drivers/i2c/exynos_hs_i2c.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (c) 2016, Google Inc
  *
  * (C) Copyright 2002
  * David Mueller, ELSOFT AG, d.mueller@elsoft.ch
  */

 #include <common.h>
 #include <dm.h>
 #include <i2c.h>
 #include <log.h>
 #include <asm/arch/clk.h>
 #include <asm/arch/cpu.h>
 #include <asm/arch/pinmux.h>
 #include <asm/global_data.h>
 #include <linux/delay.h>
 #include "s3c24x0_i2c.h"

 DECLARE_GLOBAL_DATA_PTR;

 /* HSI2C-specific register description */

 /* I2C_CTL Register bits */
 #define HSI2C_FUNC_MODE_I2C		(1u << 0)
 #define HSI2C_MASTER			(1u << 3)
 #define HSI2C_RXCHON			(1u << 6)	/* Write/Send */
 #define HSI2C_TXCHON			(1u << 7)	/* Read/Receive */
 #define HSI2C_SW_RST			(1u << 31)

 /* I2C_FIFO_CTL Register bits */
 #define HSI2C_RXFIFO_EN			(1u << 0)
 #define HSI2C_TXFIFO_EN			(1u << 1)
 #define HSI2C_TXFIFO_TRIGGER_LEVEL	(0x20 << 16)
 #define HSI2C_RXFIFO_TRIGGER_LEVEL	(0x20 << 4)

 /* I2C_TRAILING_CTL Register bits */
 #define HSI2C_TRAILING_COUNT		(0xff)

 /* I2C_INT_EN Register bits */
 #define HSI2C_TX_UNDERRUN_EN		(1u << 2)
 #define HSI2C_TX_OVERRUN_EN		(1u << 3)
 #define HSI2C_RX_UNDERRUN_EN		(1u << 4)
 #define HSI2C_RX_OVERRUN_EN		(1u << 5)
 #define HSI2C_INT_TRAILING_EN		(1u << 6)
 #define HSI2C_INT_I2C_EN		(1u << 9)

 #define HSI2C_INT_ERROR_MASK	(HSI2C_TX_UNDERRUN_EN |\
 				 HSI2C_TX_OVERRUN_EN  |\
 				 HSI2C_RX_UNDERRUN_EN |\
 				 HSI2C_RX_OVERRUN_EN  |\
 				 HSI2C_INT_TRAILING_EN)

 /* I2C_CONF Register bits */
 #define HSI2C_AUTO_MODE			(1u << 31)
 #define HSI2C_10BIT_ADDR_MODE		(1u << 30)
 #define HSI2C_HS_MODE			(1u << 29)

 /* I2C_AUTO_CONF Register bits */
 #define HSI2C_READ_WRITE		(1u << 16)
 #define HSI2C_STOP_AFTER_TRANS		(1u << 17)
 #define HSI2C_MASTER_RUN		(1u << 31)

 /* I2C_TIMEOUT Register bits */
 #define HSI2C_TIMEOUT_EN		(1u << 31)

 /* I2C_TRANS_STATUS register bits */
 #define HSI2C_MASTER_BUSY		(1u << 17)
 #define HSI2C_SLAVE_BUSY		(1u << 16)
 #define HSI2C_TIMEOUT_AUTO		(1u << 4)
 #define HSI2C_NO_DEV			(1u << 3)
 #define HSI2C_NO_DEV_ACK		(1u << 2)
 #define HSI2C_TRANS_ABORT		(1u << 1)
 #define HSI2C_TRANS_SUCCESS		(1u << 0)
 #define HSI2C_TRANS_ERROR_MASK	(HSI2C_TIMEOUT_AUTO |\
 				 HSI2C_NO_DEV | HSI2C_NO_DEV_ACK |\
 				 HSI2C_TRANS_ABORT)
 #define HSI2C_TRANS_FINISHED_MASK (HSI2C_TRANS_ERROR_MASK | HSI2C_TRANS_SUCCESS)


 /* I2C_FIFO_STAT Register bits */
 #define HSI2C_RX_FIFO_EMPTY		(1u << 24)
 #define HSI2C_RX_FIFO_FULL		(1u << 23)
 #define HSI2C_TX_FIFO_EMPTY		(1u << 8)
 #define HSI2C_TX_FIFO_FULL		(1u << 7)
 #define HSI2C_RX_FIFO_LEVEL(x)		(((x) >> 16) & 0x7f)
 #define HSI2C_TX_FIFO_LEVEL(x)		((x) & 0x7f)

 #define HSI2C_SLV_ADDR_MAS(x)		((x & 0x3ff) << 10)

 #define HSI2C_TIMEOUT_US 10000 /* 10 ms, finer granularity */

 /*
  * Wait for transfer completion.
  *
  * This function reads the interrupt status register waiting for the INT_I2C
  * bit to be set, which indicates copletion of a transaction.
  *
  * @param i2c: pointer to the appropriate register bank
  *
  * @return: I2C_OK in case of successful completion, I2C_NOK_TIMEOUT in case
  *          the status bits do not get set in time, or an approrpiate error
  *          value in case of transfer errors.
  */
 static int hsi2c_wait_for_trx(struct exynos5_hsi2c *i2c)
 {
 	int i = HSI2C_TIMEOUT_US;

 	while (i-- > 0) {
 		u32 int_status = readl(&i2c->usi_int_stat);

 		if (int_status & HSI2C_INT_I2C_EN) {
 			u32 trans_status = readl(&i2c->usi_trans_status);

