sw64: i2c: add i2c driver based designware for sw64

Sunway inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SPZD
CVE: NA

-------------------------------

Signed-off-by: Gu Zitao <guzitao@wxiat.com> #openEuler_contributor
Signed-off-by: NLaibin Qiu <qiulaibin@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/i2c/busses/Kconfig

@@ -553,6 +553,15 @@ config I2C_DESIGNWARE_PLATFORM
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-designware-platform.
 
+config I2C_SUNWAY_SW6
+	tristate "SUNWAY SW6 I2C Controller "
+	depends on SW64_CHIP3
+	default y if PLATFORM_XUELANG
+	help
+	  If you say yes to this option, support will be included for the
+	  Synopsys DesignWare I2C adapter in MCU of CHIP3. Only master mode
+	  is supported.
+
 config I2C_DESIGNWARE_BAYTRAIL
 	bool "Intel Baytrail I2C semaphore support"
 	depends on ACPI

drivers/i2c/busses/Makefile

@@ -51,6 +51,10 @@ obj-$(CONFIG_I2C_DAVINCI)	+= i2c-davinci.o
 obj-$(CONFIG_I2C_DESIGNWARE_CORE)			+= i2c-designware-core.o
 i2c-designware-core-y					:= i2c-designware-common.o
 i2c-designware-core-y					+= i2c-designware-master.o
+obj-$(CONFIG_I2C_SUNWAY_SW6)				+= i2c-sunway-sw6.o
+i2c-sunway-sw6-y 					:= i2c-sunway-sw6-common.o
+i2c-sunway-sw6-y 					+= i2c-sunway-sw6-master.o
+i2c-sunway-sw6-y 					+= i2c-sunway-sw6-platdrv.o
 i2c-designware-core-$(CONFIG_I2C_DESIGNWARE_SLAVE) 	+= i2c-designware-slave.o
 obj-$(CONFIG_I2C_DESIGNWARE_PLATFORM)			+= i2c-designware-platform.o
 i2c-designware-platform-y 				:= i2c-designware-platdrv.o

drivers/i2c/busses/i2c-sunway-sw6-common.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Synopsys DesignWare I2C adapter driver.
+ *
+ * Based on the TI DAVINCI I2C adapter driver.
+ *
+ * Copyright (C) 2006 Texas Instruments.
+ * Copyright (C) 2007 MontaVista Software Inc.
+ * Copyright (C) 2009 Provigent Ltd.
+ */
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/swab.h>
+
+#include "i2c-sunway-sw6-core.h"
+
+static char *abort_sources[] = {
+	[ABRT_7B_ADDR_NOACK] =
+		"slave address not acknowledged (7bit mode)",
+	[ABRT_10ADDR1_NOACK] =
+		"first address byte not acknowledged (10bit mode)",
+	[ABRT_10ADDR2_NOACK] =
+		"second address byte not acknowledged (10bit mode)",
+	[ABRT_TXDATA_NOACK] =
+		"data not acknowledged",
+	[ABRT_GCALL_NOACK] =
+		"no acknowledgement for a general call",
+	[ABRT_GCALL_READ] =
+		"read after general call",
+	[ABRT_SBYTE_ACKDET] =
+		"start byte acknowledged",
+	[ABRT_SBYTE_NORSTRT] =
+		"trying to send start byte when restart is disabled",
+	[ABRT_10B_RD_NORSTRT] =
+		"trying to read when restart is disabled (10bit mode)",
+	[ABRT_MASTER_DIS] =
+		"trying to use disabled adapter",
+	[ARB_LOST] =
+		"lost arbitration",
+	[ABRT_SLAVE_FLUSH_TXFIFO] =
+		"read command so flush old data in the TX FIFO",
+	[ABRT_SLAVE_ARBLOST] =
+		"slave lost the bus while transmitting data to a remote master",
+	[ABRT_SLAVE_RD_INTX] =
+		"incorrect slave-transmitter mode configuration",
+};
+
+u32 dw_readl(struct dw_i2c_dev *dev, int offset)
+{
+	u32 value;
+
+	offset = offset << 7;
+	if (dev->flags & ACCESS_16BIT)
+		value = readw_relaxed(dev->base + offset) |
+			(readw_relaxed(dev->base + offset + 2) << 16);
+	else
+		value = readl_relaxed(dev->base + offset);
+
+	if (dev->flags & ACCESS_SWAP)
+		return swab32(value);
+	else
+		return value;
+}
+
+void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)
+{
+	offset = offset << 7;
+	if (dev->flags & ACCESS_SWAP)
+		b = swab32(b);
+
+	if (dev->flags & ACCESS_16BIT) {
+		writew_relaxed((u16)b, dev->base + offset);
+		writew_relaxed((u16)(b >> 16), dev->base + offset + 2);
+	} else {
+		writel_relaxed(b, dev->base + offset);
+	}
+}
+
+/**
+ * i2c_dw_set_reg_access() - Set register access flags
+ * @dev: device private data
+ *
+ * Autodetects needed register access mode and sets access flags accordingly.
+ * This must be called before doing any other register access.
+ */
+int i2c_dw_set_reg_access(struct dw_i2c_dev *dev)
+{
+	u32 reg;
+	int ret;
+
+	ret = i2c_dw_acquire_lock(dev);
+	if (ret)
+		return ret;
+
+	reg = dw_readl(dev, DW_IC_COMP_TYPE);
+	i2c_dw_release_lock(dev);
+
+	if (reg == swab32(DW_IC_COMP_TYPE_VALUE)) {
+		/* Configure register endianness access */
+		dev->flags |= ACCESS_SWAP;
+	} else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) {
+		/* Configure register access mode 16bit */
+		dev->flags |= ACCESS_16BIT;
+	} else if (reg != DW_IC_COMP_TYPE_VALUE) {
+		dev_err(dev->dev,
+			"Unknown Synopsys component type: 0x%08x\n", reg);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
+{
+	/*
+	 * DesignWare I2C core doesn't seem to have solid strategy to meet
+	 * the tHD;STA timing spec.  Configuring _HCNT based on tHIGH spec
+	 * will result in violation of the tHD;STA spec.
+	 */
+	if (cond)
+		/*
+		 * Conditional expression:
+		 *
+		 *   IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH
+		 *
+		 * This is based on the DW manuals, and represents an ideal
+		 * configuration.  The resulting I2C bus speed will be
+		 * faster than any of the others.
+		 *
+		 * If your hardware is free from tHD;STA issue, try this one.
+		 */
+		return (ic_clk * tSYMBOL + 500000) / 1000000 - 8 + offset;
+	else
+		/*
+		 * Conditional expression:
+		 *
+		 *   IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf)
+		 *
+		 * This is just experimental rule; the tHD;STA period turned
+		 * out to be proportinal to (_HCNT + 3).  With this setting,
+		 * we could meet both tHIGH and tHD;STA timing specs.
+		 *
+		 * If unsure, you'd better to take this alternative.
+		 *
+		 * The reason why we need to take into account "tf" here,
+		 * is the same as described in i2c_dw_scl_lcnt().
+		 */
+		return (ic_clk * (tSYMBOL + tf) + 500000) / 1000000
+			- 3 + offset;
+}
+
+u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
+{
+	/*
+	 * Conditional expression:
+	 *
+	 *   IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf)
+	 *
+	 * DW I2C core starts counting the SCL CNTs for the LOW period
+	 * of the SCL clock (tLOW) as soon as it pulls the SCL line.
+	 * In order to meet the tLOW timing spec, we need to take into
+	 * account the fall time of SCL signal (tf).  Default tf value
+	 * should be 0.3 us, for safety.
+	 */
+	return ((ic_clk * (tLOW + tf) + 500000) / 1000000) - 1 + offset;
+}
+
+int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev)
+{
+	u32 reg;
+	int ret;
+
+	ret = i2c_dw_acquire_lock(dev);
+	if (ret)
+		return ret;
+
+	/* Configure SDA Hold Time if required */
+	reg = dw_readl(dev, DW_IC_COMP_VERSION);
+	if (reg >= DW_IC_SDA_HOLD_MIN_VERS) {
+		if (!dev->sda_hold_time) {
+			/* Keep previous hold time setting if no one set it */
+			dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD);
+		}
+
+		/*
+		 * Workaround for avoiding TX arbitration lost in case I2C
+		 * slave pulls SDA down "too quickly" after falling egde of
+		 * SCL by enabling non-zero SDA RX hold. Specification says it
+		 * extends incoming SDA low to high transition while SCL is
+		 * high but it apprears to help also above issue.
