[PATCH 5/5] i2c: i2c-sh_mobile: fix spurious transfer request timed out

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From: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 5/5] i2c: i2c-sh_mobile: fix spurious transfer request timed out
Date: Wed, 24 Oct 2012 10:58:31 +0000	[thread overview]
Message-ID: <5087C9D7.1040108@renesas.com> (raw)
In-Reply-To: <5087C93F.6080601@renesas.com>

Ensure that any of preceding register write operations to the I2C
hardware block reached the module, and the write data is reflected
in the registers, before leaving the interrupt handler.

Otherwise, we'll suffer from spurious WAIT interrupts that lead to
'Transfer request timed out' message, and the transaction failed.

Tracked-down-by: Teppei Kamijou <teppei.kamijou.yb@renesas.com>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
---
 drivers/i2c/busses/i2c-sh_mobile.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 4c28358..9411c1b 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -469,6 +469,9 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
 		wake_up(&pd->wait);
 	}
 
+	/* defeat write posting to avoid spurious WAIT interrupts */
+	iic_rd(pd, ICSR);
+
 	return IRQ_HANDLED;
 }
 
-- 
1.7.12.4

WARNING: multiple messages have this Message-ID (diff)

From: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
To: w.sang@pengutronix.de, ben-linux@fluff.org, magnus.damm@gmail.com
Cc: linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-sh@vger.kernel.org
Subject: [PATCH 5/5] i2c: i2c-sh_mobile: fix spurious transfer request timed out
Date: Wed, 24 Oct 2012 19:58:31 +0900	[thread overview]
Message-ID: <5087C9D7.1040108@renesas.com> (raw)
In-Reply-To: <5087C93F.6080601@renesas.com>

Ensure that any of preceding register write operations to the I2C
hardware block reached the module, and the write data is reflected
in the registers, before leaving the interrupt handler.

Otherwise, we'll suffer from spurious WAIT interrupts that lead to
'Transfer request timed out' message, and the transaction failed.

Tracked-down-by: Teppei Kamijou <teppei.kamijou.yb@renesas.com>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
---
 drivers/i2c/busses/i2c-sh_mobile.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 4c28358..9411c1b 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -469,6 +469,9 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
 		wake_up(&pd->wait);
 	}
 
+	/* defeat write posting to avoid spurious WAIT interrupts */
+	iic_rd(pd, ICSR);
+
 	return IRQ_HANDLED;
 }
 
-- 
1.7.12.4

WARNING: multiple messages have this Message-ID (diff)

From: shinya.kuribayashi.px@renesas.com (Shinya Kuribayashi)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 5/5] i2c: i2c-sh_mobile: fix spurious transfer request timed out
Date: Wed, 24 Oct 2012 19:58:31 +0900	[thread overview]
Message-ID: <5087C9D7.1040108@renesas.com> (raw)
In-Reply-To: <5087C93F.6080601@renesas.com>

Ensure that any of preceding register write operations to the I2C
hardware block reached the module, and the write data is reflected
in the registers, before leaving the interrupt handler.

Otherwise, we'll suffer from spurious WAIT interrupts that lead to
'Transfer request timed out' message, and the transaction failed.

Tracked-down-by: Teppei Kamijou <teppei.kamijou.yb@renesas.com>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
---
 drivers/i2c/busses/i2c-sh_mobile.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 4c28358..9411c1b 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -469,6 +469,9 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
 		wake_up(&pd->wait);
 	}
 
+	/* defeat write posting to avoid spurious WAIT interrupts */
+	iic_rd(pd, ICSR);
+
 	return IRQ_HANDLED;
 }
 
-- 
1.7.12.4

next prev parent reply	other threads:[~2012-10-24 10:58 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-24 10:55 [PATCH 0/5] i2c-sh_mobile non-urgent changes Shinya Kuribayashi
2012-10-24 10:55 ` Shinya Kuribayashi
2012-10-24 10:55 ` Shinya Kuribayashi
2012-10-24 10:56 ` [PATCH 1/5] i2c: i2c-sh_mobile: calculate clock parameters at driver probing time Shinya Kuribayashi
2012-10-24 10:56   ` Shinya Kuribayashi
2012-10-24 10:56   ` Shinya Kuribayashi
2012-10-24 10:57 ` [PATCH 2/5] i2c: i2c-sh_mobile: optimize ICCH/ICCL values according to I2C bus speed Shinya Kuribayashi
2012-10-24 10:57   ` Shinya Kuribayashi
2012-10-24 10:57   ` Shinya Kuribayashi
2012-10-24 10:57 ` [PATCH 3/5] i2c: i2c-sh_mobile: fix ICCH to avoid violation of the tHD;STA timing spec Shinya Kuribayashi
2012-10-24 10:57   ` Shinya Kuribayashi
2012-10-24 10:57   ` Shinya Kuribayashi
2012-10-24 10:58 ` [PATCH 4/5] i2c: i2c-sh_mobile: support I2C hardware block with a faster operating clock Shinya Kuribayashi
2012-10-24 10:58   ` Shinya Kuribayashi
2012-10-24 10:58   ` Shinya Kuribayashi
2012-10-24 10:58 ` Shinya Kuribayashi [this message]
2012-10-24 10:58   ` [PATCH 5/5] i2c: i2c-sh_mobile: fix spurious transfer request timed out Shinya Kuribayashi
2012-10-24 10:58   ` Shinya Kuribayashi
2012-11-16  8:07 ` [PATCH 0/5] i2c-sh_mobile non-urgent changes Wolfram Sang
2012-11-16  8:07   ` Wolfram Sang
2012-11-16  8:07   ` Wolfram Sang
2012-11-16  8:53   ` Shinya Kuribayashi
2012-11-16  8:53     ` Shinya Kuribayashi
2012-11-16  8:53     ` Shinya Kuribayashi
2012-11-17 23:27     ` Guennadi Liakhovetski
2012-11-17 23:27       ` Guennadi Liakhovetski
2012-11-17 23:27       ` Guennadi Liakhovetski

find likely ancestor, descendant, or conflicting patches for this message:
dfblob:4c28358 dfblob:4c28358 dfblob:4c28358 dfblob:9411c1b
dfblob:9411c1b dfblob:9411c1b
	(help)

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