 			/* Deassert pending interrupt. */
 			writel(int_status, &i2c->usi_int_stat);

 			if (trans_status & HSI2C_NO_DEV_ACK) {
 				debug("%s: no ACK from device\n", __func__);
 				return I2C_NACK;
 			}
 			if (trans_status & HSI2C_NO_DEV) {
 				debug("%s: no device\n", __func__);
 				return I2C_NOK;
 			}
 			if (trans_status & HSI2C_TRANS_ABORT) {
 				debug("%s: arbitration lost\n", __func__);
 				return I2C_NOK_LA;
 			}
 			if (trans_status & HSI2C_TIMEOUT_AUTO) {
 				debug("%s: device timed out\n", __func__);
 				return I2C_NOK_TOUT;
 			}
 			return I2C_OK;
 		}
 		udelay(1);
 	}
 	debug("%s: transaction timeout!\n", __func__);
 	return I2C_NOK_TOUT;
 }

 static int hsi2c_get_clk_details(struct s3c24x0_i2c_bus *i2c_bus)
 {
 	struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
 	ulong clkin;
 	unsigned int op_clk = i2c_bus->clock_frequency;
 	unsigned int i = 0, utemp0 = 0, utemp1 = 0;
 	unsigned int t_ftl_cycle;

 #if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
 	clkin = get_i2c_clk();
 #else
 	clkin = get_PCLK();
 #endif
 	/* FPCLK / FI2C =
 	 * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE
 	 * uTemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2)
 	 * uTemp1 = (TSCLK_L + TSCLK_H + 2)
 	 * uTemp2 = TSCLK_L + TSCLK_H
 	 */
 	t_ftl_cycle = (readl(&hsregs->usi_conf) >> 16) & 0x7;
 	utemp0 = (clkin / op_clk) - 8 - 2 * t_ftl_cycle;

 	/* CLK_DIV max is 256 */
 	for (i = 0; i < 256; i++) {
 		utemp1 = utemp0 / (i + 1);
 		if ((utemp1 < 512) && (utemp1 > 4)) {
 			i2c_bus->clk_cycle = utemp1 - 2;
 			i2c_bus->clk_div = i;
 			return 0;
 		}
 	}
 	return -EINVAL;
 }

 static void hsi2c_ch_init(struct s3c24x0_i2c_bus *i2c_bus)
 {
 	struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
 	unsigned int t_sr_release;
 	unsigned int n_clkdiv;
 	unsigned int t_start_su, t_start_hd;
 	unsigned int t_stop_su;
 	unsigned int t_data_su, t_data_hd;
 	unsigned int t_scl_l, t_scl_h;
 	u32 i2c_timing_s1;
 	u32 i2c_timing_s2;
 	u32 i2c_timing_s3;
 	u32 i2c_timing_sla;

 	n_clkdiv = i2c_bus->clk_div;
 	t_scl_l = i2c_bus->clk_cycle / 2;
 	t_scl_h = i2c_bus->clk_cycle / 2;
 	t_start_su = t_scl_l;
 	t_start_hd = t_scl_l;
 	t_stop_su = t_scl_l;
 	t_data_su = t_scl_l / 2;
 	t_data_hd = t_scl_l / 2;
 	t_sr_release = i2c_bus->clk_cycle;

 	i2c_timing_s1 = t_start_su << 24 | t_start_hd << 16 | t_stop_su << 8;
 	i2c_timing_s2 = t_data_su << 24 | t_scl_l << 8 | t_scl_h << 0;
 	i2c_timing_s3 = n_clkdiv << 16 | t_sr_release << 0;
 	i2c_timing_sla = t_data_hd << 0;

 	writel(HSI2C_TRAILING_COUNT, &hsregs->usi_trailing_ctl);

 	/* Clear to enable Timeout */
 	clrsetbits_le32(&hsregs->usi_timeout, HSI2C_TIMEOUT_EN, 0);

 	/* set AUTO mode */
 	writel(readl(&hsregs->usi_conf) | HSI2C_AUTO_MODE, &hsregs->usi_conf);

 	/* Enable completion conditions' reporting. */
 	writel(HSI2C_INT_I2C_EN, &hsregs->usi_int_en);

 	/* Enable FIFOs */
 	writel(HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN, &hsregs->usi_fifo_ctl);

 	/* Currently operating in Fast speed mode. */
 	writel(i2c_timing_s1, &hsregs->usi_timing_fs1);
 	writel(i2c_timing_s2, &hsregs->usi_timing_fs2);
 	writel(i2c_timing_s3, &hsregs->usi_timing_fs3);
 	writel(i2c_timing_sla, &hsregs->usi_timing_sla);
 }

 /* SW reset for the high speed bus */
 static void exynos5_i2c_reset(struct s3c24x0_i2c_bus *i2c_bus)
 {
 	struct exynos5_hsi2c *i2c = i2c_bus->hsregs;
 	u32 i2c_ctl;

