path: root/common/i2c.c

/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/* I2C cross-platform code for Chrome EC */

#include "battery.h"
#include "clock.h"
#include "charge_state.h"
#include "console.h"
#include "host_command.h"
#include "gpio.h"
#include "i2c.h"
#include "system.h"
#include "task.h"
#include "util.h"
#include "watchdog.h"

/* Delay for bitbanging i2c corresponds roughly to 100kHz. */
#define I2C_BITBANG_DELAY_US	5

/* Number of attempts to unwedge each pin. */
#define UNWEDGE_SCL_ATTEMPTS  10
#define UNWEDGE_SDA_ATTEMPTS  3

#define CPUTS(outstr) cputs(CC_I2C, outstr)
#define CPRINTS(format, args...) cprints(CC_I2C, format, ## args)

/* Only chips with multi-port controllers will define I2C_CONTROLER_COUNT */
#ifndef I2C_CONTROLLER_COUNT
#define I2C_CONTROLLER_COUNT I2C_PORT_COUNT
#endif

static struct mutex port_mutex[I2C_CONTROLLER_COUNT];
static uint32_t i2c_port_active_count;
static uint8_t port_protected[I2C_CONTROLLER_COUNT];

const struct i2c_port_t *get_i2c_port(int port)
{
	int i;

	/* Find the matching port in i2c_ports[] table. */
	for (i = 0; i < i2c_ports_used; i++) {
		if (i2c_ports[i].port == port)
			return &i2c_ports[i];
	}

	return NULL;
}

int i2c_xfer(int port, int slave_addr, const uint8_t *out, int out_size,
	     uint8_t *in, int in_size, int flags)
{
	int i;
	int ret = EC_SUCCESS;

	for (i = 0; i <= CONFIG_I2C_NACK_RETRY_COUNT; i++) {
		ret = chip_i2c_xfer(port, slave_addr, out, out_size, in,
			in_size, flags);
		if (ret != EC_ERROR_BUSY)
			break;
	}
	return ret;
}

void i2c_lock(int port, int lock)
{
#ifdef CONFIG_I2C_MULTI_PORT_CONTROLLER
	/* Lock the controller, not the port */
	port = i2c_port_to_controller(port);
	ASSERT(port != -1);
#endif
	if (lock) {
		mutex_lock(port_mutex + port);

		/* Disable interrupt during changing counter for preemption. */
		interrupt_disable();

		i2c_port_active_count++;
		/* Ec cannot enter sleep if there's any i2c port active. */
		disable_sleep(SLEEP_MASK_I2C_MASTER);

		interrupt_enable();
	} else {
		interrupt_disable();

		i2c_port_active_count--;
		/* Once there is no i2c port active, enable sleep bit of i2c. */
		if (!i2c_port_active_count)
			enable_sleep(SLEEP_MASK_I2C_MASTER);

		interrupt_enable();

		mutex_unlock(port_mutex + port);
	}
}

void i2c_prepare_sysjump(void)
{
	int i;

	/* Lock all i2c controllers */
	for (i = 0; i < I2C_CONTROLLER_COUNT; ++i)
		mutex_lock(port_mutex + i);
}

int i2c_read32(int port, int slave_addr, int offset, int *data)
{
	int rv;
	uint8_t reg, buf[sizeof(uint32_t)];

	reg = offset & 0xff;
	/* I2C read 32-bit word: transmit 8-bit offset, and read 32bits */
	i2c_lock(port, 1);
	rv = i2c_xfer(port, slave_addr, &reg, 1, buf, sizeof(uint32_t),
		      I2C_XFER_SINGLE);
	i2c_lock(port, 0);

	if (rv)
		return rv;

	if (slave_addr & I2C_FLAG_BIG_ENDIAN)
		*data = ((int)buf[0] << 24) | ((int)buf[1] << 16) |
			((int)buf[0] << 8) | buf[1];
	else
		*data = ((int)buf[3] << 24) | ((int)buf[2] << 16) |
			((int)buf[1] << 8) | buf[0];

