drivers/i2c/s3c24x0_i2c.c - platform/external/u-boot - Gitiles

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

 #include <common.h>
 #include <errno.h>
 #include <dm.h>
 #include <fdtdec.h>
 #if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
 #include <log.h>
 #include <asm/arch/clk.h>
 #include <asm/arch/cpu.h>
 #include <asm/arch/pinmux.h>
 #else
 #include <asm/arch/s3c24x0_cpu.h>
 #endif
 #include <asm/global_data.h>
 #include <asm/io.h>
 #include <i2c.h>
 #include "s3c24x0_i2c.h"

 #ifndef CONFIG_SYS_I2C_S3C24X0_SLAVE
 #define SYS_I2C_S3C24X0_SLAVE_ADDR	0
 #else
 #define SYS_I2C_S3C24X0_SLAVE_ADDR	CONFIG_SYS_I2C_S3C24X0_SLAVE
 #endif

 DECLARE_GLOBAL_DATA_PTR;

 /*
  * Wait til the byte transfer is completed.
  *
  * @param i2c- pointer to the appropriate i2c register bank.
  * @return I2C_OK, if transmission was ACKED
  *         I2C_NACK, if transmission was NACKED
  *         I2C_NOK_TIMEOUT, if transaction did not complete in I2C_TIMEOUT_MS
  */

 static int WaitForXfer(struct s3c24x0_i2c *i2c)
 {
 	ulong start_time = get_timer(0);

 	do {
 		if (readl(&i2c->iiccon) & I2CCON_IRPND)
 			return (readl(&i2c->iicstat) & I2CSTAT_NACK) ?
 				I2C_NACK : I2C_OK;
 	} while (get_timer(start_time) < I2C_TIMEOUT_MS);

 	return I2C_NOK_TOUT;
 }

 static void read_write_byte(struct s3c24x0_i2c *i2c)
 {
 	clrbits_le32(&i2c->iiccon, I2CCON_IRPND);
 }

 static void i2c_ch_init(struct s3c24x0_i2c *i2c, int speed, int slaveadd)
 {
 	ulong freq, pres = 16, div;
 #if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
 	freq = get_i2c_clk();
 #else
 	freq = get_PCLK();
 #endif
 	/* calculate prescaler and divisor values */
 	if ((freq / pres / (16 + 1)) > speed)
 		/* set prescaler to 512 */
 		pres = 512;

 	div = 0;
 	while ((freq / pres / (div + 1)) > speed)
 		div++;

 	/* set prescaler, divisor according to freq, also set ACKGEN, IRQ */
 	writel((div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0), &i2c->iiccon);

 	/* init to SLAVE REVEIVE and set slaveaddr */
 	writel(0, &i2c->iicstat);
 	writel(slaveadd, &i2c->iicadd);
 	/* program Master Transmit (and implicit STOP) */
 	writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->iicstat);
 }

 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;

 	i2c_ch_init(i2c_bus->regs, i2c_bus->clock_frequency,
 		    SYS_I2C_S3C24X0_SLAVE_ADDR);

 	return 0;
 }

 /*
  * cmd_type is 0 for write, 1 for read.
  *
  * addr_len can take any value from 0-255, it is only limited
  * by the char, we could make it larger if needed. If it is
  * 0 we skip the address write cycle.
  */
 static int i2c_transfer(struct s3c24x0_i2c *i2c,
 			unsigned char cmd_type,
 			unsigned char chip,
 			unsigned char addr[],
 			unsigned char addr_len,
 			unsigned char data[],
 			unsigned short data_len)
 {
 	int i = 0, result;
 	ulong start_time = get_timer(0);

 	if (data == 0 || data_len == 0) {
 		/*Don't support data transfer of no length or to address 0 */
 		debug("i2c_transfer: bad call\n");
 		return I2C_NOK;
 	}

 	while (readl(&i2c->iicstat) & I2CSTAT_BSY) {
 		if (get_timer(start_time) > I2C_TIMEOUT_MS)
 			return I2C_NOK_TOUT;
 	}

 	writel(readl(&i2c->iiccon) | I2CCON_ACKGEN, &i2c->iiccon);

