drivers/i2c/busses/i2c-hix5hd2.c - kernel/quantenna - Git at Google

 /*
  * Copyright (c) 2014 Linaro Ltd.
  * Copyright (c) 2014 Hisilicon Limited.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * Now only support 7 bit address.
  */

 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/io.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>

 /* Register Map */
 #define HIX5I2C_CTRL		0x00
 #define HIX5I2C_COM		0x04
 #define HIX5I2C_ICR		0x08
 #define HIX5I2C_SR		0x0c
 #define HIX5I2C_SCL_H		0x10
 #define HIX5I2C_SCL_L		0x14
 #define HIX5I2C_TXR		0x18
 #define HIX5I2C_RXR		0x1c

 /* I2C_CTRL_REG */
 #define I2C_ENABLE		BIT(8)
 #define I2C_UNMASK_TOTAL	BIT(7)
 #define I2C_UNMASK_START	BIT(6)
 #define I2C_UNMASK_END		BIT(5)
 #define I2C_UNMASK_SEND		BIT(4)
 #define I2C_UNMASK_RECEIVE	BIT(3)
 #define I2C_UNMASK_ACK		BIT(2)
 #define I2C_UNMASK_ARBITRATE	BIT(1)
 #define I2C_UNMASK_OVER		BIT(0)
 #define I2C_UNMASK_ALL		(I2C_UNMASK_ACK | I2C_UNMASK_OVER)

 /* I2C_COM_REG */
 #define I2C_NO_ACK		BIT(4)
 #define I2C_START		BIT(3)
 #define I2C_READ		BIT(2)
 #define I2C_WRITE		BIT(1)
 #define I2C_STOP		BIT(0)

 /* I2C_ICR_REG */
 #define I2C_CLEAR_START		BIT(6)
 #define I2C_CLEAR_END		BIT(5)
 #define I2C_CLEAR_SEND		BIT(4)
 #define I2C_CLEAR_RECEIVE	BIT(3)
 #define I2C_CLEAR_ACK		BIT(2)
 #define I2C_CLEAR_ARBITRATE	BIT(1)
 #define I2C_CLEAR_OVER		BIT(0)
 #define I2C_CLEAR_ALL		(I2C_CLEAR_START | I2C_CLEAR_END | \
 				I2C_CLEAR_SEND | I2C_CLEAR_RECEIVE | \
 				I2C_CLEAR_ACK | I2C_CLEAR_ARBITRATE | \
 				I2C_CLEAR_OVER)

 /* I2C_SR_REG */
 #define I2C_BUSY		BIT(7)
 #define I2C_START_INTR		BIT(6)
 #define I2C_END_INTR		BIT(5)
 #define I2C_SEND_INTR		BIT(4)
 #define I2C_RECEIVE_INTR	BIT(3)
 #define I2C_ACK_INTR		BIT(2)
 #define I2C_ARBITRATE_INTR	BIT(1)
 #define I2C_OVER_INTR		BIT(0)

 #define HIX5I2C_MAX_FREQ	400000		/* 400k */
 #define HIX5I2C_READ_OPERATION	0x01

 enum hix5hd2_i2c_state {
 	HIX5I2C_STAT_RW_ERR = -1,
 	HIX5I2C_STAT_INIT,
 	HIX5I2C_STAT_RW,
 	HIX5I2C_STAT_SND_STOP,
 	HIX5I2C_STAT_RW_SUCCESS,
 };

 struct hix5hd2_i2c_priv {
 	struct i2c_adapter adap;
 	struct i2c_msg *msg;
 	struct completion msg_complete;
 	unsigned int msg_idx;
 	unsigned int msg_len;
 	int stop;
 	void __iomem *regs;
 	struct clk *clk;
 	struct device *dev;
 	spinlock_t lock;	/* IRQ synchronization */
 	int err;
 	unsigned int freq;
 	enum hix5hd2_i2c_state state;
 };

 static u32 hix5hd2_i2c_clr_pend_irq(struct hix5hd2_i2c_priv *priv)
 {
 	u32 val = readl_relaxed(priv->regs + HIX5I2C_SR);

 	writel_relaxed(val, priv->regs + HIX5I2C_ICR);

 	return val;
 }

 static void hix5hd2_i2c_clr_all_irq(struct hix5hd2_i2c_priv *priv)
 {
 	writel_relaxed(I2C_CLEAR_ALL, priv->regs + HIX5I2C_ICR);
 }

 static void hix5hd2_i2c_disable_irq(struct hix5hd2_i2c_priv *priv)
 {
 	writel_relaxed(0, priv->regs + HIX5I2C_CTRL);
 }

 static void hix5hd2_i2c_enable_irq(struct hix5hd2_i2c_priv *priv)
 {
 	writel_relaxed(I2C_ENABLE | I2C_UNMASK_TOTAL | I2C_UNMASK_ALL,
 		       priv->regs + HIX5I2C_CTRL);
 }

 static void hix5hd2_i2c_drv_setrate(struct hix5hd2_i2c_priv *priv)
 {
 	u32 rate, val;
 	u32 scl, sysclock;

