=============================
Serge V. Semin
Leading Programmer
Embedded SW development group
T-platforms
=============================

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>

---
 .../devicetree/bindings/misc/idt_89hpesx.txt       |   41 +
 drivers/misc/eeprom/Kconfig                        |   10 +
 drivers/misc/eeprom/Makefile                       |    1 +
 drivers/misc/eeprom/idt_89hpesx.c                  | 1483 ++++++++++++++++++++
 4 files changed, 1535 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/idt_89hpesx.txt
 create mode 100644 drivers/misc/eeprom/idt_89hpesx.c

diff --git a/Documentation/devicetree/bindings/misc/idt_89hpesx.txt b/Documentation/devicetree/bindings/misc/idt_89hpesx.txt
new file mode 100644
index 0000000..469cc93
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/idt_89hpesx.txt
@@ -0,0 +1,41 @@
+EEPROM / CSR SMBus-slave interface of IDT 89HPESx devices
+
+Required properties:
+  - compatible : should be "<manufacturer>,<type>"
+		 Basically there is only one manufacturer: idt, but some
+		 compatible devices may be produced in future. Following devices
+		 are supported: 89hpes8nt2, 89hpes12nt3, 89hpes24nt6ag2,
+		 89hpes32nt8ag2, 89hpes32nt8bg2, 89hpes12nt12g2, 89hpes16nt16g2,
+		 89hpes24nt24g2, 89hpes32nt24ag2, 89hpes32nt24bg2;
+		 89hpes12n3, 89hpes12n3a, 89hpes24n3, 89hpes24n3a;
+		 89hpes32h8, 89hpes32h8g2, 89hpes48h12, 89hpes48h12g2,
+		 89hpes48h12ag2, 89hpes16h16, 89hpes22h16, 89hpes22h16g2,
+		 89hpes34h16, 89hpes34h16g2, 89hpes64h16, 89hpes64h16g2,
+		 89hpes64h16ag2;
+		 89hpes12t3g2, 89hpes24t3g2, 89hpes16t4, 89hpes4t4g2,
+		 89hpes10t4g2, 89hpes16t4g2, 89hpes16t4ag2, 89hpes5t5,
+		 89hpes6t5, 89hpes8t5, 89hpes8t5a, 89hpes24t6, 89hpes6t6g2,
+		 89hpes24t6g2, 89hpes16t7, 89hpes32t8, 89hpes32t8g2,
+		 89hpes48t12, 89hpes48t12g2.
+		 Current implementation of the driver doesn't have any device-
+		 specific functionalities. But since each of them differs
+		 by registers mapping, CSRs read/write restrictions can be
+		 added in future.
+  - reg :	 I2C address of the IDT 89HPES device.
+
+Optional properties:
+  - read-only :	 Parameterless property disables writes to the EEPROM
+  - idt,eesize : Size of EEPROM device connected to IDT 89HPES i2c-master bus
+		 (default value is 4096 bytes if option isn't specified)
+  - idt,eeaddr : Custom address of EEPROM device
+		 (If not specified IDT 89HPESx device will try to communicate
+		  with EEPROM sited by default address - 0x50)
+
+Example:
+	idt_pcie_sw@60 {
+		compatible = "idt,89hpes12nt3";
+		reg = <0x60>;
+		read-only;
+		idt,eesize = <65536>;
+		idt,eeaddr = <0x50>;
+	};
diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig
index c4e41c2..de58762 100644
--- a/drivers/misc/eeprom/Kconfig
+++ b/drivers/misc/eeprom/Kconfig
@@ -100,4 +100,14 @@ config EEPROM_DIGSY_MTC_CFG
 
 	  If unsure, say N.
 
+config EEPROM_IDT_89HPESX
+	tristate "IDT 89HPESx PCIe-swtiches EEPROM / CSR support"
+	depends on I2C && SYSFS
+	help
+	  Enable this driver to get read/write access to EEPROM / CSRs
+	  over IDT PCIe-swtich i2c-slave interface.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called idt_89hpesx.