	return EC_SUCCESS;
}

int i2c_write32(int port, int slave_addr, int offset, int data)
{
	int rv;
	uint8_t buf[1 + sizeof(uint32_t)];

	buf[0] = offset & 0xff;

	if (slave_addr & I2C_FLAG_BIG_ENDIAN) {
		buf[1] = (data >> 24) & 0xff;
		buf[2] = (data >> 16) & 0xff;
		buf[3] = (data >> 8) & 0xff;
		buf[4] = data & 0xff;
	} else {
		buf[1] = data & 0xff;
		buf[2] = (data >> 8) & 0xff;
		buf[3] = (data >> 16) & 0xff;
		buf[4] = (data >> 24) & 0xff;
	}

	i2c_lock(port, 1);
	rv = i2c_xfer(port, slave_addr, buf, sizeof(uint32_t) + 1, NULL, 0,
		      I2C_XFER_SINGLE);
	i2c_lock(port, 0);

	return rv;
}

int i2c_read16(int port, int slave_addr, int offset, int *data)
{
	int rv;
	uint8_t reg, buf[sizeof(uint16_t)];

	reg = offset & 0xff;
	/* I2C read 16-bit word: transmit 8-bit offset, and read 16bits */
	i2c_lock(port, 1);
	rv = i2c_xfer(port, slave_addr, &reg, 1, buf, sizeof(uint16_t),
		      I2C_XFER_SINGLE);
	i2c_lock(port, 0);

	if (rv)
		return rv;

	if (slave_addr & I2C_FLAG_BIG_ENDIAN)
		*data = ((int)buf[0] << 8) | buf[1];
	else
		*data = ((int)buf[1] << 8) | buf[0];

	return EC_SUCCESS;
}

int i2c_write16(int port, int slave_addr, int offset, int data)
{
	int rv;
	uint8_t buf[1 + sizeof(uint16_t)];

	buf[0] = offset & 0xff;

	if (slave_addr & I2C_FLAG_BIG_ENDIAN) {
		buf[1] = (data >> 8) & 0xff;
		buf[2] = data & 0xff;
	} else {
		buf[1] = data & 0xff;
		buf[2] = (data >> 8) & 0xff;
	}

	i2c_lock(port, 1);
	rv = i2c_xfer(port, slave_addr, buf, 1 + sizeof(uint16_t), NULL, 0,
		      I2C_XFER_SINGLE);
	i2c_lock(port, 0);

	return rv;
}

int i2c_read8(int port, int slave_addr, int offset, int *data)
{
	int rv;
	/* We use buf[1] here so it's aligned for DMA on STM32 */
	uint8_t reg, buf[1];

	reg = offset;

	i2c_lock(port, 1);
	rv = i2c_xfer(port, slave_addr, &reg, 1, buf, 1, I2C_XFER_SINGLE);
	i2c_lock(port, 0);

	if (!rv)
		*data = buf[0];

	return rv;
}

int i2c_write8(int port, int slave_addr, int offset, int data)
{
	int rv;
	uint8_t buf[2];

	buf[0] = offset;
	buf[1] = data;

	i2c_lock(port, 1);
	rv = i2c_xfer(port, slave_addr, buf, 2, 0, 0, I2C_XFER_SINGLE);
	i2c_lock(port, 0);

	return rv;
}

int i2c_read_string(int port, int slave_addr, int offset, uint8_t *data,
		    int len)
{
	int rv;
	uint8_t reg, block_length;

	i2c_lock(port, 1);

	reg = offset;
	/*
	 * Send device reg space offset, and read back block length.  Keep this
	 * session open without a stop.
	 */
	rv = i2c_xfer(port, slave_addr, &reg, 1, &block_length, 1,
		      I2C_XFER_START);
	if (rv)
		goto exit;

	if (len && block_length > (len - 1))
		block_length = len - 1;

	rv = i2c_xfer(port, slave_addr, 0, 0, data, block_length,
		      I2C_XFER_STOP);
	data[block_length] = 0;

exit:
	i2c_lock(port, 0);
	return rv;
}

int get_sda_from_i2c_port(int port, enum gpio_signal *sda)
{
	const struct i2c_port_t *i2c_port = get_i2c_port(port);