 	/* Set and clear the bit for reset */
 	i2c_ctl = readl(&i2c->usi_ctl);
 	i2c_ctl |= HSI2C_SW_RST;
 	writel(i2c_ctl, &i2c->usi_ctl);

 	i2c_ctl = readl(&i2c->usi_ctl);
 	i2c_ctl &= ~HSI2C_SW_RST;
 	writel(i2c_ctl, &i2c->usi_ctl);

 	/* Initialize the configure registers */
 	hsi2c_ch_init(i2c_bus);
 }

 /*
  * Poll the appropriate bit of the fifo status register until the interface is
  * ready to process the next byte or timeout expires.
  *
  * In addition to the FIFO status register this function also polls the
  * interrupt status register to be able to detect unexpected transaction
  * completion.
  *
  * When FIFO is ready to process the next byte, this function returns I2C_OK.
  * If in course of polling the INT_I2C assertion is detected, the function
  * returns I2C_NOK. If timeout happens before any of the above conditions is
  * met - the function returns I2C_NOK_TOUT;

  * @param i2c: pointer to the appropriate i2c register bank.
  * @param rx_transfer: set to True if the receive transaction is in progress.
  * @return: as described above.
  */
 static unsigned hsi2c_poll_fifo(struct exynos5_hsi2c *i2c, bool rx_transfer)
 {
 	u32 fifo_bit = rx_transfer ? HSI2C_RX_FIFO_EMPTY : HSI2C_TX_FIFO_FULL;
 	int i = HSI2C_TIMEOUT_US;

 	while (readl(&i2c->usi_fifo_stat) & fifo_bit) {
 		if (readl(&i2c->usi_int_stat) & HSI2C_INT_I2C_EN) {
 			/*
 			 * There is a chance that assertion of
 			 * HSI2C_INT_I2C_EN and deassertion of
 			 * HSI2C_RX_FIFO_EMPTY happen simultaneously. Let's
 			 * give FIFO status priority and check it one more
 			 * time before reporting interrupt. The interrupt will
 			 * be reported next time this function is called.
 			 */
 			if (rx_transfer &&
 			    !(readl(&i2c->usi_fifo_stat) & fifo_bit))
 				break;
 			return I2C_NOK;
 		}
 		if (!i--) {
 			debug("%s: FIFO polling timeout!\n", __func__);
 			return I2C_NOK_TOUT;
 		}
 		udelay(1);
 	}
 	return I2C_OK;
 }

 /*
  * Preapre hsi2c transaction, either read or write.
  *
  * Set up transfer as described in section 27.5.1.2 'I2C Channel Auto Mode' of
  * the 5420 UM.
  *
  * @param i2c: pointer to the appropriate i2c register bank.
  * @param chip: slave address on the i2c bus (with read/write bit exlcuded)
  * @param len: number of bytes expected to be sent or received
  * @param rx_transfer: set to true for receive transactions
  * @param: issue_stop: set to true if i2c stop condition should be generated
  *         after this transaction.
  * @return: I2C_NOK_TOUT in case the bus remained busy for HSI2C_TIMEOUT_US,
  *          I2C_OK otherwise.
  */
 static int hsi2c_prepare_transaction(struct exynos5_hsi2c *i2c,
 				     u8 chip,
 				     u16 len,
 				     bool rx_transfer,
 				     bool issue_stop)
 {
 	u32 conf;

 	conf = len | HSI2C_MASTER_RUN;

 	if (issue_stop)
 		conf |= HSI2C_STOP_AFTER_TRANS;

 	/* Clear to enable Timeout */
 	writel(readl(&i2c->usi_timeout) & ~HSI2C_TIMEOUT_EN, &i2c->usi_timeout);

 	/* Set slave address */
 	writel(HSI2C_SLV_ADDR_MAS(chip), &i2c->i2c_addr);

 	if (rx_transfer) {
 		/* i2c master, read transaction */
 		writel((HSI2C_RXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
 		       &i2c->usi_ctl);

 		/* read up to len bytes, stop after transaction is finished */
 		writel(conf | HSI2C_READ_WRITE, &i2c->usi_auto_conf);
 	} else {
 		/* i2c master, write transaction */
 		writel((HSI2C_TXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
 		       &i2c->usi_ctl);

 		/* write up to len bytes, stop after transaction is finished */
 		writel(conf, &i2c->usi_auto_conf);
 	}

 	/* Reset all pending interrupt status bits we care about, if any */
 	writel(HSI2C_INT_I2C_EN, &i2c->usi_int_stat);

 	return I2C_OK;
 }

 /*
  * Wait while i2c bus is settling down (mostly stop gets completed).
  */
 static int hsi2c_wait_while_busy(struct exynos5_hsi2c *i2c)
 {
 	int i = HSI2C_TIMEOUT_US;

 	while (readl(&i2c->usi_trans_status) & HSI2C_MASTER_BUSY) {
 		if (!i--) {
 			debug("%s: bus busy\n", __func__);
 			return I2C_NOK_TOUT;
 		}
 		udelay(1);
 	}
 	return I2C_OK;
 }

 static int hsi2c_write(struct exynos5_hsi2c *i2c,
 		       unsigned char chip,
 		       unsigned char addr[],
 		       unsigned char alen,
 		       unsigned char data[],
 		       unsigned short len,
 		       bool issue_stop)
 {
 	int i, rv = 0;

 	if (!(len + alen)) {
 		/* Writes of zero length not supported in auto mode. */
 		debug("%s: zero length writes not supported\n", __func__);
 		return I2C_NOK;
 	}

 	rv = hsi2c_prepare_transaction
 		(i2c, chip, len + alen, false, issue_stop);
 	if (rv != I2C_OK)
 		return rv;

