[PATCH] i2c: designware: slave should do WRITE_RECEIVED before SLAVE_STOP

[tianye@sugon.com]

From: Tian Ye <tianye@sugon.com>

Sometimes when designware slave receive 3byte in high speed mode:
0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
I2C_SLAVE_WRITE_REQUESTED
I2C_SLAVE_WRITE_RECEIVED
0x1 STATUS SLAVE_ACTIVITY=0 : RAW_INTR_STAT=0x714 : INTR_STAT=0x204
I2C_SLAVE_WRITE_RECEIVED
I2C_SLAVE_STOP
0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
I2C_SLAVE_WRITE_REQUESTED
I2C_SLAVE_WRITE_RECEIVED

When second slave interrupt occus:slave rx fifo receive two bytes and
stop interrupt occus at the same time.

Signed-off-by: Tian Ye <tianye@sugon.com>
---
 drivers/i2c/busses/i2c-designware-slave.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index 0d15f4c1e9f7..801d84fa7e7d 100644
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -158,6 +158,7 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
 {
 	u32 raw_stat, stat, enabled, tmp;
 	u8 val = 0, slave_activity;
+	u32 rx_valid;
 
 	regmap_read(dev->map, DW_IC_ENABLE, &enabled);
 	regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &raw_stat);
@@ -179,11 +180,14 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
 					&val);
 		}
 
-		regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);
-		val = tmp;
-		if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
-				     &val))
-			dev_vdbg(dev->dev, "Byte %X acked!", val);
+		regmap_read(dev, DW_IC_RXFLR, &rx_valid);
+		for (; rx_valid > 0; rx_valid--) {
+			regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);
+			val = tmp;
+			if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
+					     &val))
+				dev_vdbg(dev->dev, "Byte %X acked!", val);
+		}
 	}
 
 	if (stat & DW_IC_INTR_RD_REQ) {
-- 
2.25.1