drivers/i2c/designware_i2c.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2009
  * Vipin Kumar, ST Micoelectronics, vipin.kumar@st.com.
  */

 #include <common.h>
 #include <clk.h>
 #include <dm.h>
 #include <i2c.h>
 #include <log.h>
 #include <malloc.h>
 #include <pci.h>
 #include <reset.h>
 #include <asm/io.h>
 #include "designware_i2c.h"
 #include <dm/device_compat.h>
 #include <linux/err.h>

 #ifdef CONFIG_SYS_I2C_DW_ENABLE_STATUS_UNSUPPORTED
 static int  dw_i2c_enable(struct i2c_regs *i2c_base, bool enable)
 {
 	u32 ena = enable ? IC_ENABLE_0B : 0;

 	writel(ena, &i2c_base->ic_enable);

 	return 0;
 }
 #else
 static int dw_i2c_enable(struct i2c_regs *i2c_base, bool enable)
 {
 	u32 ena = enable ? IC_ENABLE_0B : 0;
 	int timeout = 100;

 	do {
 		writel(ena, &i2c_base->ic_enable);
 		if ((readl(&i2c_base->ic_enable_status) & IC_ENABLE_0B) == ena)
 			return 0;

 		/*
 		 * Wait 10 times the signaling period of the highest I2C
 		 * transfer supported by the driver (for 400KHz this is
 		 * 25us) as described in the DesignWare I2C databook.
 		 */
 		udelay(25);
 	} while (timeout--);
 	printf("timeout in %sabling I2C adapter\n", enable ? "en" : "dis");

 	return -ETIMEDOUT;
 }
 #endif

 /* High and low times in different speed modes (in ns) */
 enum {
 	/* SDA Hold Time */
 	DEFAULT_SDA_HOLD_TIME		= 300,
 };

 /**
  * calc_counts() - Convert a period to a number of IC clk cycles
  *
  * @ic_clk: Input clock in Hz
  * @period_ns: Period to represent, in ns
  * @return calculated count
  */
 static uint calc_counts(uint ic_clk, uint period_ns)
 {
 	return DIV_ROUND_UP(ic_clk / 1000 * period_ns, NANO_TO_KILO);
 }

 /**
  * struct i2c_mode_info - Information about an I2C speed mode
  *
  * Each speed mode has its own characteristics. This struct holds these to aid
  * calculations in dw_i2c_calc_timing().
  *
  * @speed: Speed in Hz
  * @min_scl_lowtime_ns: Minimum value for SCL low period in ns
  * @min_scl_hightime_ns: Minimum value for SCL high period in ns
  * @def_rise_time_ns: Default rise time in ns
  * @def_fall_time_ns: Default fall time in ns
  */
 struct i2c_mode_info {
 	int speed;
 	int min_scl_hightime_ns;
 	int min_scl_lowtime_ns;
 	int def_rise_time_ns;
 	int def_fall_time_ns;
 };

 static const struct i2c_mode_info info_for_mode[] = {
 	[IC_SPEED_MODE_STANDARD] = {
 		I2C_SPEED_STANDARD_RATE,
 		MIN_SS_SCL_HIGHTIME,
 		MIN_SS_SCL_LOWTIME,
 		1000,
 		300,
 	},
 	[IC_SPEED_MODE_FAST] = {
 		I2C_SPEED_FAST_RATE,
 		MIN_FS_SCL_HIGHTIME,
 		MIN_FS_SCL_LOWTIME,
 		300,
 		300,
 	},
 	[IC_SPEED_MODE_FAST_PLUS] = {
 		I2C_SPEED_FAST_PLUS_RATE,
 		MIN_FP_SCL_HIGHTIME,
 		MIN_FP_SCL_LOWTIME,
 		260,
 		500,
 	},
 	[IC_SPEED_MODE_HIGH] = {
 		I2C_SPEED_HIGH_RATE,
 		MIN_HS_SCL_HIGHTIME,
 		MIN_HS_SCL_LOWTIME,
 		120,
 		120,
 	},
 };

 /**
  * dw_i2c_calc_timing() - Calculate the timings to use for a bus
  *
  * @priv: Bus private information (NULL if not using driver model)
  * @mode: Speed mode to use
  * @ic_clk: IC clock speed in Hz
  * @spk_cnt: Spike-suppression count
  * @config: Returns value to use
  * @return 0 if OK, -EINVAL if the calculation failed due to invalid data
  */
 static int dw_i2c_calc_timing(struct dw_i2c *priv, enum i2c_speed_mode mode,
 			      int ic_clk, int spk_cnt,
 			      struct dw_i2c_speed_config *config)
 {
 	int fall_cnt, rise_cnt, min_tlow_cnt, min_thigh_cnt;
 	int hcnt, lcnt, period_cnt, diff, tot;
 	int sda_hold_time_ns, scl_rise_time_ns, scl_fall_time_ns;
 	const struct i2c_mode_info *info;

 	/*
 	 * Find the period, rise, fall, min tlow, and min thigh in terms of
 	 * counts of the IC clock
 	 */
 	info = &info_for_mode[mode];
 	period_cnt = ic_clk / info->speed;
 	scl_rise_time_ns = priv && priv->scl_rise_time_ns ?
 		 priv->scl_rise_time_ns : info->def_rise_time_ns;
 	scl_fall_time_ns = priv && priv->scl_fall_time_ns ?
 		 priv->scl_fall_time_ns : info->def_fall_time_ns;
 	rise_cnt = calc_counts(ic_clk, scl_rise_time_ns);
 	fall_cnt = calc_counts(ic_clk, scl_fall_time_ns);
 	min_tlow_cnt = calc_counts(ic_clk, info->min_scl_lowtime_ns);
 	min_thigh_cnt = calc_counts(ic_clk, info->min_scl_hightime_ns);

 	debug("dw_i2c: period %d rise %d fall %d tlow %d thigh %d spk %d\n",
 	      period_cnt, rise_cnt, fall_cnt, min_tlow_cnt, min_thigh_cnt,
 	      spk_cnt);

 	/*
 	 * Back-solve for hcnt and lcnt according to the following equations:
 	 * SCL_High_time = [(HCNT + IC_*_SPKLEN + 7) * ic_clk] + SCL_Fall_time
 	 * SCL_Low_time = [(LCNT + 1) * ic_clk] - SCL_Fall_time + SCL_Rise_time
 	 */
 	hcnt = min_thigh_cnt - fall_cnt - 7 - spk_cnt;
 	lcnt = min_tlow_cnt - rise_cnt + fall_cnt - 1;

 	if (hcnt < 0 || lcnt < 0) {
 		debug("dw_i2c: bad counts. hcnt = %d lcnt = %d\n", hcnt, lcnt);
 		return -EINVAL;
 	}

 	/*
 	 * Now add things back up to ensure the period is hit. If it is off,
 	 * split the difference and bias to lcnt for remainder
 	 */
 	tot = hcnt + lcnt + 7 + spk_cnt + rise_cnt + 1;

 	if (tot < period_cnt) {
 		diff = (period_cnt - tot) / 2;
 		hcnt += diff;
 		lcnt += diff;
 		tot = hcnt + lcnt + 7 + spk_cnt + rise_cnt + 1;
 		lcnt += period_cnt - tot;
 	}

 	config->scl_lcnt = lcnt;
 	config->scl_hcnt = hcnt;