+
 endmenu
diff --git a/drivers/misc/eeprom/Makefile b/drivers/misc/eeprom/Makefile
index fc1e81d..90a5262 100644
--- a/drivers/misc/eeprom/Makefile
+++ b/drivers/misc/eeprom/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_EEPROM_MAX6875)	+= max6875.o
 obj-$(CONFIG_EEPROM_93CX6)	+= eeprom_93cx6.o
 obj-$(CONFIG_EEPROM_93XX46)	+= eeprom_93xx46.o
 obj-$(CONFIG_EEPROM_DIGSY_MTC_CFG) += digsy_mtc_eeprom.o
+obj-$(CONFIG_EEPROM_IDT_89HPESX) += idt_89hpesx.o
diff --git a/drivers/misc/eeprom/idt_89hpesx.c b/drivers/misc/eeprom/idt_89hpesx.c
new file mode 100644
index 0000000..f95f4f0
--- /dev/null
+++ b/drivers/misc/eeprom/idt_89hpesx.c
@@ -0,0 +1,1483 @@
+/*
+ *   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 another sysfs-file to perform
+ * simple IO operations using that ability for just basic debug purpose.
+ * Particularly next file is created in the device specific sysfs-directory:
+ * /sys/bus/i2c/devices/<bus>-<devaddr>/csr
+ * Format of the sysfs-node is:
+ * $ cat /sys/bus/i2c/devices/<bus>-<devaddr>/csr;
+ * <CSR address>:<CSR value>
+ * So reading the content of the sysfs-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/bus/i2c/devices/<bus>-<devaddr>/csr
+ * If it wants to change the CSR value as well, the format of the write
+ * operation is:
+ * $ echo "<CSR address>:<CSR value>" > \
+ *        /sys/bus/i2c/devices/<bus>-<devaddr>/csr;
+ * CSR address and value can be any of hexadecimal, decimal or octal format.
+ */
+
+/*
+ * Note: You can load this module with either option 'dyndbg=+p' or define the
+ * next preprocessor constant
+ */
+/* #define DEBUG */
+
+#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/mod_devicetable.h>
+#include <linux/of.h>
+#include <linux/i2c.h>
+#include <linux/pci_ids.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");
+
+/*
+ * Some common constant used in the driver for better readability:
+ * @SUCCESS:	Success of a function execution
+ */
+#define SUCCESS (0)
+
+/*
+ * 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
+ *
+ * @eenode:	EEPROM sysfs-node to read/write data to/from EEPROM
+ * @regnode:	Register sysfs-node to read/write CSRs
+ */
+struct idt_smb_seq;
+struct idt_89hpesx_dev {
+	u32 eesize;
+	bool eero;
+	u8 eeaddr;
+
+	u8 inieecmd;
+	u8 inicsrcmd;
+	u8 iniccode;
+
+	atomic_t 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 eenode;
+	struct bin_attribute regnode;
+};
+#define to_pdev_kobj(__kobj) \
+	dev_get_drvdata(container_of(__kobj, struct device, kobj))
+
+/*
+ * 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
+ */
+#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)
+
+/*
+ * 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 < SUCCESS); \
+	__sts; \
+})
+
+/*
+ * Wrapper dev_err/dev_warn/dev_info/dev_dbg macros
+ */
+#define dev_err_idt(pdev, args...) \
+	dev_err(&pdev->client->dev, ## args)
+#define dev_warn_idt(pdev, args...) \
+	dev_warn(&pdev->client->dev, ## args)
+#define dev_info_idt(pdev, args...) \
+	dev_info(&pdev->client->dev, ## args)
+#define dev_dbg_idt(pdev, args...) \
+	dev_dbg(&pdev->client->dev, ## args)
+
+/*===========================================================================
+ *                         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 != SUCCESS)
+			return (int)sts;
+	}
+
+	return SUCCESS;
+}
+
+/*
+ * 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 < SUCCESS)
+			return (int)sts;
+
+		seq->data[idx] = (u8)sts;
