 2);

        /* Print the "0x<reg addr>:0x<value>" to buffer */
        size = snprintf(buf, CSRBUF_SIZE, "0x%05x:0x%08x\n",
                (unsigned int)csraddr, (unsigned int)csrval);

        /* Copy data to User-space */
        return simple_read_from_buffer(ubuf, count, offp, buf, size);
}

/*
 * eeprom_attribute - EEPROM sysfs-node attributes
 *
 * NOTE Size will be changed in compliance with OF node. EEPROM attribute will
 * be read-only as well if the corresponding flag is specified in OF node.
 */
static BIN_ATTR_RW(eeprom, EEPROM_DEF_SIZE);

/*
 * csr_dbgfs_ops - CSR debugfs-node read/write operations
 */
static const struct file_operations csr_dbgfs_ops = {
        .owner = THIS_MODULE,
        .open = simple_open,
        .write = idt_dbgfs_csr_write,
        .read = idt_dbgfs_csr_read
};

/*===========================================================================
 *                       Driver init/deinit methods
 *===========================================================================
 */

/*
 * idt_set_defval() - disable EEPROM access by default
 * @pdev:       Pointer to the driver data
 */
static void idt_set_defval(struct idt_89hpesx_dev *pdev)
{
        /* If OF info is missing then use next values */
        pdev->eesize = 0;
        pdev->eero = true;
        pdev->inieecmd = 0;
        pdev->eeaddr = 0;
}

static const struct i2c_device_id ee_ids[];

/*
 * idt_ee_match_id() - check whether the node belongs to compatible EEPROMs
 */
static const struct i2c_device_id *idt_ee_match_id(struct fwnode_handle *fwnode)
{
        const struct i2c_device_id *id = ee_ids;
        const char *compatible, *p;
        char devname[I2C_NAME_SIZE];
        int ret;

        ret = fwnode_property_read_string(fwnode, "compatible", &compatible);
        if (ret)
                return NULL;

        p = strchr(compatible, ',');
        strlcpy(devname, p ? p + 1 : compatible, sizeof(devname));
        /* Search through the device name */
        while (id->name[0]) {
                if (strcmp(devname, id->name) == 0)
                        return id;
                id++;
        }
        return NULL;
}

/*
 * idt_get_fw_data() - get IDT i2c-device parameters from device tree
 * @pdev:       Pointer to the driver data
 */
static void idt_get_fw_data(struct idt_89hpesx_dev *pdev)
{
        struct device *dev = &pdev->client->dev;
        struct fwnode_handle *fwnode;
        const struct i2c_device_id *ee_id = NULL;
        u32 eeprom_addr;
        int ret;

        device_for_each_child_node(dev, fwnode) {
                ee_id = idt_ee_match_id(fwnode);
                if (IS_ERR_OR_NULL(ee_id)) {
                        dev_warn(dev, "Skip unsupported EEPROM device");
                        continue;
                } else
                        break;
        }

        /* If there is no fwnode EEPROM device, then set zero size */
        if (!ee_id) {
                dev_warn(dev, "No fwnode, EEPROM access disabled");
                idt_set_defval(pdev);
                return;
        }

        /* Retrieve EEPROM size */
        pdev->eesize = (u32)ee_id->driver_data;

        /* Get custom EEPROM address from 'reg' attribute */
        ret = fwnode_property_read_u32(fwnode, "reg", &eeprom_addr);
        if (ret || (eeprom_addr == 0)) {
                dev_warn(dev, "No EEPROM reg found, use default address 0x%x",
                         EEPROM_DEF_ADDR);
                pdev->inieecmd = 0;
                pdev->eeaddr = EEPROM_DEF_ADDR << 1;
        } else {
                pdev->inieecmd = EEPROM_USA;
                pdev->eeaddr = eeprom_addr << 1;
        }

        /* Check EEPROM 'read-only' flag */
        if (fwnode_property_read_bool(fwnode, "read-only"))
                pdev->eero = true;
        else /* if (!fwnode_property_read_bool(node, "read-only")) */
                pdev->eero = false;

        dev_info(dev, "EEPROM of %d bytes found by 0x%x",
                pdev->eesize, pdev->eeaddr);
}

