drivers/i2c/busses/i2c-xlp9xx.c - kernel/quantenna - Git at Google

 /*
  * Copyright (c) 2003-2015 Broadcom Corporation
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  */

 #include <linux/completion.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>

 #define XLP9XX_I2C_DIV			0x0
 #define XLP9XX_I2C_CTRL			0x1
 #define XLP9XX_I2C_CMD			0x2
 #define XLP9XX_I2C_STATUS		0x3
 #define XLP9XX_I2C_MTXFIFO		0x4
 #define XLP9XX_I2C_MRXFIFO		0x5
 #define XLP9XX_I2C_MFIFOCTRL		0x6
 #define XLP9XX_I2C_STXFIFO		0x7
 #define XLP9XX_I2C_SRXFIFO		0x8
 #define XLP9XX_I2C_SFIFOCTRL		0x9
 #define XLP9XX_I2C_SLAVEADDR		0xA
 #define XLP9XX_I2C_OWNADDR		0xB
 #define XLP9XX_I2C_FIFOWCNT		0xC
 #define XLP9XX_I2C_INTEN		0xD
 #define XLP9XX_I2C_INTST		0xE
 #define XLP9XX_I2C_WAITCNT		0xF
 #define XLP9XX_I2C_TIMEOUT		0X10
 #define XLP9XX_I2C_GENCALLADDR		0x11

 #define XLP9XX_I2C_CMD_START		BIT(7)
 #define XLP9XX_I2C_CMD_STOP		BIT(6)
 #define XLP9XX_I2C_CMD_READ		BIT(5)
 #define XLP9XX_I2C_CMD_WRITE		BIT(4)
 #define XLP9XX_I2C_CMD_ACK		BIT(3)

 #define XLP9XX_I2C_CTRL_MCTLEN_SHIFT	16
 #define XLP9XX_I2C_CTRL_MCTLEN_MASK	0xffff0000
 #define XLP9XX_I2C_CTRL_RST		BIT(8)
 #define XLP9XX_I2C_CTRL_EN		BIT(6)
 #define XLP9XX_I2C_CTRL_MASTER		BIT(4)
 #define XLP9XX_I2C_CTRL_FIFORD		BIT(1)
 #define XLP9XX_I2C_CTRL_ADDMODE		BIT(0)

 #define XLP9XX_I2C_INTEN_NACKADDR	BIT(25)
 #define XLP9XX_I2C_INTEN_SADDR		BIT(13)
 #define XLP9XX_I2C_INTEN_DATADONE	BIT(12)
 #define XLP9XX_I2C_INTEN_ARLOST		BIT(11)
 #define XLP9XX_I2C_INTEN_MFIFOFULL	BIT(4)
 #define XLP9XX_I2C_INTEN_MFIFOEMTY	BIT(3)
 #define XLP9XX_I2C_INTEN_MFIFOHI	BIT(2)
 #define XLP9XX_I2C_INTEN_BUSERR		BIT(0)

 #define XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT		8
 #define XLP9XX_I2C_MFIFOCTRL_LOTH_SHIFT		0
 #define XLP9XX_I2C_MFIFOCTRL_RST		BIT(16)

 #define XLP9XX_I2C_SLAVEADDR_RW			BIT(0)
 #define XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT		1

 #define XLP9XX_I2C_IP_CLK_FREQ		133000000UL
 #define XLP9XX_I2C_DEFAULT_FREQ		100000
 #define XLP9XX_I2C_HIGH_FREQ		400000
 #define XLP9XX_I2C_FIFO_SIZE		0x80U
 #define XLP9XX_I2C_TIMEOUT_MS		1000

