i2c: owl: Clear NACK and BUS error bits

When the NACK and BUS error bits are set by the hardware, the driver is
responsible for clearing them by writing "1" into the corresponding
status registers.

Hence perform the necessary operations in owl_i2c_interrupt().

Fixes: d211e62af466 ("i2c: Add Actions Semiconductor Owl family S900 I2C driver")
Reported-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
diff --git a/drivers/i2c/busses/i2c-owl.c b/drivers/i2c/busses/i2c-owl.c
index 672f1f2..a163b8f 100644
--- a/drivers/i2c/busses/i2c-owl.c
+++ b/drivers/i2c/busses/i2c-owl.c
@@ -176,6 +176,9 @@
 	fifostat = readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT);
 	if (fifostat & OWL_I2C_FIFOSTAT_RNB) {
 		i2c_dev->err = -ENXIO;
+		/* Clear NACK error bit by writing "1" */
+		owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOSTAT,
+				   OWL_I2C_FIFOSTAT_RNB, true);
 		goto stop;
 	}
 
@@ -183,6 +186,9 @@
 	stat = readl(i2c_dev->base + OWL_I2C_REG_STAT);
 	if (stat & OWL_I2C_STAT_BEB) {
 		i2c_dev->err = -EIO;
+		/* Clear BUS error bit by writing "1" */
+		owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_STAT,
+				   OWL_I2C_STAT_BEB, true);
 		goto stop;
 	}