 	/* close all i2c interrupt */
 	val = readl_relaxed(priv->regs + HIX5I2C_CTRL);
 	writel_relaxed(val & (~I2C_UNMASK_TOTAL), priv->regs + HIX5I2C_CTRL);

 	rate = priv->freq;
 	sysclock = clk_get_rate(priv->clk);
 	scl = (sysclock / (rate * 2)) / 2 - 1;
 	writel_relaxed(scl, priv->regs + HIX5I2C_SCL_H);
 	writel_relaxed(scl, priv->regs + HIX5I2C_SCL_L);

 	/* restore original interrupt*/
 	writel_relaxed(val, priv->regs + HIX5I2C_CTRL);

 	dev_dbg(priv->dev, "%s: sysclock=%d, rate=%d, scl=%d\n",
 		__func__, sysclock, rate, scl);
 }

 static void hix5hd2_i2c_init(struct hix5hd2_i2c_priv *priv)
 {
 	hix5hd2_i2c_disable_irq(priv);
 	hix5hd2_i2c_drv_setrate(priv);
 	hix5hd2_i2c_clr_all_irq(priv);
 	hix5hd2_i2c_enable_irq(priv);
 }

 static void hix5hd2_i2c_reset(struct hix5hd2_i2c_priv *priv)
 {
 	clk_disable_unprepare(priv->clk);
 	msleep(20);
 	clk_prepare_enable(priv->clk);
 	hix5hd2_i2c_init(priv);
 }

 static int hix5hd2_i2c_wait_bus_idle(struct hix5hd2_i2c_priv *priv)
 {
 	unsigned long stop_time;
 	u32 int_status;

 	/* wait for 100 milli seconds for the bus to be idle */
 	stop_time = jiffies + msecs_to_jiffies(100);
 	do {
 		int_status = hix5hd2_i2c_clr_pend_irq(priv);
 		if (!(int_status & I2C_BUSY))
 			return 0;

 		usleep_range(50, 200);
 	} while (time_before(jiffies, stop_time));

 	return -EBUSY;
 }

 static void hix5hd2_rw_over(struct hix5hd2_i2c_priv *priv)
 {
 	if (priv->state == HIX5I2C_STAT_SND_STOP)
 		dev_dbg(priv->dev, "%s: rw and send stop over\n", __func__);
 	else
 		dev_dbg(priv->dev, "%s: have not data to send\n", __func__);

 	priv->state = HIX5I2C_STAT_RW_SUCCESS;
 	priv->err = 0;
 }

 static void hix5hd2_rw_handle_stop(struct hix5hd2_i2c_priv *priv)
 {
 	if (priv->stop) {
 		priv->state = HIX5I2C_STAT_SND_STOP;
 		writel_relaxed(I2C_STOP, priv->regs + HIX5I2C_COM);
 	} else {
 		hix5hd2_rw_over(priv);
 	}
 }

 static void hix5hd2_read_handle(struct hix5hd2_i2c_priv *priv)
 {
 	if (priv->msg_len == 1) {
 		/* the last byte don't need send ACK */
 		writel_relaxed(I2C_READ | I2C_NO_ACK, priv->regs + HIX5I2C_COM);
 	} else if (priv->msg_len > 1) {
 		/* if i2c master receive data will send ACK */
 		writel_relaxed(I2C_READ, priv->regs + HIX5I2C_COM);
 	} else {
 		hix5hd2_rw_handle_stop(priv);
 	}
 }

 static void hix5hd2_write_handle(struct hix5hd2_i2c_priv *priv)
 {
 	u8 data;

 	if (priv->msg_len > 0) {
 		data = priv->msg->buf[priv->msg_idx++];
 		writel_relaxed(data, priv->regs + HIX5I2C_TXR);
 		writel_relaxed(I2C_WRITE, priv->regs + HIX5I2C_COM);
 	} else {
 		hix5hd2_rw_handle_stop(priv);
 	}
 }

 static int hix5hd2_rw_preprocess(struct hix5hd2_i2c_priv *priv)
 {
 	u8 data;

 	if (priv->state == HIX5I2C_STAT_INIT) {
 		priv->state = HIX5I2C_STAT_RW;
 	} else if (priv->state == HIX5I2C_STAT_RW) {
 		if (priv->msg->flags & I2C_M_RD) {
 			data = readl_relaxed(priv->regs + HIX5I2C_RXR);
 			priv->msg->buf[priv->msg_idx++] = data;
 		}
 		priv->msg_len--;
 	} else {
 		dev_dbg(priv->dev, "%s: error: priv->state = %d, msg_len = %d\n",
 			__func__, priv->state, priv->msg_len);
 		return -EAGAIN;
 	}
 	return 0;
 }

 static irqreturn_t hix5hd2_i2c_irq(int irqno, void *dev_id)
 {
 	struct hix5hd2_i2c_priv *priv = dev_id;
 	u32 int_status;
 	int ret;

 	spin_lock(&priv->lock);

 	int_status = hix5hd2_i2c_clr_pend_irq(priv);