+		 */
+		if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK))
+			dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT;
+
+		dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n",
+			dev->sda_hold_time & ~(u32)DW_IC_SDA_HOLD_RX_MASK,
+			dev->sda_hold_time >> DW_IC_SDA_HOLD_RX_SHIFT);
+	} else if (dev->sda_hold_time) {
+		dev_warn(dev->dev,
+			"Hardware too old to adjust SDA hold time.\n");
+		dev->sda_hold_time = 0;
+	}
+
+	i2c_dw_release_lock(dev);
+
+	return 0;
+}
+
+void __i2c_dw_disable(struct dw_i2c_dev *dev)
+{
+	int timeout = 100;
+
+	do {
+		__i2c_dw_disable_nowait(dev);
+		/*
+		 * The enable status register may be unimplemented, but
+		 * in that case this test reads zero and exits the loop.
+		 */
+		if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == 0)
+			return;
+
+		/*
+		 * Wait 10 times the signaling period of the highest I2C
+		 * transfer supported by the driver (for 400KHz this is
+		 * 25us) as described in the DesignWare I2C databook.
+		 */
+		usleep_range(25, 250);
+	} while (timeout--);
+
+	dev_warn(dev->dev, "timeout in disabling adapter\n");
+}
+
+unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev)
+{
+	/*
+	 * Clock is not necessary if we got LCNT/HCNT values directly from
+	 * the platform code.
+	 */
+	if (WARN_ON_ONCE(!dev->get_clk_rate_khz))
+		return 0;
+	return dev->get_clk_rate_khz(dev);
+}
+
+int i2c_dw_prepare_clk(struct dw_i2c_dev *dev, bool prepare)
+{
+	if (IS_ERR(dev->clk))
+		return PTR_ERR(dev->clk);
+
+	if (prepare)
+		return clk_prepare_enable(dev->clk);
+
+	clk_disable_unprepare(dev->clk);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_dw_prepare_clk);
+
+int i2c_dw_acquire_lock(struct dw_i2c_dev *dev)
+{
+	int ret;
+
+	if (!dev->acquire_lock)
+		return 0;
+
+	ret = dev->acquire_lock(dev);
+	if (!ret)
+		return 0;
+
+	dev_err(dev->dev, "couldn't acquire bus ownership\n");
+
+	return ret;
+}
+
+void i2c_dw_release_lock(struct dw_i2c_dev *dev)
+{
+	if (dev->release_lock)
+		dev->release_lock(dev);
+}
+
+/*
+ * Waiting for bus not busy
+ */
+int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
+{
+	int timeout = TIMEOUT;
+
+	while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
+		if (timeout <= 0) {
+			dev_warn(dev->dev, "timeout waiting for bus ready\n");
+			i2c_recover_bus(&dev->adapter);
+
+			if (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY)
+				return -ETIMEDOUT;
+			return 0;
+		}
+		timeout--;
+		usleep_range(1000, 1100);
+	}
+
+	return 0;
+}
+
+int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev)
+{
+	unsigned long abort_source = dev->abort_source;
+	int i;
+
+	if (abort_source & DW_IC_TX_ABRT_NOACK) {
+		for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
+			dev_dbg(dev->dev,
+				"%s: %s\n", __func__, abort_sources[i]);
+		return -EREMOTEIO;
+	}
+
+	for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
+		dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]);
+
+	if (abort_source & DW_IC_TX_ARB_LOST)
+		return -EAGAIN;
+	else if (abort_source & DW_IC_TX_ABRT_GCALL_READ)
+		return -EINVAL; /* wrong msgs[] data */
+	else
+		return -EIO;
+}
+
+u32 i2c_dw_func(struct i2c_adapter *adap)
+{
+	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+
+	return dev->functionality;
+}
+
+void i2c_dw_disable(struct dw_i2c_dev *dev)
+{
+	/* Disable controller */
+	__i2c_dw_disable(dev);
+
+	/* Disable all interrupts */
+	dw_writel(dev, 0, DW_IC_INTR_MASK);
+	dw_readl(dev, DW_IC_CLR_INTR);
+}
+
+void i2c_dw_disable_int(struct dw_i2c_dev *dev)
+{
+	dw_writel(dev, 0, DW_IC_INTR_MASK);
+}
+
+u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev)
+{
+	return dw_readl(dev, DW_IC_COMP_PARAM_1);
+}
+EXPORT_SYMBOL_GPL(i2c_dw_read_comp_param);
+
+MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core");
+MODULE_LICENSE("GPL");

drivers/i2c/busses/i2c-sunway-sw6-core.h

+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Synopsys DesignWare I2C adapter driver.
+ *
+ * Based on the TI DAVINCI I2C adapter driver.
+ *
+ * Copyright (C) 2006 Texas Instruments.
+ * Copyright (C) 2007 MontaVista Software Inc.
+ * Copyright (C) 2009 Provigent Ltd.
+ */
+
+#include <linux/i2c.h>
+#include <linux/pm_qos.h>
+
+#define DW_IC_DEFAULT_FUNCTIONALITY (I2C_FUNC_I2C |			\
+					I2C_FUNC_SMBUS_BYTE |		\
+					I2C_FUNC_SMBUS_BYTE_DATA |	\
+					I2C_FUNC_SMBUS_WORD_DATA |	\
+					I2C_FUNC_SMBUS_BLOCK_DATA |	\
+					I2C_FUNC_SMBUS_I2C_BLOCK)
+
+#define DW_IC_CON_MASTER		0x1
+#define DW_IC_CON_SPEED_STD		0x2
+#define DW_IC_CON_SPEED_FAST		0x4
+#define DW_IC_CON_SPEED_HIGH		0x6
+#define DW_IC_CON_SPEED_MASK		0x6
+#define DW_IC_CON_10BITADDR_SLAVE		0x8
+#define DW_IC_CON_10BITADDR_MASTER	0x10
+#define DW_IC_CON_RESTART_EN		0x20
+#define DW_IC_CON_SLAVE_DISABLE		0x40
+#define DW_IC_CON_STOP_DET_IFADDRESSED		0x80
+#define DW_IC_CON_TX_EMPTY_CTRL		0x100
+#define DW_IC_CON_RX_FIFO_FULL_HLD_CTRL		0x200
+
+/*
+ * Registers offset
+ */
+#define DW_IC_CON		0x0
+#define DW_IC_TAR		0x4
+#define DW_IC_SAR		0x8
+#define DW_IC_DATA_CMD		0x10
+#define DW_IC_SS_SCL_HCNT	0x14
+#define DW_IC_SS_SCL_LCNT	0x18
+#define DW_IC_FS_SCL_HCNT	0x1c
+#define DW_IC_FS_SCL_LCNT	0x20
+#define DW_IC_HS_SCL_HCNT	0x24
+#define DW_IC_HS_SCL_LCNT	0x28
+#define DW_IC_INTR_STAT		0x2c
+#define DW_IC_INTR_MASK		0x30
+#define DW_IC_RAW_INTR_STAT	0x34
+#define DW_IC_RX_TL		0x38
+#define DW_IC_TX_TL		0x3c
+#define DW_IC_CLR_INTR		0x40
+#define DW_IC_CLR_RX_UNDER	0x44
+#define DW_IC_CLR_RX_OVER	0x48
+#define DW_IC_CLR_TX_OVER	0x4c
+#define DW_IC_CLR_RD_REQ	0x50
+#define DW_IC_CLR_TX_ABRT	0x54
+#define DW_IC_CLR_RX_DONE	0x58
+#define DW_IC_CLR_ACTIVITY	0x5c
+#define DW_IC_CLR_STOP_DET	0x60
+#define DW_IC_CLR_START_DET	0x64
+#define DW_IC_CLR_GEN_CALL	0x68
+#define DW_IC_ENABLE		0x6c
+#define DW_IC_STATUS		0x70
+#define DW_IC_TXFLR		0x74
+#define DW_IC_RXFLR		0x78