+	}
+
+	return SUCCESS;
+}
+
+/*
+ * 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 != SUCCESS)
+			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 != SUCCESS)
+			return (int)sts;
+	}
+
+	return SUCCESS;
+}
+
+/*
+ * 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 < SUCCESS)
+			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 < SUCCESS)
+			return (int)sts;
+
+		seq->data[idx] = (u8)sts;
+	}
+
+	return SUCCESS;
+}
+
+/*
+ * 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 < SUCCESS ? sts : -ENODATA);
+
+	return SUCCESS;
+}
+
+/*
+ * 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 < SUCCESS ? 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 SUCCESS;
+}
+
+/*===========================================================================
+ *                          EEPROM IO-operations
+ *===========================================================================
+ */
+
+/*
+ * 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 idt_eeprom_seq eeseq;
+	struct idt_smb_seq smbseq;
+	int ret, retry;
+	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 != SUCCESS) {
+			dev_err_idt(pdev,
+				"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. Sometimes EEPROM may
+		 * respond with NACK if it's busy with writing previous data,
+		 * 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;
+			ret = pdev->smb_write(pdev, &smbseq);
+			if (ret != SUCCESS) {
+				dev_err_idt(pdev,
+					"Failed to init mem address 0x%02hhx",
+					memaddr);
+				goto err_mutex_unlock;
+			}
+
+			/* Perform read operation */
+			smbseq.bytecnt = EEPROM_RD_CNT;
+			eeseq.data = ~data[idx];
+			ret = pdev->smb_read(pdev, &smbseq);
+			if (ret != SUCCESS) {
+				dev_err_idt(pdev,
+					"Failed to read mem address 0x%02hhx",
+					memaddr);
+				goto err_mutex_unlock;
+			}
+		} while (retry-- && (eeseq.cmd & EEPROM_NAERR));
+
+		/* Check whether IDT successfully sent data to EEPROM */
+		if (eeseq.cmd & (EEPROM_NAERR | EEPROM_LAERR | EEPROM_MSS)) {
+			dev_err_idt(pdev, "Communication with EEPROM failed");
+			ret = -EREMOTEIO;
+			goto err_mutex_unlock;
+		}
+		if (eeseq.data != data[idx]) {
+			dev_err_idt(pdev,
+				"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 != SUCCESS)
+			return ret;
+	}
+
+	return SUCCESS;
+}
+
+/*
+ * 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)
+{
+	struct idt_eeprom_seq eeseq;
+	struct idt_smb_seq smbseq;
+	u16 idx;
+	int ret;
+
+	/* Initialize SMBus sequence fields */
+	smbseq.ccode = pdev->iniccode | CCODE_EEPROM;
+	smbseq.data = (u8 *)&eeseq;
+
+	/* Send data one-by-one, checking if it is successfully written */
+	for (idx = 0; idx < len; idx++, memaddr++) {
+		/* Lock IDT SMBus device */
+		mutex_lock(&pdev->smb_mtx);
+
+		/* 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 != SUCCESS) {
+			dev_err_idt(pdev, "Failed to init mem address 0x%02hhx",
+				memaddr);
+			goto err_mutex_unlock;
+		}
+
+		/* Perform read operation (rest of fields stay the same) */
+		smbseq.bytecnt = EEPROM_RD_CNT;
+		ret = pdev->smb_read(pdev, &smbseq);
+		if (ret != SUCCESS) {
+			dev_err_idt(pdev,
+				"Failed to read eeprom address 0x%02hhx",
+				memaddr);
+			ret = -EREMOTEIO;
+			goto err_mutex_unlock;
+		}
+
+		/* Check whether IDT successfully read data from EEPROM */
+		if (eeseq.cmd & (EEPROM_NAERR | EEPROM_LAERR | EEPROM_MSS)) {
+			dev_err_idt(pdev, "Communication with eeprom failed");
+			ret = -EREMOTEIO;
