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From:   Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
To:     <linux-i2c@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <wsa@kernel.org>
CC:     <andriy.shevchenko@linux.intel.com>, <krzk@kernel.org>,
        <jarkko.nikula@linux.intel.com>, <robh@kernel.org>,
        <semen.protsenko@linaro.org>, <sven@svenpeter.dev>,
        <jsd@semihalf.com>, <rafal@milecki.pl>, <olof@lixom.net>,
        <arnd@arndb.de>, <UNGLinuxDriver@microchip.com>
Subject: [PATCH v5 i2c-master] i2c: microchip: pci1xxxx: Add driver for I2C host controller in multifunction endpoint of pci1xxxx switch
Date:   Mon, 26 Sep 2022 14:16:54 +0530
Message-ID: <20220926084654.2580827-1-tharunkumar.pasumarthi@microchip.com>
MIME-Version: 1.0
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Microchip pci1xxxx is an unmanaged PCIe3.1a Switch for Consumer,
Industrial and Automotive applications. This switch has multiple
downstream ports. In one of the Switch's Downstream port, there
is a multifunction endpoint for peripherals which includes an I2C
host controller. The I2C function in the endpoint operates at 100KHz,
400KHz and 1 MHz and has buffer depth of 128 bytes.
This patch provides the I2C controller driver for the I2C function
of the switch.

---
V4 -> V5:
1. Removed autoprobe
---
V3 -> V4:
1. Removed typecasting for fields of min_t
2. Replaced TRUE with true
---
V2 -> V3:
1. Replaced SIMPLE_DEV_PM_OPS with DEFINE_SIMPLE_DEV_PM_OPS
2. Used devm_add_action API to avoid mixing devm and non-devm APIs
---
RFC -> V2:
1. Removed pci_free_irq_vectors API in code since pcim_enable_device
is used
2. Added pci1xxxx_i2c_shutdown API in failure case of
pci_alloc_irq_vectors and devm_request_irq
3. Used devm variant of i2c_add_adapter
4. Resolved name collision and fixed styling issues in comments
---

Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
---
 MAINTAINERS                            |    8 +
 drivers/i2c/busses/Kconfig             |   10 +
 drivers/i2c/busses/Makefile            |    1 +
 drivers/i2c/busses/i2c-mchp-pci1xxxx.c | 1210 ++++++++++++++++++++++++
 4 files changed, 1229 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-mchp-pci1xxxx.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 3cf9842d9233..204885ab5200 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13110,6 +13110,14 @@ S:	Supported
 F:	Documentation/devicetree/bindings/mtd/atmel-nand.txt
 F:	drivers/mtd/nand/raw/atmel/*
 
+MICROCHIP PCI1XXXX I2C DRIVER
+M:	Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
+M:	Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
+M:	Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
+L:	linux-i2c@vger.kernel.org
+S:	Maintained
+F:	drivers/i2c/busses/i2c-mchp-pci1xxxx.c
+
 MICROCHIP PWM DRIVER
 M:	Claudiu Beznea <claudiu.beznea@microchip.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index a1bae59208e3..7e967d87dc04 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1244,6 +1244,16 @@ config I2C_PARPORT
 	  This support is also available as a module.  If so, the module
 	  will be called i2c-parport.
 
+config I2C_PCI1XXXX
+	tristate "PCI1XXXX I2C Host Adapter"
+	depends on PCI
+	help
+	  If you say yes to this option, support will be included for
+	  Microchip PCI1XXXX's I2C interface.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called i2c-mchp-pci1xxxx.
+
 config I2C_ROBOTFUZZ_OSIF
 	tristate "RobotFuzz Open Source InterFace USB adapter"
 	depends on USB
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 479f60e4ee3d..2372ed91e7ad 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -131,6 +131,7 @@ obj-$(CONFIG_I2C_DIOLAN_U2C)	+= i2c-diolan-u2c.o
 obj-$(CONFIG_I2C_DLN2)		+= i2c-dln2.o
 obj-$(CONFIG_I2C_CP2615) += i2c-cp2615.o
 obj-$(CONFIG_I2C_PARPORT)	+= i2c-parport.o
+obj-$(CONFIG_I2C_PCI1XXXX)	+= i2c-mchp-pci1xxxx.o
 obj-$(CONFIG_I2C_ROBOTFUZZ_OSIF)	+= i2c-robotfuzz-osif.o
 obj-$(CONFIG_I2C_TAOS_EVM)	+= i2c-taos-evm.o
 obj-$(CONFIG_I2C_TINY_USB)	+= i2c-tiny-usb.o
diff --git a/drivers/i2c/busses/i2c-mchp-pci1xxxx.c b/drivers/i2c/busses/i2c-mchp-pci1xxxx.c
new file mode 100644
index 000000000000..b2b7dbff5ef4
--- /dev/null
+++ b/drivers/i2c/busses/i2c-mchp-pci1xxxx.c
@@ -0,0 +1,1210 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Microchip PCI1XXXX I2C adapter driver for PCIe Switch
+ * which has I2C controller in one of its downstream functions
+ *
+ * Copyright (C) 2021 - 2022 Microchip Technology Inc.
+ *
+ * Authors: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
+ *          Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/types.h>
+
+#define SMBUS_MAST_CORE_ADDR_BASE		0x00000
+#define SMBUS_MAST_SYS_REG_ADDR_BASE		0x01000
+
+/* SMB register space. */
+#define SMB_CORE_CTRL_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x00)
+
+#define SMB_CORE_CTRL_ESO		BIT(6)
+#define SMB_CORE_CTRL_FW_ACK		BIT(4)
+#define SMB_CORE_CTRL_ACK		BIT(0)
+
+#define SMB_CORE_CMD_REG_OFF3	(SMBUS_MAST_CORE_ADDR_BASE + 0x0F)
+#define SMB_CORE_CMD_REG_OFF2	(SMBUS_MAST_CORE_ADDR_BASE + 0x0E)
+#define SMB_CORE_CMD_REG_OFF1	(SMBUS_MAST_CORE_ADDR_BASE + 0x0D)
+
+#define SMB_CORE_CMD_READM		BIT(4)
+#define SMB_CORE_CMD_STOP		BIT(2)
+#define SMB_CORE_CMD_START		BIT(0)
+
+#define SMB_CORE_CMD_REG_OFF0	(SMBUS_MAST_CORE_ADDR_BASE + 0x0C)
+
+#define SMB_CORE_CMD_M_PROCEED		BIT(1)
+#define SMB_CORE_CMD_M_RUN		BIT(0)
+
+#define SMB_CORE_SR_HOLD_TIME_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x18)
+
+/*
+ * SR_HOLD_TIME_XK_TICKS field will indicate the number of ticks of the
+ * baud clock required to program 'Hold Time' at X KHz.
+ */
+#define SR_HOLD_TIME_100K_TICKS	133
+#define SR_HOLD_TIME_400K_TICKS	20
+#define SR_HOLD_TIME_1000K_TICKS	11
+
+#define SMB_CORE_COMPLETION_REG_OFF3	(SMBUS_MAST_CORE_ADDR_BASE + 0x23)
+
+#define COMPLETION_MDONE		BIT(6)
+#define COMPLETION_IDLE			BIT(5)
+#define COMPLETION_MNAKX		BIT(0)
+
+#define SMB_CORE_IDLE_SCALING_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x24)
+
+/*
+ * FAIR_BUS_IDLE_MIN_XK_TICKS field will indicate the number of ticks of
+ * the baud clock required to program 'fair idle delay' at X KHz. Fair idle
+ * delay establishes the MCTP T(IDLE_DELAY) period.
