[PATCH 1/2] i2c: uniphier: issue STOP only for last message or I2C_M_STOP
From: Masahiro Yamada <hidden>
Date: 2018-08-31 14:31:37
Also in:
linux-i2c, lkml
Subsystem:
arm/uniphier architecture, i2c subsystem, i2c subsystem host drivers, the rest · Maintainers:
Kunihiko Hayashi, Masami Hiramatsu, Andi Shyti, Linus Torvalds
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 <redacted>
---
drivers/i2c/busses/i2c-uniphier.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/i2c/busses/i2c-uniphier.c b/drivers/i2c/busses/i2c-uniphier.c
index bb181b0..454f914 100644
--- a/drivers/i2c/busses/i2c-uniphier.c
+++ b/drivers/i2c/busses/i2c-uniphier.c@@ -248,11 +248,8 @@ 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)
--
2.7.4