i2c: imx: Check for I2SR_IAL after every byte

commit 1de67a3dee7a279ebe4d892b359fe3696938ec15 upstream.

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>
Tested (not extensively) on Vybrid VF500 (Toradex VF50):
Tested-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index c80793da6fb3cb196fac8fc988856b3ac213bdb1..b7413655353c658e0d660850ea7839e08678f9a2 100644 (file)
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -465,6 +465,16 @@ static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
                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;