+ */
+#define FAIR_BUS_IDLE_MIN_100K_TICKS		969
+#define FAIR_BUS_IDLE_MIN_400K_TICKS		157
+#define FAIR_BUS_IDLE_MIN_1000K_TICKS		157
+
+/*
+ * FAIR_IDLE_DELAY_XK_TICKS field will indicate the number of ticks of the
+ * baud clock required to satisfy the fairness protocol at X KHz.
+ */
+#define FAIR_IDLE_DELAY_100K_TICKS	1000
+#define FAIR_IDLE_DELAY_400K_TICKS	500
+#define FAIR_IDLE_DELAY_1000K_TICKS	500
+
+#define SMB_IDLE_SCALING_100K		\
+	((FAIR_IDLE_DELAY_100K_TICKS << 16) | FAIR_BUS_IDLE_MIN_100K_TICKS)
+#define SMB_IDLE_SCALING_400K		\
+	((FAIR_IDLE_DELAY_400K_TICKS << 16) | FAIR_BUS_IDLE_MIN_400K_TICKS)
+#define SMB_IDLE_SCALING_1000K	\
+	((FAIR_IDLE_DELAY_1000K_TICKS << 16) | FAIR_BUS_IDLE_MIN_1000K_TICKS)
+
+#define SMB_CORE_CONFIG_REG3		(SMBUS_MAST_CORE_ADDR_BASE + 0x2B)
+
+#define SMB_CONFIG3_ENMI		BIT(6)
+#define SMB_CONFIG3_ENIDI		BIT(5)
+
+#define SMB_CORE_CONFIG_REG2		(SMBUS_MAST_CORE_ADDR_BASE + 0x2A)
+#define SMB_CORE_CONFIG_REG1		(SMBUS_MAST_CORE_ADDR_BASE + 0x29)
+
+#define SMB_CONFIG1_ASR			BIT(7)
+#define SMB_CONFIG1_ENAB		BIT(2)
+#define SMB_CONFIG1_RESET		BIT(1)
+#define SMB_CONFIG1_FEN			BIT(0)
+
+#define SMB_CORE_BUS_CLK_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x2C)
+
+/*
+ * BUS_CLK_XK_LOW_PERIOD_TICKS field defines the number of I2C Baud Clock
+ * periods that make up the low phase of the I2C/SMBus bus clock at X KHz.
+ */
+#define BUS_CLK_100K_LOW_PERIOD_TICKS		156
+#define BUS_CLK_400K_LOW_PERIOD_TICKS		41
+#define BUS_CLK_1000K_LOW_PERIOD_TICKS	15
+
+/*
+ * BUS_CLK_XK_HIGH_PERIOD_TICKS field defines the number of I2C Baud Clock
+ * periods that make up the high phase of the I2C/SMBus bus clock at X KHz.
+ */
+#define BUS_CLK_100K_HIGH_PERIOD_TICKS	154
+#define BUS_CLK_400K_HIGH_PERIOD_TICKS	35
+#define BUS_CLK_1000K_HIGH_PERIOD_TICKS	14
+
+#define BUS_CLK_100K			\
+	((BUS_CLK_100K_HIGH_PERIOD_TICKS << 8) | BUS_CLK_100K_LOW_PERIOD_TICKS)
+#define BUS_CLK_400K			\
+	((BUS_CLK_400K_HIGH_PERIOD_TICKS << 8) | BUS_CLK_400K_LOW_PERIOD_TICKS)
+#define BUS_CLK_1000K			\
+	((BUS_CLK_1000K_HIGH_PERIOD_TICKS << 8) | BUS_CLK_1000K_LOW_PERIOD_TICKS)
+
+#define SMB_CORE_CLK_SYNC_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x3C)
+
+/*
+ * CLK_SYNC_XK defines the number of clock cycles to sync up to the external
+ * clock before comparing the internal and external clocks for clock stretching
+ * at X KHz.
+ */
+#define CLK_SYNC_100K			4
+#define CLK_SYNC_400K			4
+#define CLK_SYNC_1000K		4
+
+#define SMB_CORE_DATA_TIMING_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x40)
+
+/*
+ *
+ * FIRST_START_HOLD_XK_TICKS will indicate the number of ticks of the baud
+ * clock required to program 'FIRST_START_HOLD' timer at X KHz. This timer
+ * determines the SCLK hold time following SDAT driven low during the first
+ * START bit in a transfer.
+ */
+#define FIRST_START_HOLD_100K_TICKS	22
+#define FIRST_START_HOLD_400K_TICKS	16
+#define FIRST_START_HOLD_1000K_TICKS	6
+
+/*
+ * STOP_SETUP_XK_TICKS will indicate the number of ticks of the baud clock
+ * required to program 'STOP_SETUP' timer at X KHz. This timer determines the
+ * SDAT setup time from the rising edge of SCLK for a STOP condition.
+ */
+#define STOP_SETUP_100K_TICKS		157
+#define STOP_SETUP_400K_TICKS		20
+#define STOP_SETUP_1000K_TICKS	12
+
+/*
+ * RESTART_SETUP_XK_TICKS will indicate the number of ticks of the baud clock
+ * required to program 'RESTART_SETUP' timer at X KHz. This timer determines the
+ * SDAT setup time from the rising edge of SCLK for a repeated START condition.
+ */
+#define RESTART_SETUP_100K_TICKS	157
+#define RESTART_SETUP_400K_TICKS	20
+#define RESTART_SETUP_1000K_TICKS	12
+
+/*
+ * DATA_HOLD_XK_TICKS will indicate the number of ticks of the baud clock
+ * required to program 'DATA_HOLD' timer at X KHz. This timer determines the
+ * SDAT hold time following SCLK driven low.
+ */
+#define DATA_HOLD_100K_TICKS		2
+#define DATA_HOLD_400K_TICKS		2
+#define DATA_HOLD_1000K_TICKS		2
+
+#define DATA_TIMING_100K		\
+	((FIRST_START_HOLD_100K_TICKS << 24) | (STOP_SETUP_100K_TICKS << 16) | \
+	(RESTART_SETUP_100K_TICKS << 8) | DATA_HOLD_100K_TICKS)
+#define DATA_TIMING_400K		\
+	((FIRST_START_HOLD_400K_TICKS << 24) | (STOP_SETUP_400K_TICKS << 16) | \
+	(RESTART_SETUP_400K_TICKS << 8) | DATA_HOLD_400K_TICKS)
+#define DATA_TIMING_1000K		\
+	((FIRST_START_HOLD_1000K_TICKS << 24) | (STOP_SETUP_1000K_TICKS << 16) | \
+	(RESTART_SETUP_1000K_TICKS << 8) | DATA_HOLD_1000K_TICKS)
+
+#define SMB_CORE_TO_SCALING_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x44)
+
+/*
+ * BUS_IDLE_MIN_XK_TICKS defines Bus Idle Minimum Time.
