i2c: at91_i2c: Wait for TXRDY after sending the first byte

The driver must wait for TXRDY after each byte is pushed into
the i2c FIFO before pushing the next byte. Previously this was
not done for the first byte, causing a race condition with zeros
sometimes being sent for the next byte (which is typically the
first actual data byte).

Signed-off-by: Alan Ott <alan@softiron.com>
Reviewed-by: Heiko Schocher <hs@denx.de>

diff --git a/drivers/i2c/at91_i2c.c b/drivers/i2c/at91_i2c.c
index d394044f80de5362d8b8a77862800093f878602c..20d09296a1320f672267b995af1286659981cf0d 100644 (file)
--- a/drivers/i2c/at91_i2c.c
+++ b/drivers/i2c/at91_i2c.c
@@ -72,6 +72,8 @@ static int at91_i2c_xfer_msg(struct at91_i2c_bus *bus, struct i2c_msg *msg)
 
        } else {
                writel(msg->buf[0], &reg->thr);
+               ret = at91_wait_for_xfer(bus, TWI_SR_TXRDY);
+
                for (i = 1; !ret && (i < msg->len); i++) {
                        writel(msg->buf[i], &reg->thr);
                        ret = at91_wait_for_xfer(bus, TWI_SR_TXRDY);