drivers/i2c/imx_lpi2c.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright 2016 Freescale Semiconductors, Inc.
  */

 #include <common.h>
 #include <errno.h>
 #include <log.h>
 #include <asm/io.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/imx-regs.h>
 #include <imx_lpi2c.h>
 #include <asm/arch/sys_proto.h>
 #include <dm.h>
 #include <fdtdec.h>
 #include <i2c.h>
 #include <dm/device_compat.h>

 #define LPI2C_FIFO_SIZE 4
 #define LPI2C_NACK_TOUT_MS 1
 #define LPI2C_TIMEOUT_MS 100

 static int bus_i2c_init(struct udevice *bus, int speed);

 /* Weak linked function for overridden by some SoC power function */
 int __weak init_i2c_power(unsigned i2c_num)
 {
 	return 0;
 }

 static int imx_lpci2c_check_busy_bus(const struct imx_lpi2c_reg *regs)
 {
 	lpi2c_status_t result = LPI2C_SUCESS;
 	u32 status;

 	status = readl(&regs->msr);

 	if ((status & LPI2C_MSR_BBF_MASK) && !(status & LPI2C_MSR_MBF_MASK))
 		result = LPI2C_BUSY;

 	return result;
 }

 static int imx_lpci2c_check_clear_error(struct imx_lpi2c_reg *regs)
 {
 	lpi2c_status_t result = LPI2C_SUCESS;
 	u32 val, status;

 	status = readl(&regs->msr);
 	/* errors to check for */
 	status &= LPI2C_MSR_NDF_MASK | LPI2C_MSR_ALF_MASK |
 		LPI2C_MSR_FEF_MASK | LPI2C_MSR_PLTF_MASK;

 	if (status) {
 		if (status & LPI2C_MSR_PLTF_MASK)
 			result = LPI2C_PIN_LOW_TIMEOUT_ERR;
 		else if (status & LPI2C_MSR_ALF_MASK)
 			result = LPI2C_ARB_LOST_ERR;
 		else if (status & LPI2C_MSR_NDF_MASK)
 			result = LPI2C_NAK_ERR;
 		else if (status & LPI2C_MSR_FEF_MASK)
 			result = LPI2C_FIFO_ERR;

 		/* clear status flags */
 		writel(0x7f00, &regs->msr);
 		/* reset fifos */
 		val = readl(&regs->mcr);
 		val |= LPI2C_MCR_RRF_MASK | LPI2C_MCR_RTF_MASK;
 		writel(val, &regs->mcr);
 	}

 	return result;
 }

 static int bus_i2c_wait_for_tx_ready(struct imx_lpi2c_reg *regs)
 {
 	lpi2c_status_t result = LPI2C_SUCESS;
 	u32 txcount = 0;
 	ulong start_time = get_timer(0);

 	do {
 		txcount = LPI2C_MFSR_TXCOUNT(readl(&regs->mfsr));
 		txcount = LPI2C_FIFO_SIZE - txcount;
 		result = imx_lpci2c_check_clear_error(regs);
 		if (result) {
 			debug("i2c: wait for tx ready: result 0x%x\n", result);
 			return result;
 		}
 		if (get_timer(start_time) > LPI2C_TIMEOUT_MS) {
 			debug("i2c: wait for tx ready: timeout\n");
 			return -1;
 		}
 	} while (!txcount);

 	return result;
 }

 static int bus_i2c_send(struct udevice *bus, u8 *txbuf, int len)
 {
 	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
 	struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)(i2c_bus->base);
 	lpi2c_status_t result = LPI2C_SUCESS;

 	/* empty tx */
 	if (!len)
 		return result;

 	while (len--) {
 		result = bus_i2c_wait_for_tx_ready(regs);
 		if (result) {
 			debug("i2c: send wait for tx ready: %d\n", result);
 			return result;
 		}
 		writel(*txbuf++, &regs->mtdr);
 	}

 	return result;
 }

 static int bus_i2c_receive(struct udevice *bus, u8 *rxbuf, int len)
 {
 	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
 	struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)(i2c_bus->base);
 	lpi2c_status_t result = LPI2C_SUCESS;
 	u32 val;
 	ulong start_time = get_timer(0);