+ * Bus Idle Minimum time = BUS_IDLE_MIN[7:0] x Baud_Clock_Period x
+ * (BUS_IDLE_MIN_XK_TICKS[7] ? 4,1)
+ */
+#define BUS_IDLE_MIN_100K_TICKS		167
+#define BUS_IDLE_MIN_400K_TICKS		139
+#define BUS_IDLE_MIN_1000K_TICKS		133
+
+/*
+ * CTRL_CUM_TIME_OUT_XK_TICKS defines SMBus Controller Cumulative Time-Out.
+ * SMBus Controller Cumulative Time-Out duration =
+ * CTRL_CUM_TIME_OUT_XK_TICKS[7:0] x Baud_Clock_Period x 2048
+ */
+#define CTRL_CUM_TIME_OUT_100K_TICKS		159
+#define CTRL_CUM_TIME_OUT_400K_TICKS		159
+#define CTRL_CUM_TIME_OUT_1000K_TICKS		159
+
+/*
+ * TARGET_CUM_TIME_OUT_XK_TICKS defines SMBus Target Cumulative Time-Out duration.
+ * SMBus Target Cumulative Time-Out duration = TARGET_CUM_TIME_OUT_XK_TICKS[7:0] x
+ * Baud_Clock_Period x 4096
+ */
+#define TARGET_CUM_TIME_OUT_100K_TICKS	199
+#define TARGET_CUM_TIME_OUT_400K_TICKS	199
+#define TARGET_CUM_TIME_OUT_1000K_TICKS	199
+
+/*
+ * CLOCK_HIGH_TIME_OUT_XK defines Clock High time out period.
+ * Clock High time out period = CLOCK_HIGH_TIME_OUT_XK[7:0] x Baud_Clock_Period x 8
+ */
+#define CLOCK_HIGH_TIME_OUT_100K_TICKS	204
+#define CLOCK_HIGH_TIME_OUT_400K_TICKS	204
+#define CLOCK_HIGH_TIME_OUT_1000K_TICKS	204
+
+#define TO_SCALING_100K		\
+	((BUS_IDLE_MIN_100K_TICKS << 24) | (CTRL_CUM_TIME_OUT_100K_TICKS << 16) | \
+	(TARGET_CUM_TIME_OUT_100K_TICKS << 8) | CLOCK_HIGH_TIME_OUT_100K_TICKS)
+#define TO_SCALING_400K		\
+	((BUS_IDLE_MIN_400K_TICKS << 24) | (CTRL_CUM_TIME_OUT_400K_TICKS << 16) | \
+	(TARGET_CUM_TIME_OUT_400K_TICKS << 8) | CLOCK_HIGH_TIME_OUT_400K_TICKS)
+#define TO_SCALING_1000K		\
+	((BUS_IDLE_MIN_1000K_TICKS << 24) | (CTRL_CUM_TIME_OUT_1000K_TICKS << 16) | \
+	(TARGET_CUM_TIME_OUT_1000K_TICKS << 8) | CLOCK_HIGH_TIME_OUT_1000K_TICKS)
+
+#define I2C_SCL_PAD_CTRL_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x100)
+#define I2C_SDA_PAD_CTRL_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x101)
+
+#define I2C_FOD_EN			BIT(4)
+#define I2C_PULL_UP_EN			BIT(3)
+#define I2C_PULL_DOWN_EN		BIT(2)
+#define I2C_INPUT_EN			BIT(1)
+#define I2C_OUTPUT_EN			BIT(0)
+
+#define SMBUS_CONTROL_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x200)
+
+#define CTL_RESET_COUNTERS		BIT(3)
+#define CTL_TRANSFER_DIR		BIT(2)
+#define CTL_HOST_FIFO_ENTRY		BIT(1)
+#define CTL_RUN				BIT(0)
+
+#define I2C_DIRN_WRITE			0
+#define I2C_DIRN_READ			1
+
+#define SMBUS_STATUS_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x204)
+
+#define STA_DMA_TERM			BIT(7)
+#define STA_DMA_REQ			BIT(6)
+#define STA_THRESHOLD			BIT(2)
+#define STA_BUF_FULL			BIT(1)
+#define STA_BUF_EMPTY			BIT(0)
+
+#define SMBUS_INTR_STAT_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x208)
+
+#define INTR_STAT_DMA_TERM		BIT(7)
+#define INTR_STAT_THRESHOLD		BIT(2)
+#define INTR_STAT_BUF_FULL		BIT(1)
+#define INTR_STAT_BUF_EMPTY		BIT(0)
+
+#define SMBUS_INTR_MSK_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x20C)
+
+#define INTR_MSK_DMA_TERM		BIT(7)
+#define INTR_MSK_THRESHOLD		BIT(2)
+#define INTR_MSK_BUF_FULL		BIT(1)
+#define INTR_MSK_BUF_EMPTY		BIT(0)
+
+#define ALL_NW_LAYER_INTERRUPTS  \
+	(INTR_MSK_DMA_TERM | INTR_MSK_THRESHOLD | INTR_MSK_BUF_FULL | \
+	 INTR_MSK_BUF_EMPTY)
+
+#define SMBUS_MCU_COUNTER_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x214)
+
+#define SMBALERT_MST_PAD_CTRL_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x230)
+
+#define SMBALERT_MST_PU			BIT(0)
+
+#define SMBUS_GEN_INT_STAT_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x23C)
+
+#define SMBUS_GEN_INT_MASK_REG_OFF	(SMBUS_MAST_CORE_ADDR_BASE + 0x240)
+
+#define SMBALERT_INTR_MASK		BIT(10)
+#define I2C_BUF_MSTR_INTR_MASK		BIT(9)
+#define I2C_INTR_MASK			BIT(8)
+#define SMBALERT_WAKE_INTR_MASK		BIT(2)
+#define I2C_BUF_MSTR_WAKE_INTR_MASK	BIT(1)
+#define I2C_WAKE_INTR_MASK		BIT(0)
+
+#define ALL_HIGH_LAYER_INTR     \
+	(SMBALERT_INTR_MASK | I2C_BUF_MSTR_INTR_MASK | I2C_INTR_MASK | \
+	SMBALERT_WAKE_INTR_MASK | I2C_BUF_MSTR_WAKE_INTR_MASK | \
+	I2C_WAKE_INTR_MASK)
+
+#define SMBUS_RESET_REG		(SMBUS_MAST_CORE_ADDR_BASE + 0x248)
+
+#define PERI_SMBUS_D3_RESET_DIS		BIT(16)
+
+#define SMBUS_MST_BUF		(SMBUS_MAST_CORE_ADDR_BASE + 0x280)
+
+#define SMBUS_BUF_MAX_SIZE		0x80
+
+#define I2C_FLAGS_DIRECT_MODE		BIT(7)
+#define I2C_FLAGS_POLLING_MODE		BIT(6)
+#define I2C_FLAGS_STOP			BIT(5)
+#define I2C_FLAGS_SMB_BLK_READ		BIT(4)
+
+#define PCI1XXXX_I2C_TIMEOUT_MS		1000
+
+/* General Purpose Register. */
+#define SMB_GPR_REG		(SMBUS_MAST_CORE_ADDR_BASE + 0x1000 + 0x0c00 + \
+				0x00)
+
+/* Lock Register. */
+#define SMB_GPR_LOCK_REG	(SMBUS_MAST_CORE_ADDR_BASE + 0x1000 + 0x0000 + \
+				0x00A0)
+
+#define SMBUS_PERI_LOCK		BIT(3)
+
+struct pci1xxxx_i2c {
+	struct completion i2c_xfer_done;
+	bool i2c_xfer_in_progress;
+	struct i2c_adapter adap;