 	/* Get the slave chip address going */
 	writel(chip, &i2c->iicds);
 	if ((cmd_type == I2C_WRITE) || (addr && addr_len))
 		writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP,
 		       &i2c->iicstat);
 	else
 		writel(I2C_MODE_MR | I2C_TXRX_ENA | I2C_START_STOP,
 		       &i2c->iicstat);

 	/* Wait for chip address to transmit. */
 	result = WaitForXfer(i2c);
 	if (result != I2C_OK)
 		goto bailout;

 	/* If register address needs to be transmitted - do it now. */
 	if (addr && addr_len) {
 		while ((i < addr_len) && (result == I2C_OK)) {
 			writel(addr[i++], &i2c->iicds);
 			read_write_byte(i2c);
 			result = WaitForXfer(i2c);
 		}
 		i = 0;
 		if (result != I2C_OK)
 			goto bailout;
 	}

 	switch (cmd_type) {
 	case I2C_WRITE:
 		while ((i < data_len) && (result == I2C_OK)) {
 			writel(data[i++], &i2c->iicds);
 			read_write_byte(i2c);
 			result = WaitForXfer(i2c);
 		}
 		break;

 	case I2C_READ:
 		if (addr && addr_len) {
 			/*
 			 * Register address has been sent, now send slave chip
 			 * address again to start the actual read transaction.
 			 */
 			writel(chip, &i2c->iicds);

 			/* Generate a re-START. */
 			writel(I2C_MODE_MR | I2C_TXRX_ENA | I2C_START_STOP,
 				&i2c->iicstat);
 			read_write_byte(i2c);
 			result = WaitForXfer(i2c);

 			if (result != I2C_OK)
 				goto bailout;
 		}

 		while ((i < data_len) && (result == I2C_OK)) {
 			/* disable ACK for final READ */
 			if (i == data_len - 1)
 				writel(readl(&i2c->iiccon)
 				       & ~I2CCON_ACKGEN,
 				       &i2c->iiccon);
 			read_write_byte(i2c);
 			result = WaitForXfer(i2c);
 			data[i++] = readl(&i2c->iicds);
 		}
 		if (result == I2C_NACK)
 			result = I2C_OK; /* Normal terminated read. */
 		break;

 	default:
 		debug("i2c_transfer: bad call\n");
 		result = I2C_NOK;
 		break;
 	}

 bailout:
 	/* Send STOP. */
 	writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat);
 	read_write_byte(i2c);

 	return result;
 }

 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 = i2c_transfer(i2c_bus->regs, I2C_READ, chip << 1, 0, 0, buf, 1);

 	return ret != I2C_OK;
 }

 static int s3c24x0_do_msg(struct s3c24x0_i2c_bus *i2c_bus, struct i2c_msg *msg,
 			  int seq)
 {
 	struct s3c24x0_i2c *i2c = i2c_bus->regs;
 	bool is_read = msg->flags & I2C_M_RD;
 	uint status;
 	uint addr;
 	int ret, i;

 	if (!seq)
 		setbits_le32(&i2c->iiccon, I2CCON_ACKGEN);

 	/* Get the slave chip address going */
 	addr = msg->addr << 1;
 	writel(addr, &i2c->iicds);
 	status = I2C_TXRX_ENA | I2C_START_STOP;
 	if (is_read)
 		status |= I2C_MODE_MR;
 	else
 		status |= I2C_MODE_MT;
 	writel(status, &i2c->iicstat);
 	if (seq)
 		read_write_byte(i2c);

 	/* Wait for chip address to transmit */
 	ret = WaitForXfer(i2c);
 	if (ret)
 		goto err;

 	if (is_read) {
 		for (i = 0; !ret && i < msg->len; i++) {
 			/* disable ACK for final READ */
 			if (i == msg->len - 1)
 				clrbits_le32(&i2c->iiccon, I2CCON_ACKGEN);
 			read_write_byte(i2c);
 			ret = WaitForXfer(i2c);
 			msg->buf[i] = readl(&i2c->iicds);
 		}
 		if (ret == I2C_NACK)
 			ret = I2C_OK; /* Normal terminated read */
 	} else {
 		for (i = 0; !ret && i < msg->len; i++) {
 			writel(msg->buf[i], &i2c->iicds);
 			read_write_byte(i2c);
 			ret = WaitForXfer(i2c);
 		}
 	}