+#define DW_IC_SDA_HOLD		0x7c
+#define DW_IC_TX_ABRT_SOURCE	0x80
+#define DW_IC_ENABLE_STATUS	0x9c
+#define DW_IC_CLR_RESTART_DET	0xa8
+#define DW_IC_COMP_PARAM_1	0xf4
+#define DW_IC_COMP_VERSION	0xf8
+#define DW_IC_SDA_HOLD_MIN_VERS	0x3131312A
+#define DW_IC_COMP_TYPE		0xfc
+#define DW_IC_COMP_TYPE_VALUE	0x44570140
+
+#define DW_IC_INTR_RX_UNDER	0x001
+#define DW_IC_INTR_RX_OVER	0x002
+#define DW_IC_INTR_RX_FULL	0x004
+#define DW_IC_INTR_TX_OVER	0x008
+#define DW_IC_INTR_TX_EMPTY	0x010
+#define DW_IC_INTR_RD_REQ	0x020
+#define DW_IC_INTR_TX_ABRT	0x040
+#define DW_IC_INTR_RX_DONE	0x080
+#define DW_IC_INTR_ACTIVITY	0x100
+#define DW_IC_INTR_STOP_DET	0x200
+#define DW_IC_INTR_START_DET	0x400
+#define DW_IC_INTR_GEN_CALL	0x800
+#define DW_IC_INTR_RESTART_DET	0x1000
+
+#define DW_IC_INTR_DEFAULT_MASK		(DW_IC_INTR_RX_FULL | \
+					 DW_IC_INTR_TX_ABRT | \
+					 DW_IC_INTR_STOP_DET)
+#define DW_IC_INTR_MASTER_MASK		(DW_IC_INTR_DEFAULT_MASK | \
+					 DW_IC_INTR_TX_EMPTY)
+#define DW_IC_INTR_SLAVE_MASK		(DW_IC_INTR_DEFAULT_MASK | \
+					 DW_IC_INTR_RX_DONE | \
+					 DW_IC_INTR_RX_UNDER | \
+					 DW_IC_INTR_RD_REQ)
+
+#define DW_IC_STATUS_ACTIVITY		0x1
+#define DW_IC_STATUS_TFE		BIT(2)
+#define DW_IC_STATUS_MASTER_ACTIVITY	BIT(5)
+#define DW_IC_STATUS_SLAVE_ACTIVITY	BIT(6)
+
+#define DW_IC_SDA_HOLD_RX_SHIFT		16
+#define DW_IC_SDA_HOLD_RX_MASK		GENMASK(23, DW_IC_SDA_HOLD_RX_SHIFT)
+
+#define DW_IC_ERR_TX_ABRT	0x1
+
+#define DW_IC_TAR_10BITADDR_MASTER BIT(12)
+
+#define DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH	(BIT(2) | BIT(3))
+#define DW_IC_COMP_PARAM_1_SPEED_MODE_MASK	GENMASK(3, 2)
+
+/*
+ * status codes
+ */
+#define STATUS_IDLE			0x0
+#define STATUS_WRITE_IN_PROGRESS	0x1
+#define STATUS_READ_IN_PROGRESS		0x2
+
+#define TIMEOUT			20 /* ms */
+
+/*
+ * operation modes
+ */
+#define DW_IC_MASTER		0
+#define DW_IC_SLAVE		1
+
+/*
+ * Hardware abort codes from the DW_IC_TX_ABRT_SOURCE register
+ *
+ * Only expected abort codes are listed here
+ * refer to the datasheet for the full list
+ */
+#define ABRT_7B_ADDR_NOACK	0
+#define ABRT_10ADDR1_NOACK	1
+#define ABRT_10ADDR2_NOACK	2
+#define ABRT_TXDATA_NOACK	3
+#define ABRT_GCALL_NOACK	4
+#define ABRT_GCALL_READ		5
+#define ABRT_SBYTE_ACKDET	7
+#define ABRT_SBYTE_NORSTRT	9
+#define ABRT_10B_RD_NORSTRT	10
+#define ABRT_MASTER_DIS		11
+#define ARB_LOST		12
+#define ABRT_SLAVE_FLUSH_TXFIFO	13
+#define ABRT_SLAVE_ARBLOST	14
+#define ABRT_SLAVE_RD_INTX	15
+
+#define DW_IC_TX_ABRT_7B_ADDR_NOACK	(1UL << ABRT_7B_ADDR_NOACK)
+#define DW_IC_TX_ABRT_10ADDR1_NOACK	(1UL << ABRT_10ADDR1_NOACK)
+#define DW_IC_TX_ABRT_10ADDR2_NOACK	(1UL << ABRT_10ADDR2_NOACK)
+#define DW_IC_TX_ABRT_TXDATA_NOACK	(1UL << ABRT_TXDATA_NOACK)
+#define DW_IC_TX_ABRT_GCALL_NOACK	(1UL << ABRT_GCALL_NOACK)
+#define DW_IC_TX_ABRT_GCALL_READ	(1UL << ABRT_GCALL_READ)
+#define DW_IC_TX_ABRT_SBYTE_ACKDET	(1UL << ABRT_SBYTE_ACKDET)
+#define DW_IC_TX_ABRT_SBYTE_NORSTRT	(1UL << ABRT_SBYTE_NORSTRT)
+#define DW_IC_TX_ABRT_10B_RD_NORSTRT	(1UL << ABRT_10B_RD_NORSTRT)
+#define DW_IC_TX_ABRT_MASTER_DIS	(1UL << ABRT_MASTER_DIS)
+#define DW_IC_TX_ARB_LOST		(1UL << ARB_LOST)
+#define DW_IC_RX_ABRT_SLAVE_RD_INTX	(1UL << ABRT_SLAVE_RD_INTX)
+#define DW_IC_RX_ABRT_SLAVE_ARBLOST	(1UL << ABRT_SLAVE_ARBLOST)
+#define DW_IC_RX_ABRT_SLAVE_FLUSH_TXFIFO	(1UL << ABRT_SLAVE_FLUSH_TXFIFO)
+
+#define DW_IC_TX_ABRT_NOACK		(DW_IC_TX_ABRT_7B_ADDR_NOACK | \
+					 DW_IC_TX_ABRT_10ADDR1_NOACK | \
+					 DW_IC_TX_ABRT_10ADDR2_NOACK | \
+					 DW_IC_TX_ABRT_TXDATA_NOACK | \
+					 DW_IC_TX_ABRT_GCALL_NOACK)
+
+
+/**
+ * struct dw_i2c_dev - private i2c-designware data
+ * @dev: driver model device node
+ * @base: IO registers pointer
+ * @cmd_complete: tx completion indicator
+ * @clk: input reference clock
+ * @slave: represent an I2C slave device
+ * @cmd_err: run time hadware error code
+ * @msgs: points to an array of messages currently being transferred
+ * @msgs_num: the number of elements in msgs
+ * @msg_write_idx: the element index of the current tx message in the msgs
+ *	array
+ * @tx_buf_len: the length of the current tx buffer
+ * @tx_buf: the current tx buffer
+ * @msg_read_idx: the element index of the current rx message in the msgs
+ *	array
+ * @rx_buf_len: the length of the current rx buffer
+ * @rx_buf: the current rx buffer
+ * @msg_err: error status of the current transfer
+ * @status: i2c master status, one of STATUS_*
+ * @abort_source: copy of the TX_ABRT_SOURCE register
+ * @irq: interrupt number for the i2c master
+ * @adapter: i2c subsystem adapter node
+ * @slave_cfg: configuration for the slave device
+ * @tx_fifo_depth: depth of the hardware tx fifo
+ * @rx_fifo_depth: depth of the hardware rx fifo
+ * @rx_outstanding: current master-rx elements in tx fifo
+ * @timings: bus clock frequency, SDA hold and other timings
+ * @sda_hold_time: SDA hold value
+ * @ss_hcnt: standard speed HCNT value
+ * @ss_lcnt: standard speed LCNT value
+ * @fs_hcnt: fast speed HCNT value
+ * @fs_lcnt: fast speed LCNT value
+ * @fp_hcnt: fast plus HCNT value
+ * @fp_lcnt: fast plus LCNT value
+ * @hs_hcnt: high speed HCNT value
+ * @hs_lcnt: high speed LCNT value
+ * @pm_qos: pm_qos_request used while holding a hardware lock on the bus
+ * @acquire_lock: function to acquire a hardware lock on the bus
+ * @release_lock: function to release a hardware lock on the bus
+ * @pm_disabled: true if power-management should be disabled for this i2c-bus
+ * @disable: function to disable the controller
+ * @disable_int: function to disable all interrupts
+ * @init: function to initialize the I2C hardware
+ * @mode: operation mode - DW_IC_MASTER or DW_IC_SLAVE
+ *
+ * HCNT and LCNT parameters can be used if the platform knows more accurate
+ * values than the one computed based only on the input clock frequency.
+ * Leave them to be %0 if not used.