 	/* handle error */
 	if (int_status & I2C_ARBITRATE_INTR) {
 		/* bus error */
 		dev_dbg(priv->dev, "ARB bus loss\n");
 		priv->err = -EAGAIN;
 		priv->state = HIX5I2C_STAT_RW_ERR;
 		goto stop;
 	} else if (int_status & I2C_ACK_INTR) {
 		/* ack error */
 		dev_dbg(priv->dev, "No ACK from device\n");
 		priv->err = -ENXIO;
 		priv->state = HIX5I2C_STAT_RW_ERR;
 		goto stop;
 	}

 	if (int_status & I2C_OVER_INTR) {
 		if (priv->msg_len > 0) {
 			ret = hix5hd2_rw_preprocess(priv);
 			if (ret) {
 				priv->err = ret;
 				priv->state = HIX5I2C_STAT_RW_ERR;
 				goto stop;
 			}
 			if (priv->msg->flags & I2C_M_RD)
 				hix5hd2_read_handle(priv);
 			else
 				hix5hd2_write_handle(priv);
 		} else {
 			hix5hd2_rw_over(priv);
 		}
 	}

 stop:
 	if ((priv->state == HIX5I2C_STAT_RW_SUCCESS &&
 	     priv->msg->len == priv->msg_idx) ||
 	    (priv->state == HIX5I2C_STAT_RW_ERR)) {
 		hix5hd2_i2c_disable_irq(priv);
 		hix5hd2_i2c_clr_pend_irq(priv);
 		complete(&priv->msg_complete);
 	}

 	spin_unlock(&priv->lock);

 	return IRQ_HANDLED;
 }

 static void hix5hd2_i2c_message_start(struct hix5hd2_i2c_priv *priv, int stop)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&priv->lock, flags);
 	hix5hd2_i2c_clr_all_irq(priv);
 	hix5hd2_i2c_enable_irq(priv);

 	if (priv->msg->flags & I2C_M_RD)
 		writel_relaxed((priv->msg->addr << 1) | HIX5I2C_READ_OPERATION,
 			       priv->regs + HIX5I2C_TXR);
 	else
 		writel_relaxed(priv->msg->addr << 1,
 			       priv->regs + HIX5I2C_TXR);

 	writel_relaxed(I2C_WRITE | I2C_START, priv->regs + HIX5I2C_COM);
 	spin_unlock_irqrestore(&priv->lock, flags);
 }

 static int hix5hd2_i2c_xfer_msg(struct hix5hd2_i2c_priv *priv,
 				struct i2c_msg *msgs, int stop)
 {
 	unsigned long timeout;
 	int ret;

 	priv->msg = msgs;
 	priv->msg_idx = 0;
 	priv->msg_len = priv->msg->len;
 	priv->stop = stop;
 	priv->err = 0;
 	priv->state = HIX5I2C_STAT_INIT;

 	reinit_completion(&priv->msg_complete);
 	hix5hd2_i2c_message_start(priv, stop);

 	timeout = wait_for_completion_timeout(&priv->msg_complete,
 					      priv->adap.timeout);
 	if (timeout == 0) {
 		priv->state = HIX5I2C_STAT_RW_ERR;
 		priv->err = -ETIMEDOUT;
 		dev_warn(priv->dev, "%s timeout=%d\n",
 			 msgs->flags & I2C_M_RD ? "rx" : "tx",
 			 priv->adap.timeout);
 	}
 	ret = priv->state;

 	/*
 	 * If this is the last message to be transfered (stop == 1)
 	 * Then check if the bus can be brought back to idle.
 	 */
 	if (priv->state == HIX5I2C_STAT_RW_SUCCESS && stop)
 		ret = hix5hd2_i2c_wait_bus_idle(priv);

 	if (ret < 0)
 		hix5hd2_i2c_reset(priv);

 	return priv->err;
 }

 static int hix5hd2_i2c_xfer(struct i2c_adapter *adap,
 			    struct i2c_msg *msgs, int num)
 {
 	struct hix5hd2_i2c_priv *priv = i2c_get_adapdata(adap);
 	int i, ret, stop;

 	pm_runtime_get_sync(priv->dev);

 	for (i = 0; i < num; i++, msgs++) {
 		stop = (i == num - 1);
 		ret = hix5hd2_i2c_xfer_msg(priv, msgs, stop);
 		if (ret < 0)
 			goto out;
 	}

 	if (i == num) {
 		ret = num;
 	} else {
 		/* Only one message, cannot access the device */
 		if (i == 1)
 			ret = -EREMOTEIO;
 		else
 			ret = i;

 		dev_warn(priv->dev, "xfer message failed\n");
 	}

 out:
 	pm_runtime_mark_last_busy(priv->dev);
 	pm_runtime_put_autosuspend(priv->dev);
 	return ret;
 }

 static u32 hix5hd2_i2c_func(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 }

 static const struct i2c_algorithm hix5hd2_i2c_algorithm = {
 	.master_xfer		= hix5hd2_i2c_xfer,
 	.functionality		= hix5hd2_i2c_func,
 };

 static int hix5hd2_i2c_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct hix5hd2_i2c_priv *priv;
 	struct resource *mem;
 	unsigned int freq;
 	int irq, ret;