 	/* Move address, if any, and the data, if any, into the FIFO. */
 	for (i = 0; i < alen; i++) {
 		rv = hsi2c_poll_fifo(i2c, false);
 		if (rv != I2C_OK) {
 			debug("%s: address write failed\n", __func__);
 			goto write_error;
 		}
 		writel(addr[i], &i2c->usi_txdata);
 	}

 	for (i = 0; i < len; i++) {
 		rv = hsi2c_poll_fifo(i2c, false);
 		if (rv != I2C_OK) {
 			debug("%s: data write failed\n", __func__);
 			goto write_error;
 		}
 		writel(data[i], &i2c->usi_txdata);
 	}

 	rv = hsi2c_wait_for_trx(i2c);

  write_error:
 	if (issue_stop) {
 		int tmp_ret = hsi2c_wait_while_busy(i2c);
 		if (rv == I2C_OK)
 			rv = tmp_ret;
 	}

 	writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
 	return rv;
 }

 static int hsi2c_read(struct exynos5_hsi2c *i2c,
 		      unsigned char chip,
 		      unsigned char addr[],
 		      unsigned char alen,
 		      unsigned char data[],
 		      unsigned short len)
 {
 	int i, rv, tmp_ret;
 	bool drop_data = false;

 	if (!len) {
 		/* Reads of zero length not supported in auto mode. */
 		debug("%s: zero length read adjusted\n", __func__);
 		drop_data = true;
 		len = 1;
 	}

 	if (alen) {
 		/* Internal register adress needs to be written first. */
 		rv = hsi2c_write(i2c, chip, addr, alen, NULL, 0, false);
 		if (rv != I2C_OK)
 			return rv;
 	}

 	rv = hsi2c_prepare_transaction(i2c, chip, len, true, true);

 	if (rv != I2C_OK)
 		return rv;

 	for (i = 0; i < len; i++) {
 		rv = hsi2c_poll_fifo(i2c, true);
 		if (rv != I2C_OK)
 			goto read_err;
 		if (drop_data)
 			continue;
 		data[i] = readl(&i2c->usi_rxdata);
 	}

 	rv = hsi2c_wait_for_trx(i2c);

  read_err:
 	tmp_ret = hsi2c_wait_while_busy(i2c);
 	if (rv == I2C_OK)
 		rv = tmp_ret;

 	writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
 	return rv;
 }

 static int exynos_hs_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
 			      int nmsgs)
 {
 	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
 	struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
 	int ret;

 	for (; nmsgs > 0; nmsgs--, msg++) {
 		if (msg->flags & I2C_M_RD) {
 			ret = hsi2c_read(hsregs, msg->addr, 0, 0, msg->buf,
 					 msg->len);
 		} else {
 			ret = hsi2c_write(hsregs, msg->addr, 0, 0, msg->buf,
 					  msg->len, true);
 		}
 		if (ret) {
 			exynos5_i2c_reset(i2c_bus);
 			return -EREMOTEIO;
 		}
 	}

 	return 0;
 }

 static int s3c24x0_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
 {
 	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);

 	i2c_bus->clock_frequency = speed;

 	if (hsi2c_get_clk_details(i2c_bus))
 		return -EFAULT;
 	hsi2c_ch_init(i2c_bus);

 	return 0;
 }

 static int s3c24x0_i2c_probe(struct udevice *dev, uint chip, uint chip_flags)
 {
 	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
 	uchar buf[1];
 	int ret;

 	buf[0] = 0;

 	/*
 	 * What is needed is to send the chip address and verify that the
 	 * address was <ACK>ed (i.e. there was a chip at that address which
 	 * drove the data line low).
 	 */
 	ret = hsi2c_read(i2c_bus->hsregs, chip, 0, 0, buf, 1);

 	return ret != I2C_OK;
 }

 static int s3c_i2c_of_to_plat(struct udevice *dev)
 {
 	const void *blob = gd->fdt_blob;
 	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
 	int node;

 	node = dev_of_offset(dev);

 	i2c_bus->hsregs = dev_read_addr_ptr(dev);

 	i2c_bus->id = pinmux_decode_periph_id(blob, node);

 	i2c_bus->clock_frequency =
 		dev_read_u32_default(dev, "clock-frequency",
 				     I2C_SPEED_STANDARD_RATE);
 	i2c_bus->node = node;
 	i2c_bus->bus_num = dev_seq(dev);

 	exynos_pinmux_config(i2c_bus->id, PINMUX_FLAG_HS_MODE);

 	i2c_bus->active = true;

 	return 0;
 }

 static const struct dm_i2c_ops exynos_hs_i2c_ops = {
 	.xfer		= exynos_hs_i2c_xfer,
 	.probe_chip	= s3c24x0_i2c_probe,
 	.set_bus_speed	= s3c24x0_i2c_set_bus_speed,
 };

 static const struct udevice_id exynos_hs_i2c_ids[] = {
 	{ .compatible = "samsung,exynos5-hsi2c" },
 	{ }
 };