	/* Crash if the port given is not in the i2c_ports[] table. */
	ASSERT(i2c_port);

	/* Check if the SCL and SDA pins have been defined for this port. */
	if (i2c_port->scl == 0 && i2c_port->sda == 0)
		return EC_ERROR_INVAL;

	*sda = i2c_port->sda;
	return EC_SUCCESS;
}

int get_scl_from_i2c_port(int port, enum gpio_signal *scl)
{
	const struct i2c_port_t *i2c_port = get_i2c_port(port);

	/* Crash if the port given is not in the i2c_ports[] table. */
	ASSERT(i2c_port);

	/* Check if the SCL and SDA pins have been defined for this port. */
	if (i2c_port->scl == 0 && i2c_port->sda == 0)
		return EC_ERROR_INVAL;

	*scl = i2c_port->scl;
	return EC_SUCCESS;
}

void i2c_raw_set_scl(int port, int level)
{
	enum gpio_signal g;

	if (get_scl_from_i2c_port(port, &g) == EC_SUCCESS)
		gpio_set_level(g, level);
}

void i2c_raw_set_sda(int port, int level)
{
	enum gpio_signal g;

	if (get_sda_from_i2c_port(port, &g) == EC_SUCCESS)
		gpio_set_level(g, level);
}

int i2c_raw_mode(int port, int enable)
{
	enum gpio_signal sda, scl;
	int ret_sda, ret_scl;

	/* Get the SDA and SCL pins for this port. If none, then return. */
	if (get_sda_from_i2c_port(port, &sda) != EC_SUCCESS)
		return EC_ERROR_INVAL;
	if (get_scl_from_i2c_port(port, &scl) != EC_SUCCESS)
		return EC_ERROR_INVAL;

	if (enable) {
		/*
		 * To enable raw mode, take out of alternate function mode and
		 * set the flags to open drain output.
		 */
		ret_sda = gpio_config_pin(MODULE_I2C, sda, 0);
		ret_scl = gpio_config_pin(MODULE_I2C, scl, 0);

		gpio_set_flags(scl, GPIO_ODR_HIGH);
		gpio_set_flags(sda, GPIO_ODR_HIGH);
	} else {
		/*
		 * Configure the I2C pins to exit raw mode and return
		 * to normal mode.
		 */
		ret_sda = gpio_config_pin(MODULE_I2C, sda, 1);
		ret_scl = gpio_config_pin(MODULE_I2C, scl, 1);
	}

	return ret_sda == EC_SUCCESS ? ret_scl : ret_sda;
}


/*
 * Unwedge the i2c bus for the given port.
 *
 * Some devices on our i2c busses keep power even if we get a reset.  That
 * means that they could be part way through a transaction and could be
 * driving the bus in a way that makes it hard for us to talk on the bus.
 * ...or they might listen to the next transaction and interpret it in a
 * weird way.
 *
 * Note that devices could be in one of several states:
 * - If a device got interrupted in a write transaction it will be watching
 *   for additional data to finish its write.  It will probably be looking to
 *   ack the data (drive the data line low) after it gets everything.
 * - If a device got interrupted while responding to a register read, it will
 *   be watching for clocks and will drive data out when it sees clocks.  At
 *   the moment it might be trying to send out a 1 (so both clock and data
 *   may be high) or it might be trying to send out a 0 (so it's driving data
 *   low).
 *
 * We attempt to unwedge the bus by doing:
 * - If SCL is being held low, then a slave is clock extending. The only
 *   thing we can do is try to wait until the slave stops clock extending.
 * - Otherwise, we will toggle the clock until the slave releases the SDA line.
 *   Once the SDA line is released, try to send a STOP bit. Rinse and repeat
 *   until either the bus is normal, or we run out of attempts.
 *
 * Note this should work for most devices, but depending on the slaves i2c
 * state machine, it may not be possible to unwedge the bus.
 */
int i2c_unwedge(int port)
{
	int i, j;
	int ret = EC_SUCCESS;

