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i2c: qup: send NACK for last read sub transfers 

According to I2c specification, “If a master-receiver sends a
repeated START condition, it sends a not-acknowledge (A) just
before the repeated START condition”. QUP v2 supports sending
of NACK without stop with QUP_TAG_V2_DATARD_NACK so added the
same.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Reviewed-by: Austin Christ <austinwc@codeaurora.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Abhishek Sahu 2018-03-12 18:45:00 +05:30 committed by Wolfram Sang
parent 6f2f0f6465
commit f7714b4e45
1 changed files with 4 additions and 1 deletions
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5
drivers/i2c/busses/i2c-qup.c
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@ -104,6 +104,7 @@
#define QUP_TAG_V2_DATAWR 0x82
#define QUP_TAG_V2_DATAWR_STOP 0x83
#define QUP_TAG_V2_DATARD 0x85
#define QUP_TAG_V2_DATARD_NACK 0x86
#define QUP_TAG_V2_DATARD_STOP 0x87
/* Status, Error flags */
@ -606,7 +607,9 @@ static int qup_i2c_set_tags(u8 *tags, struct qup_i2c_dev *qup,
tags[len++] = QUP_TAG_V2_DATAWR_STOP;
} else {
if (msg->flags & I2C_M_RD)
tags[len++] = QUP_TAG_V2_DATARD;
tags[len++] = qup->blk.pos == (qup->blk.count - 1) ?
QUP_TAG_V2_DATARD_NACK :
QUP_TAG_V2_DATARD;
else
tags[len++] = QUP_TAG_V2_DATAWR;
}