 #define XLP9XX_I2C_FIFO_WCNT_MASK	0xff
 #define XLP9XX_I2C_STATUS_ERRMASK	(XLP9XX_I2C_INTEN_ARLOST | \
 			XLP9XX_I2C_INTEN_NACKADDR | XLP9XX_I2C_INTEN_BUSERR)

 struct xlp9xx_i2c_dev {
 	struct device *dev;
 	struct i2c_adapter adapter;
 	struct completion msg_complete;
 	int irq;
 	bool msg_read;
 	u32 __iomem *base;
 	u32 msg_buf_remaining;
 	u32 msg_len;
 	u32 clk_hz;
 	u32 msg_err;
 	u8 *msg_buf;
 };

 static inline void xlp9xx_write_i2c_reg(struct xlp9xx_i2c_dev *priv,
 					unsigned long reg, u32 val)
 {
 	writel(val, priv->base + reg);
 }

 static inline u32 xlp9xx_read_i2c_reg(struct xlp9xx_i2c_dev *priv,
 				      unsigned long reg)
 {
 	return readl(priv->base + reg);
 }

 static void xlp9xx_i2c_mask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
 {
 	u32 inten;

 	inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) & ~mask;
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
 }

 static void xlp9xx_i2c_unmask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
 {
 	u32 inten;

 	inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) | mask;
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
 }

 static void xlp9xx_i2c_update_rx_fifo_thres(struct xlp9xx_i2c_dev *priv)
 {
 	u32 thres;

 	thres = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
 			     thres << XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT);
 }

 static void xlp9xx_i2c_fill_tx_fifo(struct xlp9xx_i2c_dev *priv)
 {
 	u32 len, i;
 	u8 *buf = priv->msg_buf;

 	len = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
 	for (i = 0; i < len; i++)
 		xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MTXFIFO, buf[i]);
 	priv->msg_buf_remaining -= len;
 	priv->msg_buf += len;
 }

 static void xlp9xx_i2c_drain_rx_fifo(struct xlp9xx_i2c_dev *priv)
 {
 	u32 len, i;
 	u8 *buf = priv->msg_buf;

 	len = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_FIFOWCNT) &
 				  XLP9XX_I2C_FIFO_WCNT_MASK;
 	len = min(priv->msg_buf_remaining, len);
 	for (i = 0; i < len; i++, buf++)
 		*buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);

 	priv->msg_buf_remaining -= len;
 	priv->msg_buf = buf;

 	if (priv->msg_buf_remaining)
 		xlp9xx_i2c_update_rx_fifo_thres(priv);
 }

 static irqreturn_t xlp9xx_i2c_isr(int irq, void *dev_id)
 {
 	struct xlp9xx_i2c_dev *priv = dev_id;
 	u32 status;

 	status = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTST);
 	if (status == 0)
 		return IRQ_NONE;

 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTST, status);
 	if (status & XLP9XX_I2C_STATUS_ERRMASK) {
 		priv->msg_err = status;
 		goto xfer_done;
 	}

 	/* SADDR ACK for SMBUS_QUICK */
 	if ((status & XLP9XX_I2C_INTEN_SADDR) && (priv->msg_len == 0))
 		goto xfer_done;

 	if (!priv->msg_read) {
 		if (status & XLP9XX_I2C_INTEN_MFIFOEMTY) {
 			/* TX FIFO got empty, fill it up again */
 			if (priv->msg_buf_remaining)
 				xlp9xx_i2c_fill_tx_fifo(priv);
 			else
 				xlp9xx_i2c_mask_irq(priv,
 						    XLP9XX_I2C_INTEN_MFIFOEMTY);
 		}
 	} else {
 		if (status & (XLP9XX_I2C_INTEN_DATADONE |
 			      XLP9XX_I2C_INTEN_MFIFOHI)) {
 			/* data is in FIFO, read it */
 			if (priv->msg_buf_remaining)
 				xlp9xx_i2c_drain_rx_fifo(priv);
 		}
 	}

 	/* Transfer complete */
 	if (status & XLP9XX_I2C_INTEN_DATADONE)
 		goto xfer_done;

 	return IRQ_HANDLED;

 xfer_done:
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
 	complete(&priv->msg_complete);
 	return IRQ_HANDLED;
 }

 static int xlp9xx_i2c_init(struct xlp9xx_i2c_dev *priv)
 {
 	u32 prescale;