/*
 * idt_create_pdev() - create and init data structure of the driver
 * @client:     i2c client of IDT PCIe-switch device
 */
static struct idt_89hpesx_dev *idt_create_pdev(struct i2c_client *client)
{
        struct idt_89hpesx_dev *pdev;

        /* Allocate memory for driver data */
        pdev = devm_kmalloc(&client->dev, sizeof(struct idt_89hpesx_dev),
                GFP_KERNEL);
        if (pdev == NULL)
                return ERR_PTR(-ENOMEM);

        /* Initialize basic fields of the data */
        pdev->client = client;
        i2c_set_clientdata(client, pdev);

        /* Read firmware nodes information */
        idt_get_fw_data(pdev);

        /* Initialize basic CSR CMD field - use full DWORD-sized r/w ops */
        pdev->inicsrcmd = CSR_DWE;
        pdev->csr = CSR_DEF;

        /* Enable Packet Error Checking if it's supported by adapter */
        if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_PEC)) {
                pdev->iniccode = CCODE_PEC;
                client->flags |= I2C_CLIENT_PEC;
        } else /* PEC is unsupported */ {
                pdev->iniccode = 0;
        }

        return pdev;
}

/*
 * idt_free_pdev() - free data structure of the driver
 * @pdev:       Pointer to the driver data
 */
static void idt_free_pdev(struct idt_89hpesx_dev *pdev)
{
        /* Clear driver data from device private field */
        i2c_set_clientdata(pdev->client, NULL);
}

/*
 * idt_set_smbus_ops() - set supported SMBus operations
 * @pdev:       Pointer to the driver data
 * Return status of smbus check operations
 */
static int idt_set_smbus_ops(struct idt_89hpesx_dev *pdev)
{
        struct i2c_adapter *adapter = pdev->client->adapter;
        struct device *dev = &pdev->client->dev;

        /* Check i2c adapter read functionality */
        if (i2c_check_functionality(adapter,
                                    I2C_FUNC_SMBUS_READ_BLOCK_DATA)) {
                pdev->smb_read = idt_smb_read_block;
                dev_dbg(dev, "SMBus block-read op chosen");
        } else if (i2c_check_functionality(adapter,
                                           I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
                pdev->smb_read = idt_smb_read_i2c_block;
                dev_dbg(dev, "SMBus i2c-block-read op chosen");
        } else if (i2c_check_functionality(adapter,
                                           I2C_FUNC_SMBUS_READ_WORD_DATA) &&
                   i2c_check_functionality(adapter,
                                           I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
                pdev->smb_read = idt_smb_read_word;
                dev_warn(dev, "Use slow word/byte SMBus read ops");
        } else if (i2c_check_functionality(adapter,
                                           I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
                pdev->smb_read = idt_smb_read_byte;
                dev_warn(dev, "Use slow byte SMBus read op");
        } else /* no supported smbus read operations */ {
                dev_err(dev, "No supported SMBus read op");
                return -EPFNOSUPPORT;
        }

        /* Check i2c adapter write functionality */
        if (i2c_check_functionality(adapter,
                                    I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)) {
                pdev->smb_write = idt_smb_write_block;
                dev_dbg(dev, "SMBus block-write op chosen");
        } else if (i2c_check_functionality(adapter,
                                           I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
                pdev->smb_write = idt_smb_write_i2c_block;
                dev_dbg(dev, "SMBus i2c-block-write op chosen");
        } else if (i2c_check_functionality(adapter,
                                           I2C_FUNC_SMBUS_WRITE_WORD_DATA) &&
                   i2c_check_functionality(adapter,
                                           I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
                pdev->smb_write = idt_smb_write_word;
                dev_warn(dev, "Use slow word/byte SMBus write op");
        } else if (i2c_check_functionality(adapter,
                                           I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
                pdev->smb_write = idt_smb_write_byte;
                dev_warn(dev, "Use slow byte SMBus write op");
        } else /* no supported smbus write operations */ {
                dev_err(dev, "No supported SMBus write op");
                return -EPFNOSUPPORT;
        }