 	/* Use internal default unless other value is specified */
 	sda_hold_time_ns = priv && priv->sda_hold_time_ns ?
 		 priv->sda_hold_time_ns : DEFAULT_SDA_HOLD_TIME;
 	config->sda_hold = calc_counts(ic_clk, sda_hold_time_ns);

 	debug("dw_i2c: hcnt = %d lcnt = %d sda hold = %d\n", hcnt, lcnt,
 	      config->sda_hold);

 	return 0;
 }

 static int calc_bus_speed(struct dw_i2c *priv, int speed, ulong bus_clk,
 			  struct dw_i2c_speed_config *config)
 {
 	const struct dw_scl_sda_cfg *scl_sda_cfg = NULL;
 	struct i2c_regs *regs = priv->regs;
 	enum i2c_speed_mode i2c_spd;
 	u32 comp_param1;
 	int spk_cnt;
 	int ret;

 	comp_param1 = readl(&regs->comp_param1);

 	if (priv)
 		scl_sda_cfg = priv->scl_sda_cfg;
 	/* Allow high speed if there is no config, or the config allows it */
 	if (speed >= I2C_SPEED_HIGH_RATE)
 		i2c_spd = IC_SPEED_MODE_HIGH;
 	else if (speed >= I2C_SPEED_FAST_PLUS_RATE)
 		i2c_spd = IC_SPEED_MODE_FAST_PLUS;
 	else if (speed >= I2C_SPEED_FAST_RATE)
 		i2c_spd = IC_SPEED_MODE_FAST;
 	else
 		i2c_spd = IC_SPEED_MODE_STANDARD;

 	/* Check is high speed possible and fall back to fast mode if not */
 	if (i2c_spd == IC_SPEED_MODE_HIGH) {
 		if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK)
 				!= DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH)
 			i2c_spd = IC_SPEED_MODE_FAST;
 	}

 	/* Get the proper spike-suppression count based on target speed */
 	if (!priv || !priv->has_spk_cnt)
 		spk_cnt = 0;
 	else if (i2c_spd >= IC_SPEED_MODE_HIGH)
 		spk_cnt = readl(&regs->hs_spklen);
 	else
 		spk_cnt = readl(&regs->fs_spklen);
 	if (scl_sda_cfg) {
 		config->sda_hold = scl_sda_cfg->sda_hold;
 		if (i2c_spd == IC_SPEED_MODE_STANDARD) {
 			config->scl_hcnt = scl_sda_cfg->ss_hcnt;
 			config->scl_lcnt = scl_sda_cfg->ss_lcnt;
 		} else if (i2c_spd == IC_SPEED_MODE_HIGH) {
 			config->scl_hcnt = scl_sda_cfg->hs_hcnt;
 			config->scl_lcnt = scl_sda_cfg->hs_lcnt;
 		} else {
 			config->scl_hcnt = scl_sda_cfg->fs_hcnt;
 			config->scl_lcnt = scl_sda_cfg->fs_lcnt;
 		}
 	} else {
 		ret = dw_i2c_calc_timing(priv, i2c_spd, bus_clk, spk_cnt,
 					 config);
 		if (ret)
 			return log_msg_ret("gen_confg", ret);
 	}
 	config->speed_mode = i2c_spd;

 	return 0;
 }

 /*
  * _dw_i2c_set_bus_speed - Set the i2c speed
  * @speed:	required i2c speed
  *
  * Set the i2c speed.
  */
 static int _dw_i2c_set_bus_speed(struct dw_i2c *priv, struct i2c_regs *i2c_base,
 				 unsigned int speed, unsigned int bus_clk)
 {
 	struct dw_i2c_speed_config config;
 	unsigned int cntl;
 	unsigned int ena;
 	int ret;

 	ret = calc_bus_speed(priv, speed, bus_clk, &config);
 	if (ret)
 		return ret;

 	/* Get enable setting for restore later */
 	ena = readl(&i2c_base->ic_enable) & IC_ENABLE_0B;

 	/* to set speed cltr must be disabled */
 	dw_i2c_enable(i2c_base, false);

 	cntl = (readl(&i2c_base->ic_con) & (~IC_CON_SPD_MSK));

 	switch (config.speed_mode) {
 	case IC_SPEED_MODE_HIGH:
 		cntl |= IC_CON_SPD_HS;
 		writel(config.scl_hcnt, &i2c_base->ic_hs_scl_hcnt);
 		writel(config.scl_lcnt, &i2c_base->ic_hs_scl_lcnt);
 		break;
 	case IC_SPEED_MODE_STANDARD:
 		cntl |= IC_CON_SPD_SS;
 		writel(config.scl_hcnt, &i2c_base->ic_ss_scl_hcnt);
 		writel(config.scl_lcnt, &i2c_base->ic_ss_scl_lcnt);
 		break;
 	case IC_SPEED_MODE_FAST_PLUS:
 	case IC_SPEED_MODE_FAST:
 	default:
 		cntl |= IC_CON_SPD_FS;
 		writel(config.scl_hcnt, &i2c_base->ic_fs_scl_hcnt);
 		writel(config.scl_lcnt, &i2c_base->ic_fs_scl_lcnt);
 		break;
 	}

 	writel(cntl, &i2c_base->ic_con);

 	/* Configure SDA Hold Time if required */
 	if (config.sda_hold)
 		writel(config.sda_hold, &i2c_base->ic_sda_hold);

 	/* Restore back i2c now speed set */
 	if (ena == IC_ENABLE_0B)
 		dw_i2c_enable(i2c_base, true);

 	return 0;
 }

 /*
  * i2c_setaddress - Sets the target slave address
  * @i2c_addr:	target i2c address
  *
  * Sets the target slave address.
  */
 static void i2c_setaddress(struct i2c_regs *i2c_base, unsigned int i2c_addr)
 {
 	/* Disable i2c */
 	dw_i2c_enable(i2c_base, false);

 	writel(i2c_addr, &i2c_base->ic_tar);

 	/* Enable i2c */
 	dw_i2c_enable(i2c_base, true);
 }

 /*
  * i2c_flush_rxfifo - Flushes the i2c RX FIFO
  *
  * Flushes the i2c RX FIFO
  */
 static void i2c_flush_rxfifo(struct i2c_regs *i2c_base)
 {
 	while (readl(&i2c_base->ic_status) & IC_STATUS_RFNE)
 		readl(&i2c_base->ic_cmd_data);
 }

 /*
  * i2c_wait_for_bb - Waits for bus busy
  *
  * Waits for bus busy
  */
 static int i2c_wait_for_bb(struct i2c_regs *i2c_base)
 {
 	unsigned long start_time_bb = get_timer(0);

 	while ((readl(&i2c_base->ic_status) & IC_STATUS_MA) ||
 	       !(readl(&i2c_base->ic_status) & IC_STATUS_TFE)) {

