Messages in this thread Patch in this message | | | From | Abhishek Sahu <> | Subject | [PATCH 10/12] i2c: qup: send NACK for last read sub transfers | Date | Sat, 3 Feb 2018 13:28:15 +0530 |
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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> --- drivers/i2c/busses/i2c-qup.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c index ba717bb..edea3b9 100644 --- a/drivers/i2c/busses/i2c-qup.c +++ b/drivers/i2c/busses/i2c-qup.c @@ -113,6 +113,7 @@ #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 */ @@ -609,7 +610,9 @@ 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; } -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
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