 	/*
 	 * The controller uses 5 * SCL clock internally.
 	 * So prescale value should be divided by 5.
 	 */
 	prescale = DIV_ROUND_UP(XLP9XX_I2C_IP_CLK_FREQ, priv->clk_hz);
 	prescale = ((prescale - 8) / 5) - 1;
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_RST);
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_EN |
 			     XLP9XX_I2C_CTRL_MASTER);
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_DIV, prescale);
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);

 	return 0;
 }

 static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg,
 			       int last_msg)
 {
 	unsigned long timeleft;
 	u32 intr_mask, cmd, val;

 	priv->msg_buf = msg->buf;
 	priv->msg_buf_remaining = priv->msg_len = msg->len;
 	priv->msg_err = 0;
 	priv->msg_read = (msg->flags & I2C_M_RD);
 	reinit_completion(&priv->msg_complete);

 	/* Reset FIFO */
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
 			     XLP9XX_I2C_MFIFOCTRL_RST);

 	/* set FIFO threshold if reading */
 	if (priv->msg_read)
 		xlp9xx_i2c_update_rx_fifo_thres(priv);

 	/* set slave addr */
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_SLAVEADDR,
 			     (msg->addr << XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT) |
 			     (priv->msg_read ? XLP9XX_I2C_SLAVEADDR_RW : 0));

 	/* Build control word for transfer */
 	val = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_CTRL);
 	if (!priv->msg_read)
 		val &= ~XLP9XX_I2C_CTRL_FIFORD;
 	else
 		val |= XLP9XX_I2C_CTRL_FIFORD;	/* read */

 	if (msg->flags & I2C_M_TEN)
 		val |= XLP9XX_I2C_CTRL_ADDMODE;	/* 10-bit address mode*/
 	else
 		val &= ~XLP9XX_I2C_CTRL_ADDMODE;

 	/* set data length to be transferred */
 	val = (val & ~XLP9XX_I2C_CTRL_MCTLEN_MASK) |
 	      (msg->len << XLP9XX_I2C_CTRL_MCTLEN_SHIFT);
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, val);

 	/* fill fifo during tx */
 	if (!priv->msg_read)
 		xlp9xx_i2c_fill_tx_fifo(priv);

 	/* set interrupt mask */
 	intr_mask = (XLP9XX_I2C_INTEN_ARLOST | XLP9XX_I2C_INTEN_BUSERR |
 		     XLP9XX_I2C_INTEN_NACKADDR | XLP9XX_I2C_INTEN_DATADONE);

 	if (priv->msg_read) {
 		intr_mask |= XLP9XX_I2C_INTEN_MFIFOHI;
 		if (msg->len == 0)
 			intr_mask |= XLP9XX_I2C_INTEN_SADDR;
 	} else {
 		if (msg->len == 0)
 			intr_mask |= XLP9XX_I2C_INTEN_SADDR;
 		else
 			intr_mask |= XLP9XX_I2C_INTEN_MFIFOEMTY;
 	}
 	xlp9xx_i2c_unmask_irq(priv, intr_mask);

 	/* set cmd reg */
 	cmd = XLP9XX_I2C_CMD_START;
 	cmd |= (priv->msg_read ? XLP9XX_I2C_CMD_READ : XLP9XX_I2C_CMD_WRITE);
 	if (last_msg)
 		cmd |= XLP9XX_I2C_CMD_STOP;

 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CMD, cmd);

 	timeleft = msecs_to_jiffies(XLP9XX_I2C_TIMEOUT_MS);
 	timeleft = wait_for_completion_timeout(&priv->msg_complete, timeleft);

 	if (priv->msg_err) {
 		dev_dbg(priv->dev, "transfer error %x!\n", priv->msg_err);
 		if (priv->msg_err & XLP9XX_I2C_INTEN_BUSERR)
 			xlp9xx_i2c_init(priv);
 		return -EIO;
 	}

 	if (timeleft == 0) {
 		dev_dbg(priv->dev, "i2c transfer timed out!\n");
 		xlp9xx_i2c_init(priv);
 		return -ETIMEDOUT;
 	}