 		/* Evaluate timeout */
 		if (get_timer(start_time_bb) > (unsigned long)(I2C_BYTE_TO_BB))
 			return 1;
 	}

 	return 0;
 }

 static int i2c_xfer_init(struct i2c_regs *i2c_base, uchar chip, uint addr,
 			 int alen)
 {
 	if (i2c_wait_for_bb(i2c_base))
 		return 1;

 	i2c_setaddress(i2c_base, chip);
 	while (alen) {
 		alen--;
 		/* high byte address going out first */
 		writel((addr >> (alen * 8)) & 0xff,
 		       &i2c_base->ic_cmd_data);
 	}
 	return 0;
 }

 static int i2c_xfer_finish(struct i2c_regs *i2c_base)
 {
 	ulong start_stop_det = get_timer(0);

 	while (1) {
 		if ((readl(&i2c_base->ic_raw_intr_stat) & IC_STOP_DET)) {
 			readl(&i2c_base->ic_clr_stop_det);
 			break;
 		} else if (get_timer(start_stop_det) > I2C_STOPDET_TO) {
 			break;
 		}
 	}

 	if (i2c_wait_for_bb(i2c_base)) {
 		printf("Timed out waiting for bus\n");
 		return 1;
 	}

 	i2c_flush_rxfifo(i2c_base);

 	return 0;
 }

 /*
  * i2c_read - Read from i2c memory
  * @chip:	target i2c address
  * @addr:	address to read from
  * @alen:
  * @buffer:	buffer for read data
  * @len:	no of bytes to be read
  *
  * Read from i2c memory.
  */
 static int __dw_i2c_read(struct i2c_regs *i2c_base, u8 dev, uint addr,
 			 int alen, u8 *buffer, int len)
 {
 	unsigned long start_time_rx;
 	unsigned int active = 0;

 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
 	/*
 	 * EEPROM chips that implement "address overflow" are ones
 	 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
 	 * address and the extra bits end up in the "chip address"
 	 * bit slots. This makes a 24WC08 (1Kbyte) chip look like
 	 * four 256 byte chips.
 	 *
 	 * Note that we consider the length of the address field to
 	 * still be one byte because the extra address bits are
 	 * hidden in the chip address.
 	 */
 	dev |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
 	addr &= ~(CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW << (alen * 8));

 	debug("%s: fix addr_overflow: dev %02x addr %02x\n", __func__, dev,
 	      addr);
 #endif

 	if (i2c_xfer_init(i2c_base, dev, addr, alen))
 		return 1;

 	start_time_rx = get_timer(0);
 	while (len) {
 		if (!active) {
 			/*
 			 * Avoid writing to ic_cmd_data multiple times
 			 * in case this loop spins too quickly and the
 			 * ic_status RFNE bit isn't set after the first
 			 * write. Subsequent writes to ic_cmd_data can
 			 * trigger spurious i2c transfer.
 			 */
 			if (len == 1)
 				writel(IC_CMD | IC_STOP, &i2c_base->ic_cmd_data);
 			else
 				writel(IC_CMD, &i2c_base->ic_cmd_data);
 			active = 1;
 		}

 		if (readl(&i2c_base->ic_status) & IC_STATUS_RFNE) {
 			*buffer++ = (uchar)readl(&i2c_base->ic_cmd_data);
 			len--;
 			start_time_rx = get_timer(0);
 			active = 0;
 		} else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
 			return 1;
 		}
 	}

 	return i2c_xfer_finish(i2c_base);
 }

 /*
  * i2c_write - Write to i2c memory
  * @chip:	target i2c address
  * @addr:	address to read from
  * @alen:
  * @buffer:	buffer for read data
  * @len:	no of bytes to be read
  *
  * Write to i2c memory.
  */
 static int __dw_i2c_write(struct i2c_regs *i2c_base, u8 dev, uint addr,
 			  int alen, u8 *buffer, int len)
 {
 	int nb = len;
 	unsigned long start_time_tx;

 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
 	/*
 	 * EEPROM chips that implement "address overflow" are ones
 	 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
 	 * address and the extra bits end up in the "chip address"
 	 * bit slots. This makes a 24WC08 (1Kbyte) chip look like
 	 * four 256 byte chips.
 	 *
 	 * Note that we consider the length of the address field to
 	 * still be one byte because the extra address bits are
 	 * hidden in the chip address.
 	 */
 	dev |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
 	addr &= ~(CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW << (alen * 8));

 	debug("%s: fix addr_overflow: dev %02x addr %02x\n", __func__, dev,
 	      addr);
 #endif

 	if (i2c_xfer_init(i2c_base, dev, addr, alen))
 		return 1;

 	start_time_tx = get_timer(0);
 	while (len) {
 		if (readl(&i2c_base->ic_status) & IC_STATUS_TFNF) {
 			if (--len == 0) {
 				writel(*buffer | IC_STOP,
 				       &i2c_base->ic_cmd_data);
 			} else {
 				writel(*buffer, &i2c_base->ic_cmd_data);
 			}
 			buffer++;
 			start_time_tx = get_timer(0);

 		} else if (get_timer(start_time_tx) > (nb * I2C_BYTE_TO)) {
 				printf("Timed out. i2c write Failed\n");
 				return 1;
 		}
 	}

 	return i2c_xfer_finish(i2c_base);
 }

 /*
  * __dw_i2c_init - Init function
  * @speed:	required i2c speed
  * @slaveaddr:	slave address for the device
  *
  * Initialization function.
  */
 static int __dw_i2c_init(struct i2c_regs *i2c_base, int speed, int slaveaddr)
 {
 	int ret;

 	/* Disable i2c */
 	ret = dw_i2c_enable(i2c_base, false);
 	if (ret)
 		return ret;

 	writel(IC_CON_SD | IC_CON_RE | IC_CON_SPD_FS | IC_CON_MM,
 	       &i2c_base->ic_con);
 	writel(IC_RX_TL, &i2c_base->ic_rx_tl);
 	writel(IC_TX_TL, &i2c_base->ic_tx_tl);
 	writel(IC_STOP_DET, &i2c_base->ic_intr_mask);
 #ifndef CONFIG_DM_I2C
 	_dw_i2c_set_bus_speed(NULL, i2c_base, speed, IC_CLK);
 	writel(slaveaddr, &i2c_base->ic_sar);
 #endif