 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	if (of_property_read_u32(np, "clock-frequency", &freq)) {
 		/* use 100k as default value */
 		priv->freq = 100000;
 	} else {
 		if (freq > HIX5I2C_MAX_FREQ) {
 			priv->freq = HIX5I2C_MAX_FREQ;
 			dev_warn(priv->dev, "use max freq %d instead\n",
 				 HIX5I2C_MAX_FREQ);
 		} else {
 			priv->freq = freq;
 		}
 	}

 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	priv->regs = devm_ioremap_resource(&pdev->dev, mem);
 	if (IS_ERR(priv->regs))
 		return PTR_ERR(priv->regs);

 	irq = platform_get_irq(pdev, 0);
 	if (irq <= 0) {
 		dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n");
 		return irq;
 	}

 	priv->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(priv->clk)) {
 		dev_err(&pdev->dev, "cannot get clock\n");
 		return PTR_ERR(priv->clk);
 	}
 	clk_prepare_enable(priv->clk);

 	strlcpy(priv->adap.name, "hix5hd2-i2c", sizeof(priv->adap.name));
 	priv->dev = &pdev->dev;
 	priv->adap.owner = THIS_MODULE;
 	priv->adap.algo = &hix5hd2_i2c_algorithm;
 	priv->adap.retries = 3;
 	priv->adap.dev.of_node = np;
 	priv->adap.algo_data = priv;
 	priv->adap.dev.parent = &pdev->dev;
 	i2c_set_adapdata(&priv->adap, priv);
 	platform_set_drvdata(pdev, priv);
 	spin_lock_init(&priv->lock);
 	init_completion(&priv->msg_complete);

 	hix5hd2_i2c_init(priv);

 	ret = devm_request_irq(&pdev->dev, irq, hix5hd2_i2c_irq,
 			       IRQF_NO_SUSPEND | IRQF_ONESHOT,
 			       dev_name(&pdev->dev), priv);
 	if (ret != 0) {
 		dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", irq);
 		goto err_clk;
 	}

 	pm_suspend_ignore_children(&pdev->dev, true);
 	pm_runtime_set_autosuspend_delay(priv->dev, MSEC_PER_SEC);
 	pm_runtime_use_autosuspend(priv->dev);
 	pm_runtime_set_active(priv->dev);
 	pm_runtime_enable(priv->dev);

 	ret = i2c_add_adapter(&priv->adap);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to add bus to i2c core\n");
 		goto err_runtime;
 	}

 	return ret;

 err_runtime:
 	pm_runtime_disable(priv->dev);
 	pm_runtime_set_suspended(priv->dev);
 err_clk:
 	clk_disable_unprepare(priv->clk);
 	return ret;
 }

 static int hix5hd2_i2c_remove(struct platform_device *pdev)
 {
 	struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);

 	i2c_del_adapter(&priv->adap);
 	pm_runtime_disable(priv->dev);
 	pm_runtime_set_suspended(priv->dev);

 	return 0;
 }

 #ifdef CONFIG_PM
 static int hix5hd2_i2c_runtime_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);

 	clk_disable_unprepare(priv->clk);

 	return 0;
 }

 static int hix5hd2_i2c_runtime_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);

 	clk_prepare_enable(priv->clk);
 	hix5hd2_i2c_init(priv);

 	return 0;
 }
 #endif

 static const struct dev_pm_ops hix5hd2_i2c_pm_ops = {
 	SET_RUNTIME_PM_OPS(hix5hd2_i2c_runtime_suspend,
 			      hix5hd2_i2c_runtime_resume,
 			      NULL)
 };

 static const struct of_device_id hix5hd2_i2c_match[] = {
 	{ .compatible = "hisilicon,hix5hd2-i2c" },
 	{},
 };
 MODULE_DEVICE_TABLE(of, hix5hd2_i2c_match);

 static struct platform_driver hix5hd2_i2c_driver = {
 	.probe		= hix5hd2_i2c_probe,
 	.remove		= hix5hd2_i2c_remove,
 	.driver		= {
 		.name	= "hix5hd2-i2c",
 		.pm	= &hix5hd2_i2c_pm_ops,
 		.of_match_table = hix5hd2_i2c_match,
 	},
 };

 module_platform_driver(hix5hd2_i2c_driver);