 U_BOOT_DRIVER(hs_i2c) = {
 	.name	= "i2c_s3c_hs",
 	.id	= UCLASS_I2C,
 	.of_match = exynos_hs_i2c_ids,
 	.of_to_plat = s3c_i2c_of_to_plat,
 	.priv_auto	= sizeof(struct s3c24x0_i2c_bus),
 	.ops	= &exynos_hs_i2c_ops,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (c) 2016, Google Inc
	*
	* (C) Copyright 2002
	* David Mueller, ELSOFT AG, d.mueller@elsoft.ch
	*/

	#include <common.h>
	#include <dm.h>
	#include <i2c.h>
	#include <log.h>
	#include <asm/arch/clk.h>
	#include <asm/arch/cpu.h>
	#include <asm/arch/pinmux.h>
	#include <asm/global_data.h>
	#include <linux/delay.h>
	#include "s3c24x0_i2c.h"

	DECLARE_GLOBAL_DATA_PTR;

	/* HSI2C-specific register description */

	/* I2C_CTL Register bits */
	#define HSI2C_FUNC_MODE_I2C (1u << 0)
	#define HSI2C_MASTER (1u << 3)
	#define HSI2C_RXCHON (1u << 6) /* Write/Send */
	#define HSI2C_TXCHON (1u << 7) /* Read/Receive */
	#define HSI2C_SW_RST (1u << 31)

	/* I2C_FIFO_CTL Register bits */
	#define HSI2C_RXFIFO_EN (1u << 0)
	#define HSI2C_TXFIFO_EN (1u << 1)
	#define HSI2C_TXFIFO_TRIGGER_LEVEL (0x20 << 16)
	#define HSI2C_RXFIFO_TRIGGER_LEVEL (0x20 << 4)

	/* I2C_TRAILING_CTL Register bits */
	#define HSI2C_TRAILING_COUNT (0xff)

	/* I2C_INT_EN Register bits */
	#define HSI2C_TX_UNDERRUN_EN (1u << 2)
	#define HSI2C_TX_OVERRUN_EN (1u << 3)
	#define HSI2C_RX_UNDERRUN_EN (1u << 4)
	#define HSI2C_RX_OVERRUN_EN (1u << 5)
	#define HSI2C_INT_TRAILING_EN (1u << 6)
	#define HSI2C_INT_I2C_EN (1u << 9)

	#define HSI2C_INT_ERROR_MASK (HSI2C_TX_UNDERRUN_EN \|\
	HSI2C_TX_OVERRUN_EN \|\
	HSI2C_RX_UNDERRUN_EN \|\
	HSI2C_RX_OVERRUN_EN \|\
	HSI2C_INT_TRAILING_EN)

	/* I2C_CONF Register bits */
	#define HSI2C_AUTO_MODE (1u << 31)
	#define HSI2C_10BIT_ADDR_MODE (1u << 30)
	#define HSI2C_HS_MODE (1u << 29)

	/* I2C_AUTO_CONF Register bits */
	#define HSI2C_READ_WRITE (1u << 16)
	#define HSI2C_STOP_AFTER_TRANS (1u << 17)
	#define HSI2C_MASTER_RUN (1u << 31)

	/* I2C_TIMEOUT Register bits */
	#define HSI2C_TIMEOUT_EN (1u << 31)

	/* I2C_TRANS_STATUS register bits */
	#define HSI2C_MASTER_BUSY (1u << 17)
	#define HSI2C_SLAVE_BUSY (1u << 16)
	#define HSI2C_TIMEOUT_AUTO (1u << 4)
	#define HSI2C_NO_DEV (1u << 3)
	#define HSI2C_NO_DEV_ACK (1u << 2)
	#define HSI2C_TRANS_ABORT (1u << 1)
	#define HSI2C_TRANS_SUCCESS (1u << 0)
	#define HSI2C_TRANS_ERROR_MASK (HSI2C_TIMEOUT_AUTO \|\
	HSI2C_NO_DEV \| HSI2C_NO_DEV_ACK \|\
	HSI2C_TRANS_ABORT)
	#define HSI2C_TRANS_FINISHED_MASK (HSI2C_TRANS_ERROR_MASK \| HSI2C_TRANS_SUCCESS)


	/* I2C_FIFO_STAT Register bits */
	#define HSI2C_RX_FIFO_EMPTY (1u << 24)
	#define HSI2C_RX_FIFO_FULL (1u << 23)
	#define HSI2C_TX_FIFO_EMPTY (1u << 8)
	#define HSI2C_TX_FIFO_FULL (1u << 7)
	#define HSI2C_RX_FIFO_LEVEL(x) (((x) >> 16) & 0x7f)
	#define HSI2C_TX_FIFO_LEVEL(x) ((x) & 0x7f)

	#define HSI2C_SLV_ADDR_MAS(x) ((x & 0x3ff) << 10)

	#define HSI2C_TIMEOUT_US 10000 /* 10 ms, finer granularity */

	/*
	* Wait for transfer completion.
	*
	* This function reads the interrupt status register waiting for the INT_I2C
	* bit to be set, which indicates copletion of a transaction.
	*
	* @param i2c: pointer to the appropriate register bank
	*
	* @return: I2C_OK in case of successful completion, I2C_NOK_TIMEOUT in case
	* the status bits do not get set in time, or an approrpiate error
	* value in case of transfer errors.
	*/
	static int hsi2c_wait_for_trx(struct exynos5_hsi2c *i2c)
	{
	int i = HSI2C_TIMEOUT_US;

	while (i-- > 0) {
	u32 int_status = readl(&i2c->usi_int_stat);

	if (int_status & HSI2C_INT_I2C_EN) {
	u32 trans_status = readl(&i2c->usi_trans_status);

