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 | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 34648df7f1a6..1db1e2f5296e 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -483,6 +483,24 @@ 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; + + dev_dbg(&i2c_imx->adapter.dev, "<%s> Arbitration lost\n", __func__); + /* + * i2sr_clr_opcode is the value to clear all interrupts. + * Here we want to clear only I2SR_IAL, so we write + * ~i2sr_clr_opcode with just the I2SR_IAL bit toggled. + */ + 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;