Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 748 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
new file mode 100644
index 000000000..18cc324f3
--- /dev/null
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -0,0 +1,748 @@
+// 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-designware-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);
+	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;
+
+	dw_writel(dev, intr_mask,  DW_IC_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);
+
+	/*
+	 * 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.
+		 */
+		dw_writel(dev, 0, DW_IC_INTR_MASK);
+		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;
+}
+
+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");