 err:
 	return ret;
 }

 static int s3c24x0_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
 			    int nmsgs)
 {
 	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
 	struct s3c24x0_i2c *i2c = i2c_bus->regs;
 	ulong start_time;
 	int ret, i;

 	start_time = get_timer(0);
 	while (readl(&i2c->iicstat) & I2CSTAT_BSY) {
 		if (get_timer(start_time) > I2C_TIMEOUT_MS) {
 			debug("Timeout\n");
 			return -ETIMEDOUT;
 		}
 	}

 	for (ret = 0, i = 0; !ret && i < nmsgs; i++)
 		ret = s3c24x0_do_msg(i2c_bus, &msg[i], i);

 	/* Send STOP */
 	writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat);
 	read_write_byte(i2c);

 	return ret ? -EREMOTEIO : 0;
 }

 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->regs = 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, 0);

 	i2c_bus->active = true;

 	return 0;
 }

 static const struct dm_i2c_ops s3c_i2c_ops = {
 	.xfer		= s3c24x0_i2c_xfer,
 	.probe_chip	= s3c24x0_i2c_probe,
 	.set_bus_speed	= s3c24x0_i2c_set_bus_speed,
 };

 static const struct udevice_id s3c_i2c_ids[] = {
 	{ .compatible = "samsung,s3c2440-i2c" },
 	{ }
 };

 U_BOOT_DRIVER(i2c_s3c) = {
 	.name	= "i2c_s3c",
 	.id	= UCLASS_I2C,
 	.of_match = s3c_i2c_ids,
 	.of_to_plat = s3c_i2c_of_to_plat,
 	.priv_auto	= sizeof(struct s3c24x0_i2c_bus),
 	.ops	= &s3c_i2c_ops,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* (C) Copyright 2002
	* David Mueller, ELSOFT AG, d.mueller@elsoft.ch
	*/

	#include <common.h>
	#include <errno.h>
	#include <dm.h>
	#include <fdtdec.h>
	#if (defined CONFIG_EXYNOS4 \|\| defined CONFIG_EXYNOS5)
	#include <log.h>
	#include <asm/arch/clk.h>
	#include <asm/arch/cpu.h>
	#include <asm/arch/pinmux.h>
	#else
	#include <asm/arch/s3c24x0_cpu.h>
	#endif
	#include <asm/global_data.h>
	#include <asm/io.h>
	#include <i2c.h>
	#include "s3c24x0_i2c.h"

	#ifndef CONFIG_SYS_I2C_S3C24X0_SLAVE
	#define SYS_I2C_S3C24X0_SLAVE_ADDR 0
	#else
	#define SYS_I2C_S3C24X0_SLAVE_ADDR CONFIG_SYS_I2C_S3C24X0_SLAVE
	#endif

	DECLARE_GLOBAL_DATA_PTR;

	/*
	* Wait til the byte transfer is completed.
	*
	* @param i2c- pointer to the appropriate i2c register bank.
	* @return I2C_OK, if transmission was ACKED
	* I2C_NACK, if transmission was NACKED
	* I2C_NOK_TIMEOUT, if transaction did not complete in I2C_TIMEOUT_MS
	*/

	static int WaitForXfer(struct s3c24x0_i2c *i2c)
	{
	ulong start_time = get_timer(0);

	do {
	if (readl(&i2c->iiccon) & I2CCON_IRPND)
	return (readl(&i2c->iicstat) & I2CSTAT_NACK) ?
	I2C_NACK : I2C_OK;
	} while (get_timer(start_time) < I2C_TIMEOUT_MS);

	return I2C_NOK_TOUT;
	}

	static void read_write_byte(struct s3c24x0_i2c *i2c)
	{
	clrbits_le32(&i2c->iiccon, I2CCON_IRPND);
	}

	static void i2c_ch_init(struct s3c24x0_i2c *i2c, int speed, int slaveadd)
	{
	ulong freq, pres = 16, div;
	#if (defined CONFIG_EXYNOS4 \|\| defined CONFIG_EXYNOS5)
	freq = get_i2c_clk();
	#else
	freq = get_PCLK();
	#endif
	/* calculate prescaler and divisor values */
	if ((freq / pres / (16 + 1)) > speed)
	/* set prescaler to 512 */
	pres = 512;

	div = 0;
	while ((freq / pres / (div + 1)) > speed)
	div++;