+	void __iomem *i2c_base;
+	u32 freq;
+	u32 flags;
+};
+
+static int set_sys_lock(struct pci1xxxx_i2c *i2c)
+{
+	void __iomem *p = i2c->i2c_base + SMB_GPR_LOCK_REG;
+	u8 data;
+
+	writel(SMBUS_PERI_LOCK, p);
+	data = readl(p);
+	if (data != SMBUS_PERI_LOCK)
+		return -EPERM;
+
+	return 0;
+}
+
+static int release_sys_lock(struct pci1xxxx_i2c *i2c)
+{
+	void __iomem *p = i2c->i2c_base + SMB_GPR_LOCK_REG;
+	u8 data;
+
+	data = readl(p);
+	if (data != SMBUS_PERI_LOCK)
+		return 0;
+
+	writel(0, p);
+	data = readl(p);
+	if (data & SMBUS_PERI_LOCK)
+		return -EPERM;
+
+	return 0;
+}
+
+static void pci1xxxx_ack_high_level_intr(struct pci1xxxx_i2c *i2c, u16 intr_msk)
+{
+	writew(intr_msk, i2c->i2c_base + SMBUS_GEN_INT_STAT_REG_OFF);
+}
+
+static void pci1xxxx_i2c_configure_smbalert_pin(struct pci1xxxx_i2c *i2c,
+						bool enable)
+{
+	void __iomem *p = i2c->i2c_base + SMBALERT_MST_PAD_CTRL_REG_OFF;
+	u8 regval;
+
+	regval = readb(p);
+
+	if (enable)
+		regval |= SMBALERT_MST_PU;
+	else
+		regval &= ~SMBALERT_MST_PU;
+
+	writeb(regval, p);
+}
+
+static void pci1xxxx_i2c_send_start_stop(struct pci1xxxx_i2c *i2c, bool start)
+{
+	void __iomem *p = i2c->i2c_base + SMB_CORE_CMD_REG_OFF1;
+	u8 regval;
+
+	regval = readb(p);
+
+	if (start)
+		regval |= SMB_CORE_CMD_START;
+	else
+		regval |= SMB_CORE_CMD_STOP;
+
+	writeb(regval, p);
+}
+
+/*
+ * When accessing the core control reg, we should not do a read modified write
+ * as they are write '1' to clear bits. Instead we need to write with the
+ * specific bits that needs to be set.
+ */
+static void pci1xxxx_i2c_set_clear_FW_ACK(struct pci1xxxx_i2c *i2c, bool set)
+{
+	u8 regval;
+
+	if (set)
+		regval = SMB_CORE_CTRL_FW_ACK | SMB_CORE_CTRL_ESO | SMB_CORE_CTRL_ACK;
+	else
+		regval = SMB_CORE_CTRL_ESO | SMB_CORE_CTRL_ACK;
+
+	writeb(regval, i2c->i2c_base + SMB_CORE_CTRL_REG_OFF);
+}
+
+static void pci1xxxx_i2c_buffer_write(struct pci1xxxx_i2c *i2c, u8 slaveaddr,
+				      u8 transferlen, unsigned char *buf)
+{
+	void __iomem *p = i2c->i2c_base + SMBUS_MST_BUF;
+
+	if (slaveaddr)
+		writeb(slaveaddr, p++);
+
+	if (buf)
+		memcpy_toio(p, buf, transferlen);
+}
+
+/*
+ * When accessing the core control reg, we should not do a read modified write
+ * as there are write '1' to clear bits. Instead we need to write with the
+ * specific bits that needs to be set.
+ */
+static void pci1xxxx_i2c_enable_ESO(struct pci1xxxx_i2c *i2c)
+{
+	writeb(SMB_CORE_CTRL_ESO, i2c->i2c_base + SMB_CORE_CTRL_REG_OFF);
+}
+
+static void pci1xxxx_i2c_reset_counters(struct pci1xxxx_i2c *i2c)
+{
+	void __iomem *p = i2c->i2c_base + SMBUS_CONTROL_REG_OFF;
+	u8 regval;
+
+	regval = readb(p);
+	regval |= CTL_RESET_COUNTERS;
+	writeb(regval, p);
+}
+
+static void pci1xxxx_i2c_set_transfer_dir(struct pci1xxxx_i2c *i2c, u8 direction)
+{
+	void __iomem *p = i2c->i2c_base + SMBUS_CONTROL_REG_OFF;
+	u8 regval;
+
+	regval = readb(p);
+	if (direction == I2C_DIRN_WRITE)
+		regval &= ~CTL_TRANSFER_DIR;
+	else
+		regval |= CTL_TRANSFER_DIR;
+
+	writeb(regval, p);
+}
+
+static void pci1xxxx_i2c_set_mcu_count(struct pci1xxxx_i2c *i2c, u8 count)
+{
+	writeb(count, i2c->i2c_base + SMBUS_MCU_COUNTER_REG_OFF);
+}
+
+static void pci1xxxx_i2c_set_read_count(struct pci1xxxx_i2c *i2c, u8 readcount)
+{
+	writeb(readcount, i2c->i2c_base + SMB_CORE_CMD_REG_OFF3);
+}
+
+static void pci1xxxx_i2c_set_write_count(struct pci1xxxx_i2c *i2c, u8 writecount)
+{
+	writeb(writecount, i2c->i2c_base + SMB_CORE_CMD_REG_OFF2);
+}
+
+static void pci1xxxx_i2c_set_DMA_run(struct pci1xxxx_i2c *i2c)
+{
+	void __iomem *p = i2c->i2c_base + SMBUS_CONTROL_REG_OFF;
+	u8 regval;
+
+	regval = readb(p);
+	regval |= CTL_RUN;
+	writeb(regval, p);
+}
+
+static void pci1xxxx_i2c_set_mrun_proceed(struct pci1xxxx_i2c *i2c)
+{
+	void __iomem *p = i2c->i2c_base + SMB_CORE_CMD_REG_OFF0;
+	u8 regval;
+
+	regval = readb(p);
+	regval |= SMB_CORE_CMD_M_RUN;
+	regval |= SMB_CORE_CMD_M_PROCEED;
+	writeb(regval, p);
+}
+
+static void pci1xxxx_i2c_start_DMA(struct pci1xxxx_i2c *i2c)
+{
+	pci1xxxx_i2c_set_DMA_run(i2c);
+	pci1xxxx_i2c_set_mrun_proceed(i2c);
+}
+
+static void pci1xxxx_i2c_config_asr(struct pci1xxxx_i2c *i2c, bool enable)
+{
+	void __iomem *p = i2c->i2c_base + SMB_CORE_CONFIG_REG1;
+	u8 regval;
+
+	regval = readb(p);
+	if (enable)
+		regval |= SMB_CONFIG1_ASR;
+	else
+		regval &= ~SMB_CONFIG1_ASR;
+	writeb(regval, p);
+}
+
+static irqreturn_t pci1xxxx_i2c_isr(int irq, void *dev)
+{
+	struct pci1xxxx_i2c *i2c = dev;
+	void __iomem *p1 = i2c->i2c_base + SMBUS_GEN_INT_STAT_REG_OFF;
+	void __iomem *p2 = i2c->i2c_base + SMBUS_INTR_STAT_REG_OFF;
+	irqreturn_t intr_handled = IRQ_NONE;
+	u16 reg1;
+	u8 reg3;
+
+	/*
+	 *  Read the SMBus interrupt status register to see if the
+	 *  DMA_TERM interrupt has caused this callback.
