[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1517644697-30806-11-git-send-email-absahu@codeaurora.org>
Date: Sat, 3 Feb 2018 13:28:15 +0530
From: Abhishek Sahu <absahu@...eaurora.org>
To: Andy Gross <andy.gross@...aro.org>,
Wolfram Sang <wsa@...-dreams.de>
Cc: David Brown <david.brown@...aro.org>,
Sricharan R <sricharan@...eaurora.org>,
linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
Abhishek Sahu <absahu@...eaurora.org>
Subject: [PATCH 10/12] 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@...eaurora.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
Powered by blists - more mailing lists