+			goto err_mutex_unlock;
+		}
+
+		/* Save retrieved data */
+		buf[idx] = eeseq.data;
+
+		/* Unlock IDT SMBus device */
+err_mutex_unlock:
+		mutex_unlock(&pdev->smb_mtx);
+		if (ret != SUCCESS)
+			return ret;
+	}
+
+	return SUCCESS;
+}
+
+/*===========================================================================
+ *                          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 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 != SUCCESS) {
+		dev_err_idt(pdev, "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 != SUCCESS) {
+		dev_err_idt(pdev, "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 != SUCCESS) {
+		dev_err_idt(pdev, "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_idt(pdev, "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 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 != SUCCESS) {
+		dev_err_idt(pdev, "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 != SUCCESS) {
+		dev_err_idt(pdev, "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_idt(pdev, "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-nodes IO-operations
+ *===========================================================================
+ */
+
+/*
+ * idt_sysfs_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 idt_sysfs_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 = to_pdev_kobj(kobj);
+
+	/* Perform EEPROM write operation */
+	ret = idt_eeprom_write(pdev, (u16)off, (u16)count, (u8 *)buf);
+	return (ret != SUCCESS ? ret : count);
+}
+
+/*
+ * idt_sysfs_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 idt_sysfs_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 = to_pdev_kobj(kobj);
+
+	/* Perform EEPROM read operation */
+	ret = idt_eeprom_read(pdev, (u16)off, (u16)count, (u8 *)buf);
+	return (ret != SUCCESS ? ret : count);
+}
+
+/*
+ * idt_sysfs_csr_store() - CSR sysfs-node write callback
+ * @kobj:	Pointer to the kernel object related to the sysfs-node
+ * @attr:	Attributes of the file
+ * @buf:	Buffer to write data to
+ * @count:	Size of the buffer
+ *
+ * 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_sysfs_csr_store(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t count)
+{
+	struct idt_89hpesx_dev *pdev;
+	char *colon_ch, *csraddr_str, *csrval_str;
+	int ret, csraddr_len, csrval_len;
+	u32 csraddr, csrval;
+
+	/* Retrieve driver data */
+	pdev = dev_get_drvdata(dev);
+
+	/* 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(sizeof(char)*(csraddr_len + 1), GFP_KERNEL);
+		if (csraddr_str == NULL)
+			return -ENOMEM;
+		/* 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 != SUCCESS)
+		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 */
+	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 != SUCCESS)
+			goto free_csraddr_str;
+
+		ret = idt_csr_write(pdev, (u16)csraddr, csrval);
+		if (ret != SUCCESS)
+			goto free_csraddr_str;
+	}
+
+	/* Save CSR address in the data structure for future read operations */
+	atomic_set(&pdev->csr, (int)csraddr);
+
+	/* Free memory only if colon has been found */
+free_csraddr_str:
+	if (colon_ch != NULL)
+		kfree(csraddr_str);
+
+	return (ret != SUCCESS ? ret : count);
+}
+
+/*
+ * idt_sysfs_csr_show() - CSR sysfs-node read callback
+ * @kobj:	Pointer to the kernel object related to the sysfs-node
+ * @attr:	Attributes of the file
+ * @buf:	Buffer to write data to
+ *
+ * It just prints the pair "0x<reg addr>:0x<value>" to passed buffer.