 	/* Enable i2c */
 	ret = dw_i2c_enable(i2c_base, true);
 	if (ret)
 		return ret;

 	return 0;
 }

 #ifndef CONFIG_DM_I2C
 /*
  * The legacy I2C functions. These need to get removed once
  * all users of this driver are converted to DM.
  */
 static struct i2c_regs *i2c_get_base(struct i2c_adapter *adap)
 {
 	switch (adap->hwadapnr) {
 #if CONFIG_SYS_I2C_BUS_MAX >= 4
 	case 3:
 		return (struct i2c_regs *)CONFIG_SYS_I2C_BASE3;
 #endif
 #if CONFIG_SYS_I2C_BUS_MAX >= 3
 	case 2:
 		return (struct i2c_regs *)CONFIG_SYS_I2C_BASE2;
 #endif
 #if CONFIG_SYS_I2C_BUS_MAX >= 2
 	case 1:
 		return (struct i2c_regs *)CONFIG_SYS_I2C_BASE1;
 #endif
 	case 0:
 		return (struct i2c_regs *)CONFIG_SYS_I2C_BASE;
 	default:
 		printf("Wrong I2C-adapter number %d\n", adap->hwadapnr);
 	}

 	return NULL;
 }

 static unsigned int dw_i2c_set_bus_speed(struct i2c_adapter *adap,
 					 unsigned int speed)
 {
 	adap->speed = speed;
 	return _dw_i2c_set_bus_speed(NULL, i2c_get_base(adap), speed, IC_CLK);
 }

 static void dw_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
 {
 	__dw_i2c_init(i2c_get_base(adap), speed, slaveaddr);
 }

 static int dw_i2c_read(struct i2c_adapter *adap, u8 dev, uint addr,
 		       int alen, u8 *buffer, int len)
 {
 	return __dw_i2c_read(i2c_get_base(adap), dev, addr, alen, buffer, len);
 }

 static int dw_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr,
 			int alen, u8 *buffer, int len)
 {
 	return __dw_i2c_write(i2c_get_base(adap), dev, addr, alen, buffer, len);
 }

 /* dw_i2c_probe - Probe the i2c chip */
 static int dw_i2c_probe(struct i2c_adapter *adap, u8 dev)
 {
 	struct i2c_regs *i2c_base = i2c_get_base(adap);
 	u32 tmp;
 	int ret;

 	/*
 	 * Try to read the first location of the chip.
 	 */
 	ret = __dw_i2c_read(i2c_base, dev, 0, 1, (uchar *)&tmp, 1);
 	if (ret)
 		dw_i2c_init(adap, adap->speed, adap->slaveaddr);

 	return ret;
 }

 U_BOOT_I2C_ADAP_COMPLETE(dw_0, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
 			 dw_i2c_write, dw_i2c_set_bus_speed,
 			 CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE, 0)

 #if CONFIG_SYS_I2C_BUS_MAX >= 2
 U_BOOT_I2C_ADAP_COMPLETE(dw_1, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
 			 dw_i2c_write, dw_i2c_set_bus_speed,
 			 CONFIG_SYS_I2C_SPEED1, CONFIG_SYS_I2C_SLAVE1, 1)
 #endif

 #if CONFIG_SYS_I2C_BUS_MAX >= 3
 U_BOOT_I2C_ADAP_COMPLETE(dw_2, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
 			 dw_i2c_write, dw_i2c_set_bus_speed,
 			 CONFIG_SYS_I2C_SPEED2, CONFIG_SYS_I2C_SLAVE2, 2)
 #endif

 #if CONFIG_SYS_I2C_BUS_MAX >= 4
 U_BOOT_I2C_ADAP_COMPLETE(dw_3, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
 			 dw_i2c_write, dw_i2c_set_bus_speed,
 			 CONFIG_SYS_I2C_SPEED3, CONFIG_SYS_I2C_SLAVE3, 3)
 #endif

 #else /* CONFIG_DM_I2C */
 /* The DM I2C functions */

 static int designware_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
 			       int nmsgs)
 {
 	struct dw_i2c *i2c = dev_get_priv(bus);
 	int ret;

 	debug("i2c_xfer: %d messages\n", nmsgs);
 	for (; nmsgs > 0; nmsgs--, msg++) {
 		debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
 		if (msg->flags & I2C_M_RD) {
 			ret = __dw_i2c_read(i2c->regs, msg->addr, 0, 0,
 					    msg->buf, msg->len);
 		} else {
 			ret = __dw_i2c_write(i2c->regs, msg->addr, 0, 0,
 					     msg->buf, msg->len);
 		}
 		if (ret) {
 			debug("i2c_write: error sending\n");
 			return -EREMOTEIO;
 		}
 	}

 	return 0;
 }

 static int designware_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
 {
 	struct dw_i2c *i2c = dev_get_priv(bus);
 	ulong rate;

 #if CONFIG_IS_ENABLED(CLK)
 	rate = clk_get_rate(&i2c->clk);
 	if (IS_ERR_VALUE(rate))
 		return -EINVAL;
 #else
 	rate = IC_CLK;
 #endif
 	return _dw_i2c_set_bus_speed(i2c, i2c->regs, speed, rate);
 }

 static int designware_i2c_probe_chip(struct udevice *bus, uint chip_addr,
 				     uint chip_flags)
 {
 	struct dw_i2c *i2c = dev_get_priv(bus);
 	struct i2c_regs *i2c_base = i2c->regs;
 	u32 tmp;
 	int ret;

 	/* Try to read the first location of the chip */
 	ret = __dw_i2c_read(i2c_base, chip_addr, 0, 1, (uchar *)&tmp, 1);
 	if (ret)
 		__dw_i2c_init(i2c_base, 0, 0);

 	return ret;
 }

 int designware_i2c_ofdata_to_platdata(struct udevice *bus)
 {
 	struct dw_i2c *priv = dev_get_priv(bus);
 	int ret;

 	if (!priv->regs)
 		priv->regs = (struct i2c_regs *)devfdt_get_addr_ptr(bus);
 	dev_read_u32(bus, "i2c-scl-rising-time-ns", &priv->scl_rise_time_ns);
 	dev_read_u32(bus, "i2c-scl-falling-time-ns", &priv->scl_fall_time_ns);
 	dev_read_u32(bus, "i2c-sda-hold-time-ns", &priv->sda_hold_time_ns);

 	ret = reset_get_bulk(bus, &priv->resets);
 	if (ret)
 		dev_warn(bus, "Can't get reset: %d\n", ret);
 	else
 		reset_deassert_bulk(&priv->resets);

 #if CONFIG_IS_ENABLED(CLK)
 	ret = clk_get_by_index(bus, 0, &priv->clk);
 	if (ret)
 		return ret;

 	ret = clk_enable(&priv->clk);
 	if (ret && ret != -ENOSYS && ret != -ENOTSUPP) {
 		clk_free(&priv->clk);
 		dev_err(bus, "failed to enable clock\n");
 		return ret;
 	}
 #endif

 	return 0;
 }

 int designware_i2c_probe(struct udevice *bus)
 {
 	struct dw_i2c *priv = dev_get_priv(bus);

 	return __dw_i2c_init(priv->regs, 0, 0);
 }

 int designware_i2c_remove(struct udevice *dev)
 {
 	struct dw_i2c *priv = dev_get_priv(dev);

 #if CONFIG_IS_ENABLED(CLK)
 	clk_disable(&priv->clk);
 	clk_free(&priv->clk);
 #endif

 	return reset_release_bulk(&priv->resets);
 }

 const struct dm_i2c_ops designware_i2c_ops = {
 	.xfer		= designware_i2c_xfer,
 	.probe_chip	= designware_i2c_probe_chip,
 	.set_bus_speed	= designware_i2c_set_bus_speed,
 };

 static const struct udevice_id designware_i2c_ids[] = {
 	{ .compatible = "snps,designware-i2c" },
 	{ }
 };