 MODULE_DESCRIPTION("Hix5hd2 I2C Bus driver");
 MODULE_AUTHOR("Wei Yan <sledge.yanwei@huawei.com>");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:hix5hd2-i2c");
	/*
	* Copyright (c) 2014 Linaro Ltd.
	* Copyright (c) 2014 Hisilicon Limited.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* Now only support 7 bit address.
	*/

	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/i2c.h>
	#include <linux/io.h>
	#include <linux/interrupt.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/pm_runtime.h>

	/* Register Map */
	#define HIX5I2C_CTRL 0x00
	#define HIX5I2C_COM 0x04
	#define HIX5I2C_ICR 0x08
	#define HIX5I2C_SR 0x0c
	#define HIX5I2C_SCL_H 0x10
	#define HIX5I2C_SCL_L 0x14
	#define HIX5I2C_TXR 0x18
	#define HIX5I2C_RXR 0x1c

	/* I2C_CTRL_REG */
	#define I2C_ENABLE BIT(8)
	#define I2C_UNMASK_TOTAL BIT(7)
	#define I2C_UNMASK_START BIT(6)
	#define I2C_UNMASK_END BIT(5)
	#define I2C_UNMASK_SEND BIT(4)
	#define I2C_UNMASK_RECEIVE BIT(3)
	#define I2C_UNMASK_ACK BIT(2)
	#define I2C_UNMASK_ARBITRATE BIT(1)
	#define I2C_UNMASK_OVER BIT(0)
	#define I2C_UNMASK_ALL (I2C_UNMASK_ACK \| I2C_UNMASK_OVER)

	/* I2C_COM_REG */
	#define I2C_NO_ACK BIT(4)
	#define I2C_START BIT(3)
	#define I2C_READ BIT(2)
	#define I2C_WRITE BIT(1)
	#define I2C_STOP BIT(0)

	/* I2C_ICR_REG */
	#define I2C_CLEAR_START BIT(6)
	#define I2C_CLEAR_END BIT(5)
	#define I2C_CLEAR_SEND BIT(4)
	#define I2C_CLEAR_RECEIVE BIT(3)
	#define I2C_CLEAR_ACK BIT(2)
	#define I2C_CLEAR_ARBITRATE BIT(1)
	#define I2C_CLEAR_OVER BIT(0)
	#define I2C_CLEAR_ALL (I2C_CLEAR_START \| I2C_CLEAR_END \| \
	I2C_CLEAR_SEND \| I2C_CLEAR_RECEIVE \| \
	I2C_CLEAR_ACK \| I2C_CLEAR_ARBITRATE \| \
	I2C_CLEAR_OVER)

	/* I2C_SR_REG */
	#define I2C_BUSY BIT(7)
	#define I2C_START_INTR BIT(6)
	#define I2C_END_INTR BIT(5)
	#define I2C_SEND_INTR BIT(4)
	#define I2C_RECEIVE_INTR BIT(3)
	#define I2C_ACK_INTR BIT(2)
	#define I2C_ARBITRATE_INTR BIT(1)
	#define I2C_OVER_INTR BIT(0)

	#define HIX5I2C_MAX_FREQ 400000 /* 400k */
	#define HIX5I2C_READ_OPERATION 0x01

	enum hix5hd2_i2c_state {
	HIX5I2C_STAT_RW_ERR = -1,
	HIX5I2C_STAT_INIT,
	HIX5I2C_STAT_RW,
	HIX5I2C_STAT_SND_STOP,
	HIX5I2C_STAT_RW_SUCCESS,
	};

	struct hix5hd2_i2c_priv {
	struct i2c_adapter adap;
	struct i2c_msg *msg;
	struct completion msg_complete;
	unsigned int msg_idx;
	unsigned int msg_len;
	int stop;
	void __iomem *regs;
	struct clk *clk;
	struct device *dev;
	spinlock_t lock; /* IRQ synchronization */
	int err;
	unsigned int freq;
	enum hix5hd2_i2c_state state;
	};

	static u32 hix5hd2_i2c_clr_pend_irq(struct hix5hd2_i2c_priv *priv)
	{
	u32 val = readl_relaxed(priv->regs + HIX5I2C_SR);

	writel_relaxed(val, priv->regs + HIX5I2C_ICR);

	return val;
	}

	static void hix5hd2_i2c_clr_all_irq(struct hix5hd2_i2c_priv *priv)
	{
	writel_relaxed(I2C_CLEAR_ALL, priv->regs + HIX5I2C_ICR);
	}

	static void hix5hd2_i2c_disable_irq(struct hix5hd2_i2c_priv *priv)
	{
	writel_relaxed(0, priv->regs + HIX5I2C_CTRL);
	}

	static void hix5hd2_i2c_enable_irq(struct hix5hd2_i2c_priv *priv)
	{
	writel_relaxed(I2C_ENABLE \| I2C_UNMASK_TOTAL \| I2C_UNMASK_ALL,
	priv->regs + HIX5I2C_CTRL);
	}

	static void hix5hd2_i2c_drv_setrate(struct hix5hd2_i2c_priv *priv)
	{
	u32 rate, val;
	u32 scl, sysclock;