+ */
+static ssize_t idt_sysfs_csr_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct idt_89hpesx_dev *pdev;
+	u32 csraddr, csrval;
+	int ret;
+
+	/* Retrieve driver data */
+	pdev = dev_get_drvdata(dev);
+
+	/* Read current CSR address */
+	csraddr = atomic_read(&pdev->csr);
+
+	/* Perform CSR read operation */
+	ret = idt_csr_read(pdev, (u16)csraddr, &csrval);
+	if (ret != SUCCESS)
+		return ret;
+
+	/* Shift register address to the left so to have real address */
+	csraddr <<= 2;
+
+	/* Print the "0x<reg addr>:0x<value>" to buffer */
+	return snprintf(buf, PAGE_SIZE, "0x%05x:0x%08x\n",
+		(unsigned int)csraddr, (unsigned int)csrval);
+}
+
+/*
+ * 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 struct bin_attribute eeprom_attribute = {
+	.attr = {
+		.name = "eeprom",
+		.mode = S_IRUGO | S_IWUSR
+	},
+	.size = EEPROM_DEF_SIZE,
+	.write = idt_sysfs_eeprom_write,
+	.read = idt_sysfs_eeprom_read
+};
+
+/*
+ * csr_attribute - CSR sysfs-node attributes
+ */
+static struct device_attribute csr_attribute = {
+	.attr = {
+		.name = "csr",
+		.mode = S_IRUGO | S_IWUSR
+	},
+	.store = idt_sysfs_csr_store,
+	.show = idt_sysfs_csr_show,
+};
+
+/*===========================================================================
+ *                       Driver init/deinit methods
+ *===========================================================================
+ */
+
+/*
+ * idt_set_defval() - set default device data parameters
+ * @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 = EEPROM_DEF_SIZE;
+	pdev->eero = true;
+	pdev->inieecmd = 0;
+	pdev->eeaddr = EEPROM_DEF_ADDR << 1;
+}
+
+#ifdef CONFIG_OF
+/*
+ * idt_get_ofdata() - get IDT i2c-device parameters from device tree
+ * @pdev:	Pointer to the driver data
+ */
+static void idt_get_ofdata(struct idt_89hpesx_dev *pdev)
+{
+	struct device_node *node = pdev->client->dev.of_node;
+	const __be32 *val;
+
+	/* Read dts node parameters */
+	if (node) {
+		/* Get EEPROM size from 'idt,eesize' */
+		val = of_get_property(node, "idt,eesize", NULL);
+		if (val != NULL) {
+			pdev->eesize = be32_to_cpup(val);
+			if (!is_power_of_2(pdev->eesize))
+				dev_warn_idt(pdev,
+					"EEPROM size %u is not power of 2",
+					pdev->eesize);
+		} else /* if (val == NULL) */ {
+			pdev->eesize = EEPROM_DEF_SIZE;
+			dev_warn_idt(pdev,
+				"No EEPROM size, set default %u bytes",
+				pdev->eesize);
+		}
+
+		/* Get custom EEPROM address from 'idt,eeaddr' */
+		val = of_get_property(node, "idt,eeaddr", NULL);
+		if (val != NULL) {
+			pdev->inieecmd = EEPROM_USA;
+			pdev->eeaddr = be32_to_cpup(val) << 1;
+		} else /* if (val != NULL) */ {
+			pdev->inieecmd = 0;
+			pdev->eeaddr = EEPROM_DEF_ADDR << 1;
+		}
+
+		/* Check EEPROM 'read-only' flag */
+		if (of_get_property(node, "read-only", NULL))
+			pdev->eero = true;
+		else /* if (!of_get_property(node, "read-only", NULL)) */
+			pdev->eero = false;
+	} else {
+		dev_warn_idt(pdev, "No dts node, set default values");
+		idt_set_defval(pdev);
+	}
+}
+#else
+static void idt_get_ofdata(struct idt_89hpesx_dev *pdev)
+{
+	dev_warn_idt(pdev, "OF table is unsupported, set default values");
+
+	/* Nothing we can do, just set the default values */
+	idt_set_defval(pdev);
+}
+#endif /* CONFIG_OF */
+
+/*
+ * 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 OF nodes information */
+	idt_get_ofdata(pdev);
+
+	/* Initialize basic CSR CMD field - use full DWORD-sized r/w ops */
+	pdev->inicsrcmd = CSR_DWE;
+	atomic_set(&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;
+	}
+
+	dev_dbg_idt(pdev, "IDT 89HPESx data created");
+
+	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);
+
+	/* Just free memory allocated for data */
+	devm_kfree(&pdev->client->dev, pdev);
+
+	dev_dbg_idt(pdev, "IDT 89HPESx data discarded");