 U_BOOT_DRIVER(i2c_designware) = {
 	.name	= "i2c_designware",
 	.id	= UCLASS_I2C,
 	.of_match = designware_i2c_ids,
 	.ofdata_to_platdata = designware_i2c_ofdata_to_platdata,
 	.probe	= designware_i2c_probe,
 	.priv_auto_alloc_size = sizeof(struct dw_i2c),
 	.remove = designware_i2c_remove,
 	.flags	= DM_FLAG_OS_PREPARE,
 	.ops	= &designware_i2c_ops,
 };

 #endif /* CONFIG_DM_I2C */
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* (C) Copyright 2009
	* Vipin Kumar, ST Micoelectronics, vipin.kumar@st.com.
	*/

	#include <common.h>
	#include <clk.h>
	#include <dm.h>
	#include <i2c.h>
	#include <log.h>
	#include <malloc.h>
	#include <pci.h>
	#include <reset.h>
	#include <asm/io.h>
	#include "designware_i2c.h"
	#include <dm/device_compat.h>
	#include <linux/err.h>

	#ifdef CONFIG_SYS_I2C_DW_ENABLE_STATUS_UNSUPPORTED
	static int dw_i2c_enable(struct i2c_regs *i2c_base, bool enable)
	{
	u32 ena = enable ? IC_ENABLE_0B : 0;

	writel(ena, &i2c_base->ic_enable);

	return 0;
	}
	#else
	static int dw_i2c_enable(struct i2c_regs *i2c_base, bool enable)
	{
	u32 ena = enable ? IC_ENABLE_0B : 0;
	int timeout = 100;

	do {
	writel(ena, &i2c_base->ic_enable);
	if ((readl(&i2c_base->ic_enable_status) & IC_ENABLE_0B) == ena)
	return 0;

	/*
	* Wait 10 times the signaling period of the highest I2C
	* transfer supported by the driver (for 400KHz this is
	* 25us) as described in the DesignWare I2C databook.
	*/
	udelay(25);
	} while (timeout--);
	printf("timeout in %sabling I2C adapter\n", enable ? "en" : "dis");

	return -ETIMEDOUT;
	}
	#endif

	/* High and low times in different speed modes (in ns) */
	enum {
	/* SDA Hold Time */
	DEFAULT_SDA_HOLD_TIME = 300,
	};

	/**
	* calc_counts() - Convert a period to a number of IC clk cycles
	*
	* @ic_clk: Input clock in Hz
	* @period_ns: Period to represent, in ns
	* @return calculated count
	*/
	static uint calc_counts(uint ic_clk, uint period_ns)
	{
	return DIV_ROUND_UP(ic_clk / 1000 * period_ns, NANO_TO_KILO);
	}

	/**
	* struct i2c_mode_info - Information about an I2C speed mode
	*
	* Each speed mode has its own characteristics. This struct holds these to aid
	* calculations in dw_i2c_calc_timing().
	*
	* @speed: Speed in Hz
	* @min_scl_lowtime_ns: Minimum value for SCL low period in ns
	* @min_scl_hightime_ns: Minimum value for SCL high period in ns
	* @def_rise_time_ns: Default rise time in ns
	* @def_fall_time_ns: Default fall time in ns
	*/
	struct i2c_mode_info {
	int speed;
	int min_scl_hightime_ns;
	int min_scl_lowtime_ns;
	int def_rise_time_ns;
	int def_fall_time_ns;
	};

	static const struct i2c_mode_info info_for_mode[] = {
	[IC_SPEED_MODE_STANDARD] = {
	I2C_SPEED_STANDARD_RATE,
	MIN_SS_SCL_HIGHTIME,
	MIN_SS_SCL_LOWTIME,
	1000,
	300,
	},
	[IC_SPEED_MODE_FAST] = {
	I2C_SPEED_FAST_RATE,
	MIN_FS_SCL_HIGHTIME,
	MIN_FS_SCL_LOWTIME,
	300,
	300,
	},
	[IC_SPEED_MODE_FAST_PLUS] = {
	I2C_SPEED_FAST_PLUS_RATE,
	MIN_FP_SCL_HIGHTIME,
	MIN_FP_SCL_LOWTIME,
	260,
	500,
	},
	[IC_SPEED_MODE_HIGH] = {
	I2C_SPEED_HIGH_RATE,
	MIN_HS_SCL_HIGHTIME,
	MIN_HS_SCL_LOWTIME,
	120,
	120,
	},
	};

	/**
	* dw_i2c_calc_timing() - Calculate the timings to use for a bus
	*
	* @priv: Bus private information (NULL if not using driver model)
	* @mode: Speed mode to use
	* @ic_clk: IC clock speed in Hz
	* @spk_cnt: Spike-suppression count
	* @config: Returns value to use
	* @return 0 if OK, -EINVAL if the calculation failed due to invalid data
	*/
	static int dw_i2c_calc_timing(struct dw_i2c *priv, enum i2c_speed_mode mode,
	int ic_clk, int spk_cnt,
	struct dw_i2c_speed_config *config)
	{
	int fall_cnt, rise_cnt, min_tlow_cnt, min_thigh_cnt;
	int hcnt, lcnt, period_cnt, diff, tot;
	int sda_hold_time_ns, scl_rise_time_ns, scl_fall_time_ns;
	const struct i2c_mode_info *info;

	/*
	* Find the period, rise, fall, min tlow, and min thigh in terms of
	* counts of the IC clock
	*/
	info = &info_for_mode[mode];
	period_cnt = ic_clk / info->speed;
	scl_rise_time_ns = priv && priv->scl_rise_time_ns ?
	priv->scl_rise_time_ns : info->def_rise_time_ns;
	scl_fall_time_ns = priv && priv->scl_fall_time_ns ?
	priv->scl_fall_time_ns : info->def_fall_time_ns;
	rise_cnt = calc_counts(ic_clk, scl_rise_time_ns);
	fall_cnt = calc_counts(ic_clk, scl_fall_time_ns);
	min_tlow_cnt = calc_counts(ic_clk, info->min_scl_lowtime_ns);
	min_thigh_cnt = calc_counts(ic_clk, info->min_scl_hightime_ns);

	debug("dw_i2c: period %d rise %d fall %d tlow %d thigh %d spk %d\n",
	period_cnt, rise_cnt, fall_cnt, min_tlow_cnt, min_thigh_cnt,
	spk_cnt);

	/*
	* Back-solve for hcnt and lcnt according to the following equations:
	* SCL_High_time = [(HCNT + IC__SPKLEN + 7) ic_clk] + SCL_Fall_time
	* SCL_Low_time = [(LCNT + 1) * ic_clk] - SCL_Fall_time + SCL_Rise_time
	*/
	hcnt = min_thigh_cnt - fall_cnt - 7 - spk_cnt;
	lcnt = min_tlow_cnt - rise_cnt + fall_cnt - 1;

	if (hcnt < 0 \|\| lcnt < 0) {
	debug("dw_i2c: bad counts. hcnt = %d lcnt = %d\n", hcnt, lcnt);
	return -EINVAL;
	}

