[U-Boot] [PATCH v2 1/3] dm: i2c: Add a flag that needs to generate a stop bit

[Chuanhua Han]

Usually the i2c bus needs to write the address of the register before
reading the internal register data of the device (ignoring the
transmission of the slave address).

Generally, the stop signal is not needed before the register is read,
but there is a special chip that needs this stop signal (such as
pcf2127), this patch adds a flag that needs to generate a stop
bit to determine whether the i2c host needs to generate a stop signal
before reading the register data.

Signed-off-by: Biwen Li <biwen.li at nxp.com>
Signed-off-by: Chuanhua Han <chuanhua.han at nxp.com>
---
Changes in v2:
	- Split the original patch into 3 patches
	- Add detailed description information for each patch

 drivers/i2c/i2c-uclass.c | 2 ++
 include/i2c.h            | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
index e47abf1833..18f7364d72 100644
--- a/drivers/i2c/i2c-uclass.c
+++ b/drivers/i2c/i2c-uclass.c
@@ -141,6 +141,8 @@ int dm_i2c_read(struct udevice *dev, uint offset, uint8_t *buffer, int len)
 	if (len) {
 		ptr->addr = chip->chip_addr;
 		ptr->flags = chip->flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0;
+		ptr->flags |= chip->flags & DM_I2C_CHIP_RD_NEED_STOP_BIT ?
+			      I2C_M_RD_NEED_STOP_BIT : 0;
 		ptr->flags |= I2C_M_RD;
 		ptr->len = len;
 		ptr->buf = buffer;
diff --git a/include/i2c.h b/include/i2c.h
index a5c760c711..beaa028349 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -28,6 +28,7 @@ enum dm_i2c_chip_flags {
 	DM_I2C_CHIP_10BIT	= 1 << 0, /* Use 10-bit addressing */
 	DM_I2C_CHIP_RD_ADDRESS	= 1 << 1, /* Send address for each read byte */
 	DM_I2C_CHIP_WR_ADDRESS	= 1 << 2, /* Send address for each write byte */
+	DM_I2C_CHIP_RD_NEED_STOP_BIT    = 1 << 3, /* Need generate stop bit */
 };
 
 struct udevice;
@@ -87,6 +88,7 @@ enum dm_i2c_msg_flags {
 	I2C_M_IGNORE_NAK	= 0x1000, /* continue after NAK */
 	I2C_M_NO_RD_ACK		= 0x0800, /* skip the Ack bit on reads */
 	I2C_M_RECV_LEN		= 0x0400, /* length is first received byte */
+	I2C_M_RD_NEED_STOP_BIT  = 0x0002, /* need generate stop bit */
 };
 
 /**
-- 
2.17.1