        /* Initialize IDT SMBus slave interface mutex */
        mutex_init(&pdev->smb_mtx);

        return 0;
}

/*
 * idt_check_dev() - check whether it's really IDT 89HPESx device
 * @pdev:       Pointer to the driver data
 * Return status of i2c adapter check operation
 */
static int idt_check_dev(struct idt_89hpesx_dev *pdev)
{
        struct device *dev = &pdev->client->dev;
        u32 viddid;
        int ret;

        /* Read VID and DID directly from IDT memory space */
        ret = idt_csr_read(pdev, IDT_VIDDID_CSR, &viddid);
        if (ret != 0) {
                dev_err(dev, "Failed to read VID/DID");
                return ret;
        }

        /* Check whether it's IDT device */
        if ((viddid & IDT_VID_MASK) != PCI_VENDOR_ID_IDT) {
                dev_err(dev, "Got unsupported VID/DID: 0x%08x", viddid);
                return -ENODEV;
        }

        dev_info(dev, "Found IDT 89HPES device VID:0x%04x, DID:0x%04x",
                (viddid & IDT_VID_MASK), (viddid >> 16));

        return 0;
}

/*
 * idt_create_sysfs_files() - create sysfs attribute files
 * @pdev:       Pointer to the driver data
 * Return status of operation
 */
static int idt_create_sysfs_files(struct idt_89hpesx_dev *pdev)
{
        struct device *dev = &pdev->client->dev;
        int ret;

        /* Don't do anything if EEPROM isn't accessible */
        if (pdev->eesize == 0) {
                dev_dbg(dev, "Skip creating sysfs-files");
                return 0;
        }

        /* Allocate memory for attribute file */
        pdev->ee_file = devm_kmalloc(dev, sizeof(*pdev->ee_file), GFP_KERNEL);
        if (!pdev->ee_file)
                return -ENOMEM;

        /* Copy the declared EEPROM attr structure to change some of fields */
        memcpy(pdev->ee_file, &bin_attr_eeprom, sizeof(*pdev->ee_file));

        /* In case of read-only EEPROM get rid of write ability */
        if (pdev->eero) {
                pdev->ee_file->attr.mode &= ~0200;
                pdev->ee_file->write = NULL;
        }
        /* Create EEPROM sysfs file */
        pdev->ee_file->size = pdev->eesize;
        ret = sysfs_create_bin_file(&dev->kobj, pdev->ee_file);
        if (ret != 0) {
                dev_err(dev, "Failed to create EEPROM sysfs-node");
                return ret;
        }

        return 0;
}

/*
 * idt_remove_sysfs_files() - remove sysfs attribute files
 * @pdev:       Pointer to the driver data
 */
static void idt_remove_sysfs_files(struct idt_89hpesx_dev *pdev)
{
        struct device *dev = &pdev->client->dev;

        /* Don't do anything if EEPROM wasn't accessible */
        if (pdev->eesize == 0)
                return;

        /* Remove EEPROM sysfs file */
        sysfs_remove_bin_file(&dev->kobj, pdev->ee_file);
}

/*
 * idt_create_dbgfs_files() - create debugfs files
 * @pdev:       Pointer to the driver data
 */
#define CSRNAME_LEN     ((size_t)32)
static void idt_create_dbgfs_files(struct idt_89hpesx_dev *pdev)
{
        struct i2c_client *cli = pdev->client;
        char fname[CSRNAME_LEN];

        /* Create Debugfs directory for CSR file */
        snprintf(fname, CSRNAME_LEN, "%d-%04hx", cli->adapter->nr, cli->addr);
        pdev->csr_dir = debugfs_create_dir(fname, csr_dbgdir);

        /* Create Debugfs file for CSR read/write operations */
        pdev->csr_file = debugfs_create_file(cli->name, 0600,
                pdev->csr_dir, pdev, &csr_dbgfs_ops);
}