+	 */
+	reg1 = readw(p1);
+
+	if (reg1 & I2C_BUF_MSTR_INTR_MASK) {
+		reg3 = readb(p2);
+		if (reg3 & INTR_STAT_DMA_TERM) {
+			complete(&i2c->i2c_xfer_done);
+			intr_handled = IRQ_HANDLED;
+			writeb(INTR_STAT_DMA_TERM, p2);
+		}
+		pci1xxxx_ack_high_level_intr(i2c, I2C_BUF_MSTR_INTR_MASK);
+	}
+
+	if (reg1 & SMBALERT_INTR_MASK) {
+		intr_handled = IRQ_HANDLED;
+		pci1xxxx_ack_high_level_intr(i2c, SMBALERT_INTR_MASK);
+	}
+
+	return intr_handled;
+}
+
+static void pci1xxxx_i2c_set_count(struct pci1xxxx_i2c *i2c, u8 mcucount,
+				   u8 writecount, u8 readcount)
+{
+	pci1xxxx_i2c_set_mcu_count(i2c, mcucount);
+	pci1xxxx_i2c_set_write_count(i2c, writecount);
+	pci1xxxx_i2c_set_read_count(i2c, readcount);
+}
+
+static void pci1xxxx_i2c_set_readm(struct pci1xxxx_i2c *i2c, bool enable)
+{
+	void __iomem *p = i2c->i2c_base + SMB_CORE_CMD_REG_OFF1;
+	u8 regval;
+
+	regval = readb(p);
+	if (enable)
+		regval |= SMB_CORE_CMD_READM;
+	else
+		regval &= ~SMB_CORE_CMD_READM;
+
+	writeb(regval, p);
+}
+
+static void pci1xxxx_ack_nw_layer_intr(struct pci1xxxx_i2c *i2c, u8 ack_intr_msk)
+{
+	writeb(ack_intr_msk, i2c->i2c_base + SMBUS_INTR_STAT_REG_OFF);
+}
+
+static void pci1xxxx_config_nw_layer_intr(struct pci1xxxx_i2c *i2c,
+					  u8 intr_msk, bool enable)
+{
+	void __iomem *p = i2c->i2c_base + SMBUS_INTR_MSK_REG_OFF;
+	u8 regval;
+
+	regval = readb(p);
+	if (enable)
+		regval &= ~intr_msk;
+	else
+		regval |= intr_msk;
+
+	writeb(regval, p);
+}
+
+static void pci1xxxx_i2c_config_padctrl(struct pci1xxxx_i2c *i2c, bool enable)
+{
+	void __iomem *p1 = i2c->i2c_base + I2C_SCL_PAD_CTRL_REG_OFF;
+	void __iomem *p2 = i2c->i2c_base + I2C_SDA_PAD_CTRL_REG_OFF;
+	u8 regval;
+
+	regval = readb(p1);
+	if (enable)
+		regval |= I2C_INPUT_EN | I2C_OUTPUT_EN;
+	else
+		regval &= ~(I2C_INPUT_EN | I2C_OUTPUT_EN);
+
+	writeb(regval, p1);
+
+	regval = readb(p2);
+	if (enable)
+		regval |= I2C_INPUT_EN | I2C_OUTPUT_EN;
+	else
+		regval &= ~(I2C_INPUT_EN | I2C_OUTPUT_EN);
+
+	writeb(regval, p2);
+}
+
+static void pci1xxxx_i2c_set_mode(struct pci1xxxx_i2c *i2c)
+{
+	void __iomem *p = i2c->i2c_base + SMBUS_CONTROL_REG_OFF;
+	u8 regval;
+
+	regval = readb(p);
+	if (i2c->flags & I2C_FLAGS_DIRECT_MODE)
+		regval &= ~CTL_HOST_FIFO_ENTRY;
+	else
+		regval |= CTL_HOST_FIFO_ENTRY;
+
+	writeb(regval, p);
+}
+
+static void pci1xxxx_i2c_config_high_level_intr(struct pci1xxxx_i2c *i2c,
+						u16 intr_msk, bool enable)
+{
+	void __iomem *p = i2c->i2c_base + SMBUS_GEN_INT_MASK_REG_OFF;
+	u16 regval;
+
+	regval = readw(p);
+	if (enable)
+		regval &= ~intr_msk;
+	else
+		regval |= intr_msk;
+	writew(regval, p);
+}
+
+static void pci1xxxx_i2c_configure_core_reg(struct pci1xxxx_i2c *i2c, bool enable)
+{
+	void __iomem *p1 = i2c->i2c_base + SMB_CORE_CONFIG_REG1;
+	void __iomem *p3 = i2c->i2c_base + SMB_CORE_CONFIG_REG3;
+	u8 reg1;
+	u8 reg3;
+
+	reg1 = readb(p1);
+	reg3 = readb(p3);
+	if (enable) {
+		reg1 |= SMB_CONFIG1_ENAB | SMB_CONFIG1_FEN;
+		reg3 |= SMB_CONFIG3_ENMI | SMB_CONFIG3_ENIDI;
+	} else {
+		reg1 &= ~(SMB_CONFIG1_ENAB | SMB_CONFIG1_FEN);
+		reg3 &= ~(SMB_CONFIG3_ENMI | SMB_CONFIG3_ENIDI);
+	}
+
+	writeb(reg1, p1);
+	writeb(reg3, p3);
+}
+
+static void pci1xxxx_i2c_set_freq(struct pci1xxxx_i2c *i2c)
+{
+	void __iomem *bp = i2c->i2c_base;
+	void __iomem *p_idle_scaling = bp + SMB_CORE_IDLE_SCALING_REG_OFF;
+	void __iomem *p_data_timing = bp + SMB_CORE_DATA_TIMING_REG_OFF;
+	void __iomem *p_hold_time = bp + SMB_CORE_SR_HOLD_TIME_REG_OFF;
+	void __iomem *p_to_scaling = bp + SMB_CORE_TO_SCALING_REG_OFF;
+	void __iomem *p_clk_sync = bp + SMB_CORE_CLK_SYNC_REG_OFF;
+	void __iomem *p_clk_reg = bp + SMB_CORE_BUS_CLK_REG_OFF;
+
+	switch (i2c->freq) {
+	case I2C_MAX_STANDARD_MODE_FREQ:
+		writeb(SR_HOLD_TIME_100K_TICKS, p_hold_time);
+		writel(SMB_IDLE_SCALING_100K, p_idle_scaling);
+		writew(BUS_CLK_100K, p_clk_reg);
+		writel(CLK_SYNC_100K, p_clk_sync);
+		writel(DATA_TIMING_100K, p_data_timing);
+		writel(TO_SCALING_100K, p_to_scaling);
+		break;
+
+	case I2C_MAX_FAST_MODE_PLUS_FREQ:
+		writeb(SR_HOLD_TIME_1000K_TICKS, p_hold_time);
+		writel(SMB_IDLE_SCALING_1000K, p_idle_scaling);
+		writew(BUS_CLK_1000K, p_clk_reg);
+		writel(CLK_SYNC_1000K, p_clk_sync);
+		writel(DATA_TIMING_1000K, p_data_timing);
+		writel(TO_SCALING_1000K, p_to_scaling);
+		break;
+
+	case I2C_MAX_FAST_MODE_FREQ:
+	default:
+		writeb(SR_HOLD_TIME_400K_TICKS, p_hold_time);
+		writel(SMB_IDLE_SCALING_400K, p_idle_scaling);
+		writew(BUS_CLK_400K, p_clk_reg);
+		writel(CLK_SYNC_400K, p_clk_sync);
+		writel(DATA_TIMING_400K, p_data_timing);
+		writel(TO_SCALING_400K, p_to_scaling);
+		break;
+	}
+}
+
+static void pci1xxxx_i2c_init(struct pci1xxxx_i2c *i2c)
+{
+	void __iomem *p2 = i2c->i2c_base + SMBUS_STATUS_REG_OFF;
+	void __iomem *p1 = i2c->i2c_base + SMB_GPR_REG;
+	u8 regval;
+	u8 ret;
+
+	ret = set_sys_lock(i2c);
+	if (ret == -EPERM) {
+		/*
+		 * Configure I2C Fast Mode as default frequency if unable
+		 * to acquire sys lock.