 	/* empty read */
 	if (!len)
 		return result;

 	result = bus_i2c_wait_for_tx_ready(regs);
 	if (result) {
 		debug("i2c: receive wait fot tx ready: %d\n", result);
 		return result;
 	}

 	/* clear all status flags */
 	writel(0x7f00, &regs->msr);
 	/* send receive command */
 	val = LPI2C_MTDR_CMD(0x1) | LPI2C_MTDR_DATA(len - 1);
 	writel(val, &regs->mtdr);

 	while (len--) {
 		do {
 			result = imx_lpci2c_check_clear_error(regs);
 			if (result) {
 				debug("i2c: receive check clear error: %d\n",
 				      result);
 				return result;
 			}
 			if (get_timer(start_time) > LPI2C_TIMEOUT_MS) {
 				debug("i2c: receive mrdr: timeout\n");
 				return -1;
 			}
 			val = readl(&regs->mrdr);
 		} while (val & LPI2C_MRDR_RXEMPTY_MASK);
 		*rxbuf++ = LPI2C_MRDR_DATA(val);
 	}

 	return result;
 }

 static int bus_i2c_start(struct udevice *bus, u8 addr, u8 dir)
 {
 	lpi2c_status_t result;
 	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
 	struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)(i2c_bus->base);
 	u32 val;

 	result = imx_lpci2c_check_busy_bus(regs);
 	if (result) {
 		debug("i2c: start check busy bus: 0x%x\n", result);

 		/* Try to init the lpi2c then check the bus busy again */
 		bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
 		result = imx_lpci2c_check_busy_bus(regs);
 		if (result) {
 			printf("i2c: Error check busy bus: 0x%x\n", result);
 			return result;
 		}
 	}
 	/* clear all status flags */
 	writel(0x7f00, &regs->msr);
 	/* turn off auto-stop condition */
 	val = readl(&regs->mcfgr1) & ~LPI2C_MCFGR1_AUTOSTOP_MASK;
 	writel(val, &regs->mcfgr1);
 	/* wait tx fifo ready */
 	result = bus_i2c_wait_for_tx_ready(regs);
 	if (result) {
 		debug("i2c: start wait for tx ready: 0x%x\n", result);
 		return result;
 	}
 	/* issue start command */
 	val = LPI2C_MTDR_CMD(0x4) | (addr << 0x1) | dir;
 	writel(val, &regs->mtdr);

 	return result;
 }

 static int bus_i2c_stop(struct udevice *bus)
 {
 	lpi2c_status_t result;
 	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
 	struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)(i2c_bus->base);
 	u32 status;
 	ulong start_time;

 	result = bus_i2c_wait_for_tx_ready(regs);
 	if (result) {
 		debug("i2c: stop wait for tx ready: 0x%x\n", result);
 		return result;
 	}

 	/* send stop command */
 	writel(LPI2C_MTDR_CMD(0x2), &regs->mtdr);

 	start_time = get_timer(0);
 	while (1) {
 		status = readl(&regs->msr);
 		result = imx_lpci2c_check_clear_error(regs);
 		/* stop detect flag */
 		if (status & LPI2C_MSR_SDF_MASK) {
 			/* clear stop flag */
 			status &= LPI2C_MSR_SDF_MASK;
 			writel(status, &regs->msr);
 			break;
 		}

 		if (get_timer(start_time) > LPI2C_NACK_TOUT_MS) {
 			debug("stop timeout\n");
 			return -ETIMEDOUT;
 		}
 	}

 	return result;
 }

 static int bus_i2c_read(struct udevice *bus, u32 chip, u8 *buf, int len)
 {
 	lpi2c_status_t result;

 	result = bus_i2c_start(bus, chip, 1);
 	if (result)
 		return result;
 	result = bus_i2c_receive(bus, buf, len);
 	if (result)
 		return result;

 	return result;
 }

 static int bus_i2c_write(struct udevice *bus, u32 chip, u8 *buf, int len)
 {
 	lpi2c_status_t result;

 	result = bus_i2c_start(bus, chip, 0);
 	if (result)
 		return result;
 	result = bus_i2c_send(bus, buf, len);
 	if (result)
 		return result;

