common: remove CONFIG_SMBUS dead code

CONFIG_SMBUS is not used.  Cleaning up the code by
removing this.

Added a comment to document the removal and why.  This will
give a way to find the code if we ever needed to bring it back

BUG=chromium:982316
BRANCH=none
TEST=make buildall

Change-Id: I40703a95bc849538e1aee32f6f96beab811285bd
Signed-off-by: Denis Brockus <dbrockus@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1704279
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

2 files changed, 0 insertions, 163 deletions

diff --git a/common/build.mk b/common/build.mk
index 425a5ba4fc..61f64fca35 100644
--- a/common/build.mk
+++ b/common/build.mk
@@ -113,7 +113,6 @@ common-$(CONFIG_RWSIG_TYPE_RWSIG)+=vboot/vb21_lib.o
 common-$(CONFIG_MATH_UTIL)+=math_util.o
 common-$(CONFIG_SHA1)+= sha1.o
 common-$(CONFIG_SHA256)+=sha256.o
-common-$(CONFIG_SMBUS)+= smbus.o
 common-$(CONFIG_SOFTWARE_CLZ)+=clz.o
 common-$(CONFIG_SOFTWARE_CTZ)+=ctz.o
 common-$(CONFIG_CMD_SPI_XFER)+=spi_commands.o
diff --git a/common/smbus.c b/common/smbus.c
deleted file mode 100644
index dfe0dcc964..0000000000
--- a/common/smbus.c
+++ /dev/null
@@ -1,162 +0,0 @@
-/* Copyright 2014 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.
- *
- * smbus cross-platform code for Chrome EC
- *  ref: http://smbus.org/specs/smbus20.pdf
- */
-
-#include "common.h"
-#include "console.h"
-#include "util.h"
-#include "i2c.h"
-#include "smbus.h"
-#include "crc8.h"
-
-#define CPRINTF(format, args...) cprintf(CC_I2C, format, ## args)
-
-/* Write 2 bytes using smbus word access protocol */
-int smbus_write_word(uint8_t i2c_port, uint8_t slave_addr,
-			uint8_t smbus_cmd, uint16_t d16)
-{
-	uint8_t buf[5];
-
-	/* Command sequence for CRC calculation */
-	buf[0] = slave_addr;
-	buf[1] = smbus_cmd;
-	buf[2] = d16 & 0xff;
-	buf[3] = (d16 >> 8) & 0xff;
-	buf[4] = crc8(buf, 4);
-	return i2c_xfer(i2c_port, slave_addr, buf + 1, 4, NULL, 0);
-}
-
-/* Write up to SMBUS_MAX_BLOCK_SIZE bytes using smbus block access protocol */
-int smbus_write_block(uint8_t i2c_port, uint8_t slave_addr,
-			uint8_t smbus_cmd, uint8_t *data, uint8_t len)
-{
-	uint8_t buf[3];
-	int rv;
-
-	/* Command sequence for CRC calculation */
-	buf[0] = slave_addr;
-	buf[1] = smbus_cmd;
-	buf[2] = len;
-
-	i2c_lock(i2c_port, 1);
-
-	/* Send command + length */
-	rv = i2c_xfer_unlocked(i2c_port, slave_addr,
-		      buf + 1, 2, NULL, 0, I2C_XFER_START);
-	if (rv != EC_SUCCESS)
-		goto smbus_write_block_done;
-
-	/* Send data */
-	rv = i2c_xfer_unlocked(i2c_port, slave_addr, data, len, NULL, 0, 0);
-	if (rv != EC_SUCCESS)
-		goto smbus_write_block_done;
-
-	/* Send CRC */
-	buf[0] = crc8(buf, 3);
-	buf[0] = crc8_arg(data, len, buf[0]);
-	rv = i2c_xfer_unlocked(i2c_port, slave_addr, buf, 1, NULL, 0,
-			I2C_XFER_STOP);
-
-smbus_write_block_done:
-	i2c_lock(i2c_port, 0);
-	return rv;
-}
-
-/* Read 2 bytes using smbus word access protocol */
-int smbus_read_word(uint8_t i2c_port, uint8_t slave_addr,
-			uint8_t smbus_cmd, uint16_t *p16)
-{
-	uint8_t buf[3];
-	int rv;
-	uint8_t crc;
-
-	/* Command sequence for CRC calculation */
-	buf[0] = slave_addr;
-	buf[1] = smbus_cmd;
-	buf[2] = slave_addr | 0x1;
-	crc = crc8(buf, 3);
-
-	/* Read data bytes + CRC byte */
-	rv = i2c_xfer(i2c_port, slave_addr, &smbus_cmd, 1, buf, 3);
-
-	/* Verify CRC */
-	if (crc8_arg(buf, 2, crc) != buf[2])
-		rv = EC_ERROR_CRC;
-
-	if (rv == EC_SUCCESS)
-		*p16 = (buf[1] << 8) | buf[0];
-	else
-		*p16 = 0;
-
-	return rv;
-}
-
-/* Read up to SMBUS_MAX_BLOCK_SIZE bytes using smbus block access protocol */
-int smbus_read_block(uint8_t i2c_port, uint8_t slave_addr,
-			uint8_t smbus_cmd, uint8_t *data, uint8_t *plen)
-{
-	int rv, read_len;
-	uint8_t buf[4];
-	uint8_t crc;
-	int do_crc = 1;
-
-	/* Command sequence for CRC calculation */
-	buf[0] = slave_addr;
-	buf[1] = smbus_cmd;
-	buf[2] = slave_addr | 0x1;
-
-	i2c_lock(i2c_port, 1);
-
-	/* First read size from slave */
-	rv = i2c_xfer_unlocked(i2c_port, slave_addr,
-		      &smbus_cmd, 1, buf + 3, 1, I2C_XFER_START);
-	if (rv != EC_SUCCESS)
-			goto smbus_read_block_done;
-	crc = crc8(buf, 4);
-
-	/*
-	 * If our input buffer isn't large enough to hold the entire input,
-	 * don't bother verifying crc since it may require reading numerous
-	 * data bytes that will be thrown away.
-	 */
-	read_len = MIN(buf[3], SMBUS_MAX_BLOCK_SIZE);
-	if (*plen < read_len) {
-		do_crc = 0;
-		read_len = *plen;
-	}
-
-	/* Now read back all bytes */
-	rv = i2c_xfer_unlocked(i2c_port, slave_addr,
-			NULL, 0, data, read_len, 0);
-	if (rv)
-		goto smbus_read_block_done;
-
-	/* Read CRC + verify */
-	rv = i2c_xfer_unlocked(i2c_port, slave_addr,
-		      NULL, 0, buf, 1, I2C_XFER_STOP);
-	if (do_crc && crc8_arg(data, read_len, crc) != buf[0])
-		rv = EC_ERROR_CRC;
-
-smbus_read_block_done:
-	if (rv != EC_SUCCESS)
-		memset(data, 0x0, *plen);
-	else
-		*plen = read_len;
-
-	i2c_lock(i2c_port, 0);
-	return rv;
-}
-
-int smbus_read_string(int i2c_port, uint8_t slave_addr, uint8_t smbus_cmd,
-			uint8_t *data, uint8_t len)
-{
-	int rv;
-	len -= 1;
-	rv = smbus_read_block(i2c_port, slave_addr, smbus_cmd, data, &len);
-	data[len] = '\0';
-	return rv;
-}