	/* Try to put port in to raw bit bang mode. */
	if (i2c_raw_mode(port, 1) != EC_SUCCESS)
		return EC_ERROR_UNKNOWN;

	/*
	 * If clock is low, wait for a while in case of clock stretched
	 * by a slave.
	 */
	if (!i2c_raw_get_scl(port)) {
		for (i = 0;; i++) {
			if (i >= UNWEDGE_SCL_ATTEMPTS) {
				/*
				 * If we get here, a slave is holding the clock
				 * low and there is nothing we can do.
				 */
				CPRINTS("I2C unwedge failed, SCL is being held low");
				ret = EC_ERROR_UNKNOWN;
				goto unwedge_done;
			}
			udelay(I2C_BITBANG_DELAY_US);
			if (i2c_raw_get_scl(port))
				break;
		}
	}

	if (i2c_raw_get_sda(port))
		goto unwedge_done;

	CPRINTS("I2C unwedge called with SDA held low");

	/* Keep trying to unwedge the SDA line until we run out of attempts. */
	for (i = 0; i < UNWEDGE_SDA_ATTEMPTS; i++) {
		/* Drive the clock high. */
		i2c_raw_set_scl(port, 1);
		udelay(I2C_BITBANG_DELAY_US);

		/*
		 * Clock through the problem by clocking out 9 bits. If slave
		 * releases the SDA line, then we can stop clocking bits and
		 * send a STOP.
		 */
		for (j = 0; j < 9; j++) {
			if (i2c_raw_get_sda(port))
				break;

			i2c_raw_set_scl(port, 0);
			udelay(I2C_BITBANG_DELAY_US);
			i2c_raw_set_scl(port, 1);
			udelay(I2C_BITBANG_DELAY_US);
		}

		/* Take control of SDA line and issue a STOP command. */
		i2c_raw_set_sda(port, 0);
		udelay(I2C_BITBANG_DELAY_US);
		i2c_raw_set_sda(port, 1);
		udelay(I2C_BITBANG_DELAY_US);

		/* Check if the bus is unwedged. */
		if (i2c_raw_get_sda(port) && i2c_raw_get_scl(port))
			break;
	}

	if (!i2c_raw_get_sda(port)) {
		CPRINTS("I2C unwedge failed, SDA still low");
		ret = EC_ERROR_UNKNOWN;
	}
	if (!i2c_raw_get_scl(port)) {
		CPRINTS("I2C unwedge failed, SCL still low");
		ret = EC_ERROR_UNKNOWN;
	}

unwedge_done:
	/* Take port out of raw bit bang mode. */
	i2c_raw_mode(port, 0);

	return ret;
}

/*****************************************************************************/
/* Host commands */

#ifdef CONFIG_I2C_DEBUG_PASSTHRU
#define PTHRUPRINTF(format, args...) CPRINTS(format, ## args)
#else
#define PTHRUPRINTF(format, args...)
#endif

/**
 * Perform the voluminous checking required for this message
 *
 * @param args	Arguments
 * @return 0 if OK, EC_RES_INVALID_PARAM on error
 */
static int check_i2c_params(const struct host_cmd_handler_args *args)
{
	const struct ec_params_i2c_passthru *params = args->params;
	const struct ec_params_i2c_passthru_msg *msg;
	int read_len = 0, write_len = 0;
	unsigned int size;
	int msgnum;

	if (args->params_size < sizeof(*params)) {
		PTHRUPRINTF("i2c passthru no params, params_size=%d, "
			    "need at least %d",
			    args->params_size, sizeof(*params));
		return EC_RES_INVALID_PARAM;
	}
	size = sizeof(*params) + params->num_msgs * sizeof(*msg);
	if (args->params_size < size) {
		PTHRUPRINTF("i2c passthru params_size=%d, "
			    "need at least %d",
			    args->params_size, size);
		return EC_RES_INVALID_PARAM;
	}