	/* close all i2c interrupt */
	val = readl_relaxed(priv->regs + HIX5I2C_CTRL);
	writel_relaxed(val & (~I2C_UNMASK_TOTAL), priv->regs + HIX5I2C_CTRL);

	rate = priv->freq;
	sysclock = clk_get_rate(priv->clk);
	scl = (sysclock / (rate * 2)) / 2 - 1;
	writel_relaxed(scl, priv->regs + HIX5I2C_SCL_H);
	writel_relaxed(scl, priv->regs + HIX5I2C_SCL_L);

	/* restore original interrupt*/
	writel_relaxed(val, priv->regs + HIX5I2C_CTRL);

	dev_dbg(priv->dev, "%s: sysclock=%d, rate=%d, scl=%d\n",
	__func__, sysclock, rate, scl);
	}

	static void hix5hd2_i2c_init(struct hix5hd2_i2c_priv *priv)
	{
	hix5hd2_i2c_disable_irq(priv);
	hix5hd2_i2c_drv_setrate(priv);
	hix5hd2_i2c_clr_all_irq(priv);
	hix5hd2_i2c_enable_irq(priv);
	}

	static void hix5hd2_i2c_reset(struct hix5hd2_i2c_priv *priv)
	{
	clk_disable_unprepare(priv->clk);
	msleep(20);
	clk_prepare_enable(priv->clk);
	hix5hd2_i2c_init(priv);
	}

	static int hix5hd2_i2c_wait_bus_idle(struct hix5hd2_i2c_priv *priv)
	{
	unsigned long stop_time;
	u32 int_status;

	/* wait for 100 milli seconds for the bus to be idle */
	stop_time = jiffies + msecs_to_jiffies(100);
	do {
	int_status = hix5hd2_i2c_clr_pend_irq(priv);
	if (!(int_status & I2C_BUSY))
	return 0;

	usleep_range(50, 200);
	} while (time_before(jiffies, stop_time));

	return -EBUSY;
	}

	static void hix5hd2_rw_over(struct hix5hd2_i2c_priv *priv)
	{
	if (priv->state == HIX5I2C_STAT_SND_STOP)
	dev_dbg(priv->dev, "%s: rw and send stop over\n", __func__);
	else
	dev_dbg(priv->dev, "%s: have not data to send\n", __func__);

	priv->state = HIX5I2C_STAT_RW_SUCCESS;
	priv->err = 0;
	}

	static void hix5hd2_rw_handle_stop(struct hix5hd2_i2c_priv *priv)
	{
	if (priv->stop) {
	priv->state = HIX5I2C_STAT_SND_STOP;
	writel_relaxed(I2C_STOP, priv->regs + HIX5I2C_COM);
	} else {
	hix5hd2_rw_over(priv);
	}
	}

	static void hix5hd2_read_handle(struct hix5hd2_i2c_priv *priv)
	{
	if (priv->msg_len == 1) {
	/* the last byte don't need send ACK */
	writel_relaxed(I2C_READ \| I2C_NO_ACK, priv->regs + HIX5I2C_COM);
	} else if (priv->msg_len > 1) {
	/* if i2c master receive data will send ACK */
	writel_relaxed(I2C_READ, priv->regs + HIX5I2C_COM);
	} else {
	hix5hd2_rw_handle_stop(priv);
	}
	}

	static void hix5hd2_write_handle(struct hix5hd2_i2c_priv *priv)
	{
	u8 data;

	if (priv->msg_len > 0) {
	data = priv->msg->buf[priv->msg_idx++];
	writel_relaxed(data, priv->regs + HIX5I2C_TXR);
	writel_relaxed(I2C_WRITE, priv->regs + HIX5I2C_COM);
	} else {
	hix5hd2_rw_handle_stop(priv);
	}
	}

	static int hix5hd2_rw_preprocess(struct hix5hd2_i2c_priv *priv)
	{
	u8 data;

	if (priv->state == HIX5I2C_STAT_INIT) {
	priv->state = HIX5I2C_STAT_RW;
	} else if (priv->state == HIX5I2C_STAT_RW) {
	if (priv->msg->flags & I2C_M_RD) {
	data = readl_relaxed(priv->regs + HIX5I2C_RXR);
	priv->msg->buf[priv->msg_idx++] = data;
	}
	priv->msg_len--;
	} else {
	dev_dbg(priv->dev, "%s: error: priv->state = %d, msg_len = %d\n",
	__func__, priv->state, priv->msg_len);
	return -EAGAIN;
	}
	return 0;
	}

	static irqreturn_t hix5hd2_i2c_irq(int irqno, void *dev_id)
	{
	struct hix5hd2_i2c_priv *priv = dev_id;
	u32 int_status;
	int ret;

	spin_lock(&priv->lock);

	int_status = hix5hd2_i2c_clr_pend_irq(priv);