+ */
+struct dw_i2c_dev {
+	struct device		*dev;
+	void __iomem		*base;
+	struct completion	cmd_complete;
+	struct clk		*clk;
+	struct reset_control	*rst;
+	struct i2c_client	*slave;
+	u32			(*get_clk_rate_khz)(struct dw_i2c_dev *dev);
+	struct dw_pci_controller *controller;
+	int			cmd_err;
+	struct i2c_msg		*msgs;
+	int			msgs_num;
+	int			msg_write_idx;
+	u32			tx_buf_len;
+	u8			*tx_buf;
+	int			msg_read_idx;
+	u32			rx_buf_len;
+	u8			*rx_buf;
+	int			msg_err;
+	unsigned int		status;
+	u32			abort_source;
+	int			irq;
+	u32			flags;
+	struct i2c_adapter	adapter;
+	u32			functionality;
+	u32			master_cfg;
+	u32			slave_cfg;
+	unsigned int		tx_fifo_depth;
+	unsigned int		rx_fifo_depth;
+	int			rx_outstanding;
+	struct i2c_timings	timings;
+	u32			sda_hold_time;
+	u32                     intr_mask_value;
+	u16			ss_hcnt;
+	u16			ss_lcnt;
+	u16			fs_hcnt;
+	u16			fs_lcnt;
+	u16			fp_hcnt;
+	u16			fp_lcnt;
+	u16			hs_hcnt;
+	u16			hs_lcnt;
+	struct pm_qos_request	pm_qos;
+	int			(*acquire_lock)(struct dw_i2c_dev *dev);
+	void			(*release_lock)(struct dw_i2c_dev *dev);
+	bool			pm_disabled;
+	void			(*disable)(struct dw_i2c_dev *dev);
+	void			(*disable_int)(struct dw_i2c_dev *dev);
+	int			(*init)(struct dw_i2c_dev *dev);
+	int			mode;
+	struct i2c_bus_recovery_info rinfo;
+};
+
+#define ACCESS_SWAP		0x00000001
+#define ACCESS_16BIT		0x00000002
+#define ACCESS_INTR_MASK	0x00000004
+
+#define MODEL_CHERRYTRAIL	0x00000100
+
+u32 dw_readl(struct dw_i2c_dev *dev, int offset);
+void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset);
+int i2c_dw_set_reg_access(struct dw_i2c_dev *dev);
+u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset);
+u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset);
+int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev);
+unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev);
+int i2c_dw_prepare_clk(struct dw_i2c_dev *dev, bool prepare);
+int i2c_dw_acquire_lock(struct dw_i2c_dev *dev);
+void i2c_dw_release_lock(struct dw_i2c_dev *dev);
+int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev);
+int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev);
+u32 i2c_dw_func(struct i2c_adapter *adap);
+void i2c_dw_disable(struct dw_i2c_dev *dev);
+void i2c_dw_disable_int(struct dw_i2c_dev *dev);
+
+static inline void __i2c_dw_enable(struct dw_i2c_dev *dev)
+{
+	dw_writel(dev, 1, DW_IC_ENABLE);
+}
+
+static inline void __i2c_dw_disable_nowait(struct dw_i2c_dev *dev)
+{
+	dw_writel(dev, 0, DW_IC_ENABLE);
+}
+
+void __i2c_dw_disable(struct dw_i2c_dev *dev);
+
+extern u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev);
+extern int i2c_dw_probe(struct dw_i2c_dev *dev);
+#if IS_ENABLED(CONFIG_I2C_DESIGNWARE_SLAVE)
+extern int i2c_dw_probe_slave(struct dw_i2c_dev *dev);
+#else
+static inline int i2c_dw_probe_slave(struct dw_i2c_dev *dev) { return -EINVAL; }
+#endif
+
+#if IS_ENABLED(CONFIG_I2C_DESIGNWARE_BAYTRAIL)
+extern int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev);
+extern void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev);
+#else
+static inline int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev) { return 0; }
+static inline void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev) {}
+#endif

drivers/i2c/busses/i2c-sunway-sw6-master.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Synopsys DesignWare I2C adapter driver (master only).
+ *
+ * Based on the TI DAVINCI I2C adapter driver.
+ *
+ * Copyright (C) 2006 Texas Instruments.
+ * Copyright (C) 2007 MontaVista Software Inc.
+ * Copyright (C) 2009 Provigent Ltd.
+ */
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+
+#include "i2c-sunway-sw6-core.h"
+
+static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
+{
+	/* Configure Tx/Rx FIFO threshold levels */
+	dw_writel(dev, dev->tx_fifo_depth / 2, DW_IC_TX_TL);
+	dw_writel(dev, 0, DW_IC_RX_TL);
+
+	/* Configure the I2C master */
+	dw_writel(dev, dev->master_cfg, DW_IC_CON);
+}
+
+static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
+{
+	const char *mode_str, *fp_str = "";
+	u32 comp_param1;
+	u32 sda_falling_time, scl_falling_time;
+	struct i2c_timings *t = &dev->timings;
+	u32 ic_clk;
+	int ret;
+
+	ret = i2c_dw_acquire_lock(dev);
+	if (ret)
+		return ret;
+	comp_param1 = dw_readl(dev, DW_IC_COMP_PARAM_1);
+	i2c_dw_release_lock(dev);
+
+	/* Set standard and fast speed dividers for high/low periods */
+	sda_falling_time = t->sda_fall_ns ?: 300; /* ns */
+	scl_falling_time = t->scl_fall_ns ?: 300; /* ns */
+
+	/* Calculate SCL timing parameters for standard mode if not set */
+	if (!dev->ss_hcnt || !dev->ss_lcnt) {
+		ic_clk = i2c_dw_clk_rate(dev);
+		dev->ss_hcnt =
+			i2c_dw_scl_hcnt(ic_clk,
+					4000,	/* tHD;STA = tHIGH = 4.0 us */
+					sda_falling_time,
+					0,	/* 0: DW default, 1: Ideal */
+					0);	/* No offset */
+		dev->ss_lcnt =
+			i2c_dw_scl_lcnt(ic_clk,
+					4700,	/* tLOW = 4.7 us */
+					scl_falling_time,
+					0);	/* No offset */
+	}
+	dev_dbg(dev->dev, "Standard Mode HCNT:LCNT = %d:%d\n",
+		dev->ss_hcnt, dev->ss_lcnt);
+
+	/*
+	 * Set SCL timing parameters for fast mode or fast mode plus. Only
+	 * difference is the timing parameter values since the registers are
+	 * the same.
+	 */
+	if (t->bus_freq_hz == 1000000) {
+		/*
+		 * Check are fast mode plus parameters available and use
+		 * fast mode if not.
+		 */
+		if (dev->fp_hcnt && dev->fp_lcnt) {
+			dev->fs_hcnt = dev->fp_hcnt;
+			dev->fs_lcnt = dev->fp_lcnt;
+			fp_str = " Plus";
+		}
+	}
+	/*
+	 * Calculate SCL timing parameters for fast mode if not set. They are
+	 * needed also in high speed mode.
+	 */
+	if (!dev->fs_hcnt || !dev->fs_lcnt) {
+		ic_clk = i2c_dw_clk_rate(dev);
+		dev->fs_hcnt =
+			i2c_dw_scl_hcnt(ic_clk,
+					600,	/* tHD;STA = tHIGH = 0.6 us */
+					sda_falling_time,
+					0,	/* 0: DW default, 1: Ideal */
+					0);	/* No offset */
+		dev->fs_lcnt =
+			i2c_dw_scl_lcnt(ic_clk,
+					1300,	/* tLOW = 1.3 us */
+					scl_falling_time,
+					0);	/* No offset */
+	}
+	dev_dbg(dev->dev, "Fast Mode%s HCNT:LCNT = %d:%d\n",
+		fp_str, dev->fs_hcnt, dev->fs_lcnt);
+
+	/* Check is high speed possible and fall back to fast mode if not */
+	if ((dev->master_cfg & DW_IC_CON_SPEED_MASK) ==
+		DW_IC_CON_SPEED_HIGH) {
+		if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK)
+			!= DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH) {
+			dev_err(dev->dev, "High Speed not supported!\n");
+			dev->master_cfg &= ~DW_IC_CON_SPEED_MASK;
+			dev->master_cfg |= DW_IC_CON_SPEED_FAST;
+			dev->hs_hcnt = 0;
+			dev->hs_lcnt = 0;
+		} else if (dev->hs_hcnt && dev->hs_lcnt) {
+			dev_dbg(dev->dev, "High Speed Mode HCNT:LCNT = %d:%d\n",
+				dev->hs_hcnt, dev->hs_lcnt);
+		}
+	}
+
+	ret = i2c_dw_set_sda_hold(dev);
+	if (ret)
+		goto out;
+
+	switch (dev->master_cfg & DW_IC_CON_SPEED_MASK) {
+	case DW_IC_CON_SPEED_STD:
+		mode_str = "Standard Mode";
+		break;
+	case DW_IC_CON_SPEED_HIGH:
+		mode_str = "High Speed Mode";
+		break;
+	default:
+		mode_str = "Fast Mode";
+	}
+	dev_dbg(dev->dev, "Bus speed: %s%s\n", mode_str, fp_str);
+
+out:
+	return ret;
+}
+
+/**
+ * i2c_dw_init() - Initialize the designware I2C master hardware
+ * @dev: device private data
+ *
+ * This functions configures and enables the I2C master.
+ * This function is called during I2C init function, and in case of timeout at
+ * run time.