 	return 0;
 }

 static int xlp9xx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 			   int num)
 {
 	int i, ret;
 	struct xlp9xx_i2c_dev *priv = i2c_get_adapdata(adap);

 	for (i = 0; i < num; i++) {
 		ret = xlp9xx_i2c_xfer_msg(priv, &msgs[i], i == num - 1);
 		if (ret != 0)
 			return ret;
 	}

 	return num;
 }

 static u32 xlp9xx_i2c_functionality(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C |
 		I2C_FUNC_10BIT_ADDR;
 }

 static struct i2c_algorithm xlp9xx_i2c_algo = {
 	.master_xfer = xlp9xx_i2c_xfer,
 	.functionality = xlp9xx_i2c_functionality,
 };

 static int xlp9xx_i2c_get_frequency(struct platform_device *pdev,
 				    struct xlp9xx_i2c_dev *priv)
 {
 	struct device_node *np = pdev->dev.of_node;
 	u32 freq;
 	int err;

 	err = of_property_read_u32(np, "clock-frequency", &freq);
 	if (err) {
 		freq = XLP9XX_I2C_DEFAULT_FREQ;
 		dev_dbg(&pdev->dev, "using default frequency %u\n", freq);
 	} else if (freq == 0 || freq > XLP9XX_I2C_HIGH_FREQ) {
 		dev_warn(&pdev->dev, "invalid frequency %u, using default\n",
 			 freq);
 		freq = XLP9XX_I2C_DEFAULT_FREQ;
 	}
 	priv->clk_hz = freq;

 	return 0;
 }

 static int xlp9xx_i2c_probe(struct platform_device *pdev)
 {
 	struct xlp9xx_i2c_dev *priv;
 	struct resource *res;
 	int err = 0;

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

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

 	priv->irq = platform_get_irq(pdev, 0);
 	if (priv->irq <= 0) {
 		dev_err(&pdev->dev, "invalid irq!\n");
 		return priv->irq;
 	}

 	xlp9xx_i2c_get_frequency(pdev, priv);
 	xlp9xx_i2c_init(priv);

 	err = devm_request_irq(&pdev->dev, priv->irq, xlp9xx_i2c_isr, 0,
 			       pdev->name, priv);
 	if (err) {
 		dev_err(&pdev->dev, "IRQ request failed!\n");
 		return err;
 	}

 	init_completion(&priv->msg_complete);
 	priv->adapter.dev.parent = &pdev->dev;
 	priv->adapter.algo = &xlp9xx_i2c_algo;
 	priv->adapter.dev.of_node = pdev->dev.of_node;
 	priv->dev = &pdev->dev;

 	snprintf(priv->adapter.name, sizeof(priv->adapter.name), "xlp9xx-i2c");
 	i2c_set_adapdata(&priv->adapter, priv);

 	err = i2c_add_adapter(&priv->adapter);
 	if (err) {
 		dev_err(&pdev->dev, "failed to add I2C adapter!\n");
 		return err;
 	}

 	platform_set_drvdata(pdev, priv);
 	dev_dbg(&pdev->dev, "I2C bus:%d added\n", priv->adapter.nr);

 	return 0;
 }

 static int xlp9xx_i2c_remove(struct platform_device *pdev)
 {
 	struct xlp9xx_i2c_dev *priv;

 	priv = platform_get_drvdata(pdev);
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
 	synchronize_irq(priv->irq);
 	i2c_del_adapter(&priv->adapter);
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, 0);

 	return 0;
 }

 static const struct of_device_id xlp9xx_i2c_of_match[] = {
 	{ .compatible = "netlogic,xlp980-i2c", },
 	{ /* sentinel */ },
 };

 static struct platform_driver xlp9xx_i2c_driver = {
 	.probe = xlp9xx_i2c_probe,
 	.remove = xlp9xx_i2c_remove,
 	.driver = {
 		.name = "xlp9xx-i2c",
 		.of_match_table = xlp9xx_i2c_of_match,
 	},
 };

 module_platform_driver(xlp9xx_i2c_driver);