 	return result;
 }


 u32 __weak imx_get_i2cclk(u32 i2c_num)
 {
 	return 0;
 }

 static int bus_i2c_set_bus_speed(struct udevice *bus, int speed)
 {
 	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
 	struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)(i2c_bus->base);
 	u32 val;
 	u32 preescale = 0, best_pre = 0, clkhi = 0;
 	u32 best_clkhi = 0, abs_error = 0, rate;
 	u32 error = 0xffffffff;
 	u32 clock_rate;
 	bool mode;
 	int i;

 	if (IS_ENABLED(CONFIG_CLK)) {
 		clock_rate = clk_get_rate(&i2c_bus->per_clk);
 		if (clock_rate <= 0) {
 			dev_err(bus, "Failed to get i2c clk: %d\n", clock_rate);
 			return clock_rate;
 		}
 	} else {
 		clock_rate = imx_get_i2cclk(bus->seq);
 		if (!clock_rate)
 			return -EPERM;
 	}

 	mode = (readl(&regs->mcr) & LPI2C_MCR_MEN_MASK) >> LPI2C_MCR_MEN_SHIFT;
 	/* disable master mode */
 	val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
 	writel(val | LPI2C_MCR_MEN(0), &regs->mcr);

 	for (preescale = 1; (preescale <= 128) &&
 		(error != 0); preescale = 2 * preescale) {
 		for (clkhi = 1; clkhi < 32; clkhi++) {
 			if (clkhi == 1)
 				rate = (clock_rate / preescale) / (1 + 3 + 2 + 2 / preescale);
 			else
 				rate = (clock_rate / preescale / (3 * clkhi + 2 + 2 / preescale));

 			abs_error = speed > rate ? speed - rate : rate - speed;

 			if (abs_error < error) {
 				best_pre = preescale;
 				best_clkhi = clkhi;
 				error = abs_error;
 				if (abs_error == 0)
 					break;
 			}
 		}
 	}

 	/* Standard, fast, fast mode plus and ultra-fast transfers. */
 	val = LPI2C_MCCR0_CLKHI(best_clkhi);
 	if (best_clkhi < 2)
 		val |= LPI2C_MCCR0_CLKLO(3) | LPI2C_MCCR0_SETHOLD(2) | LPI2C_MCCR0_DATAVD(1);
 	else
 		val |= LPI2C_MCCR0_CLKLO(2 * best_clkhi) | LPI2C_MCCR0_SETHOLD(best_clkhi) |
 			LPI2C_MCCR0_DATAVD(best_clkhi / 2);
 	writel(val, &regs->mccr0);

 	for (i = 0; i < 8; i++) {
 		if (best_pre == (1 << i)) {
 			best_pre = i;
 			break;
 		}
 	}

 	val = readl(&regs->mcfgr1) & ~LPI2C_MCFGR1_PRESCALE_MASK;
 	writel(val | LPI2C_MCFGR1_PRESCALE(best_pre), &regs->mcfgr1);

 	if (mode) {
 		val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
 		writel(val | LPI2C_MCR_MEN(1), &regs->mcr);
 	}

 	return 0;
 }

 static int bus_i2c_init(struct udevice *bus, int speed)
 {
 	u32 val;
 	int ret;

 	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
 	struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)(i2c_bus->base);
 	/* reset peripheral */
 	writel(LPI2C_MCR_RST_MASK, &regs->mcr);
 	writel(0x0, &regs->mcr);
 	/* Disable Dozen mode */
 	writel(LPI2C_MCR_DBGEN(0) | LPI2C_MCR_DOZEN(1), &regs->mcr);
 	/* host request disable, active high, external pin */
 	val = readl(&regs->mcfgr0);
 	val &= (~(LPI2C_MCFGR0_HREN_MASK | LPI2C_MCFGR0_HRPOL_MASK |
 				LPI2C_MCFGR0_HRSEL_MASK));
 	val |= LPI2C_MCFGR0_HRPOL(0x1);
 	writel(val, &regs->mcfgr0);
 	/* pincfg and ignore ack */
 	val = readl(&regs->mcfgr1);
 	val &= ~(LPI2C_MCFGR1_PINCFG_MASK | LPI2C_MCFGR1_IGNACK_MASK);
 	val |= LPI2C_MCFGR1_PINCFG(0x0); /* 2 pin open drain */
 	val |= LPI2C_MCFGR1_IGNACK(0x0); /* ignore nack */
 	writel(val, &regs->mcfgr1);

 	ret = bus_i2c_set_bus_speed(bus, speed);