+ */
+static int i2c_dw_init_master(struct dw_i2c_dev *dev)
+{
+	int ret;
+
+	ret = i2c_dw_acquire_lock(dev);
+	if (ret)
+		return ret;
+
+	/* Disable the adapter */
+	__i2c_dw_disable(dev);
+
+	/* Write standard speed timing parameters */
+	dw_writel(dev, dev->ss_hcnt, DW_IC_SS_SCL_HCNT);
+	dw_writel(dev, dev->ss_lcnt, DW_IC_SS_SCL_LCNT);
+
+	/* Write fast mode/fast mode plus timing parameters */
+	dw_writel(dev, dev->fs_hcnt, DW_IC_FS_SCL_HCNT);
+	dw_writel(dev, dev->fs_lcnt, DW_IC_FS_SCL_LCNT);
+
+	/* Write high speed timing parameters if supported */
+	if (dev->hs_hcnt && dev->hs_lcnt) {
+		dw_writel(dev, dev->hs_hcnt, DW_IC_HS_SCL_HCNT);
+		dw_writel(dev, dev->hs_lcnt, DW_IC_HS_SCL_LCNT);
+	}
+
+	/* Write SDA hold time if supported */
+	if (dev->sda_hold_time)
+		dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
+
+	i2c_dw_configure_fifo_master(dev);
+	i2c_dw_release_lock(dev);
+
+	return 0;
+}
+
+static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
+{
+	struct i2c_msg *msgs = dev->msgs;
+	u32 ic_con, ic_tar = 0;
+
+	/* Disable the adapter */
+	__i2c_dw_disable(dev);
+
+	/* If the slave address is ten bit address, enable 10BITADDR */
+	ic_con = dw_readl(dev, DW_IC_CON);
+	if (msgs[dev->msg_write_idx].flags & I2C_M_TEN) {
+		ic_con |= DW_IC_CON_10BITADDR_MASTER;
+		/*
+		 * If I2C_DYNAMIC_TAR_UPDATE is set, the 10-bit addressing
+		 * mode has to be enabled via bit 12 of IC_TAR register.
+		 * We set it always as I2C_DYNAMIC_TAR_UPDATE can't be
+		 * detected from registers.
+		 */
+		ic_tar = DW_IC_TAR_10BITADDR_MASTER;
+	} else {
+		ic_con &= ~DW_IC_CON_10BITADDR_MASTER;
+	}
+
+	dw_writel(dev, ic_con, DW_IC_CON);
+
+	/*
+	 * Set the slave (target) address and enable 10-bit addressing mode
+	 * if applicable.
+	 */
+	dw_writel(dev, msgs[dev->msg_write_idx].addr | ic_tar, DW_IC_TAR);
+
+	/* Enforce disabled interrupts (due to HW issues) */
+	i2c_dw_disable_int(dev);
+
+	/* Enable the adapter */
+	__i2c_dw_enable(dev);
+
+	/* Dummy read to avoid the register getting stuck on Bay Trail */
+	dw_readl(dev, DW_IC_ENABLE_STATUS);
+
+	/* Clear and enable interrupts */
+	dw_readl(dev, DW_IC_CLR_INTR);
+	dev->intr_mask_value = DW_IC_INTR_DEFAULT_MASK;
+	dw_writel(dev, DW_IC_INTR_MASTER_MASK, DW_IC_INTR_MASK);
+}
+
+/*
+ * Initiate (and continue) low level master read/write transaction.
+ * This function is only called from i2c_dw_isr, and pumping i2c_msg
+ * messages into the tx buffer.  Even if the size of i2c_msg data is
+ * longer than the size of the tx buffer, it handles everything.
+ */
+static void
+i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
+{
+	struct i2c_msg *msgs = dev->msgs;
+	u32 intr_mask;
+	int tx_limit, rx_limit;
+	u32 addr = msgs[dev->msg_write_idx].addr;
+	u32 buf_len = dev->tx_buf_len;
+	u8 *buf = dev->tx_buf;
+	bool need_restart = false;
+
+	intr_mask = DW_IC_INTR_MASTER_MASK;
+
+	for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) {
+		u32 flags = msgs[dev->msg_write_idx].flags;
+
+		/*
+		 * If target address has changed, we need to
+		 * reprogram the target address in the I2C
+		 * adapter when we are done with this transfer.
+		 */
+		if (msgs[dev->msg_write_idx].addr != addr) {
+			dev_err(dev->dev,
+				"%s: invalid target address\n", __func__);
+			dev->msg_err = -EINVAL;
+			break;
+		}
+
+		if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
+			/* new i2c_msg */
+			buf = msgs[dev->msg_write_idx].buf;
+			buf_len = msgs[dev->msg_write_idx].len;
+
+			/* If both IC_EMPTYFIFO_HOLD_MASTER_EN and
+			 * IC_RESTART_EN are set, we must manually
+			 * set restart bit between messages.
+			 */
+			if ((dev->master_cfg & DW_IC_CON_RESTART_EN) &&
+					(dev->msg_write_idx > 0))
+				need_restart = true;
+		}
+
+		tx_limit = dev->tx_fifo_depth - dw_readl(dev, DW_IC_TXFLR);
+		rx_limit = dev->rx_fifo_depth - dw_readl(dev, DW_IC_RXFLR);
+
+		while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
+			u32 cmd = 0;
+
+			/*
+			 * If IC_EMPTYFIFO_HOLD_MASTER_EN is set we must
+			 * manually set the stop bit. However, it cannot be
+			 * detected from the registers so we set it always
+			 * when writing/reading the last byte.
+			 */
+
+			/*
+			 * i2c-core always sets the buffer length of
+			 * I2C_FUNC_SMBUS_BLOCK_DATA to 1. The length will
+			 * be adjusted when receiving the first byte.
+			 * Thus we can't stop the transaction here.
+			 */
+			if (dev->msg_write_idx == dev->msgs_num - 1 &&
+			    buf_len == 1 && !(flags & I2C_M_RECV_LEN))
+				cmd |= BIT(9);
+
+			if (need_restart) {
+				cmd |= BIT(10);
+				need_restart = false;
+			}
+
+			if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {
+
+				/* Avoid rx buffer overrun */
+				if (dev->rx_outstanding >= dev->rx_fifo_depth)
+					break;
+
+				dw_writel(dev, cmd | 0x100, DW_IC_DATA_CMD);
+				rx_limit--;
+				dev->rx_outstanding++;
+			} else
+				dw_writel(dev, cmd | *buf++, DW_IC_DATA_CMD);
+			tx_limit--; buf_len--;
+		}
+
+		dev->tx_buf = buf;
+		dev->tx_buf_len = buf_len;
+
+		/*
+		 * Because we don't know the buffer length in the
+		 * I2C_FUNC_SMBUS_BLOCK_DATA case, we can't stop
+		 * the transaction here.
+		 */
+		if (buf_len > 0 || flags & I2C_M_RECV_LEN) {
+			/* more bytes to be written */
+			dev->status |= STATUS_WRITE_IN_PROGRESS;
+			break;
+		} else
+			dev->status &= ~STATUS_WRITE_IN_PROGRESS;
+	}
+
+	/*
+	 * If i2c_msg index search is completed, we don't need TX_EMPTY
+	 * interrupt any more.
+	 */
+	if (dev->msg_write_idx == dev->msgs_num)
+		intr_mask &= ~DW_IC_INTR_TX_EMPTY;
+
+	if (dev->msg_err)
+		intr_mask = 0;
+
+	dev->intr_mask_value = intr_mask;
+}
+
+static u8
+i2c_dw_recv_len(struct dw_i2c_dev *dev, u8 len)
+{
+	struct i2c_msg *msgs = dev->msgs;
+	u32 flags = msgs[dev->msg_read_idx].flags;
+
+	/*
+	 * Adjust the buffer length and mask the flag
+	 * after receiving the first byte.
+	 */
+	len += (flags & I2C_CLIENT_PEC) ? 2 : 1;
+	dev->tx_buf_len = len - min_t(u8, len, dev->rx_outstanding);
+	msgs[dev->msg_read_idx].len = len;
+	msgs[dev->msg_read_idx].flags &= ~I2C_M_RECV_LEN;
+
+	return len;
+}
+
+static void
+i2c_dw_read(struct dw_i2c_dev *dev)
+{
+	struct i2c_msg *msgs = dev->msgs;
+	int rx_valid;
+
+	for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) {
+		u32 len;
+		u8 *buf;
+
+		if (!(msgs[dev->msg_read_idx].flags & I2C_M_RD))
+			continue;
+
+		if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
+			len = msgs[dev->msg_read_idx].len;
+			buf = msgs[dev->msg_read_idx].buf;
+		} else {
+			len = dev->rx_buf_len;
+			buf = dev->rx_buf;
+		}
+
+		rx_valid = dw_readl(dev, DW_IC_RXFLR);
+
+		for (; len > 0 && rx_valid > 0; len--, rx_valid--) {
+			u32 flags = msgs[dev->msg_read_idx].flags;
+
+			*buf = dw_readl(dev, DW_IC_DATA_CMD);
+			/* Ensure length byte is a valid value */
+			if (flags & I2C_M_RECV_LEN &&
+				*buf <= I2C_SMBUS_BLOCK_MAX && *buf > 0) {
+				len = i2c_dw_recv_len(dev, *buf);
+			}
+			buf++;
+			dev->rx_outstanding--;
+		}
+
+		if (len > 0) {
+			dev->status |= STATUS_READ_IN_PROGRESS;
+			dev->rx_buf_len = len;
+			dev->rx_buf = buf;
+			return;
+		} else
+			dev->status &= ~STATUS_READ_IN_PROGRESS;
+	}
+}
+
+/*
+ * Prepare controller for a transaction and call i2c_dw_xfer_msg.