	/*
	* Now add things back up to ensure the period is hit. If it is off,
	* split the difference and bias to lcnt for remainder
	*/
	tot = hcnt + lcnt + 7 + spk_cnt + rise_cnt + 1;

	if (tot < period_cnt) {
	diff = (period_cnt - tot) / 2;
	hcnt += diff;
	lcnt += diff;
	tot = hcnt + lcnt + 7 + spk_cnt + rise_cnt + 1;
	lcnt += period_cnt - tot;
	}

	config->scl_lcnt = lcnt;
	config->scl_hcnt = hcnt;

	/* Use internal default unless other value is specified */
	sda_hold_time_ns = priv && priv->sda_hold_time_ns ?
	priv->sda_hold_time_ns : DEFAULT_SDA_HOLD_TIME;
	config->sda_hold = calc_counts(ic_clk, sda_hold_time_ns);

	debug("dw_i2c: hcnt = %d lcnt = %d sda hold = %d\n", hcnt, lcnt,
	config->sda_hold);

	return 0;
	}

	static int calc_bus_speed(struct dw_i2c *priv, int speed, ulong bus_clk,
	struct dw_i2c_speed_config *config)
	{
	const struct dw_scl_sda_cfg *scl_sda_cfg = NULL;
	struct i2c_regs *regs = priv->regs;
	enum i2c_speed_mode i2c_spd;
	u32 comp_param1;
	int spk_cnt;
	int ret;

	comp_param1 = readl(&regs->comp_param1);

	if (priv)
	scl_sda_cfg = priv->scl_sda_cfg;
	/* Allow high speed if there is no config, or the config allows it */
	if (speed >= I2C_SPEED_HIGH_RATE)
	i2c_spd = IC_SPEED_MODE_HIGH;
	else if (speed >= I2C_SPEED_FAST_PLUS_RATE)
	i2c_spd = IC_SPEED_MODE_FAST_PLUS;
	else if (speed >= I2C_SPEED_FAST_RATE)
	i2c_spd = IC_SPEED_MODE_FAST;
	else
	i2c_spd = IC_SPEED_MODE_STANDARD;

	/* Check is high speed possible and fall back to fast mode if not */
	if (i2c_spd == IC_SPEED_MODE_HIGH) {
	if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK)
	!= DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH)
	i2c_spd = IC_SPEED_MODE_FAST;
	}

	/* Get the proper spike-suppression count based on target speed */
	if (!priv \|\| !priv->has_spk_cnt)
	spk_cnt = 0;
	else if (i2c_spd >= IC_SPEED_MODE_HIGH)
	spk_cnt = readl(&regs->hs_spklen);
	else
	spk_cnt = readl(&regs->fs_spklen);
	if (scl_sda_cfg) {
	config->sda_hold = scl_sda_cfg->sda_hold;
	if (i2c_spd == IC_SPEED_MODE_STANDARD) {
	config->scl_hcnt = scl_sda_cfg->ss_hcnt;
	config->scl_lcnt = scl_sda_cfg->ss_lcnt;
	} else if (i2c_spd == IC_SPEED_MODE_HIGH) {
	config->scl_hcnt = scl_sda_cfg->hs_hcnt;
	config->scl_lcnt = scl_sda_cfg->hs_lcnt;
	} else {
	config->scl_hcnt = scl_sda_cfg->fs_hcnt;
	config->scl_lcnt = scl_sda_cfg->fs_lcnt;
	}
	} else {
	ret = dw_i2c_calc_timing(priv, i2c_spd, bus_clk, spk_cnt,
	config);
	if (ret)
	return log_msg_ret("gen_confg", ret);
	}
	config->speed_mode = i2c_spd;

	return 0;
	}

	/*
	* _dw_i2c_set_bus_speed - Set the i2c speed
	* @speed: required i2c speed
	*
	* Set the i2c speed.
	*/
	static int _dw_i2c_set_bus_speed(struct dw_i2c priv, struct i2c_regs i2c_base,
	unsigned int speed, unsigned int bus_clk)
	{
	struct dw_i2c_speed_config config;
	unsigned int cntl;
	unsigned int ena;
	int ret;

	ret = calc_bus_speed(priv, speed, bus_clk, &config);
	if (ret)
	return ret;

	/* Get enable setting for restore later */
	ena = readl(&i2c_base->ic_enable) & IC_ENABLE_0B;

	/* to set speed cltr must be disabled */
	dw_i2c_enable(i2c_base, false);

	cntl = (readl(&i2c_base->ic_con) & (~IC_CON_SPD_MSK));

	switch (config.speed_mode) {
	case IC_SPEED_MODE_HIGH:
	cntl \|= IC_CON_SPD_HS;
	writel(config.scl_hcnt, &i2c_base->ic_hs_scl_hcnt);
	writel(config.scl_lcnt, &i2c_base->ic_hs_scl_lcnt);
	break;
	case IC_SPEED_MODE_STANDARD:
	cntl \|= IC_CON_SPD_SS;
	writel(config.scl_hcnt, &i2c_base->ic_ss_scl_hcnt);
	writel(config.scl_lcnt, &i2c_base->ic_ss_scl_lcnt);
	break;
	case IC_SPEED_MODE_FAST_PLUS:
	case IC_SPEED_MODE_FAST:
	default:
	cntl \|= IC_CON_SPD_FS;
	writel(config.scl_hcnt, &i2c_base->ic_fs_scl_hcnt);
	writel(config.scl_lcnt, &i2c_base->ic_fs_scl_lcnt);
	break;
	}

	writel(cntl, &i2c_base->ic_con);

	/* Configure SDA Hold Time if required */
	if (config.sda_hold)
	writel(config.sda_hold, &i2c_base->ic_sda_hold);

	/* Restore back i2c now speed set */
	if (ena == IC_ENABLE_0B)
	dw_i2c_enable(i2c_base, true);

	return 0;
	}

	/*
	* i2c_setaddress - Sets the target slave address
	* @i2c_addr: target i2c address
	*
	* Sets the target slave address.
	*/
	static void i2c_setaddress(struct i2c_regs *i2c_base, unsigned int i2c_addr)
	{
	/* Disable i2c */
	dw_i2c_enable(i2c_base, false);

	writel(i2c_addr, &i2c_base->ic_tar);

	/* Enable i2c */
	dw_i2c_enable(i2c_base, true);
	}

	/*
	* i2c_flush_rxfifo - Flushes the i2c RX FIFO
	*
	* Flushes the i2c RX FIFO
	*/
	static void i2c_flush_rxfifo(struct i2c_regs *i2c_base)
	{
	while (readl(&i2c_base->ic_status) & IC_STATUS_RFNE)
	readl(&i2c_base->ic_cmd_data);
	}

	/*
	* i2c_wait_for_bb - Waits for bus busy
	*
	* Waits for bus busy
	*/
	static int i2c_wait_for_bb(struct i2c_regs *i2c_base)
	{
	unsigned long start_time_bb = get_timer(0);

	while ((readl(&i2c_base->ic_status) & IC_STATUS_MA) \|\|
	!(readl(&i2c_base->ic_status) & IC_STATUS_TFE)) {