	/* handle error */
	if (int_status & I2C_ARBITRATE_INTR) {
	/* bus error */
	dev_dbg(priv->dev, "ARB bus loss\n");
	priv->err = -EAGAIN;
	priv->state = HIX5I2C_STAT_RW_ERR;
	goto stop;
	} else if (int_status & I2C_ACK_INTR) {
	/* ack error */
	dev_dbg(priv->dev, "No ACK from device\n");
	priv->err = -ENXIO;
	priv->state = HIX5I2C_STAT_RW_ERR;
	goto stop;
	}

	if (int_status & I2C_OVER_INTR) {
	if (priv->msg_len > 0) {
	ret = hix5hd2_rw_preprocess(priv);
	if (ret) {
	priv->err = ret;
	priv->state = HIX5I2C_STAT_RW_ERR;
	goto stop;
	}
	if (priv->msg->flags & I2C_M_RD)
	hix5hd2_read_handle(priv);
	else
	hix5hd2_write_handle(priv);
	} else {
	hix5hd2_rw_over(priv);
	}
	}

	stop:
	if ((priv->state == HIX5I2C_STAT_RW_SUCCESS &&
	priv->msg->len == priv->msg_idx) \|\|
	(priv->state == HIX5I2C_STAT_RW_ERR)) {
	hix5hd2_i2c_disable_irq(priv);
	hix5hd2_i2c_clr_pend_irq(priv);
	complete(&priv->msg_complete);
	}

	spin_unlock(&priv->lock);

	return IRQ_HANDLED;
	}

	static void hix5hd2_i2c_message_start(struct hix5hd2_i2c_priv *priv, int stop)
	{
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	hix5hd2_i2c_clr_all_irq(priv);
	hix5hd2_i2c_enable_irq(priv);

	if (priv->msg->flags & I2C_M_RD)
	writel_relaxed((priv->msg->addr << 1) \| HIX5I2C_READ_OPERATION,
	priv->regs + HIX5I2C_TXR);
	else
	writel_relaxed(priv->msg->addr << 1,
	priv->regs + HIX5I2C_TXR);

	writel_relaxed(I2C_WRITE \| I2C_START, priv->regs + HIX5I2C_COM);
	spin_unlock_irqrestore(&priv->lock, flags);
	}

	static int hix5hd2_i2c_xfer_msg(struct hix5hd2_i2c_priv *priv,
	struct i2c_msg *msgs, int stop)
	{
	unsigned long timeout;
	int ret;

	priv->msg = msgs;
	priv->msg_idx = 0;
	priv->msg_len = priv->msg->len;
	priv->stop = stop;
	priv->err = 0;
	priv->state = HIX5I2C_STAT_INIT;

	reinit_completion(&priv->msg_complete);
	hix5hd2_i2c_message_start(priv, stop);

	timeout = wait_for_completion_timeout(&priv->msg_complete,
	priv->adap.timeout);
	if (timeout == 0) {
	priv->state = HIX5I2C_STAT_RW_ERR;
	priv->err = -ETIMEDOUT;
	dev_warn(priv->dev, "%s timeout=%d\n",
	msgs->flags & I2C_M_RD ? "rx" : "tx",
	priv->adap.timeout);
	}
	ret = priv->state;

	/*
	* If this is the last message to be transfered (stop == 1)
	* Then check if the bus can be brought back to idle.
	*/
	if (priv->state == HIX5I2C_STAT_RW_SUCCESS && stop)
	ret = hix5hd2_i2c_wait_bus_idle(priv);

	if (ret < 0)
	hix5hd2_i2c_reset(priv);

	return priv->err;
	}

	static int hix5hd2_i2c_xfer(struct i2c_adapter *adap,
	struct i2c_msg *msgs, int num)
	{
	struct hix5hd2_i2c_priv *priv = i2c_get_adapdata(adap);
	int i, ret, stop;

	pm_runtime_get_sync(priv->dev);

	for (i = 0; i < num; i++, msgs++) {
	stop = (i == num - 1);
	ret = hix5hd2_i2c_xfer_msg(priv, msgs, stop);
	if (ret < 0)
	goto out;
	}

	if (i == num) {
	ret = num;
	} else {
	/* Only one message, cannot access the device */
	if (i == 1)
	ret = -EREMOTEIO;
	else
	ret = i;

	dev_warn(priv->dev, "xfer message failed\n");
	}

	out:
	pm_runtime_mark_last_busy(priv->dev);
	pm_runtime_put_autosuspend(priv->dev);
	return ret;
	}

	static u32 hix5hd2_i2c_func(struct i2c_adapter *adap)
	{
	return I2C_FUNC_I2C \| (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
	}

	static const struct i2c_algorithm hix5hd2_i2c_algorithm = {
	.master_xfer = hix5hd2_i2c_xfer,
	.functionality = hix5hd2_i2c_func,
	};

	static int hix5hd2_i2c_probe(struct platform_device *pdev)
	{
	struct device_node *np = pdev->dev.of_node;
	struct hix5hd2_i2c_priv *priv;
	struct resource *mem;
	unsigned int freq;
	int irq, ret;

