[PATCH 2/3] i2c: imx: Check for I2SR_IAL after every byte

[Christian Eggers]

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 at arri.de>
Cc: stable at vger.kernel.org
---
 drivers/i2c/busses/i2c-imx.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d8b2e632dd10..9d9b668ec7f2 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -479,6 +479,20 @@ 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) {
+		unsigned int temp = i2c_imx->i2csr;
+
+		dev_dbg(&i2c_imx->adapter.dev, "<%s> Arbitration lost\n", __func__);
+		temp &= ~I2SR_IAL;
+		temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL);
+		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
+
+		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

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