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Commit 3a20876c authored by Masahiro Yamada's avatar Masahiro Yamada Committed by Greg Kroah-Hartman
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i2c: uniphier: issue STOP only for last message or I2C_M_STOP 



[ 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: dd6fd4a3 ("i2c: uniphier: add UniPhier FIFO-less I2C driver")
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e02c60d8

drivers/i2c/busses/i2c-uniphier.c

+2 −5
Original line number Diff line number Diff line
@@ -247,11 +247,8 @@ static int uniphier_i2c_master_xfer(struct i2c_adapter *adap, 
		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)