i2c: microchip: pci1xxxx: Add driver for I2C host controller in multifunction endpoin...
authorTharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Tue, 27 Sep 2022 08:59:49 +0000 (14:29 +0530)
committerWolfram Sang <wsa@kernel.org>
Wed, 28 Sep 2022 20:02:17 +0000 (22:02 +0200)
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.

Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
MAINTAINERS
drivers/i2c/busses/Kconfig
drivers/i2c/busses/Makefile
drivers/i2c/busses/i2c-mchp-pci1xxxx.c [new file with mode: 0644]

index a3f380f15ff5053303b9f6c6456b82cc9fe7b7a9..d71adf29f8bb78f08805f00b5aae19d5b228614e 100644 (file)
@@ -13435,6 +13435,14 @@ F:     Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml
 F:     drivers/nvmem/microchip-otpc.c
 F:     include/dt-bindings/nvmem/microchip,sama7g5-otpc.h
 
+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)
index 7284206b278b9e84dc4be0ab81eb5d47d97eaeb0..a8b873b30b008c6dd2d66a1f9605f76996224130 100644 (file)
@@ -1267,6 +1267,16 @@ 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
index c5cac15f075cebb48c9566ce1a78982be9252a73..e73cdb1d2b5a85bf0973ee0facc92fe4b76704c4 100644 (file)
@@ -133,6 +133,7 @@ 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 (file)
index 0000000..b2b7dbf
--- /dev/null
@@ -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");