/*
 * idt_remove_dbgfs_files() - remove debugfs files
 * @pdev:       Pointer to the driver data
 */
static void idt_remove_dbgfs_files(struct idt_89hpesx_dev *pdev)
{
        /* Remove CSR directory and it sysfs-node */
        debugfs_remove_recursive(pdev->csr_dir);
}

/*
 * idt_probe() - IDT 89HPESx driver probe() callback method
 */
static int idt_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
        struct idt_89hpesx_dev *pdev;
        int ret;

        /* Create driver data */
        pdev = idt_create_pdev(client);
        if (IS_ERR(pdev))
                return PTR_ERR(pdev);

        /* Set SMBus operations */
        ret = idt_set_smbus_ops(pdev);
        if (ret != 0)
                goto err_free_pdev;

        /* Check whether it is truly IDT 89HPESx device */
        ret = idt_check_dev(pdev);
        if (ret != 0)
                goto err_free_pdev;

        /* Create sysfs files */
        ret = idt_create_sysfs_files(pdev);
        if (ret != 0)
                goto err_free_pdev;

        /* Create debugfs files */
        idt_create_dbgfs_files(pdev);

        return 0;

err_free_pdev:
        idt_free_pdev(pdev);

        return ret;
}

/*
 * idt_remove() - IDT 89HPESx driver remove() callback method
 */
static int idt_remove(struct i2c_client *client)
{
        struct idt_89hpesx_dev *pdev = i2c_get_clientdata(client);

        /* Remove debugfs files first */
        idt_remove_dbgfs_files(pdev);

        /* Remove sysfs files */
        idt_remove_sysfs_files(pdev);

        /* Discard driver data structure */
        idt_free_pdev(pdev);

        return 0;
}

/*
 * ee_ids - array of supported EEPROMs
 */
static const struct i2c_device_id ee_ids[] = {
        { "24c32",  4096},
        { "24c64",  8192},
        { "24c128", 16384},
        { "24c256", 32768},
        { "24c512", 65536},
        {}
};
MODULE_DEVICE_TABLE(i2c, ee_ids);

/*
 * idt_ids - supported IDT 89HPESx devices
 */
static const struct i2c_device_id idt_ids[] = {
        { "89hpes8nt2", 0 },
        { "89hpes12nt3", 0 },

        { "89hpes24nt6ag2", 0 },
        { "89hpes32nt8ag2", 0 },
        { "89hpes32nt8bg2", 0 },
        { "89hpes12nt12g2", 0 },
        { "89hpes16nt16g2", 0 },
        { "89hpes24nt24g2", 0 },
        { "89hpes32nt24ag2", 0 },
        { "89hpes32nt24bg2", 0 },

        { "89hpes12n3", 0 },
        { "89hpes12n3a", 0 },
        { "89hpes24n3", 0 },
        { "89hpes24n3a", 0 },

        { "89hpes32h8", 0 },
        { "89hpes32h8g2", 0 },
        { "89hpes48h12", 0 },
        { "89hpes48h12g2", 0 },
        { "89hpes48h12ag2", 0 },
        { "89hpes16h16", 0 },
        { "89hpes22h16", 0 },
        { "89hpes22h16g2", 0 },
        { "89hpes34h16", 0 },
        { "89hpes34h16g2", 0 },
        { "89hpes64h16", 0 },
        { "89hpes64h16g2", 0 },
        { "89hpes64h16ag2", 0 },

        /* { "89hpes3t3", 0 }, // No SMBus-slave iface */
        { "89hpes12t3g2", 0 },
        { "89hpes24t3g2", 0 },
        /* { "89hpes4t4", 0 }, // No SMBus-slave iface */
        { "89hpes16t4", 0 },
        { "89hpes4t4g2", 0 },
        { "89hpes10t4g2", 0 },
        { "89hpes16t4g2", 0 },
        { "89hpes16t4ag2", 0 },
        { "89hpes5t5", 0 },
        { "89hpes6t5", 0 },
        { "89hpes8t5", 0 },
        { "89hpes8t5a", 0 },
        { "89hpes24t6", 0 },
        { "89hpes6t6g2", 0 },
        { "89hpes24t6g2", 0 },
        { "89hpes16t7", 0 },
        { "89hpes32t8", 0 },
        { "89hpes32t8g2", 0 },
        { "89hpes48t12", 0 },
        { "89hpes48t12g2", 0 },
        { /* END OF LIST */ }
};
MODULE_DEVICE_TABLE(i2c, idt_ids);

static const struct of_device_id idt_of_match[] = {
        { .compatible = "idt,89hpes8nt2", },
        { .compatible = "idt,89hpes12nt3", },

