| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 28/94] i2c: uniphier: issue STOP only for last message or I2C_M_STOP | Date | Mon, 8 Oct 2018 20:31:09 +0200 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Masahiro Yamada <yamada.masahiro@socionext.com>
[ Upstream commit 38f5d8d8cbb2ffa2b54315118185332329ec891c ]
This driver currently emits a STOP if the next message is not I2C_MD_RD. It should not do it because it disturbs the I2C_RDWR ioctl, where read/write transactions are combined without STOP between.
Issue STOP only when the message is the last one _or_ flagged with I2C_M_STOP.
Fixes: dd6fd4a32793 ("i2c: uniphier: add UniPhier FIFO-less I2C driver") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/i2c/busses/i2c-uniphier.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)
--- a/drivers/i2c/busses/i2c-uniphier.c +++ b/drivers/i2c/busses/i2c-uniphier.c @@ -248,11 +248,8 @@ static int uniphier_i2c_master_xfer(stru return ret; for (msg = msgs; msg < emsg; msg++) { - /* If next message is read, skip the stop condition */ - bool stop = !(msg + 1 < emsg && msg[1].flags & I2C_M_RD); - /* but, force it if I2C_M_STOP is set */ - if (msg->flags & I2C_M_STOP) - stop = true; + /* Emit STOP if it is the last message or I2C_M_STOP is set. */ + bool stop = (msg + 1 == emsg) || (msg->flags & I2C_M_STOP); ret = uniphier_i2c_master_xfer_one(adap, msg, stop); if (ret)
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