	/* set prescaler, divisor according to freq, also set ACKGEN, IRQ */
	writel((div & 0x0F) \| 0xA0 \| ((pres == 512) ? 0x40 : 0), &i2c->iiccon);

	/* init to SLAVE REVEIVE and set slaveaddr */
	writel(0, &i2c->iicstat);
	writel(slaveadd, &i2c->iicadd);
	/* program Master Transmit (and implicit STOP) */
	writel(I2C_MODE_MT \| I2C_TXRX_ENA, &i2c->iicstat);
	}

	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;

	i2c_ch_init(i2c_bus->regs, i2c_bus->clock_frequency,
	SYS_I2C_S3C24X0_SLAVE_ADDR);

	return 0;
	}

	/*
	* cmd_type is 0 for write, 1 for read.
	*
	* addr_len can take any value from 0-255, it is only limited
	* by the char, we could make it larger if needed. If it is
	* 0 we skip the address write cycle.
	*/
	static int i2c_transfer(struct s3c24x0_i2c *i2c,
	unsigned char cmd_type,
	unsigned char chip,
	unsigned char addr[],
	unsigned char addr_len,
	unsigned char data[],
	unsigned short data_len)
	{
	int i = 0, result;
	ulong start_time = get_timer(0);

	if (data == 0 \|\| data_len == 0) {
	/Don't support data transfer of no length or to address 0 /
	debug("i2c_transfer: bad call\n");
	return I2C_NOK;
	}

	while (readl(&i2c->iicstat) & I2CSTAT_BSY) {
	if (get_timer(start_time) > I2C_TIMEOUT_MS)
	return I2C_NOK_TOUT;
	}

	writel(readl(&i2c->iiccon) \| I2CCON_ACKGEN, &i2c->iiccon);

	/* Get the slave chip address going */
	writel(chip, &i2c->iicds);
	if ((cmd_type == I2C_WRITE) \|\| (addr && addr_len))
	writel(I2C_MODE_MT \| I2C_TXRX_ENA \| I2C_START_STOP,
	&i2c->iicstat);
	else
	writel(I2C_MODE_MR \| I2C_TXRX_ENA \| I2C_START_STOP,
	&i2c->iicstat);

	/* Wait for chip address to transmit. */
	result = WaitForXfer(i2c);
	if (result != I2C_OK)
	goto bailout;

	/* If register address needs to be transmitted - do it now. */
	if (addr && addr_len) {
	while ((i < addr_len) && (result == I2C_OK)) {
	writel(addr[i++], &i2c->iicds);
	read_write_byte(i2c);
	result = WaitForXfer(i2c);
	}
	i = 0;
	if (result != I2C_OK)
	goto bailout;
	}

	switch (cmd_type) {
	case I2C_WRITE:
	while ((i < data_len) && (result == I2C_OK)) {
	writel(data[i++], &i2c->iicds);
	read_write_byte(i2c);
	result = WaitForXfer(i2c);
	}
	break;

	case I2C_READ:
	if (addr && addr_len) {
	/*
	* Register address has been sent, now send slave chip
	* address again to start the actual read transaction.
	*/
	writel(chip, &i2c->iicds);

