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From: Wolfram Sang <wsa@the-dreams.de>
To: linux-i2c@vger.kernel.org
Cc: linux-sh@vger.kernel.org, Magnus Damm <magnus.damm@gmail.com>,
	Simon Horman <horms@verge.net.au>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Wolfram Sang <wsa@the-dreams.de>,
	Kuninori Morimoto <kuninori.morimoto.gx@gmail.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Subject: [PATCH v3 07/11] i2c: rcar: don't issue stop when HW does it automatically
Date: Thu, 19 Nov 2015 15:56:47 +0000	[thread overview]
Message-ID: <1447948611-2615-8-git-send-email-wsa@the-dreams.de> (raw)
In-Reply-To: <1447948611-2615-1-git-send-email-wsa@the-dreams.de>

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

The manual says (55.4.8.6) that HW does automatically send STOP after
NACK was received. My measuerments confirm that.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/busses/i2c-rcar.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index d91acc11631554..87fccf20fc4c34 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -455,8 +455,8 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
 
 	/* Nack */
 	if (msr & MNR) {
-		/* go to stop phase */
-		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
+		/* HW automatically sends STOP after received NACK */
+		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
 		rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);
 		rcar_i2c_flags_set(priv, ID_NACK);
 		goto out;
-- 
2.1.4


WARNING: multiple messages have this Message-ID (diff)
From: Wolfram Sang <wsa@the-dreams.de>
To: linux-i2c@vger.kernel.org
Cc: linux-sh@vger.kernel.org, Magnus Damm <magnus.damm@gmail.com>,
	Simon Horman <horms@verge.net.au>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Wolfram Sang <wsa@the-dreams.de>,
	Kuninori Morimoto <kuninori.morimoto.gx@gmail.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Subject: [PATCH v3 07/11] i2c: rcar: don't issue stop when HW does it automatically
Date: Thu, 19 Nov 2015 16:56:47 +0100	[thread overview]
Message-ID: <1447948611-2615-8-git-send-email-wsa@the-dreams.de> (raw)
In-Reply-To: <1447948611-2615-1-git-send-email-wsa@the-dreams.de>

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

The manual says (55.4.8.6) that HW does automatically send STOP after
NACK was received. My measuerments confirm that.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/busses/i2c-rcar.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index d91acc11631554..87fccf20fc4c34 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -455,8 +455,8 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
 
 	/* Nack */
 	if (msr & MNR) {
-		/* go to stop phase */
-		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
+		/* HW automatically sends STOP after received NACK */
+		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
 		rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);
 		rcar_i2c_flags_set(priv, ID_NACK);
 		goto out;
-- 
2.1.4


  parent reply	other threads:[~2015-11-19 15:56 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-19 15:56 [PATCH v3 00/11] i2c: rcar: tackle race conditions in the driver Wolfram Sang
2015-11-19 15:56 ` Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 01/11] i2c: rcar: make sure clocks are on when doing clock calculation Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 02/11] i2c: rcar: rework hw init Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 03/11] i2c: rcar: remove unused IOERROR state Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 04/11] i2c: rcar: remove spinlock Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 05/11] i2c: rcar: refactor setup of a msg Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 06/11] i2c: rcar: init new messages in irq Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2015-11-19 15:56 ` Wolfram Sang [this message]
2015-11-19 15:56   ` [PATCH v3 07/11] i2c: rcar: don't issue stop when HW does it automatically Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 08/11] i2c: rcar: check master irqs before slave irqs Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 09/11] i2c: rcar: revoke START request early Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2016-03-31 21:02   ` Sergei Shtylyov
2016-03-31 21:02     ` Sergei Shtylyov
2016-03-31 22:48     ` Wolfram Sang
2016-03-31 22:48       ` Wolfram Sang
2016-04-01 19:55       ` Sergei Shtylyov
2016-04-01 19:55         ` Sergei Shtylyov
2016-04-01 20:14         ` Wolfram Sang
2016-04-01 20:14           ` Wolfram Sang
2016-04-01 23:05           ` Sergei Shtylyov
2016-04-01 23:05             ` Sergei Shtylyov
2016-04-02  7:27             ` Wolfram Sang
2016-04-02  7:27               ` Wolfram Sang
2016-04-02 12:51               ` Sergei Shtylyov
2016-04-02 12:51                 ` Sergei Shtylyov
2016-04-03  8:25                 ` Wolfram Sang
2016-04-03  8:25                   ` Wolfram Sang
2016-04-03 13:35                   ` Sergei Shtylyov
2016-04-03 13:35                     ` Sergei Shtylyov
2016-04-03 13:47                     ` Wolfram Sang
2016-04-03 13:47                       ` Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 10/11] i2c: rcar: clean up after refactoring Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2015-11-19 15:56 ` [PATCH v3 11/11] i2c: rcar: handle difference in setting up non-first message Wolfram Sang
2015-11-19 15:56   ` Wolfram Sang
2015-11-19 16:01 ` [PATCH v3 00/11] i2c: rcar: tackle race conditions in the driver Laurent Pinchart
2015-11-19 16:01   ` Laurent Pinchart
2015-11-30 13:27 ` Wolfram Sang
2015-11-30 13:27   ` Wolfram Sang

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