	/* Evaluate timeout */
	if (get_timer(start_time_bb) > (unsigned long)(I2C_BYTE_TO_BB))
	return 1;
	}

	return 0;
	}

	static int i2c_xfer_init(struct i2c_regs *i2c_base, uchar chip, uint addr,
	int alen)
	{
	if (i2c_wait_for_bb(i2c_base))
	return 1;

	i2c_setaddress(i2c_base, chip);
	while (alen) {
	alen--;
	/* high byte address going out first */
	writel((addr >> (alen * 8)) & 0xff,
	&i2c_base->ic_cmd_data);
	}
	return 0;
	}

	static int i2c_xfer_finish(struct i2c_regs *i2c_base)
	{
	ulong start_stop_det = get_timer(0);

	while (1) {
	if ((readl(&i2c_base->ic_raw_intr_stat) & IC_STOP_DET)) {
	readl(&i2c_base->ic_clr_stop_det);
	break;
	} else if (get_timer(start_stop_det) > I2C_STOPDET_TO) {
	break;
	}
	}

	if (i2c_wait_for_bb(i2c_base)) {
	printf("Timed out waiting for bus\n");
	return 1;
	}

	i2c_flush_rxfifo(i2c_base);

	return 0;
	}

	/*
	* i2c_read - Read from i2c memory
	* @chip: target i2c address
	* @addr: address to read from
	* @alen:
	* @buffer: buffer for read data
	* @len: no of bytes to be read
	*
	* Read from i2c memory.
	*/
	static int __dw_i2c_read(struct i2c_regs *i2c_base, u8 dev, uint addr,
	int alen, u8 *buffer, int len)
	{
	unsigned long start_time_rx;
	unsigned int active = 0;

	#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
	/*
	* EEPROM chips that implement "address overflow" are ones
	* like Catalyst 24WC04/08/16 which has 9/10/11 bits of
	* address and the extra bits end up in the "chip address"
	* bit slots. This makes a 24WC08 (1Kbyte) chip look like
	* four 256 byte chips.
	*
	* Note that we consider the length of the address field to
	* still be one byte because the extra address bits are
	* hidden in the chip address.
	*/
	dev \|= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
	addr &= ~(CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW << (alen * 8));

	debug("%s: fix addr_overflow: dev %02x addr %02x\n", __func__, dev,
	addr);
	#endif

	if (i2c_xfer_init(i2c_base, dev, addr, alen))
	return 1;

	start_time_rx = get_timer(0);
	while (len) {
	if (!active) {
	/*
	* Avoid writing to ic_cmd_data multiple times
	* in case this loop spins too quickly and the
	* ic_status RFNE bit isn't set after the first
	* write. Subsequent writes to ic_cmd_data can
	* trigger spurious i2c transfer.
	*/
	if (len == 1)
	writel(IC_CMD \| IC_STOP, &i2c_base->ic_cmd_data);
	else
	writel(IC_CMD, &i2c_base->ic_cmd_data);
	active = 1;
	}

	if (readl(&i2c_base->ic_status) & IC_STATUS_RFNE) {
	*buffer++ = (uchar)readl(&i2c_base->ic_cmd_data);
	len--;
	start_time_rx = get_timer(0);
	active = 0;
	} else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
	return 1;
	}
	}

	return i2c_xfer_finish(i2c_base);
	}

	/*
	* i2c_write - Write to i2c memory
	* @chip: target i2c address
	* @addr: address to read from
	* @alen:
	* @buffer: buffer for read data
	* @len: no of bytes to be read
	*
	* Write to i2c memory.
	*/
	static int __dw_i2c_write(struct i2c_regs *i2c_base, u8 dev, uint addr,
	int alen, u8 *buffer, int len)
	{
	int nb = len;
	unsigned long start_time_tx;

	#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
	/*
	* EEPROM chips that implement "address overflow" are ones
	* like Catalyst 24WC04/08/16 which has 9/10/11 bits of
	* address and the extra bits end up in the "chip address"
	* bit slots. This makes a 24WC08 (1Kbyte) chip look like
	* four 256 byte chips.
	*
	* Note that we consider the length of the address field to
	* still be one byte because the extra address bits are
	* hidden in the chip address.
	*/
	dev \|= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
	addr &= ~(CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW << (alen * 8));

	debug("%s: fix addr_overflow: dev %02x addr %02x\n", __func__, dev,
	addr);
	#endif

	if (i2c_xfer_init(i2c_base, dev, addr, alen))
	return 1;

	start_time_tx = get_timer(0);
	while (len) {
	if (readl(&i2c_base->ic_status) & IC_STATUS_TFNF) {
	if (--len == 0) {
	writel(*buffer \| IC_STOP,
	&i2c_base->ic_cmd_data);
	} else {
	writel(*buffer, &i2c_base->ic_cmd_data);
	}
	buffer++;
	start_time_tx = get_timer(0);

	} else if (get_timer(start_time_tx) > (nb * I2C_BYTE_TO)) {
	printf("Timed out. i2c write Failed\n");
	return 1;
	}
	}

	return i2c_xfer_finish(i2c_base);
	}

	/*
	* __dw_i2c_init - Init function
	* @speed: required i2c speed
	* @slaveaddr: slave address for the device
	*
	* Initialization function.
	*/
	static int __dw_i2c_init(struct i2c_regs *i2c_base, int speed, int slaveaddr)
	{
	int ret;

	/* Disable i2c */
	ret = dw_i2c_enable(i2c_base, false);
	if (ret)
	return ret;

	writel(IC_CON_SD \| IC_CON_RE \| IC_CON_SPD_FS \| IC_CON_MM,
	&i2c_base->ic_con);
	writel(IC_RX_TL, &i2c_base->ic_rx_tl);
	writel(IC_TX_TL, &i2c_base->ic_tx_tl);
	writel(IC_STOP_DET, &i2c_base->ic_intr_mask);
	#ifndef CONFIG_DM_I2C
	_dw_i2c_set_bus_speed(NULL, i2c_base, speed, IC_CLK);
	writel(slaveaddr, &i2c_base->ic_sar);
	#endif

	/* Enable i2c */
	ret = dw_i2c_enable(i2c_base, true);
	if (ret)
	return ret;

	return 0;
	}

	#ifndef CONFIG_DM_I2C
	/*
	* The legacy I2C functions. These need to get removed once
	* all users of this driver are converted to DM.
	*/
	static struct i2c_regs i2c_get_base(struct i2c_adapter adap)
	{
	switch (adap->hwadapnr) {
	#if CONFIG_SYS_I2C_BUS_MAX >= 4
	case 3:
	return (struct i2c_regs *)CONFIG_SYS_I2C_BASE3;
	#endif
	#if CONFIG_SYS_I2C_BUS_MAX >= 3
	case 2:
	return (struct i2c_regs *)CONFIG_SYS_I2C_BASE2;
	#endif
	#if CONFIG_SYS_I2C_BUS_MAX >= 2
	case 1:
	return (struct i2c_regs *)CONFIG_SYS_I2C_BASE1;
	#endif
	case 0:
	return (struct i2c_regs *)CONFIG_SYS_I2C_BASE;
	default:
	printf("Wrong I2C-adapter number %d\n", adap->hwadapnr);
	}

	return NULL;
	}

	static unsigned int dw_i2c_set_bus_speed(struct i2c_adapter *adap,
	unsigned int speed)
	{
	adap->speed = speed;
	return _dw_i2c_set_bus_speed(NULL, i2c_get_base(adap), speed, IC_CLK);
	}

	static void dw_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
	{
	__dw_i2c_init(i2c_get_base(adap), speed, slaveaddr);
	}

	static int dw_i2c_read(struct i2c_adapter *adap, u8 dev, uint addr,
	int alen, u8 *buffer, int len)
	{
	return __dw_i2c_read(i2c_get_base(adap), dev, addr, alen, buffer, len);
	}

	static int dw_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr,
	int alen, u8 *buffer, int len)
	{
	return __dw_i2c_write(i2c_get_base(adap), dev, addr, alen, buffer, len);
	}