	/* Loop and process messages */;
	for (msgnum = 0, msg = params->msg; msgnum < params->num_msgs;
	     msgnum++, msg++) {
		unsigned int addr_flags = msg->addr_flags;

		PTHRUPRINTF("i2c passthru port=%d, %s, addr=0x%02x, "
			    "len=0x%02x",
			    params->port,
			    addr_flags & EC_I2C_FLAG_READ ? "read" : "write",
			    addr_flags & EC_I2C_ADDR_MASK,
			    msg->len);

		if (addr_flags & EC_I2C_FLAG_READ)
			read_len += msg->len;
		else
			write_len += msg->len;
	}

	/* Check there is room for the data */
	if (args->response_max <
			sizeof(struct ec_response_i2c_passthru) + read_len) {
		PTHRUPRINTF("i2c passthru overflow1");
		return EC_RES_INVALID_PARAM;
	}

	/* Must have bytes to write */
	if (args->params_size < size + write_len) {
		PTHRUPRINTF("i2c passthru overflow2");
		return EC_RES_INVALID_PARAM;
	}

	return EC_RES_SUCCESS;
}

static int i2c_command_passthru(struct host_cmd_handler_args *args)
{
	const struct ec_params_i2c_passthru *params = args->params;
	const struct ec_params_i2c_passthru_msg *msg;
	struct ec_response_i2c_passthru *resp = args->response;
	const struct i2c_port_t *i2c_port;
	const uint8_t *out;
	int in_len;
	int ret, i;
#if defined(VIRTUAL_BATTERY_ADDR) && defined(I2C_PORT_VIRTUAL_BATTERY)
	uint8_t batt_param = 0;
#endif

#ifdef CONFIG_I2C_PASSTHRU_RESTRICTED
	if (system_is_locked())
		return EC_RES_ACCESS_DENIED;
#endif

#ifdef CONFIG_BATTERY_CUT_OFF
	/*
	 * Some batteries would wake up after cut-off if we talk to it.
	 */
	if (battery_is_cut_off())
		return EC_RES_ACCESS_DENIED;
#endif

	i2c_port = get_i2c_port(params->port);
	if (!i2c_port)
		return EC_RES_INVALID_PARAM;

	ret = check_i2c_params(args);
	if (ret)
		return ret;

	if (port_protected[params->port] && i2c_port->passthru_allowed) {
		for (i = 0; i < params->num_msgs; i++) {
			if (!i2c_port->passthru_allowed(i2c_port,
				  params->msg[i].addr_flags & EC_I2C_ADDR_MASK))
				return EC_RES_ACCESS_DENIED;
		}
	}

	/* Loop and process messages */
	resp->i2c_status = 0;
	out = args->params + sizeof(*params) + params->num_msgs * sizeof(*msg);
	in_len = 0;

	i2c_lock(params->port, 1);

	for (resp->num_msgs = 0, msg = params->msg;
	     resp->num_msgs < params->num_msgs;
	     resp->num_msgs++, msg++) {
		/* EC uses 8-bit slave address */
		unsigned int addr = (msg->addr_flags & EC_I2C_ADDR_MASK) << 1;
		int xferflags = I2C_XFER_START;
		int read_len = 0, write_len = 0;
		int rv = 1;

		if (msg->addr_flags & EC_I2C_FLAG_READ)
			read_len = msg->len;
		else
			write_len = msg->len;

		/* Set stop bit for last message */
		if (resp->num_msgs == params->num_msgs - 1)
			xferflags |= I2C_XFER_STOP;

