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From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: linux-i2c@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Jacopo Mondi <jacopo@jmondi.org>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>
Subject: [PATCH RFT] i2c: sh_mobile: make sure to not accidently trigger STOP
Date: Wed, 15 Nov 2017 15:32:21 +0100	[thread overview]
Message-ID: <20171115143221.30618-1-wsa+renesas@sang-engineering.com> (raw)

The datasheet was a bit vague, but after consultation with HW designers,
we came to the conclusion that we should set the SCP bit always when
dealing only with the ICE bit. A set SCP bit is ignored, and thus fine,
a cleared one may trigger STOP on the bus.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

Jacopo: another to test, please. On top of all the other patches. Thank you!

 drivers/i2c/busses/i2c-sh_mobile.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 9012d5f8fb38b8..c2841a4f5807c0 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -604,10 +604,10 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
 
 	if (do_init) {
 		/* Initialize channel registers */
-		iic_wr(pd, ICCR, 0);
+		iic_wr(pd, ICCR, ICCR_SCP);
 
 		/* Enable channel and configure rx ack */
-		iic_wr(pd, ICCR, ICCR_ICE);
+		iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
 
 		/* Set the clock */
 		iic_wr(pd, ICCL, pd->iccl & 0xff);
@@ -723,7 +723,7 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
 	}
 
 	/* Disable channel */
-	iic_wr(pd, ICCR, 0);
+	iic_wr(pd, ICCR, ICCR_SCP);
 
 	/* Disable clock and mark device as idle */
 	pm_runtime_put_sync(pd->dev);
-- 
2.11.0

             reply	other threads:[~2017-11-15 14:32 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-15 14:32 Wolfram Sang [this message]
2017-11-17 10:05 ` [PATCH RFT] i2c: sh_mobile: make sure to not accidently trigger STOP jacopo mondi
2017-11-27 17:57 ` Wolfram Sang

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