i2c: Move i2c_read_string to common code

Since stm32 and mec1322 now support open-ended i2c_xfer, we can move the
lm4 i2c_read_string implementation to common code and delete all
chip-specific versions.

BUG=chrome-os-partner:39613
TEST=Run "battery" from EC console on Cyan and Oak, verify that battery
info + strings are correctly printed.
BRANCH=None

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Change-Id: I06369df64bb2eb747d163664b4c96eeacb4b1faa
Reviewed-on: https://chromium-review.googlesource.com/272938
Reviewed-by: Alec Berg <alecaberg@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

6 files changed, 31 insertions, 140 deletions

diff --git a/chip/lm4/i2c.c b/chip/lm4/i2c.c
index 56b4666330..5f3b9bfc74 100644
--- a/chip/lm4/i2c.c
+++ b/chip/lm4/i2c.c
@@ -305,36 +305,6 @@ int i2c_get_line_levels(int port)
 	return LM4_I2C_MBMON(port) & 0x03;
 }
 
-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;
-}
-
 void i2c_set_timeout(int port, uint32_t timeout)
 {
 	pdata[port].timeout_us = timeout ? timeout : I2C_TIMEOUT_DEFAULT_US;
diff --git a/chip/mec1322/i2c.c b/chip/mec1322/i2c.c
index dd75daa845..e7254a01f9 100644
--- a/chip/mec1322/i2c.c
+++ b/chip/mec1322/i2c.c
@@ -379,41 +379,6 @@ int i2c_get_line_levels(int port)
 	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;
-
-	if ((len <= 0) || (len > SMBUS_MAX_BLOCK_SIZE))
-		return EC_ERROR_INVAL;
-
-	i2c_lock(port, 1);
-
-	/*
-	 * Read the counted string into the output buffer
-	 */
-	reg = offset;
-	rv = i2c_xfer(port, slave_addr, &reg, 1, data, len, I2C_XFER_SINGLE);
-	if (rv)
-		goto exit;
-
-	/*
-	 * Block length is the first byte of the returned buffer
-	 */
-	block_length = MIN(data[0], len - 1);
-
-	/*
-	 * Move data down, then null-terminate it
-	 */
-	memmove(data, data + 1, block_length);
-	data[block_length] = '\0';
-
-exit:
-	i2c_lock(port, 0);
-	return rv;
-}
-
 int i2c_port_to_controller(int port)
 {
 	if (port < 0 || port >= MEC1322_I2C_PORT_COUNT)
diff --git a/chip/npcx/i2c.c b/chip/npcx/i2c.c
index 33f512cc22..a8002d7573 100644
--- a/chip/npcx/i2c.c
+++ b/chip/npcx/i2c.c
@@ -481,41 +481,6 @@ int i2c_raw_get_sda(int port)
 	return 1;
 }
 
-int i2c_read_string(int port, int slave_addr, int offset, uint8_t *data,
-		    int len)
-{
-	int rv;
-	uint8_t reg, block_length;
-
-	/* Check block protocol size */
-	if ((len <= 0) || (len > 32))
-		return EC_ERROR_INVAL;
-
-	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;
-}
-
 /*****************************************************************************/
 /* Hooks */
 static void i2c_freq_changed(void)
diff --git a/chip/stm32/build.mk b/chip/stm32/build.mk
index 326edfb830..19460eacde 100644
--- a/chip/stm32/build.mk
+++ b/chip/stm32/build.mk
@@ -33,7 +33,7 @@ chip-$(CONFIG_SPI)+=spi.o
 chip-$(CONFIG_SPI_MASTER_PORT)+=spi_master.o
 chip-$(CONFIG_COMMON_GPIO)+=gpio.o gpio-$(CHIP_FAMILY).o
 chip-$(CONFIG_COMMON_TIMER)+=hwtimer$(TIMER_TYPE).o
-chip-$(CONFIG_I2C)+=i2c-$(CHIP_FAMILY).o i2c.o
+chip-$(CONFIG_I2C)+=i2c-$(CHIP_FAMILY).o
 chip-$(CONFIG_STREAM_USART)+=usart.o usart-$(CHIP_FAMILY).o
 chip-$(CONFIG_STREAM_USB)+=usb-stream.o
 chip-$(CONFIG_WATCHDOG)+=watchdog.o
diff --git a/chip/stm32/i2c.c b/chip/stm32/i2c.c
deleted file mode 100644
index 9cea83a619..0000000000
--- a/chip/stm32/i2c.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/* Copyright (c) 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.
- */
-
-/* STM32 common I2C code for Chrome EC */
-
-#include "i2c.h"
-#include "util.h"
-
-/* Maximum transfer of a SMBUS block transfer */
-#define SMBUS_MAX_BLOCK 32
-
-int i2c_read_string(int port, int slave_addr,
-	int offset, uint8_t *data, int len)
-{
-	int rv;
-	uint8_t reg, block_length;
-
-	if ((len <= 0) || (len > SMBUS_MAX_BLOCK))
-		return EC_ERROR_INVAL;
-
-	i2c_lock(port, 1);
-
-	/* Read the counted string into the output buffer */
-	reg = offset;
-	rv = i2c_xfer(port, slave_addr, &reg, 1, data, len, I2C_XFER_SINGLE);
-	if (rv == EC_SUCCESS) {
-		/* Block length is the first byte of the returned buffer */
-		block_length = MIN(data[0], len - 1);
-
-		/* Move data down, then null-terminate it */
-		memmove(data, data + 1, block_length);
-		data[block_length] = 0;
-	}
-
-	i2c_lock(port, 0);
-	return rv;
-}
diff --git a/common/i2c.c b/common/i2c.c
index 800922adea..9659db59c3 100644
--- a/common/i2c.c
+++ b/common/i2c.c
@@ -130,6 +130,36 @@ int i2c_write8(int port, int slave_addr, int offset, int data)
 	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)
 {
 	int i;