+		 */
+		regval = 0;
+	} else {
+		regval = readl(p1);
+		release_sys_lock(i2c);
+	}
+
+	switch (regval) {
+	case 0:
+		i2c->freq = I2C_MAX_FAST_MODE_FREQ;
+		pci1xxxx_i2c_set_freq(i2c);
+		break;
+	case 1:
+		i2c->freq = I2C_MAX_STANDARD_MODE_FREQ;
+		pci1xxxx_i2c_set_freq(i2c);
+		break;
+	case 2:
+		i2c->freq = I2C_MAX_FAST_MODE_PLUS_FREQ;
+		pci1xxxx_i2c_set_freq(i2c);
+		break;
+	case 3:
+	default:
+		break;
+	}
+
+	pci1xxxx_i2c_config_padctrl(i2c, true);
+	i2c->flags |= I2C_FLAGS_DIRECT_MODE;
+	pci1xxxx_i2c_set_mode(i2c);
+
+	/*
+	 * Added as a precaution since BUF_EMPTY in status register
+	 * also trigered an Interrupt.
+	 */
+	writeb(STA_BUF_EMPTY, p2);
+
+	/* Configure core I2c control registers. */
+	pci1xxxx_i2c_configure_core_reg(i2c, true);
+
+	/*
+	 * Enable pull-up for the SMB alert pin which is just used for
+	 * wakeup right now.
+	 */
+	pci1xxxx_i2c_configure_smbalert_pin(i2c, true);
+}
+
+static void pci1xxxx_i2c_clear_flags(struct pci1xxxx_i2c *i2c)
+{
+	u8 regval;
+
+	/* Reset the internal buffer counters. */
+	pci1xxxx_i2c_reset_counters(i2c);
+
+	/* Clear low level interrupts. */
+	regval = COMPLETION_MNAKX | COMPLETION_IDLE | COMPLETION_MDONE;
+	writeb(regval, i2c->i2c_base + SMB_CORE_COMPLETION_REG_OFF3);
+	reinit_completion(&i2c->i2c_xfer_done);
+	pci1xxxx_ack_nw_layer_intr(i2c, ALL_NW_LAYER_INTERRUPTS);
+	pci1xxxx_ack_high_level_intr(i2c, ALL_HIGH_LAYER_INTR);
+}
+
+static int pci1xxxx_i2c_read(struct pci1xxxx_i2c *i2c, u8 slaveaddr,
+			     unsigned char *buf, u16 total_len)
+{
+	void __iomem *p2 = i2c->i2c_base + SMB_CORE_COMPLETION_REG_OFF3;
+	void __iomem *p1 = i2c->i2c_base + SMB_CORE_CMD_REG_OFF1;
+	void __iomem *p3 = i2c->i2c_base + SMBUS_MST_BUF;
+	unsigned long time_left;
+	u16 remainingbytes;
+	u8 transferlen;
+	int retval = 0;
+	u8 read_count;
+	u32 regval;
+	u16 count;
+
+	/* Enable I2C host controller by setting the ESO bit in the CONTROL REG. */
+	pci1xxxx_i2c_enable_ESO(i2c);
+	pci1xxxx_i2c_clear_flags(i2c);
+	pci1xxxx_config_nw_layer_intr(i2c, INTR_MSK_DMA_TERM, true);
+	pci1xxxx_i2c_config_high_level_intr(i2c, I2C_BUF_MSTR_INTR_MASK, true);
+
+	/*
+	 * The I2C transfer could be more than 128 bytes. Our Core is
+	 * capable of only sending 128 at a time.
+	 * As far as the I2C read is concerned, initailly send the
+	 * read slave address along with the number of bytes to read in
+	 * ReadCount. After sending the slave address the interrupt
+	 * is generated. On seeing the ACK for the slave address, reverse the
+	 * buffer direction and run the DMA to initiate Read from slave.
+	 */
+	for (count = 0; count < total_len; count += transferlen) {
+
+		/*
+		 * Before start of any transaction clear the existing
+		 * START/STOP conditions.
+		 */
+		writeb(0, p1);
+		remainingbytes = total_len - count;
+		transferlen = min_t(u16, remainingbytes, SMBUS_BUF_MAX_SIZE);
+
+		/*
+		 * Send STOP bit for the last chunk in the transaction.
+		 * For I2C read transaction of more than BUF_SIZE, NACK should
+		 * only be sent for the last read.
+		 * Hence a bit FW_ACK is set for all the read chunks except for
+		 * the last chunk. For the last chunk NACK should be sent and
+		 * FW_ACK is cleared Send STOP only when I2C_FLAGS_STOP bit is
+		 * set in the flags and only for the last transaction.
+		 */
+		if ((count + transferlen >= total_len) &&
+		    (i2c->flags & I2C_FLAGS_STOP)) {
+			pci1xxxx_i2c_set_clear_FW_ACK(i2c, false);
+			pci1xxxx_i2c_send_start_stop(i2c, 0);
+		} else {
+			pci1xxxx_i2c_set_clear_FW_ACK(i2c, true);
+		}
+
+		/* Send START bit for the first transaction. */
+		if (count == 0) {
+			pci1xxxx_i2c_set_transfer_dir(i2c, I2C_DIRN_WRITE);
+			pci1xxxx_i2c_send_start_stop(i2c, 1);
+
+			/* Write I2c buffer with just the slave addr. */
+			pci1xxxx_i2c_buffer_write(i2c, slaveaddr, 0, NULL);
+
+			/* Set the count. Readcount is the transfer bytes. */
+			pci1xxxx_i2c_set_count(i2c, 1, 1, transferlen);
+
+			/*
+			 * Set the Auto_start_read bit so that the HW itself
+			 * will take care of the read phase.
