4.9-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 @@ -247,11 +247,8 @@ 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)