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	if (of_property_read_u32(np, "clock-frequency", &freq)) {
	/* use 100k as default value */
	priv->freq = 100000;
	} else {
	if (freq > HIX5I2C_MAX_FREQ) {
	priv->freq = HIX5I2C_MAX_FREQ;
	dev_warn(priv->dev, "use max freq %d instead\n",
	HIX5I2C_MAX_FREQ);
	} else {
	priv->freq = freq;
	}
	}

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	priv->regs = devm_ioremap_resource(&pdev->dev, mem);
	if (IS_ERR(priv->regs))
	return PTR_ERR(priv->regs);

	irq = platform_get_irq(pdev, 0);
	if (irq <= 0) {
	dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n");
	return irq;
	}

	priv->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(priv->clk)) {
	dev_err(&pdev->dev, "cannot get clock\n");
	return PTR_ERR(priv->clk);
	}
	clk_prepare_enable(priv->clk);

	strlcpy(priv->adap.name, "hix5hd2-i2c", sizeof(priv->adap.name));
	priv->dev = &pdev->dev;
	priv->adap.owner = THIS_MODULE;
	priv->adap.algo = &hix5hd2_i2c_algorithm;
	priv->adap.retries = 3;
	priv->adap.dev.of_node = np;
	priv->adap.algo_data = priv;
	priv->adap.dev.parent = &pdev->dev;
	i2c_set_adapdata(&priv->adap, priv);
	platform_set_drvdata(pdev, priv);
	spin_lock_init(&priv->lock);
	init_completion(&priv->msg_complete);

	hix5hd2_i2c_init(priv);

	ret = devm_request_irq(&pdev->dev, irq, hix5hd2_i2c_irq,
	IRQF_NO_SUSPEND \| IRQF_ONESHOT,
	dev_name(&pdev->dev), priv);
	if (ret != 0) {
	dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", irq);
	goto err_clk;
	}

	pm_suspend_ignore_children(&pdev->dev, true);
	pm_runtime_set_autosuspend_delay(priv->dev, MSEC_PER_SEC);
	pm_runtime_use_autosuspend(priv->dev);
	pm_runtime_set_active(priv->dev);
	pm_runtime_enable(priv->dev);

	ret = i2c_add_adapter(&priv->adap);
	if (ret < 0) {
	dev_err(&pdev->dev, "failed to add bus to i2c core\n");
	goto err_runtime;
	}

	return ret;

	err_runtime:
	pm_runtime_disable(priv->dev);
	pm_runtime_set_suspended(priv->dev);
	err_clk:
	clk_disable_unprepare(priv->clk);
	return ret;
	}

	static int hix5hd2_i2c_remove(struct platform_device *pdev)
	{
	struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);

	i2c_del_adapter(&priv->adap);
	pm_runtime_disable(priv->dev);
	pm_runtime_set_suspended(priv->dev);

	return 0;
	}

	#ifdef CONFIG_PM
	static int hix5hd2_i2c_runtime_suspend(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);

	clk_disable_unprepare(priv->clk);

	return 0;
	}

	static int hix5hd2_i2c_runtime_resume(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);

	clk_prepare_enable(priv->clk);
	hix5hd2_i2c_init(priv);

	return 0;
	}
	#endif

	static const struct dev_pm_ops hix5hd2_i2c_pm_ops = {
	SET_RUNTIME_PM_OPS(hix5hd2_i2c_runtime_suspend,
	hix5hd2_i2c_runtime_resume,
	NULL)
	};

	static const struct of_device_id hix5hd2_i2c_match[] = {
	{ .compatible = "hisilicon,hix5hd2-i2c" },
	{},
	};
	MODULE_DEVICE_TABLE(of, hix5hd2_i2c_match);

	static struct platform_driver hix5hd2_i2c_driver = {
	.probe = hix5hd2_i2c_probe,
	.remove = hix5hd2_i2c_remove,
	.driver = {
	.name = "hix5hd2-i2c",
	.pm = &hix5hd2_i2c_pm_ops,
	.of_match_table = hix5hd2_i2c_match,
	},
	};

	module_platform_driver(hix5hd2_i2c_driver);

	MODULE_DESCRIPTION("Hix5hd2 I2C Bus driver");
	MODULE_AUTHOR("Wei Yan <sledge.yanwei@huawei.com>");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:hix5hd2-i2c");