 MODULE_AUTHOR("Subhendu Sekhar Behera <sbehera@broadcom.com>");
 MODULE_DESCRIPTION("XLP9XX/5XX I2C Bus Controller Driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Copyright (c) 2003-2015 Broadcom Corporation
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*/

	#include <linux/completion.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>

	#define XLP9XX_I2C_DIV 0x0
	#define XLP9XX_I2C_CTRL 0x1
	#define XLP9XX_I2C_CMD 0x2
	#define XLP9XX_I2C_STATUS 0x3
	#define XLP9XX_I2C_MTXFIFO 0x4
	#define XLP9XX_I2C_MRXFIFO 0x5
	#define XLP9XX_I2C_MFIFOCTRL 0x6
	#define XLP9XX_I2C_STXFIFO 0x7
	#define XLP9XX_I2C_SRXFIFO 0x8
	#define XLP9XX_I2C_SFIFOCTRL 0x9
	#define XLP9XX_I2C_SLAVEADDR 0xA
	#define XLP9XX_I2C_OWNADDR 0xB
	#define XLP9XX_I2C_FIFOWCNT 0xC
	#define XLP9XX_I2C_INTEN 0xD
	#define XLP9XX_I2C_INTST 0xE
	#define XLP9XX_I2C_WAITCNT 0xF
	#define XLP9XX_I2C_TIMEOUT 0X10
	#define XLP9XX_I2C_GENCALLADDR 0x11

	#define XLP9XX_I2C_CMD_START BIT(7)
	#define XLP9XX_I2C_CMD_STOP BIT(6)
	#define XLP9XX_I2C_CMD_READ BIT(5)
	#define XLP9XX_I2C_CMD_WRITE BIT(4)
	#define XLP9XX_I2C_CMD_ACK BIT(3)

	#define XLP9XX_I2C_CTRL_MCTLEN_SHIFT 16
	#define XLP9XX_I2C_CTRL_MCTLEN_MASK 0xffff0000
	#define XLP9XX_I2C_CTRL_RST BIT(8)
	#define XLP9XX_I2C_CTRL_EN BIT(6)
	#define XLP9XX_I2C_CTRL_MASTER BIT(4)
	#define XLP9XX_I2C_CTRL_FIFORD BIT(1)
	#define XLP9XX_I2C_CTRL_ADDMODE BIT(0)

	#define XLP9XX_I2C_INTEN_NACKADDR BIT(25)
	#define XLP9XX_I2C_INTEN_SADDR BIT(13)
	#define XLP9XX_I2C_INTEN_DATADONE BIT(12)
	#define XLP9XX_I2C_INTEN_ARLOST BIT(11)
	#define XLP9XX_I2C_INTEN_MFIFOFULL BIT(4)
	#define XLP9XX_I2C_INTEN_MFIFOEMTY BIT(3)
	#define XLP9XX_I2C_INTEN_MFIFOHI BIT(2)
	#define XLP9XX_I2C_INTEN_BUSERR BIT(0)

	#define XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT 8
	#define XLP9XX_I2C_MFIFOCTRL_LOTH_SHIFT 0
	#define XLP9XX_I2C_MFIFOCTRL_RST BIT(16)

	#define XLP9XX_I2C_SLAVEADDR_RW BIT(0)
	#define XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT 1

	#define XLP9XX_I2C_IP_CLK_FREQ 133000000UL
	#define XLP9XX_I2C_DEFAULT_FREQ 100000
	#define XLP9XX_I2C_HIGH_FREQ 400000
	#define XLP9XX_I2C_FIFO_SIZE 0x80U
	#define XLP9XX_I2C_TIMEOUT_MS 1000

