openwrt/target/linux/ipq40xx/patches-4.14/088-0011-i2c-qup-send-NACK-for-last-read-sub-transfers.patch
Piotr Dymacz 24de7c29e5 ipq40xx: backport I2C QUP driver changes from 4.17
Backport below changes for I2C QUP driver from v4.17:

  0668bc44a426 i2c: qup: fix copyrights and update to SPDX identifier
  7239872fb340 i2c: qup: fixed releasing dma without flush operation completion
  eb422b539c1f i2c: qup: minor code reorganization for use_dma
  6d5f37f166bb i2c: qup: remove redundant variables for BAM SG count
  c5adc0fa63a9 i2c: qup: schedule EOT and FLUSH tags at the end of transfer
  7e6c35fe602d i2c: qup: fix the transfer length for BAM RX EOT FLUSH tags
  3f450d3eea14 i2c: qup: proper error handling for i2c error in BAM mode
  08f15963bc75 i2c: qup: use the complete transfer length to choose DMA mode
  ecb6e1e5f435 i2c: qup: change completion timeout according to transfer length
  6f2f0f6465ac i2c: qup: fix buffer overflow for multiple msg of maximum xfer len
  f7714b4e451b i2c: qup: send NACK for last read sub transfers
  fbfab1ab0658 i2c: qup: reorganization of driver code to remove polling for qup v1
  7545c7dba169 i2c: qup: reorganization of driver code to remove polling for qup v2

This fixes various I2C issues observed on AP120C-AC board equipped with
Atmel/Microchip AT97SC3205T TPM module.

Tested-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>
2019-03-08 19:28:31 +01:00

44 lines
1.5 KiB
Diff

From f7714b4e451bdcb7918b9aad14af22684ceac638 Mon Sep 17 00:00:00 2001
From: Abhishek Sahu <absahu@codeaurora.org>
Date: Mon, 12 Mar 2018 18:45:00 +0530
Subject: [PATCH 11/13] i2c: qup: send NACK for last read sub transfers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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>
---
drivers/i2c/busses/i2c-qup.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- 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, st
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;
}