	/* Deassert pending interrupt. */
	writel(int_status, &i2c->usi_int_stat);

	if (trans_status & HSI2C_NO_DEV_ACK) {
	debug("%s: no ACK from device\n", __func__);
	return I2C_NACK;
	}
	if (trans_status & HSI2C_NO_DEV) {
	debug("%s: no device\n", __func__);
	return I2C_NOK;
	}
	if (trans_status & HSI2C_TRANS_ABORT) {
	debug("%s: arbitration lost\n", __func__);
	return I2C_NOK_LA;
	}
	if (trans_status & HSI2C_TIMEOUT_AUTO) {
	debug("%s: device timed out\n", __func__);
	return I2C_NOK_TOUT;
	}
	return I2C_OK;
	}
	udelay(1);
	}
	debug("%s: transaction timeout!\n", __func__);
	return I2C_NOK_TOUT;
	}

	static int hsi2c_get_clk_details(struct s3c24x0_i2c_bus *i2c_bus)
	{
	struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
	ulong clkin;
	unsigned int op_clk = i2c_bus->clock_frequency;
	unsigned int i = 0, utemp0 = 0, utemp1 = 0;
	unsigned int t_ftl_cycle;

	#if (defined CONFIG_EXYNOS4 \|\| defined CONFIG_EXYNOS5)
	clkin = get_i2c_clk();
	#else
	clkin = get_PCLK();
	#endif
	/* FPCLK / FI2C =
	* (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE
	* uTemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2)
	* uTemp1 = (TSCLK_L + TSCLK_H + 2)
	* uTemp2 = TSCLK_L + TSCLK_H
	*/
	t_ftl_cycle = (readl(&hsregs->usi_conf) >> 16) & 0x7;
	utemp0 = (clkin / op_clk) - 8 - 2 * t_ftl_cycle;

	/* CLK_DIV max is 256 */
	for (i = 0; i < 256; i++) {
	utemp1 = utemp0 / (i + 1);
	if ((utemp1 < 512) && (utemp1 > 4)) {
	i2c_bus->clk_cycle = utemp1 - 2;
	i2c_bus->clk_div = i;
	return 0;
	}
	}
	return -EINVAL;
	}

	static void hsi2c_ch_init(struct s3c24x0_i2c_bus *i2c_bus)
	{
	struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
	unsigned int t_sr_release;
	unsigned int n_clkdiv;
	unsigned int t_start_su, t_start_hd;
	unsigned int t_stop_su;
	unsigned int t_data_su, t_data_hd;
	unsigned int t_scl_l, t_scl_h;
	u32 i2c_timing_s1;
	u32 i2c_timing_s2;
	u32 i2c_timing_s3;
	u32 i2c_timing_sla;

	n_clkdiv = i2c_bus->clk_div;
	t_scl_l = i2c_bus->clk_cycle / 2;
	t_scl_h = i2c_bus->clk_cycle / 2;
	t_start_su = t_scl_l;
	t_start_hd = t_scl_l;
	t_stop_su = t_scl_l;
	t_data_su = t_scl_l / 2;
	t_data_hd = t_scl_l / 2;
	t_sr_release = i2c_bus->clk_cycle;

	i2c_timing_s1 = t_start_su << 24 \| t_start_hd << 16 \| t_stop_su << 8;
	i2c_timing_s2 = t_data_su << 24 \| t_scl_l << 8 \| t_scl_h << 0;
	i2c_timing_s3 = n_clkdiv << 16 \| t_sr_release << 0;
	i2c_timing_sla = t_data_hd << 0;

	writel(HSI2C_TRAILING_COUNT, &hsregs->usi_trailing_ctl);

	/* Clear to enable Timeout */
	clrsetbits_le32(&hsregs->usi_timeout, HSI2C_TIMEOUT_EN, 0);

	/* set AUTO mode */
	writel(readl(&hsregs->usi_conf) \| HSI2C_AUTO_MODE, &hsregs->usi_conf);

	/* Enable completion conditions' reporting. */
	writel(HSI2C_INT_I2C_EN, &hsregs->usi_int_en);

	/* Enable FIFOs */
	writel(HSI2C_RXFIFO_EN \| HSI2C_TXFIFO_EN, &hsregs->usi_fifo_ctl);

	/* Currently operating in Fast speed mode. */
	writel(i2c_timing_s1, &hsregs->usi_timing_fs1);
	writel(i2c_timing_s2, &hsregs->usi_timing_fs2);
	writel(i2c_timing_s3, &hsregs->usi_timing_fs3);
	writel(i2c_timing_sla, &hsregs->usi_timing_sla);
	}

	/* SW reset for the high speed bus */
	static void exynos5_i2c_reset(struct s3c24x0_i2c_bus *i2c_bus)
	{
	struct exynos5_hsi2c *i2c = i2c_bus->hsregs;
	u32 i2c_ctl;

