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@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
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;
--
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