        { .compatible = "idt,89hpes24nt6ag2", },
        { .compatible = "idt,89hpes32nt8ag2", },
        { .compatible = "idt,89hpes32nt8bg2", },
        { .compatible = "idt,89hpes12nt12g2", },
        { .compatible = "idt,89hpes16nt16g2", },
        { .compatible = "idt,89hpes24nt24g2", },
        { .compatible = "idt,89hpes32nt24ag2", },
        { .compatible = "idt,89hpes32nt24bg2", },

        { .compatible = "idt,89hpes12n3", },
        { .compatible = "idt,89hpes12n3a", },
        { .compatible = "idt,89hpes24n3", },
        { .compatible = "idt,89hpes24n3a", },

        { .compatible = "idt,89hpes32h8", },
        { .compatible = "idt,89hpes32h8g2", },
        { .compatible = "idt,89hpes48h12", },
        { .compatible = "idt,89hpes48h12g2", },
        { .compatible = "idt,89hpes48h12ag2", },
        { .compatible = "idt,89hpes16h16", },
        { .compatible = "idt,89hpes22h16", },
        { .compatible = "idt,89hpes22h16g2", },
        { .compatible = "idt,89hpes34h16", },
        { .compatible = "idt,89hpes34h16g2", },
        { .compatible = "idt,89hpes64h16", },
        { .compatible = "idt,89hpes64h16g2", },
        { .compatible = "idt,89hpes64h16ag2", },

        { .compatible = "idt,89hpes12t3g2", },
        { .compatible = "idt,89hpes24t3g2", },

        { .compatible = "idt,89hpes16t4", },
        { .compatible = "idt,89hpes4t4g2", },
        { .compatible = "idt,89hpes10t4g2", },
        { .compatible = "idt,89hpes16t4g2", },
        { .compatible = "idt,89hpes16t4ag2", },
        { .compatible = "idt,89hpes5t5", },
        { .compatible = "idt,89hpes6t5", },
        { .compatible = "idt,89hpes8t5", },
        { .compatible = "idt,89hpes8t5a", },
        { .compatible = "idt,89hpes24t6", },
        { .compatible = "idt,89hpes6t6g2", },
        { .compatible = "idt,89hpes24t6g2", },
        { .compatible = "idt,89hpes16t7", },
        { .compatible = "idt,89hpes32t8", },
        { .compatible = "idt,89hpes32t8g2", },
        { .compatible = "idt,89hpes48t12", },
        { .compatible = "idt,89hpes48t12g2", },
        { },
};
MODULE_DEVICE_TABLE(of, idt_of_match);

/*
 * idt_driver - IDT 89HPESx driver structure
 */
static struct i2c_driver idt_driver = {
        .driver = {
                .name = IDT_NAME,
                .of_match_table = idt_of_match,
        },
        .probe = idt_probe,
        .remove = idt_remove,
        .id_table = idt_ids,
};

/*
 * idt_init() - IDT 89HPESx driver init() callback method
 */
static int __init idt_init(void)
{
        /* Create Debugfs directory first */
        if (debugfs_initialized())
                csr_dbgdir = debugfs_create_dir("idt_csr", NULL);

        /* Add new i2c-device driver */
        return i2c_add_driver(&idt_driver);
}
module_init(idt_init);

/*
 * idt_exit() - IDT 89HPESx driver exit() callback method
 */
static void __exit idt_exit(void)
{
        /* Discard debugfs directory and all files if any */
        debugfs_remove_recursive(csr_dbgdir);

        /* Unregister i2c-device driver */
        i2c_del_driver(&idt_driver);
}
module_exit(idt_exit);