	/* Set and clear the bit for reset */
	i2c_ctl = readl(&i2c->usi_ctl);
	i2c_ctl \|= HSI2C_SW_RST;
	writel(i2c_ctl, &i2c->usi_ctl);

	i2c_ctl = readl(&i2c->usi_ctl);
	i2c_ctl &= ~HSI2C_SW_RST;
	writel(i2c_ctl, &i2c->usi_ctl);

	/* Initialize the configure registers */
	hsi2c_ch_init(i2c_bus);
	}

	/*
	* Poll the appropriate bit of the fifo status register until the interface is
	* ready to process the next byte or timeout expires.
	*
	* In addition to the FIFO status register this function also polls the
	* interrupt status register to be able to detect unexpected transaction
	* completion.
	*
	* When FIFO is ready to process the next byte, this function returns I2C_OK.
	* If in course of polling the INT_I2C assertion is detected, the function
	* returns I2C_NOK. If timeout happens before any of the above conditions is
	* met - the function returns I2C_NOK_TOUT;

	* @param i2c: pointer to the appropriate i2c register bank.
	* @param rx_transfer: set to True if the receive transaction is in progress.
	* @return: as described above.
	*/
	static unsigned hsi2c_poll_fifo(struct exynos5_hsi2c *i2c, bool rx_transfer)
	{
	u32 fifo_bit = rx_transfer ? HSI2C_RX_FIFO_EMPTY : HSI2C_TX_FIFO_FULL;
	int i = HSI2C_TIMEOUT_US;

	while (readl(&i2c->usi_fifo_stat) & fifo_bit) {
	if (readl(&i2c->usi_int_stat) & HSI2C_INT_I2C_EN) {
	/*
	* There is a chance that assertion of
	* HSI2C_INT_I2C_EN and deassertion of
	* HSI2C_RX_FIFO_EMPTY happen simultaneously. Let's
	* give FIFO status priority and check it one more
	* time before reporting interrupt. The interrupt will
	* be reported next time this function is called.
	*/
	if (rx_transfer &&
	!(readl(&i2c->usi_fifo_stat) & fifo_bit))
	break;
	return I2C_NOK;
	}
	if (!i--) {
	debug("%s: FIFO polling timeout!\n", __func__);
	return I2C_NOK_TOUT;
	}
	udelay(1);
	}
	return I2C_OK;
	}

	/*
	* Preapre hsi2c transaction, either read or write.
	*
	* Set up transfer as described in section 27.5.1.2 'I2C Channel Auto Mode' of
	* the 5420 UM.
	*
	* @param i2c: pointer to the appropriate i2c register bank.
	* @param chip: slave address on the i2c bus (with read/write bit exlcuded)
	* @param len: number of bytes expected to be sent or received
	* @param rx_transfer: set to true for receive transactions
	* @param: issue_stop: set to true if i2c stop condition should be generated
	* after this transaction.
	* @return: I2C_NOK_TOUT in case the bus remained busy for HSI2C_TIMEOUT_US,
	* I2C_OK otherwise.
	*/
	static int hsi2c_prepare_transaction(struct exynos5_hsi2c *i2c,
	u8 chip,
	u16 len,
	bool rx_transfer,
	bool issue_stop)
	{
	u32 conf;

	conf = len \| HSI2C_MASTER_RUN;

	if (issue_stop)
	conf \|= HSI2C_STOP_AFTER_TRANS;

	/* Clear to enable Timeout */
	writel(readl(&i2c->usi_timeout) & ~HSI2C_TIMEOUT_EN, &i2c->usi_timeout);

	/* Set slave address */
	writel(HSI2C_SLV_ADDR_MAS(chip), &i2c->i2c_addr);

	if (rx_transfer) {
	/* i2c master, read transaction */
	writel((HSI2C_RXCHON \| HSI2C_FUNC_MODE_I2C \| HSI2C_MASTER),
	&i2c->usi_ctl);

	/* read up to len bytes, stop after transaction is finished */
	writel(conf \| HSI2C_READ_WRITE, &i2c->usi_auto_conf);
	} else {
	/* i2c master, write transaction */
	writel((HSI2C_TXCHON \| HSI2C_FUNC_MODE_I2C \| HSI2C_MASTER),
	&i2c->usi_ctl);

	/* write up to len bytes, stop after transaction is finished */
	writel(conf, &i2c->usi_auto_conf);
	}

	/* Reset all pending interrupt status bits we care about, if any */
	writel(HSI2C_INT_I2C_EN, &i2c->usi_int_stat);

	return I2C_OK;
	}

	/*
	* Wait while i2c bus is settling down (mostly stop gets completed).
	*/
	static int hsi2c_wait_while_busy(struct exynos5_hsi2c *i2c)
	{
	int i = HSI2C_TIMEOUT_US;

	while (readl(&i2c->usi_trans_status) & HSI2C_MASTER_BUSY) {
	if (!i--) {
	debug("%s: bus busy\n", __func__);
	return I2C_NOK_TOUT;
	}
	udelay(1);
	}
	return I2C_OK;
	}

	static int hsi2c_write(struct exynos5_hsi2c *i2c,
	unsigned char chip,
	unsigned char addr[],
	unsigned char alen,
	unsigned char data[],
	unsigned short len,
	bool issue_stop)
	{
	int i, rv = 0;

	if (!(len + alen)) {
	/* Writes of zero length not supported in auto mode. */
	debug("%s: zero length writes not supported\n", __func__);
	return I2C_NOK;
	}

	rv = hsi2c_prepare_transaction
	(i2c, chip, len + alen, false, issue_stop);
	if (rv != I2C_OK)
	return rv;