	#define XLP9XX_I2C_FIFO_WCNT_MASK 0xff
	#define XLP9XX_I2C_STATUS_ERRMASK (XLP9XX_I2C_INTEN_ARLOST \| \
	XLP9XX_I2C_INTEN_NACKADDR \| XLP9XX_I2C_INTEN_BUSERR)

	struct xlp9xx_i2c_dev {
	struct device *dev;
	struct i2c_adapter adapter;
	struct completion msg_complete;
	int irq;
	bool msg_read;
	u32 __iomem *base;
	u32 msg_buf_remaining;
	u32 msg_len;
	u32 clk_hz;
	u32 msg_err;
	u8 *msg_buf;
	};

	static inline void xlp9xx_write_i2c_reg(struct xlp9xx_i2c_dev *priv,
	unsigned long reg, u32 val)
	{
	writel(val, priv->base + reg);
	}

	static inline u32 xlp9xx_read_i2c_reg(struct xlp9xx_i2c_dev *priv,
	unsigned long reg)
	{
	return readl(priv->base + reg);
	}

	static void xlp9xx_i2c_mask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
	{
	u32 inten;

	inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) & ~mask;
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
	}

	static void xlp9xx_i2c_unmask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
	{
	u32 inten;

	inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) \| mask;
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
	}

	static void xlp9xx_i2c_update_rx_fifo_thres(struct xlp9xx_i2c_dev *priv)
	{
	u32 thres;

	thres = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
	thres << XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT);
	}

	static void xlp9xx_i2c_fill_tx_fifo(struct xlp9xx_i2c_dev *priv)
	{
	u32 len, i;
	u8 *buf = priv->msg_buf;

	len = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
	for (i = 0; i < len; i++)
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MTXFIFO, buf[i]);
	priv->msg_buf_remaining -= len;
	priv->msg_buf += len;
	}

	static void xlp9xx_i2c_drain_rx_fifo(struct xlp9xx_i2c_dev *priv)
	{
	u32 len, i;
	u8 *buf = priv->msg_buf;

	len = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_FIFOWCNT) &
	XLP9XX_I2C_FIFO_WCNT_MASK;
	len = min(priv->msg_buf_remaining, len);
	for (i = 0; i < len; i++, buf++)
	*buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);

	priv->msg_buf_remaining -= len;
	priv->msg_buf = buf;

	if (priv->msg_buf_remaining)
	xlp9xx_i2c_update_rx_fifo_thres(priv);
	}

	static irqreturn_t xlp9xx_i2c_isr(int irq, void *dev_id)
	{
	struct xlp9xx_i2c_dev *priv = dev_id;
	u32 status;

	status = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTST);
	if (status == 0)
	return IRQ_NONE;

	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTST, status);
	if (status & XLP9XX_I2C_STATUS_ERRMASK) {
	priv->msg_err = status;
	goto xfer_done;
	}

	/* SADDR ACK for SMBUS_QUICK */
	if ((status & XLP9XX_I2C_INTEN_SADDR) && (priv->msg_len == 0))
	goto xfer_done;

	if (!priv->msg_read) {
	if (status & XLP9XX_I2C_INTEN_MFIFOEMTY) {
	/* TX FIFO got empty, fill it up again */
	if (priv->msg_buf_remaining)
	xlp9xx_i2c_fill_tx_fifo(priv);
	else
	xlp9xx_i2c_mask_irq(priv,
	XLP9XX_I2C_INTEN_MFIFOEMTY);
	}
	} else {
	if (status & (XLP9XX_I2C_INTEN_DATADONE \|
	XLP9XX_I2C_INTEN_MFIFOHI)) {
	/* data is in FIFO, read it */
	if (priv->msg_buf_remaining)
	xlp9xx_i2c_drain_rx_fifo(priv);
	}
	}

	/* Transfer complete */
	if (status & XLP9XX_I2C_INTEN_DATADONE)
	goto xfer_done;

	return IRQ_HANDLED;

	xfer_done:
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
	complete(&priv->msg_complete);
	return IRQ_HANDLED;
	}

	static int xlp9xx_i2c_init(struct xlp9xx_i2c_dev *priv)
	{
	u32 prescale;