 	/* enable lpi2c in master mode */
 	val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
 	writel(val | LPI2C_MCR_MEN(1), &regs->mcr);

 	debug("i2c : controller bus %d, speed %d:\n", bus->seq, speed);

 	return ret;
 }

 static int imx_lpi2c_probe_chip(struct udevice *bus, u32 chip,
 				u32 chip_flags)
 {
 	lpi2c_status_t result;

 	result = bus_i2c_start(bus, chip, 0);
 	if (result) {
 		bus_i2c_stop(bus);
 		bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
 		return result;
 	}

 	result = bus_i2c_stop(bus);
 	if (result)
 		bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);

 	return result;
 }

 static int imx_lpi2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
 {
 	int ret = 0, ret_stop;

 	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 = bus_i2c_read(bus, msg->addr, msg->buf, msg->len);
 		else {
 			ret = bus_i2c_write(bus, msg->addr, msg->buf,
 					    msg->len);
 			if (ret)
 				break;
 		}
 	}

 	if (ret)
 		debug("i2c_write: error sending\n");

 	ret_stop = bus_i2c_stop(bus);
 	if (ret_stop)
 		debug("i2c_xfer: stop bus error\n");

 	ret |= ret_stop;

 	return ret;
 }

 static int imx_lpi2c_set_bus_speed(struct udevice *bus, unsigned int speed)
 {
 	return bus_i2c_set_bus_speed(bus, speed);
 }

 __weak int enable_i2c_clk(unsigned char enable, unsigned int i2c_num)
 {
 	return 0;
 }

 static int imx_lpi2c_probe(struct udevice *bus)
 {
 	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
 	fdt_addr_t addr;
 	int ret;

 	i2c_bus->driver_data = dev_get_driver_data(bus);

 	addr = dev_read_addr(bus);
 	if (addr == FDT_ADDR_T_NONE)
 		return -EINVAL;

 	i2c_bus->base = addr;
 	i2c_bus->index = bus->seq;
 	i2c_bus->bus = bus;

 	/* power up i2c resource */
 	ret = init_i2c_power(bus->seq);
 	if (ret) {
 		debug("init_i2c_power err = %d\n", ret);
 		return ret;
 	}

 	if (IS_ENABLED(CONFIG_CLK)) {
 		ret = clk_get_by_name(bus, "per", &i2c_bus->per_clk);
 		if (ret) {
 			dev_err(bus, "Failed to get per clk\n");
 			return ret;
 		}
 		ret = clk_enable(&i2c_bus->per_clk);
 		if (ret) {
 			dev_err(bus, "Failed to enable per clk\n");
 			return ret;
 		}

 		ret = clk_get_by_name(bus, "ipg", &i2c_bus->ipg_clk);
 		if (ret) {
 			dev_err(bus, "Failed to get ipg clk\n");
 			return ret;
 		}
 		ret = clk_enable(&i2c_bus->ipg_clk);
 		if (ret) {
 			dev_err(bus, "Failed to enable ipg clk\n");
 			return ret;
 		}
 	} else {
 		/* To i.MX7ULP, only i2c4-7 can be handled by A7 core */
 		ret = enable_i2c_clk(1, bus->seq);
 		if (ret < 0)
 			return ret;
 	}

 	ret = bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
 	if (ret < 0)
 		return ret;

 	debug("i2c : controller bus %d at 0x%lx , speed %d: ",
 	      bus->seq, i2c_bus->base,
 	      i2c_bus->speed);

 	return 0;
 }

 static const struct dm_i2c_ops imx_lpi2c_ops = {
 	.xfer		= imx_lpi2c_xfer,
 	.probe_chip	= imx_lpi2c_probe_chip,
 	.set_bus_speed	= imx_lpi2c_set_bus_speed,
 };

 static const struct udevice_id imx_lpi2c_ids[] = {
 	{ .compatible = "fsl,imx7ulp-lpi2c", },
 	{ .compatible = "fsl,imx8qm-lpi2c", },
 	{}
 };

 U_BOOT_DRIVER(imx_lpi2c) = {
 	.name = "imx_lpi2c",
 	.id = UCLASS_I2C,
 	.of_match = imx_lpi2c_ids,
 	.probe = imx_lpi2c_probe,
 	.priv_auto	= sizeof(struct imx_lpi2c_bus),
 	.ops = &imx_lpi2c_ops,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright 2016 Freescale Semiconductors, Inc.
	*/

