[U-Boot] [PATCH v3 2/2] xilinx_xiic: Fix transfer initialisation

[Melin Tomas]

Prior to starting a new transfer, conditionally wait for bus to not
be busy.

Reinitialise controller as otherwise operation is not stable.
For reference, see linux kernel commit: 9656eeebf3f1 ("i2c: Revert
"i2c: xiic: Do not reset controller before every transfer"")

Signed-off-by: Tomas Melin <tomas.melin at vaisala.com>
---

Changes in v2:
- Change variable declaration order
- Change timeout to 3ms

Changes in v3:
- Change timeout to 1000ms
- Add print in case of timeout

 drivers/i2c/xilinx_xiic.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/i2c/xilinx_xiic.c b/drivers/i2c/xilinx_xiic.c
index e4ca0ab936..afb5f21b75 100644
--- a/drivers/i2c/xilinx_xiic.c
+++ b/drivers/i2c/xilinx_xiic.c
@@ -266,8 +266,20 @@ static void xiic_reinit(struct xilinx_xiic_priv *priv)
 
 static int xilinx_xiic_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
 {
+	struct xilinx_xiic_priv *priv = dev_get_priv(dev);
 	int ret = 0;
 
+	ret = wait_for_bit_8(priv->base + XIIC_SR_REG_OFFSET,
+			     XIIC_SR_BUS_BUSY_MASK, false, 1000, true);
+
+	if (ret == -ETIMEDOUT)
+		dev_err(dev, "timeout waiting for bus not busy condition");
+
+	if (ret)
+		return ret;
+
+	xiic_reinit(priv);
+
 	for (; nmsgs > 0; nmsgs--, msg++) {
 		if (msg->flags & I2C_M_RD)
 			ret = xilinx_xiic_read_common(dev, msg, nmsgs);
-- 
2.17.2