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44 lines
1.5 KiB
44 lines
1.5 KiB
6 years ago
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From f7714b4e451bdcb7918b9aad14af22684ceac638 Mon Sep 17 00:00:00 2001
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From: Abhishek Sahu <absahu@codeaurora.org>
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Date: Mon, 12 Mar 2018 18:45:00 +0530
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Subject: [PATCH 11/13] i2c: qup: send NACK for last read sub transfers
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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According to I2c specification, “If a master-receiver sends a
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repeated START condition, it sends a not-acknowledge (A) just
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before the repeated START condition”. QUP v2 supports sending
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of NACK without stop with QUP_TAG_V2_DATARD_NACK so added the
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same.
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Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
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Reviewed-by: Austin Christ <austinwc@codeaurora.org>
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Reviewed-by: Andy Gross <andy.gross@linaro.org>
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Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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---
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drivers/i2c/busses/i2c-qup.c | 5 ++++-
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1 file changed, 4 insertions(+), 1 deletion(-)
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--- a/drivers/i2c/busses/i2c-qup.c
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+++ b/drivers/i2c/busses/i2c-qup.c
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@@ -104,6 +104,7 @@
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#define QUP_TAG_V2_DATAWR 0x82
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#define QUP_TAG_V2_DATAWR_STOP 0x83
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#define QUP_TAG_V2_DATARD 0x85
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+#define QUP_TAG_V2_DATARD_NACK 0x86
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#define QUP_TAG_V2_DATARD_STOP 0x87
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/* Status, Error flags */
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@@ -606,7 +607,9 @@ static int qup_i2c_set_tags(u8 *tags, st
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tags[len++] = QUP_TAG_V2_DATAWR_STOP;
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} else {
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if (msg->flags & I2C_M_RD)
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- tags[len++] = QUP_TAG_V2_DATARD;
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+ tags[len++] = qup->blk.pos == (qup->blk.count - 1) ?
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+ QUP_TAG_V2_DATARD_NACK :
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+ QUP_TAG_V2_DATARD;
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else
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tags[len++] = QUP_TAG_V2_DATAWR;
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}
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