	#include <common.h>
	#include <errno.h>
	#include <log.h>
	#include <asm/io.h>
	#include <asm/arch/clock.h>
	#include <asm/arch/imx-regs.h>
	#include <imx_lpi2c.h>
	#include <asm/arch/sys_proto.h>
	#include <dm.h>
	#include <fdtdec.h>
	#include <i2c.h>
	#include <dm/device_compat.h>

	#define LPI2C_FIFO_SIZE 4
	#define LPI2C_NACK_TOUT_MS 1
	#define LPI2C_TIMEOUT_MS 100

	static int bus_i2c_init(struct udevice *bus, int speed);

	/* Weak linked function for overridden by some SoC power function */
	int __weak init_i2c_power(unsigned i2c_num)
	{
	return 0;
	}

	static int imx_lpci2c_check_busy_bus(const struct imx_lpi2c_reg *regs)
	{
	lpi2c_status_t result = LPI2C_SUCESS;
	u32 status;

	status = readl(&regs->msr);

	if ((status & LPI2C_MSR_BBF_MASK) && !(status & LPI2C_MSR_MBF_MASK))
	result = LPI2C_BUSY;

	return result;
	}

	static int imx_lpci2c_check_clear_error(struct imx_lpi2c_reg *regs)
	{
	lpi2c_status_t result = LPI2C_SUCESS;
	u32 val, status;

	status = readl(&regs->msr);
	/* errors to check for */
	status &= LPI2C_MSR_NDF_MASK \| LPI2C_MSR_ALF_MASK \|
	LPI2C_MSR_FEF_MASK \| LPI2C_MSR_PLTF_MASK;

	if (status) {
	if (status & LPI2C_MSR_PLTF_MASK)
	result = LPI2C_PIN_LOW_TIMEOUT_ERR;
	else if (status & LPI2C_MSR_ALF_MASK)
	result = LPI2C_ARB_LOST_ERR;
	else if (status & LPI2C_MSR_NDF_MASK)
	result = LPI2C_NAK_ERR;
	else if (status & LPI2C_MSR_FEF_MASK)
	result = LPI2C_FIFO_ERR;

	/* clear status flags */
	writel(0x7f00, &regs->msr);
	/* reset fifos */
	val = readl(&regs->mcr);
	val \|= LPI2C_MCR_RRF_MASK \| LPI2C_MCR_RTF_MASK;
	writel(val, &regs->mcr);
	}

	return result;
	}

	static int bus_i2c_wait_for_tx_ready(struct imx_lpi2c_reg *regs)
	{
	lpi2c_status_t result = LPI2C_SUCESS;
	u32 txcount = 0;
	ulong start_time = get_timer(0);

	do {
	txcount = LPI2C_MFSR_TXCOUNT(readl(&regs->mfsr));
	txcount = LPI2C_FIFO_SIZE - txcount;
	result = imx_lpci2c_check_clear_error(regs);
	if (result) {
	debug("i2c: wait for tx ready: result 0x%x\n", result);
	return result;
	}
	if (get_timer(start_time) > LPI2C_TIMEOUT_MS) {
	debug("i2c: wait for tx ready: timeout\n");
	return -1;
	}
	} while (!txcount);

	return result;
	}

	static int bus_i2c_send(struct udevice bus, u8 txbuf, int len)
	{
	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
	struct imx_lpi2c_reg regs = (struct imx_lpi2c_reg )(i2c_bus->base);
	lpi2c_status_t result = LPI2C_SUCESS;

	/* empty tx */
	if (!len)
	return result;

	while (len--) {
	result = bus_i2c_wait_for_tx_ready(regs);
	if (result) {
	debug("i2c: send wait for tx ready: %d\n", result);
	return result;
	}
	writel(*txbuf++, &regs->mtdr);
	}

	return result;
	}

	static int bus_i2c_receive(struct udevice bus, u8 rxbuf, int len)
	{
	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
	struct imx_lpi2c_reg regs = (struct imx_lpi2c_reg )(i2c_bus->base);
	lpi2c_status_t result = LPI2C_SUCESS;
	u32 val;
	ulong start_time = get_timer(0);