#if defined(VIRTUAL_BATTERY_ADDR) && defined(I2C_PORT_VIRTUAL_BATTERY)
		if (params->port == I2C_PORT_VIRTUAL_BATTERY &&
		    VIRTUAL_BATTERY_ADDR == addr) {
			/* get batt param from write msg */
			if (*out)
				batt_param = *out;
			rv = virtual_battery_read(batt_param,
						  &resp->data[in_len],
						  read_len);
		}
#endif
		/* Transfer next message */
		PTHRUPRINTF("i2c passthru xfer port=%x, addr=%x, out=%p, "
			    "write_len=%x, data=%p, read_len=%x, flags=%x",
			    params->port, addr, out, write_len,
			    &resp->data[in_len], read_len, xferflags);
		if (rv)
			rv = i2c_xfer(params->port, addr, out, write_len,
				      &resp->data[in_len], read_len, xferflags);

		if (rv) {
			/* Driver will have sent a stop bit here */
			if (rv == EC_ERROR_TIMEOUT)
				resp->i2c_status = EC_I2C_STATUS_TIMEOUT;
			else
				resp->i2c_status = EC_I2C_STATUS_NAK;
			break;
		}

		in_len += read_len;
		out += write_len;
	}
	args->response_size = sizeof(*resp) + in_len;

	/* Unlock port */
	i2c_lock(params->port, 0);

	/*
	 * Return success even if transfer failed so response is sent.  Host
	 * will check message status to determine the transfer result.
	 */
	return EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_I2C_PASSTHRU, i2c_command_passthru, EC_VER_MASK(0));

static int i2c_command_passthru_protect(struct host_cmd_handler_args *args)
{
	const struct ec_params_i2c_passthru_protect *params = args->params;
	struct ec_response_i2c_passthru_protect *resp = args->response;

	if (args->params_size < sizeof(*params)) {
		PTHRUPRINTF("i2c passthru protect no params, params_size=%d, "
			    "need at least %d",
			    args->params_size, sizeof(*params));
		return EC_RES_INVALID_PARAM;
	}

	if (!get_i2c_port(params->port)) {
		PTHRUPRINTF("i2c passthru protect invalid port %d",
			    params->port);
		return EC_RES_INVALID_PARAM;
	}

	if (params->subcmd == EC_CMD_I2C_PASSTHRU_PROTECT_STATUS) {
		if (args->response_max < sizeof(*resp)) {
			PTHRUPRINTF("i2c passthru protect no response, "
				"response_max=%d, need at least %d",
				args->response_max, sizeof(*resp));
			return EC_RES_INVALID_PARAM;
		}

		resp->status = port_protected[params->port];
		args->response_size = sizeof(*resp);
	} else if (params->subcmd == EC_CMD_I2C_PASSTHRU_PROTECT_ENABLE) {
		port_protected[params->port] = 1;
	} else {
		return EC_RES_INVALID_COMMAND;
	}

	return EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_I2C_PASSTHRU_PROTECT, i2c_command_passthru_protect,
		     EC_VER_MASK(0));

/*****************************************************************************/
/* Console commands */

#ifdef CONFIG_CMD_I2C_PROTECT
static int command_i2cprotect(int argc, char **argv)
{
	if (argc == 1) {
		int i, port;

		for (i = 0; i < i2c_ports_used; i++) {
			port = i2c_ports[i].port;
			ccprintf("Port %d: %s\n", port,
			   port_protected[port] ? "Protected" : "Unprotected");
		}
	} else if (argc == 2) {
		int port;
		char *e;

		port = strtoi(argv[1], &e, 0);
		if (*e)
			return EC_ERROR_PARAM2;

		if (!get_i2c_port(port)) {
			ccprintf("i2c passthru protect invalid port %d\n",
				port);
			return EC_RES_INVALID_PARAM;
		}

		port_protected[port] = 1;
	} else {
		return EC_ERROR_PARAM_COUNT;
	}

	return EC_RES_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(i2cprotect, command_i2cprotect,
			"[port]",
			"Protect I2C bus",
			NULL);
#endif

#ifdef CONFIG_CMD_I2C_SCAN
static void scan_bus(int port, const char *desc)
{
	int a;
	uint8_t tmp;

	ccprintf("Scanning %d %s", port, desc);