+			 */
+			pci1xxxx_i2c_config_asr(i2c, true);
+			if (i2c->flags & I2C_FLAGS_SMB_BLK_READ)
+				pci1xxxx_i2c_set_readm(i2c, true);
+		} else {
+			pci1xxxx_i2c_set_count(i2c, 0, 0, transferlen);
+			pci1xxxx_i2c_config_asr(i2c, false);
+			pci1xxxx_i2c_clear_flags(i2c);
+			pci1xxxx_i2c_set_transfer_dir(i2c, I2C_DIRN_READ);
+		}
+
+		/* Start the DMA. */
+		pci1xxxx_i2c_start_DMA(i2c);
+
+		/* Wait for the DMA_TERM interrupt. */
+		time_left = wait_for_completion_timeout(&i2c->i2c_xfer_done,
+			    msecs_to_jiffies(PCI1XXXX_I2C_TIMEOUT_MS));
+		if (time_left == 0) {
+			/* Reset the I2C core to release the bus lock. */
+			pci1xxxx_i2c_init(i2c);
+			retval = -ETIMEDOUT;
+			goto cleanup;
+		}
+
+		/* Read the completion reg to know the reason for DMA_TERM. */
+		regval = readb(p2);
+
+		/* Slave did not respond. */
+		if (regval & COMPLETION_MNAKX) {
+			writeb(COMPLETION_MNAKX, p2);
+			retval = -ETIMEDOUT;
+			goto cleanup;
+		}
+
+		if (i2c->flags & I2C_FLAGS_SMB_BLK_READ) {
+			buf[0] = readb(p3);
+			read_count = buf[0];
+			memcpy_fromio(&buf[1], p3 + 1, read_count);
+		} else {
+			memcpy_fromio(&buf[count], p3, transferlen);
+		}
+	}
+
+cleanup:
+	/* Disable all the interrupts. */
+	pci1xxxx_config_nw_layer_intr(i2c, INTR_MSK_DMA_TERM, false);
+	pci1xxxx_i2c_config_high_level_intr(i2c, I2C_BUF_MSTR_INTR_MASK, false);
+	pci1xxxx_i2c_config_asr(i2c, false);
+	return retval;
+}
+
+static int pci1xxxx_i2c_write(struct pci1xxxx_i2c *i2c, u8 slaveaddr,
+			      unsigned char *buf, u16 total_len)
+{
+	void __iomem *p2 = i2c->i2c_base + SMB_CORE_COMPLETION_REG_OFF3;
+	void __iomem *p1 = i2c->i2c_base + SMB_CORE_CMD_REG_OFF1;
+	unsigned long time_left;
+	u16 remainingbytes;
+	u8 actualwritelen;
+	u8 transferlen;
+	int retval = 0;
+	u32 regval;
+	u16 count;
+
+	/* Enable I2C host controller by setting the ESO bit in the CONTROL REG. */
+	pci1xxxx_i2c_enable_ESO(i2c);
+
+	/* Set the Buffer direction. */
+	pci1xxxx_i2c_set_transfer_dir(i2c, I2C_DIRN_WRITE);
+	pci1xxxx_config_nw_layer_intr(i2c, INTR_MSK_DMA_TERM, true);
+	pci1xxxx_i2c_config_high_level_intr(i2c, I2C_BUF_MSTR_INTR_MASK, true);
+
+	/*
+	 * The i2c transfer could be more than 128 bytes. Our Core is
+	 * capable of only sending 128 at a time.
+	 */
+	for (count = 0; count < total_len; count += transferlen) {
+		/*
+		 * Before start of any transaction clear the existing
+		 * START/STOP conditions.
+		 */
+		writeb(0, p1);
+		pci1xxxx_i2c_clear_flags(i2c);
+		remainingbytes = total_len - count;
+
+		/* If it is the starting of the transaction send START. */
+		if (count == 0) {
+			pci1xxxx_i2c_send_start_stop(i2c, 1);
+
+			/* -1 for the slave address. */
+			transferlen = min_t(u16, SMBUS_BUF_MAX_SIZE - 1,
+					    remainingbytes);
+			pci1xxxx_i2c_buffer_write(i2c, slaveaddr,
+						  transferlen, &buf[count]);
+			/*
+			 * The actual number of bytes written on the I2C bus
+			 * is including the slave address.
+			 */
+			actualwritelen = transferlen + 1;
+		} else {
+			transferlen = min_t(u16, SMBUS_BUF_MAX_SIZE, remainingbytes);
+			pci1xxxx_i2c_buffer_write(i2c, 0, transferlen, &buf[count]);
+			actualwritelen = transferlen;
+		}
+
+		pci1xxxx_i2c_set_count(i2c, actualwritelen, actualwritelen, 0);
+
+		/*
+		 * Send STOP only when I2C_FLAGS_STOP bit is set in the flags and
+		 * only for the last transaction.
+		 */
+		if (remainingbytes <= transferlen &&
+		   (i2c->flags & I2C_FLAGS_STOP))
+			pci1xxxx_i2c_send_start_stop(i2c, 0);
+
+		pci1xxxx_i2c_start_DMA(i2c);
+
+		/*
+		 * Wait for the DMA_TERM interrupt.
+		 */
+		time_left = wait_for_completion_timeout(&i2c->i2c_xfer_done,
+			    msecs_to_jiffies(PCI1XXXX_I2C_TIMEOUT_MS));
+		if (time_left == 0) {
+			/* Reset the I2C core to release the bus lock. */
+			pci1xxxx_i2c_init(i2c);
+			retval = -ETIMEDOUT;
+			goto cleanup;
+		}
+
+		regval = readb(p2);
+		if (regval & COMPLETION_MNAKX) {
+			writeb(COMPLETION_MNAKX, p2);
+			retval = -ETIMEDOUT;
+			goto cleanup;
+		}
+	}
+cleanup:
+	/* Disable all the interrupts. */
+	pci1xxxx_config_nw_layer_intr(i2c, INTR_MSK_DMA_TERM, false);
+	pci1xxxx_i2c_config_high_level_intr(i2c, I2C_BUF_MSTR_INTR_MASK, false);
+
+	return retval;
+}
+
+static int pci1xxxx_i2c_xfer(struct i2c_adapter *adap,
+			     struct i2c_msg *msgs, int num)
+{
+	struct pci1xxxx_i2c *i2c = i2c_get_adapdata(adap);
+	u8 slaveaddr;
+	int retval;
+	u32 i;
+
+	i2c->i2c_xfer_in_progress = true;
+	for (i = 0; i < num; i++) {
+		slaveaddr = i2c_8bit_addr_from_msg(&msgs[i]);
+
+		/*
+		 * Send the STOP bit if the transfer is the final one or
+		 * if the I2C_M_STOP flag is set.