	/* empty read */
	if (!len)
	return result;

	result = bus_i2c_wait_for_tx_ready(regs);
	if (result) {
	debug("i2c: receive wait fot tx ready: %d\n", result);
	return result;
	}

	/* clear all status flags */
	writel(0x7f00, &regs->msr);
	/* send receive command */
	val = LPI2C_MTDR_CMD(0x1) \| LPI2C_MTDR_DATA(len - 1);
	writel(val, &regs->mtdr);

	while (len--) {
	do {
	result = imx_lpci2c_check_clear_error(regs);
	if (result) {
	debug("i2c: receive check clear error: %d\n",
	result);
	return result;
	}
	if (get_timer(start_time) > LPI2C_TIMEOUT_MS) {
	debug("i2c: receive mrdr: timeout\n");
	return -1;
	}
	val = readl(&regs->mrdr);
	} while (val & LPI2C_MRDR_RXEMPTY_MASK);
	*rxbuf++ = LPI2C_MRDR_DATA(val);
	}

	return result;
	}

	static int bus_i2c_start(struct udevice *bus, u8 addr, u8 dir)
	{
	lpi2c_status_t result;
	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
	struct imx_lpi2c_reg regs = (struct imx_lpi2c_reg )(i2c_bus->base);
	u32 val;

	result = imx_lpci2c_check_busy_bus(regs);
	if (result) {
	debug("i2c: start check busy bus: 0x%x\n", result);

	/* Try to init the lpi2c then check the bus busy again */
	bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
	result = imx_lpci2c_check_busy_bus(regs);
	if (result) {
	printf("i2c: Error check busy bus: 0x%x\n", result);
	return result;
	}
	}
	/* clear all status flags */
	writel(0x7f00, &regs->msr);
	/* turn off auto-stop condition */
	val = readl(&regs->mcfgr1) & ~LPI2C_MCFGR1_AUTOSTOP_MASK;
	writel(val, &regs->mcfgr1);
	/* wait tx fifo ready */
	result = bus_i2c_wait_for_tx_ready(regs);
	if (result) {
	debug("i2c: start wait for tx ready: 0x%x\n", result);
	return result;
	}
	/* issue start command */
	val = LPI2C_MTDR_CMD(0x4) \| (addr << 0x1) \| dir;
	writel(val, &regs->mtdr);

	return result;
	}

	static int bus_i2c_stop(struct udevice *bus)
	{
	lpi2c_status_t result;
	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
	struct imx_lpi2c_reg regs = (struct imx_lpi2c_reg )(i2c_bus->base);
	u32 status;
	ulong start_time;

	result = bus_i2c_wait_for_tx_ready(regs);
	if (result) {
	debug("i2c: stop wait for tx ready: 0x%x\n", result);
	return result;
	}

	/* send stop command */
	writel(LPI2C_MTDR_CMD(0x2), &regs->mtdr);

	start_time = get_timer(0);
	while (1) {
	status = readl(&regs->msr);
	result = imx_lpci2c_check_clear_error(regs);
	/* stop detect flag */
	if (status & LPI2C_MSR_SDF_MASK) {
	/* clear stop flag */
	status &= LPI2C_MSR_SDF_MASK;
	writel(status, &regs->msr);
	break;
	}

	if (get_timer(start_time) > LPI2C_NACK_TOUT_MS) {
	debug("stop timeout\n");
	return -ETIMEDOUT;
	}
	}

	return result;
	}

	static int bus_i2c_read(struct udevice bus, u32 chip, u8 buf, int len)
	{
	lpi2c_status_t result;

	result = bus_i2c_start(bus, chip, 1);
	if (result)
	return result;
	result = bus_i2c_receive(bus, buf, len);
	if (result)
	return result;

	return result;
	}

	static int bus_i2c_write(struct udevice bus, u32 chip, u8 buf, int len)
	{
	lpi2c_status_t result;

	result = bus_i2c_start(bus, chip, 0);
	if (result)
	return result;
	result = bus_i2c_send(bus, buf, len);
	if (result)
	return result;

	return result;
	}


	u32 __weak imx_get_i2cclk(u32 i2c_num)
	{
	return 0;
	}

	static int bus_i2c_set_bus_speed(struct udevice *bus, int speed)
	{
	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
	struct imx_lpi2c_reg regs = (struct imx_lpi2c_reg )(i2c_bus->base);
	u32 val;
	u32 preescale = 0, best_pre = 0, clkhi = 0;
	u32 best_clkhi = 0, abs_error = 0, rate;
	u32 error = 0xffffffff;
	u32 clock_rate;
	bool mode;
	int i;