	/* Don't scan a busy port, since reads will just fail / time out */
	a = i2c_get_line_levels(port);
	if (a != I2C_LINE_IDLE) {
		ccprintf(": port busy (SDA=%d, SCL=%d)\n",
			 (a & I2C_LINE_SDA_HIGH) ? 1 : 0,
			 (a & I2C_LINE_SCL_HIGH) ? 1 : 0);
		return;
	}

	i2c_lock(port, 1);

	for (a = 0; a < 0x100; a += 2) {
		watchdog_reload();  /* Otherwise a full scan trips watchdog */
		ccputs(".");

		/* Do a single read */
		if (!i2c_xfer(port, a, NULL, 0, &tmp, 1, I2C_XFER_SINGLE))
			ccprintf("\n  0x%02x", a);
	}

	i2c_lock(port, 0);
	ccputs("\n");
}

static int command_scan(int argc, char **argv)
{
	int port;
	char *e;

	if (argc == 1) {
		for (port = 0; port < i2c_ports_used; port++)
			scan_bus(i2c_ports[port].port, i2c_ports[port].name);
		return EC_SUCCESS;
	}


	port = strtoi(argv[1], &e, 0);
	if ((*e) || (port >= i2c_ports_used))
		return EC_ERROR_PARAM2;

	scan_bus(i2c_ports[port].port, i2c_ports[port].name);
	return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(i2cscan, command_scan,
			"i2cscan [port]",
			"Scan I2C ports for devices",
			NULL);
#endif

#ifdef CONFIG_CMD_I2C_XFER
static int command_i2cxfer(int argc, char **argv)
{
	int port, slave_addr;
	uint8_t offset;
	int v = 0;
	uint8_t data[32];
	char *e;
	int rv = 0;

	if (argc < 5)
		return EC_ERROR_PARAM_COUNT;

	port = strtoi(argv[2], &e, 0);
	if (*e)
		return EC_ERROR_PARAM2;

	slave_addr = strtoi(argv[3], &e, 0);
	if (*e)
		return EC_ERROR_PARAM3;

	offset = strtoi(argv[4], &e, 0);
	if (*e)
		return EC_ERROR_PARAM4;

	if (argc >= 6) {
		v = strtoi(argv[5], &e, 0);
		if (*e)
			return EC_ERROR_PARAM5;
	}

	if (strcasecmp(argv[1], "r") == 0) {
		/* 8-bit read */
		rv = i2c_read8(port, slave_addr, offset, &v);
		if (!rv)
			ccprintf("0x%02x [%d]\n", v);

	} else if (strcasecmp(argv[1], "r16") == 0) {
		/* 16-bit read */
		rv = i2c_read16(port, slave_addr, offset, &v);
		if (!rv)
			ccprintf("0x%04x [%d]\n", v);

	} else if (strcasecmp(argv[1], "rlen") == 0) {
		/* Arbitrary length read; param5 = len */
		if (argc < 6 || v < 0 || v > sizeof(data))
			return EC_ERROR_PARAM5;

		i2c_lock(port, 1);
		rv = i2c_xfer(port, slave_addr,
			      &offset, 1, data, v, I2C_XFER_SINGLE);
		i2c_lock(port, 0);

		if (!rv)
			ccprintf("Data: %.*h\n", v, data);

	} else if (strcasecmp(argv[1], "w") == 0) {
		/* 8-bit write */
		if (argc < 6)
			return EC_ERROR_PARAM5;

		rv = i2c_write8(port, slave_addr, offset, v);

	} else if (strcasecmp(argv[1], "w16") == 0) {
		/* 16-bit write */
		if (argc < 6)
			return EC_ERROR_PARAM5;

		rv = i2c_write16(port, slave_addr, offset, v);

	} else {
		return EC_ERROR_PARAM1;
	}

	return rv;
}
DECLARE_CONSOLE_COMMAND(i2cxfer, command_i2cxfer,
			"r/r16/rlen/w/w16 port addr offset [value | len]",
			"Read write I2C",
			NULL);
#endif