+		 */
+		if ((i == num - 1) || (msgs[i].flags & I2C_M_STOP))
+			i2c->flags |= I2C_FLAGS_STOP;
+		else
+			i2c->flags &= ~I2C_FLAGS_STOP;
+
+		if (msgs[i].flags & I2C_M_RECV_LEN)
+			i2c->flags |= I2C_FLAGS_SMB_BLK_READ;
+		else
+			i2c->flags &= ~I2C_FLAGS_SMB_BLK_READ;
+
+		if (msgs[i].flags & I2C_M_RD)
+			retval = pci1xxxx_i2c_read(i2c, slaveaddr,
+						   msgs[i].buf, msgs[i].len);
+		else
+			retval = pci1xxxx_i2c_write(i2c, slaveaddr,
+						    msgs[i].buf, msgs[i].len);
+
+		if (retval < 0)
+			break;
+	}
+	i2c->i2c_xfer_in_progress = false;
+
+	if (retval < 0)
+		return retval;
+
+	return num;
+}
+
+/*
+ * List of supported functions by the driver.
+ */
+static u32 pci1xxxx_i2c_get_funcs(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_PROTOCOL_MANGLING |
+		I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
+		I2C_FUNC_SMBUS_BYTE |
+		I2C_FUNC_SMBUS_BYTE_DATA |
+		I2C_FUNC_SMBUS_WORD_DATA |
+		I2C_FUNC_SMBUS_PROC_CALL |
+		I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm pci1xxxx_i2c_algo = {
+	.master_xfer = pci1xxxx_i2c_xfer,
+	.functionality = pci1xxxx_i2c_get_funcs,
+};
+
+static const struct i2c_adapter_quirks pci1xxxx_i2c_quirks = {
+	.flags = I2C_AQ_NO_ZERO_LEN,
+};
+
+static const struct i2c_adapter pci1xxxx_i2c_ops = {
+	.owner	= THIS_MODULE,
+	.name	= "PCI1xxxx I2C Adapter",
+	.algo	= &pci1xxxx_i2c_algo,
+	.quirks = &pci1xxxx_i2c_quirks,
+};
+
+static int pci1xxxx_i2c_suspend(struct device *dev)
+{
+	struct pci1xxxx_i2c *i2c = dev_get_drvdata(dev);
+	void __iomem *p = i2c->i2c_base + SMBUS_RESET_REG;
+	struct pci_dev *pdev = to_pci_dev(dev);
+	u32 regval;
+
+	i2c_mark_adapter_suspended(&i2c->adap);
+
+	/*
+	 * If the system is put into 'suspend' state when the I2C transfer is in
+	 * progress, wait until the transfer completes.
+	 */
+	while (i2c->i2c_xfer_in_progress)
+		msleep(20);
+
+	pci1xxxx_i2c_config_high_level_intr(i2c, SMBALERT_WAKE_INTR_MASK, true);
+
+	/*
+	 * Enable the PERST_DIS bit to mask the PERST from resetting the core
+	 * registers.
+	 */
+	regval = readl(p);
+	regval |= PERI_SMBUS_D3_RESET_DIS;
+	writel(regval, p);
+
+	/* Enable PCI wake in the PMCSR register. */
+	device_set_wakeup_enable(dev, true);
+	pci_wake_from_d3(pdev, true);
+
+	return 0;
+}
+
+static int pci1xxxx_i2c_resume(struct device *dev)
+{
+	struct pci1xxxx_i2c *i2c = dev_get_drvdata(dev);
+	void __iomem *p1 = i2c->i2c_base + SMBUS_GEN_INT_STAT_REG_OFF;
+	void __iomem *p2 = i2c->i2c_base + SMBUS_RESET_REG;
+	struct pci_dev *pdev = to_pci_dev(dev);
+	u32 regval;
+
+	regval = readw(p1);
+	writew(regval, p1);
+	pci1xxxx_i2c_config_high_level_intr(i2c, SMBALERT_WAKE_INTR_MASK, false);
+	regval = readl(p2);
+	regval &= ~PERI_SMBUS_D3_RESET_DIS;
+	writel(regval, p2);
+	i2c_mark_adapter_resumed(&i2c->adap);
+	pci_wake_from_d3(pdev, false);
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(pci1xxxx_i2c_pm_ops, pci1xxxx_i2c_suspend,
+			 pci1xxxx_i2c_resume);
+
+static void pci1xxxx_i2c_shutdown(struct pci1xxxx_i2c *i2c)
+{
+	pci1xxxx_i2c_config_padctrl(i2c, false);
+	pci1xxxx_i2c_configure_core_reg(i2c, false);
+}
+
+static int pci1xxxx_i2c_probe_pci(struct pci_dev *pdev,
+				  const struct pci_device_id *ent)
+{
+	struct device *dev = &pdev->dev;
+	struct pci1xxxx_i2c *i2c;
+	int ret;
+
+	i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
+	if (!i2c)
+		return -ENOMEM;
+
+	pci_set_drvdata(pdev, i2c);
+	i2c->i2c_xfer_in_progress = false;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return ret;
+
+	pci_set_master(pdev);
+
+	/*
+	 * We are getting the base address of the SMB core. SMB core uses
+	 * BAR0 and size is 32K.
+	 */
+	ret = pcim_iomap_regions(pdev, BIT(0), pci_name(pdev));
+	if (ret < 0)
+		return ret;
+
+	i2c->i2c_base =	pcim_iomap_table(pdev)[0];
+	init_completion(&i2c->i2c_xfer_done);
+	pci1xxxx_i2c_init(i2c);
+
+	ret = devm_add_action(dev, (void (*)(void *))pci1xxxx_i2c_shutdown, i2c);
+	if (ret)
+		return ret;
+
+	ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
+	if (ret < 0)
+		return ret;
+
+	ret = devm_request_irq(dev, pci_irq_vector(pdev, 0), pci1xxxx_i2c_isr,
+			       0, pci_name(pdev), i2c);
+	if (ret)
+		return ret;
+
+	i2c->adap = pci1xxxx_i2c_ops;
+	i2c->adap.dev.parent = dev;
+
+	snprintf(i2c->adap.name, sizeof(i2c->adap.name),
+		 "MCHP PCI1xxxx i2c adapter at %s", pci_name(pdev));
+
+	i2c_set_adapdata(&i2c->adap, i2c);
+
+	ret = devm_i2c_add_adapter(dev, &i2c->adap);
+	if (ret)
+		return dev_err_probe(dev, ret, "i2c add adapter failed\n");
+
+	return 0;
+}
+
+static const struct pci_device_id pci1xxxx_i2c_pci_id_table[] = {
+	{ PCI_VDEVICE(EFAR, 0xA003) },
+	{ PCI_VDEVICE(EFAR, 0xA013) },
+	{ PCI_VDEVICE(EFAR, 0xA023) },
+	{ PCI_VDEVICE(EFAR, 0xA033) },
+	{ PCI_VDEVICE(EFAR, 0xA043) },
+	{ }
+};
+MODULE_DEVICE_TABLE(pci, pci1xxxx_i2c_pci_id_table);
+
+static struct pci_driver pci1xxxx_i2c_pci_driver = {
+	.name		= "i2c-mchp-pci1xxxx",
+	.id_table	= pci1xxxx_i2c_pci_id_table,
+	.probe		= pci1xxxx_i2c_probe_pci,
+	.driver = {
+		.pm = pm_sleep_ptr(&pci1xxxx_i2c_pm_ops),
+	},
+};
+module_pci_driver(pci1xxxx_i2c_pci_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tharun Kumar P<tharunkumar.pasumarthi@microchip.com>");
+MODULE_AUTHOR("Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>");
+MODULE_DESCRIPTION("Microchip Technology Inc. pci1xxxx I2C bus driver");
-- 
2.25.1