	/* Generate a re-START. */
	writel(I2C_MODE_MR \| I2C_TXRX_ENA \| I2C_START_STOP,
	&i2c->iicstat);
	read_write_byte(i2c);
	result = WaitForXfer(i2c);

	if (result != I2C_OK)
	goto bailout;
	}

	while ((i < data_len) && (result == I2C_OK)) {
	/* disable ACK for final READ */
	if (i == data_len - 1)
	writel(readl(&i2c->iiccon)
	& ~I2CCON_ACKGEN,
	&i2c->iiccon);
	read_write_byte(i2c);
	result = WaitForXfer(i2c);
	data[i++] = readl(&i2c->iicds);
	}
	if (result == I2C_NACK)
	result = I2C_OK; /* Normal terminated read. */
	break;

	default:
	debug("i2c_transfer: bad call\n");
	result = I2C_NOK;
	break;
	}

	bailout:
	/* Send STOP. */
	writel(I2C_MODE_MR \| I2C_TXRX_ENA, &i2c->iicstat);
	read_write_byte(i2c);

	return result;
	}

	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 = i2c_transfer(i2c_bus->regs, I2C_READ, chip << 1, 0, 0, buf, 1);

	return ret != I2C_OK;
	}

	static int s3c24x0_do_msg(struct s3c24x0_i2c_bus i2c_bus, struct i2c_msg msg,
	int seq)
	{
	struct s3c24x0_i2c *i2c = i2c_bus->regs;
	bool is_read = msg->flags & I2C_M_RD;
	uint status;
	uint addr;
	int ret, i;

	if (!seq)
	setbits_le32(&i2c->iiccon, I2CCON_ACKGEN);

	/* Get the slave chip address going */
	addr = msg->addr << 1;
	writel(addr, &i2c->iicds);
	status = I2C_TXRX_ENA \| I2C_START_STOP;
	if (is_read)
	status \|= I2C_MODE_MR;
	else
	status \|= I2C_MODE_MT;
	writel(status, &i2c->iicstat);
	if (seq)
	read_write_byte(i2c);

	/* Wait for chip address to transmit */
	ret = WaitForXfer(i2c);
	if (ret)
	goto err;

	if (is_read) {
	for (i = 0; !ret && i < msg->len; i++) {
	/* disable ACK for final READ */
	if (i == msg->len - 1)
	clrbits_le32(&i2c->iiccon, I2CCON_ACKGEN);
	read_write_byte(i2c);
	ret = WaitForXfer(i2c);
	msg->buf[i] = readl(&i2c->iicds);
	}
	if (ret == I2C_NACK)
	ret = I2C_OK; /* Normal terminated read */
	} else {
	for (i = 0; !ret && i < msg->len; i++) {
	writel(msg->buf[i], &i2c->iicds);
	read_write_byte(i2c);
	ret = WaitForXfer(i2c);
	}
	}

	err:
	return ret;
	}

	static int s3c24x0_i2c_xfer(struct udevice dev, struct i2c_msg msg,
	int nmsgs)
	{
	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
	struct s3c24x0_i2c *i2c = i2c_bus->regs;
	ulong start_time;
	int ret, i;

	start_time = get_timer(0);
	while (readl(&i2c->iicstat) & I2CSTAT_BSY) {
	if (get_timer(start_time) > I2C_TIMEOUT_MS) {
	debug("Timeout\n");
	return -ETIMEDOUT;
	}
	}

	for (ret = 0, i = 0; !ret && i < nmsgs; i++)
	ret = s3c24x0_do_msg(i2c_bus, &msg[i], i);

	/* Send STOP */
	writel(I2C_MODE_MR \| I2C_TXRX_ENA, &i2c->iicstat);
	read_write_byte(i2c);

	return ret ? -EREMOTEIO : 0;
	}

	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->regs = 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, 0);

	i2c_bus->active = true;

	return 0;
	}

	static const struct dm_i2c_ops s3c_i2c_ops = {
	.xfer = s3c24x0_i2c_xfer,
	.probe_chip = s3c24x0_i2c_probe,
	.set_bus_speed = s3c24x0_i2c_set_bus_speed,
	};

	static const struct udevice_id s3c_i2c_ids[] = {
	{ .compatible = "samsung,s3c2440-i2c" },
	{ }
	};

	U_BOOT_DRIVER(i2c_s3c) = {
	.name = "i2c_s3c",
	.id = UCLASS_I2C,
	.of_match = s3c_i2c_ids,
	.of_to_plat = s3c_i2c_of_to_plat,
	.priv_auto = sizeof(struct s3c24x0_i2c_bus),
	.ops = &s3c_i2c_ops,
	};