xilinx_xiic: Fix transfer initialisation

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")

hs: Fixed DOS line endings
    added missing '\n'
    Fixed git commit description style

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

diff --git a/drivers/i2c/xilinx_xiic.c b/drivers/i2c/xilinx_xiic.c
index e4ca0ab..5ce0f86 100644 (file)
--- 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\n");
+
+       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);