	if (IS_ENABLED(CONFIG_CLK)) {
	clock_rate = clk_get_rate(&i2c_bus->per_clk);
	if (clock_rate <= 0) {
	dev_err(bus, "Failed to get i2c clk: %d\n", clock_rate);
	return clock_rate;
	}
	} else {
	clock_rate = imx_get_i2cclk(bus->seq);
	if (!clock_rate)
	return -EPERM;
	}

	mode = (readl(&regs->mcr) & LPI2C_MCR_MEN_MASK) >> LPI2C_MCR_MEN_SHIFT;
	/* disable master mode */
	val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
	writel(val \| LPI2C_MCR_MEN(0), &regs->mcr);

	for (preescale = 1; (preescale <= 128) &&
	(error != 0); preescale = 2 * preescale) {
	for (clkhi = 1; clkhi < 32; clkhi++) {
	if (clkhi == 1)
	rate = (clock_rate / preescale) / (1 + 3 + 2 + 2 / preescale);
	else
	rate = (clock_rate / preescale / (3 * clkhi + 2 + 2 / preescale));

	abs_error = speed > rate ? speed - rate : rate - speed;

	if (abs_error < error) {
	best_pre = preescale;
	best_clkhi = clkhi;
	error = abs_error;
	if (abs_error == 0)
	break;
	}
	}
	}

	/* Standard, fast, fast mode plus and ultra-fast transfers. */
	val = LPI2C_MCCR0_CLKHI(best_clkhi);
	if (best_clkhi < 2)
	val \|= LPI2C_MCCR0_CLKLO(3) \| LPI2C_MCCR0_SETHOLD(2) \| LPI2C_MCCR0_DATAVD(1);
	else
	val \|= LPI2C_MCCR0_CLKLO(2 * best_clkhi) \| LPI2C_MCCR0_SETHOLD(best_clkhi) \|
	LPI2C_MCCR0_DATAVD(best_clkhi / 2);
	writel(val, &regs->mccr0);

	for (i = 0; i < 8; i++) {
	if (best_pre == (1 << i)) {
	best_pre = i;
	break;
	}
	}

	val = readl(&regs->mcfgr1) & ~LPI2C_MCFGR1_PRESCALE_MASK;
	writel(val \| LPI2C_MCFGR1_PRESCALE(best_pre), &regs->mcfgr1);

	if (mode) {
	val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
	writel(val \| LPI2C_MCR_MEN(1), &regs->mcr);
	}

	return 0;
	}

	static int bus_i2c_init(struct udevice *bus, int speed)
	{
	u32 val;
	int ret;

	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
	struct imx_lpi2c_reg regs = (struct imx_lpi2c_reg )(i2c_bus->base);
	/* reset peripheral */
	writel(LPI2C_MCR_RST_MASK, &regs->mcr);
	writel(0x0, &regs->mcr);
	/* Disable Dozen mode */
	writel(LPI2C_MCR_DBGEN(0) \| LPI2C_MCR_DOZEN(1), &regs->mcr);
	/* host request disable, active high, external pin */
	val = readl(&regs->mcfgr0);
	val &= (~(LPI2C_MCFGR0_HREN_MASK \| LPI2C_MCFGR0_HRPOL_MASK \|
	LPI2C_MCFGR0_HRSEL_MASK));
	val \|= LPI2C_MCFGR0_HRPOL(0x1);
	writel(val, &regs->mcfgr0);
	/* pincfg and ignore ack */
	val = readl(&regs->mcfgr1);
	val &= ~(LPI2C_MCFGR1_PINCFG_MASK \| LPI2C_MCFGR1_IGNACK_MASK);
	val \|= LPI2C_MCFGR1_PINCFG(0x0); /* 2 pin open drain */
	val \|= LPI2C_MCFGR1_IGNACK(0x0); /* ignore nack */
	writel(val, &regs->mcfgr1);

	ret = bus_i2c_set_bus_speed(bus, speed);