	/* Move address, if any, and the data, if any, into the FIFO. */
	for (i = 0; i < alen; i++) {
	rv = hsi2c_poll_fifo(i2c, false);
	if (rv != I2C_OK) {
	debug("%s: address write failed\n", __func__);
	goto write_error;
	}
	writel(addr[i], &i2c->usi_txdata);
	}

	for (i = 0; i < len; i++) {
	rv = hsi2c_poll_fifo(i2c, false);
	if (rv != I2C_OK) {
	debug("%s: data write failed\n", __func__);
	goto write_error;
	}
	writel(data[i], &i2c->usi_txdata);
	}

	rv = hsi2c_wait_for_trx(i2c);

	write_error:
	if (issue_stop) {
	int tmp_ret = hsi2c_wait_while_busy(i2c);
	if (rv == I2C_OK)
	rv = tmp_ret;
	}

	writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
	return rv;
	}

	static int hsi2c_read(struct exynos5_hsi2c *i2c,
	unsigned char chip,
	unsigned char addr[],
	unsigned char alen,
	unsigned char data[],
	unsigned short len)
	{
	int i, rv, tmp_ret;
	bool drop_data = false;

	if (!len) {
	/* Reads of zero length not supported in auto mode. */
	debug("%s: zero length read adjusted\n", __func__);
	drop_data = true;
	len = 1;
	}

	if (alen) {
	/* Internal register adress needs to be written first. */
	rv = hsi2c_write(i2c, chip, addr, alen, NULL, 0, false);
	if (rv != I2C_OK)
	return rv;
	}

	rv = hsi2c_prepare_transaction(i2c, chip, len, true, true);

	if (rv != I2C_OK)
	return rv;

	for (i = 0; i < len; i++) {
	rv = hsi2c_poll_fifo(i2c, true);
	if (rv != I2C_OK)
	goto read_err;
	if (drop_data)
	continue;
	data[i] = readl(&i2c->usi_rxdata);
	}

	rv = hsi2c_wait_for_trx(i2c);

	read_err:
	tmp_ret = hsi2c_wait_while_busy(i2c);
	if (rv == I2C_OK)
	rv = tmp_ret;

	writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
	return rv;
	}

	static int exynos_hs_i2c_xfer(struct udevice dev, struct i2c_msg msg,
	int nmsgs)
	{
	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
	struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
	int ret;

	for (; nmsgs > 0; nmsgs--, msg++) {
	if (msg->flags & I2C_M_RD) {
	ret = hsi2c_read(hsregs, msg->addr, 0, 0, msg->buf,
	msg->len);
	} else {
	ret = hsi2c_write(hsregs, msg->addr, 0, 0, msg->buf,
	msg->len, true);
	}
	if (ret) {
	exynos5_i2c_reset(i2c_bus);
	return -EREMOTEIO;
	}
	}

	return 0;
	}

	static int s3c24x0_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
	{
	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);

	i2c_bus->clock_frequency = speed;

	if (hsi2c_get_clk_details(i2c_bus))
	return -EFAULT;
	hsi2c_ch_init(i2c_bus);

	return 0;
	}

	static int s3c24x0_i2c_probe(struct udevice *dev, uint chip, uint chip_flags)
	{
	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
	uchar buf[1];
	int ret;

	buf[0] = 0;

	/*
	* What is needed is to send the chip address and verify that the
	* address was <ACK>ed (i.e. there was a chip at that address which
	* drove the data line low).
	*/
	ret = hsi2c_read(i2c_bus->hsregs, chip, 0, 0, buf, 1);

	return ret != I2C_OK;
	}

	static int s3c_i2c_of_to_plat(struct udevice *dev)
	{
	const void *blob = gd->fdt_blob;
	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
	int node;

	node = dev_of_offset(dev);

	i2c_bus->hsregs = dev_read_addr_ptr(dev);

	i2c_bus->id = pinmux_decode_periph_id(blob, node);

	i2c_bus->clock_frequency =
	dev_read_u32_default(dev, "clock-frequency",
	I2C_SPEED_STANDARD_RATE);
	i2c_bus->node = node;
	i2c_bus->bus_num = dev_seq(dev);

	exynos_pinmux_config(i2c_bus->id, PINMUX_FLAG_HS_MODE);

	i2c_bus->active = true;

	return 0;
	}

	static const struct dm_i2c_ops exynos_hs_i2c_ops = {
	.xfer = exynos_hs_i2c_xfer,
	.probe_chip = s3c24x0_i2c_probe,
	.set_bus_speed = s3c24x0_i2c_set_bus_speed,
	};

	static const struct udevice_id exynos_hs_i2c_ids[] = {
	{ .compatible = "samsung,exynos5-hsi2c" },
	{ }
	};

	U_BOOT_DRIVER(hs_i2c) = {
	.name = "i2c_s3c_hs",
	.id = UCLASS_I2C,
	.of_match = exynos_hs_i2c_ids,
	.of_to_plat = s3c_i2c_of_to_plat,
	.priv_auto = sizeof(struct s3c24x0_i2c_bus),
	.ops = &exynos_hs_i2c_ops,
	};