+ */
+static int
+i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+	int ret;
+
+	dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
+
+	pm_runtime_get_sync(dev->dev);
+
+	reinit_completion(&dev->cmd_complete);
+	dev->msgs = msgs;
+	dev->msgs_num = num;
+	dev->cmd_err = 0;
+	dev->msg_write_idx = 0;
+	dev->msg_read_idx = 0;
+	dev->msg_err = 0;
+	dev->status = STATUS_IDLE;
+	dev->abort_source = 0;
+	dev->rx_outstanding = 0;
+
+	ret = i2c_dw_acquire_lock(dev);
+	if (ret)
+		goto done_nolock;
+
+	ret = i2c_dw_wait_bus_not_busy(dev);
+	if (ret < 0)
+		goto done;
+
+	/* Start the transfers */
+	i2c_dw_xfer_init(dev);
+
+	/* Wait for tx to complete */
+	if (!wait_for_completion_timeout(&dev->cmd_complete, adap->timeout)) {
+		dev_err(dev->dev, "controller timed out\n");
+		/* i2c_dw_init implicitly disables the adapter */
+		i2c_recover_bus(&dev->adapter);
+		i2c_dw_init_master(dev);
+		ret = -ETIMEDOUT;
+		goto done;
+	}
+
+	/*
+	 * We must disable the adapter before returning and signaling the end
+	 * of the current transfer. Otherwise the hardware might continue
+	 * generating interrupts which in turn causes a race condition with
+	 * the following transfer.  Needs some more investigation if the
+	 * additional interrupts are a hardware bug or this driver doesn't
+	 * handle them correctly yet.
+	 */
+	__i2c_dw_disable_nowait(dev);
+
+	if (dev->msg_err) {
+		ret = dev->msg_err;
+		goto done;
+	}
+
+	/* No error */
+	if (likely(!dev->cmd_err && !dev->status)) {
+		ret = num;
+		goto done;
+	}
+
+	/* We have an error */
+	if (dev->cmd_err == DW_IC_ERR_TX_ABRT) {
+		ret = i2c_dw_handle_tx_abort(dev);
+		goto done;
+	}
+
+	if (dev->status)
+		dev_err(dev->dev,
+			"transfer terminated early - interrupt latency too high?\n");
+
+	ret = -EIO;
+
+done:
+	i2c_dw_release_lock(dev);
+
+done_nolock:
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+
+	return ret;
+}
+
+static const struct i2c_algorithm i2c_dw_algo = {
+	.master_xfer = i2c_dw_xfer,
+	.functionality = i2c_dw_func,
+};
+
+static const struct i2c_adapter_quirks i2c_dw_quirks = {
+	.flags = I2C_AQ_NO_ZERO_LEN,
+};
+
+static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
+{
+	u32 stat;
+
+	/*
+	 * The IC_INTR_STAT register just indicates "enabled" interrupts.
+	 * Ths unmasked raw version of interrupt status bits are available
+	 * in the IC_RAW_INTR_STAT register.
+	 *
+	 * That is,
+	 *   stat = dw_readl(IC_INTR_STAT);
+	 * equals to,
+	 *   stat = dw_readl(IC_RAW_INTR_STAT) & dw_readl(IC_INTR_MASK);
+	 *
+	 * The raw version might be useful for debugging purposes.
+	 */
+	stat = dw_readl(dev, DW_IC_INTR_STAT);
+	/* Disable all interrupts */
+	dw_writel(dev, 0, DW_IC_INTR_MASK);
+	stat |= dw_readl(dev, DW_IC_RAW_INTR_STAT) & dev->intr_mask_value;              /* Avoid to miss interrupt! */
+
+
+	/*
+	 * Do not use the IC_CLR_INTR register to clear interrupts, or
+	 * you'll miss some interrupts, triggered during the period from
+	 * dw_readl(IC_INTR_STAT) to dw_readl(IC_CLR_INTR).
+	 *
+	 * Instead, use the separately-prepared IC_CLR_* registers.
+	 */
+	if (stat & DW_IC_INTR_RX_UNDER)
+		dw_readl(dev, DW_IC_CLR_RX_UNDER);
+	if (stat & DW_IC_INTR_RX_OVER)
+		dw_readl(dev, DW_IC_CLR_RX_OVER);
+	if (stat & DW_IC_INTR_TX_OVER)
+		dw_readl(dev, DW_IC_CLR_TX_OVER);
+	if (stat & DW_IC_INTR_RD_REQ)
+		dw_readl(dev, DW_IC_CLR_RD_REQ);
+	if (stat & DW_IC_INTR_TX_ABRT) {
+		/*
+		 * The IC_TX_ABRT_SOURCE register is cleared whenever
+		 * the IC_CLR_TX_ABRT is read.  Preserve it beforehand.
+		 */
+		dev->abort_source = dw_readl(dev, DW_IC_TX_ABRT_SOURCE);
+		dw_readl(dev, DW_IC_CLR_TX_ABRT);
+	}
+	if (stat & DW_IC_INTR_RX_DONE)
+		dw_readl(dev, DW_IC_CLR_RX_DONE);
+	if (stat & DW_IC_INTR_ACTIVITY)
+		dw_readl(dev, DW_IC_CLR_ACTIVITY);
+	if (stat & DW_IC_INTR_STOP_DET)
+		dw_readl(dev, DW_IC_CLR_STOP_DET);
+	if (stat & DW_IC_INTR_START_DET)
+		dw_readl(dev, DW_IC_CLR_START_DET);
+	if (stat & DW_IC_INTR_GEN_CALL)
+		dw_readl(dev, DW_IC_CLR_GEN_CALL);
+
+	return stat;
+}
+
+/*
+ * Interrupt service routine. This gets called whenever an I2C master interrupt
+ * occurs.
+ */
+static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev)
+{
+	u32 stat;
+
+	stat = i2c_dw_read_clear_intrbits(dev);
+	if (stat & DW_IC_INTR_TX_ABRT) {
+		dev->cmd_err |= DW_IC_ERR_TX_ABRT;
+		dev->status = STATUS_IDLE;
+
+		/*
+		 * Anytime TX_ABRT is set, the contents of the tx/rx
+		 * buffers are flushed. Make sure to skip them.
+		 */
+		dev->intr_mask_value = 0;
+		goto tx_aborted;
+	}
+
+	if (stat & DW_IC_INTR_RX_FULL)
+		i2c_dw_read(dev);
+
+	if (stat & DW_IC_INTR_TX_EMPTY)
+		i2c_dw_xfer_msg(dev);
+
+	/*
+	 * No need to modify or disable the interrupt mask here.
+	 * i2c_dw_xfer_msg() will take care of it according to
+	 * the current transmit status.