	/* enable lpi2c in master mode */
	val = readl(&regs->mcr) & ~LPI2C_MCR_MEN_MASK;
	writel(val \| LPI2C_MCR_MEN(1), &regs->mcr);

	debug("i2c : controller bus %d, speed %d:\n", bus->seq, speed);

	return ret;
	}

	static int imx_lpi2c_probe_chip(struct udevice *bus, u32 chip,
	u32 chip_flags)
	{
	lpi2c_status_t result;

	result = bus_i2c_start(bus, chip, 0);
	if (result) {
	bus_i2c_stop(bus);
	bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
	return result;
	}

	result = bus_i2c_stop(bus);
	if (result)
	bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);

	return result;
	}

	static int imx_lpi2c_xfer(struct udevice bus, struct i2c_msg msg, int nmsgs)
	{
	int ret = 0, ret_stop;

	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 = bus_i2c_read(bus, msg->addr, msg->buf, msg->len);
	else {
	ret = bus_i2c_write(bus, msg->addr, msg->buf,
	msg->len);
	if (ret)
	break;
	}
	}

	if (ret)
	debug("i2c_write: error sending\n");

	ret_stop = bus_i2c_stop(bus);
	if (ret_stop)
	debug("i2c_xfer: stop bus error\n");

	ret \|= ret_stop;

	return ret;
	}

	static int imx_lpi2c_set_bus_speed(struct udevice *bus, unsigned int speed)
	{
	return bus_i2c_set_bus_speed(bus, speed);
	}

	__weak int enable_i2c_clk(unsigned char enable, unsigned int i2c_num)
	{
	return 0;
	}

	static int imx_lpi2c_probe(struct udevice *bus)
	{
	struct imx_lpi2c_bus *i2c_bus = dev_get_priv(bus);
	fdt_addr_t addr;
	int ret;

	i2c_bus->driver_data = dev_get_driver_data(bus);

	addr = dev_read_addr(bus);
	if (addr == FDT_ADDR_T_NONE)
	return -EINVAL;

	i2c_bus->base = addr;
	i2c_bus->index = bus->seq;
	i2c_bus->bus = bus;

	/* power up i2c resource */
	ret = init_i2c_power(bus->seq);
	if (ret) {
	debug("init_i2c_power err = %d\n", ret);
	return ret;
	}

	if (IS_ENABLED(CONFIG_CLK)) {
	ret = clk_get_by_name(bus, "per", &i2c_bus->per_clk);
	if (ret) {
	dev_err(bus, "Failed to get per clk\n");
	return ret;
	}
	ret = clk_enable(&i2c_bus->per_clk);
	if (ret) {
	dev_err(bus, "Failed to enable per clk\n");
	return ret;
	}

	ret = clk_get_by_name(bus, "ipg", &i2c_bus->ipg_clk);
	if (ret) {
	dev_err(bus, "Failed to get ipg clk\n");
	return ret;
	}
	ret = clk_enable(&i2c_bus->ipg_clk);
	if (ret) {
	dev_err(bus, "Failed to enable ipg clk\n");
	return ret;
	}
	} else {
	/* To i.MX7ULP, only i2c4-7 can be handled by A7 core */
	ret = enable_i2c_clk(1, bus->seq);
	if (ret < 0)
	return ret;
	}

	ret = bus_i2c_init(bus, I2C_SPEED_STANDARD_RATE);
	if (ret < 0)
	return ret;

	debug("i2c : controller bus %d at 0x%lx , speed %d: ",
	bus->seq, i2c_bus->base,
	i2c_bus->speed);

	return 0;
	}

	static const struct dm_i2c_ops imx_lpi2c_ops = {
	.xfer = imx_lpi2c_xfer,
	.probe_chip = imx_lpi2c_probe_chip,
	.set_bus_speed = imx_lpi2c_set_bus_speed,
	};

	static const struct udevice_id imx_lpi2c_ids[] = {
	{ .compatible = "fsl,imx7ulp-lpi2c", },
	{ .compatible = "fsl,imx8qm-lpi2c", },
	{}
	};

	U_BOOT_DRIVER(imx_lpi2c) = {
	.name = "imx_lpi2c",
	.id = UCLASS_I2C,
	.of_match = imx_lpi2c_ids,
	.probe = imx_lpi2c_probe,
	.priv_auto = sizeof(struct imx_lpi2c_bus),
	.ops = &imx_lpi2c_ops,
	};