	/* dw_i2c_probe - Probe the i2c chip */
	static int dw_i2c_probe(struct i2c_adapter *adap, u8 dev)
	{
	struct i2c_regs *i2c_base = i2c_get_base(adap);
	u32 tmp;
	int ret;

	/*
	* Try to read the first location of the chip.
	*/
	ret = __dw_i2c_read(i2c_base, dev, 0, 1, (uchar *)&tmp, 1);
	if (ret)
	dw_i2c_init(adap, adap->speed, adap->slaveaddr);

	return ret;
	}

	U_BOOT_I2C_ADAP_COMPLETE(dw_0, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
	dw_i2c_write, dw_i2c_set_bus_speed,
	CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE, 0)

	#if CONFIG_SYS_I2C_BUS_MAX >= 2
	U_BOOT_I2C_ADAP_COMPLETE(dw_1, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
	dw_i2c_write, dw_i2c_set_bus_speed,
	CONFIG_SYS_I2C_SPEED1, CONFIG_SYS_I2C_SLAVE1, 1)
	#endif

	#if CONFIG_SYS_I2C_BUS_MAX >= 3
	U_BOOT_I2C_ADAP_COMPLETE(dw_2, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
	dw_i2c_write, dw_i2c_set_bus_speed,
	CONFIG_SYS_I2C_SPEED2, CONFIG_SYS_I2C_SLAVE2, 2)
	#endif

	#if CONFIG_SYS_I2C_BUS_MAX >= 4
	U_BOOT_I2C_ADAP_COMPLETE(dw_3, dw_i2c_init, dw_i2c_probe, dw_i2c_read,
	dw_i2c_write, dw_i2c_set_bus_speed,
	CONFIG_SYS_I2C_SPEED3, CONFIG_SYS_I2C_SLAVE3, 3)
	#endif

	#else /* CONFIG_DM_I2C */
	/* The DM I2C functions */

	static int designware_i2c_xfer(struct udevice bus, struct i2c_msg msg,
	int nmsgs)
	{
	struct dw_i2c *i2c = dev_get_priv(bus);
	int ret;

	debug("i2c_xfer: %d messages\n", nmsgs);
	for (; nmsgs > 0; nmsgs--, msg++) {
	debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
	if (msg->flags & I2C_M_RD) {
	ret = __dw_i2c_read(i2c->regs, msg->addr, 0, 0,
	msg->buf, msg->len);
	} else {
	ret = __dw_i2c_write(i2c->regs, msg->addr, 0, 0,
	msg->buf, msg->len);
	}
	if (ret) {
	debug("i2c_write: error sending\n");
	return -EREMOTEIO;
	}
	}

	return 0;
	}

	static int designware_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
	{
	struct dw_i2c *i2c = dev_get_priv(bus);
	ulong rate;

	#if CONFIG_IS_ENABLED(CLK)
	rate = clk_get_rate(&i2c->clk);
	if (IS_ERR_VALUE(rate))
	return -EINVAL;
	#else
	rate = IC_CLK;
	#endif
	return _dw_i2c_set_bus_speed(i2c, i2c->regs, speed, rate);
	}

	static int designware_i2c_probe_chip(struct udevice *bus, uint chip_addr,
	uint chip_flags)
	{
	struct dw_i2c *i2c = dev_get_priv(bus);
	struct i2c_regs *i2c_base = i2c->regs;
	u32 tmp;
	int ret;

	/* Try to read the first location of the chip */
	ret = __dw_i2c_read(i2c_base, chip_addr, 0, 1, (uchar *)&tmp, 1);
	if (ret)
	__dw_i2c_init(i2c_base, 0, 0);

	return ret;
	}

	int designware_i2c_ofdata_to_platdata(struct udevice *bus)
	{
	struct dw_i2c *priv = dev_get_priv(bus);
	int ret;

	if (!priv->regs)
	priv->regs = (struct i2c_regs *)devfdt_get_addr_ptr(bus);
	dev_read_u32(bus, "i2c-scl-rising-time-ns", &priv->scl_rise_time_ns);
	dev_read_u32(bus, "i2c-scl-falling-time-ns", &priv->scl_fall_time_ns);
	dev_read_u32(bus, "i2c-sda-hold-time-ns", &priv->sda_hold_time_ns);

	ret = reset_get_bulk(bus, &priv->resets);
	if (ret)
	dev_warn(bus, "Can't get reset: %d\n", ret);
	else
	reset_deassert_bulk(&priv->resets);

	#if CONFIG_IS_ENABLED(CLK)
	ret = clk_get_by_index(bus, 0, &priv->clk);
	if (ret)
	return ret;

	ret = clk_enable(&priv->clk);
	if (ret && ret != -ENOSYS && ret != -ENOTSUPP) {
	clk_free(&priv->clk);
	dev_err(bus, "failed to enable clock\n");
	return ret;
	}
	#endif

	return 0;
	}

	int designware_i2c_probe(struct udevice *bus)
	{
	struct dw_i2c *priv = dev_get_priv(bus);

	return __dw_i2c_init(priv->regs, 0, 0);
	}

	int designware_i2c_remove(struct udevice *dev)
	{
	struct dw_i2c *priv = dev_get_priv(dev);

	#if CONFIG_IS_ENABLED(CLK)
	clk_disable(&priv->clk);
	clk_free(&priv->clk);
	#endif

	return reset_release_bulk(&priv->resets);
	}

	const struct dm_i2c_ops designware_i2c_ops = {
	.xfer = designware_i2c_xfer,
	.probe_chip = designware_i2c_probe_chip,
	.set_bus_speed = designware_i2c_set_bus_speed,
	};

	static const struct udevice_id designware_i2c_ids[] = {
	{ .compatible = "snps,designware-i2c" },
	{ }
	};

	U_BOOT_DRIVER(i2c_designware) = {
	.name = "i2c_designware",
	.id = UCLASS_I2C,
	.of_match = designware_i2c_ids,
	.ofdata_to_platdata = designware_i2c_ofdata_to_platdata,
	.probe = designware_i2c_probe,
	.priv_auto_alloc_size = sizeof(struct dw_i2c),
	.remove = designware_i2c_remove,
	.flags = DM_FLAG_OS_PREPARE,
	.ops = &designware_i2c_ops,
	};

	#endif /* CONFIG_DM_I2C */