+	 */
+
+tx_aborted:
+	if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
+		complete(&dev->cmd_complete);
+	else if (unlikely(dev->flags & ACCESS_INTR_MASK)) {
+		/* Workaround to trigger pending interrupt */
+		stat = dw_readl(dev, DW_IC_INTR_MASK);
+		i2c_dw_disable_int(dev);
+		dw_writel(dev, stat, DW_IC_INTR_MASK);
+		return 0;
+	}
+
+	dw_writel(dev, dev->intr_mask_value, DW_IC_INTR_MASK);
+	return 0;
+
+}
+
+static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
+{
+	struct dw_i2c_dev *dev = dev_id;
+	u32 stat, enabled;
+
+	enabled = dw_readl(dev, DW_IC_ENABLE);
+	stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
+	dev_dbg(dev->dev, "enabled=%#x stat=%#x\n", enabled, stat);
+	if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
+		return IRQ_NONE;
+
+	i2c_dw_irq_handler_master(dev);
+
+	return IRQ_HANDLED;
+}
+
+static void i2c_dw_prepare_recovery(struct i2c_adapter *adap)
+{
+	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+
+	i2c_dw_disable(dev);
+	reset_control_assert(dev->rst);
+	i2c_dw_prepare_clk(dev, false);
+}
+
+static void i2c_dw_unprepare_recovery(struct i2c_adapter *adap)
+{
+	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+
+	i2c_dw_prepare_clk(dev, true);
+	reset_control_deassert(dev->rst);
+	i2c_dw_init_master(dev);
+}
+
+static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
+{
+	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
+	struct i2c_adapter *adap = &dev->adapter;
+	struct gpio_desc *gpio;
+	int r;
+
+	gpio = devm_gpiod_get(dev->dev, "scl", GPIOD_OUT_HIGH);
+	if (IS_ERR(gpio)) {
+		r = PTR_ERR(gpio);
+		if (r == -ENOENT || r == -ENOSYS)
+			return 0;
+		return r;
+	}
+	rinfo->scl_gpiod = gpio;
+
+	gpio = devm_gpiod_get_optional(dev->dev, "sda", GPIOD_IN);
+	if (IS_ERR(gpio))
+		return PTR_ERR(gpio);
+	rinfo->sda_gpiod = gpio;
+
+	rinfo->recover_bus = i2c_generic_scl_recovery;
+	rinfo->prepare_recovery = i2c_dw_prepare_recovery;
+	rinfo->unprepare_recovery = i2c_dw_unprepare_recovery;
+	adap->bus_recovery_info = rinfo;
+
+	dev_info(dev->dev, "running with gpio recovery mode! scl%s",
+		 rinfo->sda_gpiod ? ",sda" : "");
+
+	return 0;
+}
+
+int i2c_dw_probe(struct dw_i2c_dev *dev)
+{
+	struct i2c_adapter *adap = &dev->adapter;
+	unsigned long irq_flags;
+	int ret;
+
+	init_completion(&dev->cmd_complete);
+
+	dev->init = i2c_dw_init_master;
+	dev->disable = i2c_dw_disable;
+	dev->disable_int = i2c_dw_disable_int;
+
+	ret = i2c_dw_set_reg_access(dev);
+	if (ret)
+		return ret;
+
+	ret = i2c_dw_set_timings_master(dev);
+	if (ret)
+		return ret;
+
+	ret = dev->init(dev);
+	if (ret)
+		return ret;
+
+	snprintf(adap->name, sizeof(adap->name),
+		 "Synopsys DesignWare I2C adapter");
+	adap->retries = 3;
+	adap->algo = &i2c_dw_algo;
+	adap->quirks = &i2c_dw_quirks;
+	adap->dev.parent = dev->dev;
+	i2c_set_adapdata(adap, dev);
+
+	if (dev->pm_disabled)
+		irq_flags = IRQF_NO_SUSPEND;
+	else
+		irq_flags = IRQF_SHARED | IRQF_COND_SUSPEND;
+
+	i2c_dw_disable_int(dev);
+	ret = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr, irq_flags,
+			       dev_name(dev->dev), dev);
+	if (ret) {
+		dev_err(dev->dev, "failure requesting irq %i: %d\n",
+			dev->irq, ret);
+		return ret;
+	}
+
+	ret = i2c_dw_init_recovery_info(dev);
+	if (ret)
+		return ret;
+
+	/*
+	 * Increment PM usage count during adapter registration in order to
+	 * avoid possible spurious runtime suspend when adapter device is
+	 * registered to the device core and immediate resume in case bus has
+	 * registered I2C slaves that do I2C transfers in their probe.
+	 */
+	pm_runtime_get_noresume(dev->dev);
+	ret = i2c_add_numbered_adapter(adap);
+	if (ret)
+		dev_err(dev->dev, "failure adding adapter: %d\n", ret);
+	pm_runtime_put_noidle(dev->dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(i2c_dw_probe);
+
+MODULE_DESCRIPTION("Synopsys DesignWare I2C bus master adapter");
+MODULE_LICENSE("GPL");

drivers/i2c/busses/i2c-sunway-sw6-platdrv.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Synopsys DesignWare I2C adapter driver.
+ *
+ * Based on the TI DAVINCI I2C adapter driver.
+ *
+ * Copyright (C) 2006 Texas Instruments.
+ * Copyright (C) 2007 MontaVista Software Inc.
+ * Copyright (C) 2009 Provigent Ltd.
+ */
+#include <linux/acpi.h>
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dmi.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_data/i2c-designware.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/property.h>
+#include <linux/reset.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+
+#include "i2c-sunway-sw6-core.h"
+
+static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
+{
+	return clk_get_rate(dev->clk)/1000;
+}
+
+#ifdef CONFIG_ACPI
+/*
+ * The HCNT/LCNT information coming from ACPI should be the most accurate
+ * for given platform. However, some systems get it wrong. On such systems
+ * we get better results by calculating those based on the input clock.
+ */
+static const struct dmi_system_id dw_i2c_no_acpi_params[] = {
+	{
+		.ident = "Dell Inspiron 7348",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7348"),
+		},
+	},
+	{ }
+};
+
+static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
+			       u16 *hcnt, u16 *lcnt, u32 *sda_hold)
+{
+	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
+	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
+	union acpi_object *obj;
+
+	if (dmi_check_system(dw_i2c_no_acpi_params))
+		return;
+
+	if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf)))
+		return;
+
+	obj = (union acpi_object *)buf.pointer;
+	if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 3) {
+		const union acpi_object *objs = obj->package.elements;
+
+		*hcnt = (u16)objs[0].integer.value;
+		*lcnt = (u16)objs[1].integer.value;
+		*sda_hold = (u32)objs[2].integer.value;
+	}
+
+	kfree(buf.pointer);
+}
+
+static int dw_i2c_acpi_configure(struct platform_device *pdev)
+{
+	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
+	struct i2c_timings *t = &dev->timings;
+	u32 ss_ht = 0, fp_ht = 0, hs_ht = 0, fs_ht = 0;
+	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
+	const struct acpi_device_id *id;
+	struct acpi_device *adev;
+	const char *uid;
+
+	dev->adapter.nr = -1;
+	dev->tx_fifo_depth = 32;
+	dev->rx_fifo_depth = 32;
+
+	/*
+	 * Try to get SDA hold time and *CNT values from an ACPI method for
+	 * selected speed modes.
+	 */
+	dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, &ss_ht);
+	dw_i2c_acpi_params(pdev, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, &fp_ht);
+	dw_i2c_acpi_params(pdev, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, &hs_ht);
+	dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt, &fs_ht);
+
+	switch (t->bus_freq_hz) {
+	case 100000:
+		dev->sda_hold_time = ss_ht;
+		break;
+	case 1000000:
+		dev->sda_hold_time = fp_ht;
+		break;
+	case 3400000:
+		dev->sda_hold_time = hs_ht;
+		break;
+	case 400000:
+	default:
+		dev->sda_hold_time = fs_ht;
+		break;
+	}
+
+	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
+	if (id && id->driver_data)
+		dev->flags |= (u32)id->driver_data;
+
+	if (acpi_bus_get_device(handle, &adev))
+		return -ENODEV;
+
+	/*
+	 * Cherrytrail I2C7 gets used for the PMIC which gets accessed
+	 * through ACPI opregions during late suspend / early resume
+	 * disable pm for it.
+	 */
+	uid = adev->pnp.unique_id;
+	if ((dev->flags & MODEL_CHERRYTRAIL) && !strcmp(uid, "7"))
+		dev->pm_disabled = true;
+
+	return 0;
+}
+
+static const struct acpi_device_id dw_i2c_acpi_match[] = {
+	{ "INT33C2", 0 },
+	{ "INT33C3", 0 },
+	{ "INT3432", 0 },
+	{ "INT3433", 0 },
+	{ "80860F41", 0 },
+	{ "808622C1", MODEL_CHERRYTRAIL },
+	{ "AMD0010", ACCESS_INTR_MASK },
+	{ "AMDI0010", ACCESS_INTR_MASK },
+	{ "AMDI0510", 0 },
+	{ "APMC0D0F", 0 },
+	{ "HISI02A1", 0 },
+	{ "HISI02A2", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
+#else
+static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
+{
+	return -ENODEV;
+}
+#endif
+
+static void i2c_dw_configure_master(struct dw_i2c_dev *dev)
+{
+	struct i2c_timings *t = &dev->timings;
+
+	dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY;
+
+	dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
+			  DW_IC_CON_RESTART_EN;
+
+	dev->mode = DW_IC_MASTER;
+
+	switch (t->bus_freq_hz) {
+	case 100000:
+		dev->master_cfg |= DW_IC_CON_SPEED_STD;
+		break;
+	case 3400000:
+		dev->master_cfg |= DW_IC_CON_SPEED_HIGH;
+		break;
+	default:
+		dev->master_cfg |= DW_IC_CON_SPEED_FAST;
+	}
+}
+
+static void i2c_dw_configure_slave(struct dw_i2c_dev *dev)
+{
+	dev->functionality = I2C_FUNC_SLAVE | DW_IC_DEFAULT_FUNCTIONALITY;
+
+	dev->slave_cfg = DW_IC_CON_RX_FIFO_FULL_HLD_CTRL |
+			 DW_IC_CON_RESTART_EN | DW_IC_CON_STOP_DET_IFADDRESSED;
+
+	dev->mode = DW_IC_SLAVE;
+}
+
+static void dw_i2c_set_fifo_size(struct dw_i2c_dev *dev, int id)
+{
+	u32 param, tx_fifo_depth, rx_fifo_depth;
+
+	/*
+	 * Try to detect the FIFO depth if not set by interface driver,
+	 * the depth could be from 2 to 256 from HW spec.