+}
+
+/*
+ * 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;
+
+	/* 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_idt(pdev, "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_idt(pdev, "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_idt(pdev, "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_idt(pdev, "Use slow byte SMBus read op");
+	} else /* no supported smbus read operations */ {
+		dev_err_idt(pdev, "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_idt(pdev, "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_idt(pdev, "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_idt(pdev, "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_idt(pdev, "Use slow byte SMBus write op");
+	} else /* no supported smbus write operations */ {
+		dev_err_idt(pdev, "No supported SMBus write op");
+		return -EPFNOSUPPORT;
+	}
+
+	/* Initialize IDT SMBus slave interface mutex */
+	mutex_init(&pdev->smb_mtx);
+
+	dev_dbg_idt(pdev, "SMBus functionality successfully checked");
+
+	return SUCCESS;
+}
+
+/*
+ * 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)
+{
+	u32 viddid;
+	int ret;
+
+	/* Read VID and DID directly from IDT memory space */
+	ret = idt_csr_read(pdev, IDT_VIDDID_CSR, &viddid);
+	if (ret != SUCCESS) {
+		dev_err_idt(pdev, "Failed to read VID/DID");
+		return ret;
+	}
+
+	/* Check whether it's IDT device */
+	if ((viddid & IDT_VID_MASK) != PCI_VENDOR_ID_IDT) {
+		dev_err_idt(pdev, "Got unsupported VID/DID: 0x%08x", viddid);
+		return -ENODEV;
+	}
+
+	dev_info_idt(pdev, "Found IDT 89HPES device VID:0x%04x, DID:0x%04x",
+		(viddid & IDT_VID_MASK), (viddid >> 16));
+
+	return SUCCESS;
+}
+
+/*
+ * 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;
+
+	/* In case of read-only EEPROM get rid of write ability */
+	if (pdev->eero) {
+		eeprom_attribute.attr.mode &= ~S_IWUSR;
+		eeprom_attribute.write = NULL;
+	}
+	/* Create EEPROM sysfs file */
+	eeprom_attribute.size = pdev->eesize;
+	ret = sysfs_create_bin_file(&dev->kobj, &eeprom_attribute);
+	if (ret != SUCCESS) {
+		dev_err_idt(pdev, "Failed to create EEPROM sysfs-node");
+		return ret;
+	}
+
+	/* Create CSR sysfs file */
+	ret = sysfs_create_file(&dev->kobj, &csr_attribute.attr);
+	if (ret != SUCCESS) {
+		dev_err_idt(pdev, "Failed to create CSR sysfs-node");
+		sysfs_remove_bin_file(&dev->kobj, &eeprom_attribute);
+		return ret;
+	}
+
+	dev_dbg_idt(pdev, "Sysfs-files created");
+
+	return SUCCESS;
+}
+
+/*
+ * 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;
+
+	/* Remove CSR sysfs file */
+	sysfs_remove_file(&dev->kobj, &csr_attribute.attr);
+
+	/* Remove EEPROM sysfs file */
+	sysfs_remove_bin_file(&dev->kobj, &eeprom_attribute);
+
+	dev_dbg_idt(pdev, "Sysfs-files removed");
+}
+
+/*
+ * 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 != SUCCESS)
+		goto err_free_pdev;
+
+	/* Check whether it is truly IDT 89HPESx device */
+	ret = idt_check_dev(pdev);
+	if (ret != SUCCESS)
+		goto err_free_pdev;
+
+	/* Create sysfs files */
+	ret = idt_create_sysfs_files(pdev);
+	if (ret != SUCCESS)
+		goto err_free_pdev;
+
+	dev_dbg_idt(pdev, "IDT %s device probed", id->name);
+
+	return SUCCESS;
+
+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 sysfs files first */
+	idt_remove_sysfs_files(pdev);
+
+	/* Discard driver data structure */
+	idt_free_pdev(pdev);
+
+	dev_dbg_idt(pdev, "IDT 89HPESx device removed");
+
+	return SUCCESS;
+}
+
+/*
+ * 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);
+
+/*
+ * idt_driver - IDT 89HPESx driver structure
+ */
+static struct i2c_driver idt_driver = {
+	.driver = {
+		.name = IDT_NAME,
+		.owner = THIS_MODULE,
+	},
+	.probe = idt_probe,
+	.remove = idt_remove,
+	.id_table = idt_ids,
+};
+module_i2c_driver(idt_driver);
+