	/*
	* The controller uses 5 * SCL clock internally.
	* So prescale value should be divided by 5.
	*/
	prescale = DIV_ROUND_UP(XLP9XX_I2C_IP_CLK_FREQ, priv->clk_hz);
	prescale = ((prescale - 8) / 5) - 1;
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_RST);
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_EN \|
	XLP9XX_I2C_CTRL_MASTER);
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_DIV, prescale);
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);

	return 0;
	}

	static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev priv, struct i2c_msg msg,
	int last_msg)
	{
	unsigned long timeleft;
	u32 intr_mask, cmd, val;

	priv->msg_buf = msg->buf;
	priv->msg_buf_remaining = priv->msg_len = msg->len;
	priv->msg_err = 0;
	priv->msg_read = (msg->flags & I2C_M_RD);
	reinit_completion(&priv->msg_complete);

	/* Reset FIFO */
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
	XLP9XX_I2C_MFIFOCTRL_RST);

	/* set FIFO threshold if reading */
	if (priv->msg_read)
	xlp9xx_i2c_update_rx_fifo_thres(priv);

	/* set slave addr */
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_SLAVEADDR,
	(msg->addr << XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT) \|
	(priv->msg_read ? XLP9XX_I2C_SLAVEADDR_RW : 0));

	/* Build control word for transfer */
	val = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_CTRL);
	if (!priv->msg_read)
	val &= ~XLP9XX_I2C_CTRL_FIFORD;
	else
	val \|= XLP9XX_I2C_CTRL_FIFORD; /* read */

	if (msg->flags & I2C_M_TEN)
	val \|= XLP9XX_I2C_CTRL_ADDMODE; /* 10-bit address mode*/
	else
	val &= ~XLP9XX_I2C_CTRL_ADDMODE;

	/* set data length to be transferred */
	val = (val & ~XLP9XX_I2C_CTRL_MCTLEN_MASK) \|
	(msg->len << XLP9XX_I2C_CTRL_MCTLEN_SHIFT);
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, val);

	/* fill fifo during tx */
	if (!priv->msg_read)
	xlp9xx_i2c_fill_tx_fifo(priv);

	/* set interrupt mask */
	intr_mask = (XLP9XX_I2C_INTEN_ARLOST \| XLP9XX_I2C_INTEN_BUSERR \|
	XLP9XX_I2C_INTEN_NACKADDR \| XLP9XX_I2C_INTEN_DATADONE);

	if (priv->msg_read) {
	intr_mask \|= XLP9XX_I2C_INTEN_MFIFOHI;
	if (msg->len == 0)
	intr_mask \|= XLP9XX_I2C_INTEN_SADDR;
	} else {
	if (msg->len == 0)
	intr_mask \|= XLP9XX_I2C_INTEN_SADDR;
	else
	intr_mask \|= XLP9XX_I2C_INTEN_MFIFOEMTY;
	}
	xlp9xx_i2c_unmask_irq(priv, intr_mask);

	/* set cmd reg */
	cmd = XLP9XX_I2C_CMD_START;
	cmd \|= (priv->msg_read ? XLP9XX_I2C_CMD_READ : XLP9XX_I2C_CMD_WRITE);
	if (last_msg)
	cmd \|= XLP9XX_I2C_CMD_STOP;

	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CMD, cmd);

	timeleft = msecs_to_jiffies(XLP9XX_I2C_TIMEOUT_MS);
	timeleft = wait_for_completion_timeout(&priv->msg_complete, timeleft);

	if (priv->msg_err) {
	dev_dbg(priv->dev, "transfer error %x!\n", priv->msg_err);
	if (priv->msg_err & XLP9XX_I2C_INTEN_BUSERR)
	xlp9xx_i2c_init(priv);
	return -EIO;
	}

	if (timeleft == 0) {
	dev_dbg(priv->dev, "i2c transfer timed out!\n");
	xlp9xx_i2c_init(priv);
	return -ETIMEDOUT;
	}

	return 0;
	}

	static int xlp9xx_i2c_xfer(struct i2c_adapter adap, struct i2c_msg msgs,
	int num)
	{
	int i, ret;
	struct xlp9xx_i2c_dev *priv = i2c_get_adapdata(adap);

