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From: Christian Eggers <ceggers@arri.de>
To: "Oleksij Rempel" <linux@rempel-privat.de>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Fabio Estevam" <festevam@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>,
	NXP Linux Team <linux-imx@nxp.com>, <linux-i2c@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	Christian Eggers <ceggers@arri.de>, <stable@vger.kernel.org>
Subject: [PATCH v3 2/3] i2c: imx: Check for I2SR_IAL after every byte
Date: Tue, 6 Oct 2020 12:51:34 +0200	[thread overview]
Message-ID: <20201006105135.28985-3-ceggers@arri.de> (raw)
In-Reply-To: <20201006105135.28985-1-ceggers@arri.de>

Arbitration Lost (IAL) can happen after every single byte transfer. If
arbitration is lost, the I2C hardware will autonomously switch from
master mode to slave. If a transfer is not aborted in this state,
consecutive transfers will not be executed by the hardware and will
timeout.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Cc: stable@vger.kernel.org
---
 drivers/i2c/busses/i2c-imx.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 745f4071155a..bf0e94814222 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -490,6 +490,16 @@ static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx, bool atomic)
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
+
+	/* check for arbitration lost */
+	if (i2c_imx->i2csr & I2SR_IAL) {
+		dev_dbg(&i2c_imx->adapter.dev, "<%s> Arbitration lost\n", __func__);
+		i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
+
+		i2c_imx->i2csr = 0;
+		return -EAGAIN;
+	}
+
 	dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__);
 	i2c_imx->i2csr = 0;
 	return 0;
-- 
Christian Eggers
Embedded software developer

Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918
Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477
Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler


WARNING: multiple messages have this Message-ID (diff)
From: Christian Eggers <ceggers@arri.de>
To: "Oleksij Rempel" <linux@rempel-privat.de>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Fabio Estevam" <festevam@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	NXP Linux Team <linux-imx@nxp.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Christian Eggers <ceggers@arri.de>,
	linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org
Subject: [PATCH v3 2/3] i2c: imx: Check for I2SR_IAL after every byte
Date: Tue, 6 Oct 2020 12:51:34 +0200	[thread overview]
Message-ID: <20201006105135.28985-3-ceggers@arri.de> (raw)
In-Reply-To: <20201006105135.28985-1-ceggers@arri.de>

Arbitration Lost (IAL) can happen after every single byte transfer. If
arbitration is lost, the I2C hardware will autonomously switch from
master mode to slave. If a transfer is not aborted in this state,
consecutive transfers will not be executed by the hardware and will
timeout.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Cc: stable@vger.kernel.org
---
 drivers/i2c/busses/i2c-imx.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 745f4071155a..bf0e94814222 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -490,6 +490,16 @@ static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx, bool atomic)
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
+
+	/* check for arbitration lost */
+	if (i2c_imx->i2csr & I2SR_IAL) {
+		dev_dbg(&i2c_imx->adapter.dev, "<%s> Arbitration lost\n", __func__);
+		i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
+
+		i2c_imx->i2csr = 0;
+		return -EAGAIN;
+	}
+
 	dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__);
 	i2c_imx->i2csr = 0;
 	return 0;
-- 
Christian Eggers
Embedded software developer

Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918
Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477
Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler


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linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2020-10-06 11:02 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-02 15:23 [PATCH v2 0/3] i2c: imx: Fix handling of arbitration loss Christian Eggers
2020-10-02 15:23 ` Christian Eggers
2020-10-02 15:23 ` [PATCH v2 1/3] i2c: imx: Fix reset of I2SR_IAL flag Christian Eggers
2020-10-02 15:23   ` Christian Eggers
2020-10-05  8:05   ` Krzysztof Kozlowski
2020-10-05  8:05     ` Krzysztof Kozlowski
2020-10-06  6:05   ` Uwe Kleine-König
2020-10-06  6:05     ` Uwe Kleine-König
2020-10-06 10:51     ` [PATCH v3 0/3] i2c: imx: Fix handling of arbitration loss Christian Eggers
2020-10-06 10:51       ` Christian Eggers
2020-10-06 10:51       ` [PATCH v3 1/3] i2c: imx: Fix reset of I2SR_IAL flag Christian Eggers
2020-10-06 10:51         ` Christian Eggers
2020-10-06 12:06         ` David Laight
2020-10-06 12:06           ` David Laight
2020-10-06 12:30           ` Christian Eggers
2020-10-06 12:30             ` Christian Eggers
2020-10-06 12:46           ` Uwe Kleine-König
2020-10-06 12:46             ` Uwe Kleine-König
2020-10-06 12:52             ` David Laight
2020-10-06 12:52               ` David Laight
2020-10-06 10:51       ` Christian Eggers [this message]
2020-10-06 10:51         ` [PATCH v3 2/3] i2c: imx: Check for I2SR_IAL after every byte Christian Eggers
2020-10-06 10:51       ` [PATCH v3 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost Christian Eggers
2020-10-06 10:51         ` Christian Eggers
2020-10-02 15:23 ` [PATCH v2 2/3] i2c: imx: Check for I2SR_IAL after every byte Christian Eggers
2020-10-02 15:23   ` Christian Eggers
2020-10-05  8:07   ` Krzysztof Kozlowski
2020-10-05  8:07     ` Krzysztof Kozlowski
2020-10-05  9:25     ` Christian Eggers
2020-10-05  9:25       ` Christian Eggers
2020-10-02 15:23 ` [PATCH v2 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost Christian Eggers
2020-10-02 15:23   ` Christian Eggers
2020-10-05  8:16   ` Krzysztof Kozlowski
2020-10-05  8:16     ` Krzysztof Kozlowski

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