+	 */
+	param = i2c_dw_read_comp_param(dev);
+	tx_fifo_depth = ((param >> 16) & 0xff) + 1;
+	rx_fifo_depth = ((param >> 8)  & 0xff) + 1;
+	if (!dev->tx_fifo_depth) {
+		dev->tx_fifo_depth = tx_fifo_depth;
+		dev->rx_fifo_depth = rx_fifo_depth;
+		dev->adapter.nr = id;
+	} else if (tx_fifo_depth >= 2) {
+		dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth,
+				tx_fifo_depth);
+		dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth,
+				rx_fifo_depth);
+	}
+}
+
+static void dw_i2c_plat_pm_cleanup(struct dw_i2c_dev *dev)
+{
+	pm_runtime_disable(dev->dev);
+
+	if (dev->pm_disabled)
+		pm_runtime_put_noidle(dev->dev);
+}
+
+static int dw_i2c_plat_probe(struct platform_device *pdev)
+{
+	struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct i2c_adapter *adap;
+	struct dw_i2c_dev *dev;
+	struct i2c_timings *t;
+	u32 acpi_speed;
+	struct resource *mem;
+	int i, irq, ret;
+	static const int supported_speeds[] = {
+		0, 100000, 400000, 1000000, 3400000
+	};
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	dev = devm_kzalloc(&pdev->dev, sizeof(struct dw_i2c_dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dev->base = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(dev->base))
+		return PTR_ERR(dev->base);
+
+	dev->dev = &pdev->dev;
+	dev->irq = irq;
+	platform_set_drvdata(pdev, dev);
+
+	dev->rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(dev->rst)) {
+		if (PTR_ERR(dev->rst) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+	} else {
+		reset_control_deassert(dev->rst);
+	}
+
+	t = &dev->timings;
+	if (pdata)
+		t->bus_freq_hz = pdata->i2c_scl_freq;
+	else
+		i2c_parse_fw_timings(&pdev->dev, t, false);
+
+	acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
+	/*
+	 * Some DSTDs use a non standard speed, round down to the lowest
+	 * standard speed.
+	 */
+	for (i = 1; i < ARRAY_SIZE(supported_speeds); i++) {
+		if (acpi_speed < supported_speeds[i])
+			break;
+	}
+	acpi_speed = supported_speeds[i - 1];
+
+	/*
+	 * Find bus speed from the "clock-frequency" device property, ACPI
+	 * or by using fast mode if neither is set.
+	 */
+	if (acpi_speed && t->bus_freq_hz)
+		t->bus_freq_hz = min(t->bus_freq_hz, acpi_speed);
+	else if (acpi_speed || t->bus_freq_hz)
+		t->bus_freq_hz = max(t->bus_freq_hz, acpi_speed);
+	else
+		t->bus_freq_hz = 400000;
+
+	if (has_acpi_companion(&pdev->dev))
+		dw_i2c_acpi_configure(pdev);
+
+	/*
+	 * Only standard mode at 100kHz, fast mode at 400kHz,
+	 * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported.
+	 */
+	if (t->bus_freq_hz != 100000 && t->bus_freq_hz != 400000 &&
+	    t->bus_freq_hz != 1000000 && t->bus_freq_hz != 3400000) {
+		dev_err(&pdev->dev,
+			"%d Hz is unsupported, only 100kHz, 400kHz, 1MHz and 3.4MHz are supported\n",
+			t->bus_freq_hz);
+		ret = -EINVAL;
+		goto exit_reset;
+	}
+
+	ret = i2c_dw_probe_lock_support(dev);
+	if (ret)
+		goto exit_reset;
+
+	if (i2c_detect_slave_mode(&pdev->dev))
+		i2c_dw_configure_slave(dev);
+	else
+		i2c_dw_configure_master(dev);
+
+	dev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (!i2c_dw_prepare_clk(dev, true)) {
+		u64 clk_khz;
+
+		dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
+		clk_khz = dev->get_clk_rate_khz(dev);
+
+		if (!dev->sda_hold_time && t->sda_hold_ns)
+			dev->sda_hold_time =
+				div_u64(clk_khz * t->sda_hold_ns + 500000, 1000000);
+	}
+
+	dw_i2c_set_fifo_size(dev, pdev->id);
+
+	adap = &dev->adapter;
+	adap->owner = THIS_MODULE;
+	adap->class = 0;/*lm_sensors, ...*/
+	ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
+	adap->dev.of_node = pdev->dev.of_node;
+
+	dev_pm_set_driver_flags(&pdev->dev,
+				DPM_FLAG_SMART_PREPARE |
+				DPM_FLAG_SMART_SUSPEND |
+				DPM_FLAG_MAY_SKIP_RESUME);
+
+	/* The code below assumes runtime PM to be disabled. */
+	WARN_ON(pm_runtime_enabled(&pdev->dev));
+
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+
+	if (dev->pm_disabled)
+		pm_runtime_get_noresume(&pdev->dev);
+
+	pm_runtime_enable(&pdev->dev);
+
+	if (dev->mode == DW_IC_SLAVE)
+		ret = i2c_dw_probe_slave(dev);
+	else
+		ret = i2c_dw_probe(dev);
+
+	if (ret)
+		goto exit_probe;
+
+	return ret;
+
+exit_probe:
+	dw_i2c_plat_pm_cleanup(dev);
+exit_reset:
+	if (!IS_ERR_OR_NULL(dev->rst))
+		reset_control_assert(dev->rst);
+	return ret;
+}
+
+static int dw_i2c_plat_remove(struct platform_device *pdev)
+{
+	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
+
+	pm_runtime_get_sync(&pdev->dev);
+
+	i2c_del_adapter(&dev->adapter);
+
+	dev->disable(dev);
+
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
+	dw_i2c_plat_pm_cleanup(dev);
+
+	if (!IS_ERR_OR_NULL(dev->rst))
+		reset_control_assert(dev->rst);
+
+	i2c_dw_remove_lock_support(dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id dw_i2c_of_match[] = {
+	{ .compatible = "snps,designware-i2c", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
+#endif
+
+#ifdef CONFIG_PM_SLEEP
+static int dw_i2c_plat_prepare(struct device *dev)
+{
+	/*
+	 * If the ACPI companion device object is present for this device, it
+	 * may be accessed during suspend and resume of other devices via I2C
+	 * operation regions, so tell the PM core and middle layers to avoid
+	 * skipping system suspend/resume callbacks for it in that case.
+	 */
+	return !has_acpi_companion(dev);
+}
+
+static void dw_i2c_plat_complete(struct device *dev)
+{
+	/*
+	 * The device can only be in runtime suspend at this point if it has not
+	 * been resumed throughout the ending system suspend/resume cycle, so if
+	 * the platform firmware might mess up with it, request the runtime PM
+	 * framework to resume it.
+	 */
+	if (pm_runtime_suspended(dev) && pm_resume_via_firmware())
+		pm_request_resume(dev);
+}
+#else
+#define dw_i2c_plat_prepare	NULL
+#define dw_i2c_plat_complete	NULL
+#endif
+
+#ifdef CONFIG_PM
+static int dw_i2c_plat_suspend(struct device *dev)
+{
+	struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
+
+	if (i_dev->pm_disabled)
+		return 0;
+
+	i_dev->disable(i_dev);
+	i2c_dw_prepare_clk(i_dev, false);
+
+	return 0;
+}
+
+static int dw_i2c_plat_resume(struct device *dev)
+{
+	struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
+
+	if (!i_dev->pm_disabled)
+		i2c_dw_prepare_clk(i_dev, true);
+
+	i_dev->init(i_dev);
+
+	return 0;
+}
+
+static const struct dev_pm_ops dw_i2c_dev_pm_ops = {
+	.prepare = dw_i2c_plat_prepare,
+	.complete = dw_i2c_plat_complete,
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume)
+	SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL)
+};
+
+#define DW_I2C_DEV_PMOPS (&dw_i2c_dev_pm_ops)
+#else
+#define DW_I2C_DEV_PMOPS NULL
+#endif
+
+/* Work with hotplug and coldplug */
+MODULE_ALIAS("platform:i2c_designware");
+
+static struct platform_driver dw_i2c_driver = {
+	.probe = dw_i2c_plat_probe,
+	.remove = dw_i2c_plat_remove,
+	.driver		= {
+		.name	= "i2c_designware",
+		.of_match_table = of_match_ptr(dw_i2c_of_match),
+		.acpi_match_table = ACPI_PTR(dw_i2c_acpi_match),
+		.pm	= DW_I2C_DEV_PMOPS,
+	},
+};
+
+static int __init dw_i2c_init_driver(void)
+{
+	return platform_driver_register(&dw_i2c_driver);
+}
+subsys_initcall(dw_i2c_init_driver);
+
+static void __exit dw_i2c_exit_driver(void)
+{
+	platform_driver_unregister(&dw_i2c_driver);
+}
+module_exit(dw_i2c_exit_driver);
+
+MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
+MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter");
+MODULE_LICENSE("GPL");