From mboxrd@z Thu Jan 1 00:00:00 1970 From: Abhishek Sahu Subject: [PATCH v2 11/13] i2c: qup: send NACK for last read sub transfers Date: Mon, 12 Mar 2018 18:45:00 +0530 Message-ID: <1520860502-14886-12-git-send-email-absahu@codeaurora.org> References: <1520860502-14886-1-git-send-email-absahu@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <1520860502-14886-1-git-send-email-absahu@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org To: Andy Gross , Wolfram Sang Cc: David Brown , Sricharan R , Austin Christ , linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Abhishek Sahu List-Id: linux-i2c@vger.kernel.org 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 Reviewed-by: Austin Christ Reviewed-by: Andy Gross --- * Changes from v1: None 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 5bb7ebe..4ebd922 100644 --- a/drivers/i2c/busses/i2c-qup.c +++ b/drivers/i2c/busses/i2c-qup.c @@ -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; } -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation