EC: clean up i2c_read_string

- Removed duplicate (similar) i2c_read_string functions.
- Kept one generic (weak) copy in common/i2c.c.
- TBD: Need support start/stop flags for STM32 family devices

BUG=chrome-os-partner:23569
BRANCH=ToT
TEST=Verified with smart battery firmware update application on glimmer.
Passed LGC & Simplo Battery.

Change-Id: I6d9446c60b6a36aef9a6179242c081084199c8e2
Signed-off-by: Sheng-Liang Song <ssl@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/209866
Reviewed-by: Randall Spangler <rspangler@chromium.org>

6 files changed, 41 insertions, 106 deletions

diff --git a/chip/stm32/build.mk b/chip/stm32/build.mk
index c1ccab2994..d4fe146197 100644
--- a/chip/stm32/build.mk
+++ b/chip/stm32/build.mk
@@ -29,7 +29,7 @@ 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
+chip-$(CONFIG_I2C)+=i2c-$(CHIP_FAMILY).o i2c.o
 chip-$(CONFIG_WATCHDOG)+=watchdog.o
 chip-$(HAS_TASK_CONSOLE)+=uart.o
 chip-$(HAS_TASK_KEYSCAN)+=keyboard_raw.o
diff --git a/chip/stm32/i2c-stm32f.c b/chip/stm32/i2c-stm32f.c
index 8e1ab99d57..674808277c 100644
--- a/chip/stm32/i2c-stm32f.c
+++ b/chip/stm32/i2c-stm32f.c
@@ -23,9 +23,6 @@
 #define CPRINTF(format, args...) cprintf(CC_I2C, format, ## args)
 #define CPRINTS(format, args...) cprints(CC_I2C, format, ## args)
 
-/* Maximum transfer of a SMBUS block transfer */
-#define SMBUS_MAX_BLOCK 32
-
 /* 8-bit I2C slave address */
 #define I2C_ADDRESS 0x3c
 
@@ -767,34 +764,3 @@ int i2c_get_line_levels(int port)
 		(i2c_raw_get_scl(port) ? I2C_LINE_SCL_HIGH : 0);
 }
 
-int i2c_read_string(int port, int slave_addr, int offset, uint8_t *data,
-	int len)
-{
-	int rv;
-	uint8_t reg, block_length;
-
-	/*
-	 * TODO(crosbug.com/p/23569): when i2c_xfer() supports start/stop bits,
-	 * merge this with the LM4 implementation and move to i2c_common.c.
-	 */
-
-	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/chip/stm32/i2c-stm32f0.c b/chip/stm32/i2c-stm32f0.c
index 8db1d97f2d..5dc40fcebc 100644
--- a/chip/stm32/i2c-stm32f0.c
+++ b/chip/stm32/i2c-stm32f0.c
@@ -20,9 +20,6 @@
 #define CPUTS(outstr) cputs(CC_I2C, outstr)
 #define CPRINTS(format, args...) cprints(CC_I2C, format, ## args)
 
-/* Maximum transfer of a SMBUS block transfer */
-#define SMBUS_MAX_BLOCK 32
-
 /* Transmit timeout in microseconds */
 #define I2C_TX_TIMEOUT_MASTER	(10 * MSEC)
 
@@ -410,38 +407,6 @@ int i2c_get_line_levels(int port)
 		(i2c_raw_get_scl(port) ? I2C_LINE_SCL_HIGH : 0);
 }
 
-int i2c_read_string(int port, int slave_addr, int offset, uint8_t *data,
-	int len)
-{
-	int rv;
-	uint8_t reg, block_length;
-
-	/*
-	 * TODO(crosbug.com/p/23569): when i2c_xfer() supports start/stop bits,
-	 * merge this with the LM4 implementation and move to i2c_common.c.
-	 */
-
-	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;
-}
-
 static void i2c_init(void)
 {
 	const struct i2c_port_t *p = i2c_ports;
diff --git a/chip/stm32/i2c-stm32l.c b/chip/stm32/i2c-stm32l.c
index 34a80c2b3e..e274207cb8 100644
--- a/chip/stm32/i2c-stm32l.c
+++ b/chip/stm32/i2c-stm32l.c
@@ -22,9 +22,6 @@
 #define CPUTS(outstr) cputs(CC_I2C, outstr)
 #define CPRINTS(format, args...) cprints(CC_I2C, format, ## args)
 
-/* Maximum transfer of a SMBUS block transfer */
-#define SMBUS_MAX_BLOCK 32
-
 #define I2C_ERROR_FAILED_START EC_ERROR_INTERNAL_FIRST
 
 /*
@@ -367,38 +364,6 @@ int i2c_get_line_levels(int port)
 		(i2c_raw_get_scl(port) ? I2C_LINE_SCL_HIGH : 0);
 }
 
-int i2c_read_string(int port, int slave_addr, int offset, uint8_t *data,
-	int len)
-{
-	int rv;
-	uint8_t reg, block_length;
-
-	/*
-	 * TODO(crosbug.com/p/23569): when i2c_xfer() supports start/stop bits,
-	 * merge this with the LM4 implementation and move to i2c_common.c.
-	 */
-
-	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;
-}
-
 /*****************************************************************************/
 /* Hooks */
 
diff --git a/chip/stm32/i2c.c b/chip/stm32/i2c.c
new file mode 100644
index 0000000000..9cea83a619
--- /dev/null
+++ b/chip/stm32/i2c.c
@@ -0,0 +1,39 @@
+/* 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/driver/battery/smart.c b/driver/battery/smart.c
index 6dcedfd81f..0df0fefbe8 100644
--- a/driver/battery/smart.c
+++ b/driver/battery/smart.c
@@ -413,7 +413,7 @@ static int host_command_sb_read_block(struct host_cmd_handler_args *args)
 	    (p->reg != SB_DEVICE_CHEMISTRY) &&
 	    (p->reg != SB_MANUFACTURER_DATA))
 		return EC_RES_INVALID_PARAM;
-	rv = i2c_read_string(I2C_PORT_BATTERY, BATTERY_ADDR, p->reg,
+	rv = sb_read_string(I2C_PORT_BATTERY, BATTERY_ADDR, p->reg,
 			     r->data, 32);
 	if (rv)
 		return EC_RES_ERROR;