	for (i = 0; i < num; i++) {
	ret = xlp9xx_i2c_xfer_msg(priv, &msgs[i], i == num - 1);
	if (ret != 0)
	return ret;
	}

	return num;
	}

	static u32 xlp9xx_i2c_functionality(struct i2c_adapter *adapter)
	{
	return I2C_FUNC_SMBUS_EMUL \| I2C_FUNC_I2C \|
	I2C_FUNC_10BIT_ADDR;
	}

	static struct i2c_algorithm xlp9xx_i2c_algo = {
	.master_xfer = xlp9xx_i2c_xfer,
	.functionality = xlp9xx_i2c_functionality,
	};

	static int xlp9xx_i2c_get_frequency(struct platform_device *pdev,
	struct xlp9xx_i2c_dev *priv)
	{
	struct device_node *np = pdev->dev.of_node;
	u32 freq;
	int err;

	err = of_property_read_u32(np, "clock-frequency", &freq);
	if (err) {
	freq = XLP9XX_I2C_DEFAULT_FREQ;
	dev_dbg(&pdev->dev, "using default frequency %u\n", freq);
	} else if (freq == 0 \|\| freq > XLP9XX_I2C_HIGH_FREQ) {
	dev_warn(&pdev->dev, "invalid frequency %u, using default\n",
	freq);
	freq = XLP9XX_I2C_DEFAULT_FREQ;
	}
	priv->clk_hz = freq;

	return 0;
	}

	static int xlp9xx_i2c_probe(struct platform_device *pdev)
	{
	struct xlp9xx_i2c_dev *priv;
	struct resource *res;
	int err = 0;

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

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

	priv->irq = platform_get_irq(pdev, 0);
	if (priv->irq <= 0) {
	dev_err(&pdev->dev, "invalid irq!\n");
	return priv->irq;
	}

	xlp9xx_i2c_get_frequency(pdev, priv);
	xlp9xx_i2c_init(priv);

	err = devm_request_irq(&pdev->dev, priv->irq, xlp9xx_i2c_isr, 0,
	pdev->name, priv);
	if (err) {
	dev_err(&pdev->dev, "IRQ request failed!\n");
	return err;
	}

	init_completion(&priv->msg_complete);
	priv->adapter.dev.parent = &pdev->dev;
	priv->adapter.algo = &xlp9xx_i2c_algo;
	priv->adapter.dev.of_node = pdev->dev.of_node;
	priv->dev = &pdev->dev;

	snprintf(priv->adapter.name, sizeof(priv->adapter.name), "xlp9xx-i2c");
	i2c_set_adapdata(&priv->adapter, priv);

	err = i2c_add_adapter(&priv->adapter);
	if (err) {
	dev_err(&pdev->dev, "failed to add I2C adapter!\n");
	return err;
	}

	platform_set_drvdata(pdev, priv);
	dev_dbg(&pdev->dev, "I2C bus:%d added\n", priv->adapter.nr);

	return 0;
	}

	static int xlp9xx_i2c_remove(struct platform_device *pdev)
	{
	struct xlp9xx_i2c_dev *priv;

	priv = platform_get_drvdata(pdev);
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
	synchronize_irq(priv->irq);
	i2c_del_adapter(&priv->adapter);
	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, 0);

	return 0;
	}

	static const struct of_device_id xlp9xx_i2c_of_match[] = {
	{ .compatible = "netlogic,xlp980-i2c", },
	{ /* sentinel */ },
	};

	static struct platform_driver xlp9xx_i2c_driver = {
	.probe = xlp9xx_i2c_probe,
	.remove = xlp9xx_i2c_remove,
	.driver = {
	.name = "xlp9xx-i2c",
	.of_match_table = xlp9xx_i2c_of_match,
	},
	};

	module_platform_driver(xlp9xx_i2c_driver);

	MODULE_AUTHOR("Subhendu Sekhar Behera <sbehera@broadcom.com>");
	MODULE_DESCRIPTION("XLP9XX/5XX I2C Bus Controller Driver");
	MODULE_LICENSE("GPL v2");