i2c-designware: Disable TX_EMPTY when all i2c_msg msgs has been processed

Currently we disable TX_EMPTY interrupt when buf_len is zero, but this
is wrong.  (buf_len == 0) means that all transmit data in the current
i2c_msg message has been sent out, but that doesn't necessarily mean
all i2c_msg messages have been processed.

TX_EMPTY interrupt is used as the driving force of DW I2C transactions,
so we need to keep it enabled as long as i2c_msg messages are available.

Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 8 insertions, 3 deletions

diff --git a/drivers/i2c/busses/i2c-designware.c b/drivers/i2c/busses/i2c-designware.c
index f184d822d3d4..6acbe846e9c6 100644
--- a/drivers/i2c/busses/i2c-designware.c
+++ b/drivers/i2c/busses/i2c-designware.c
@@ -415,12 +415,17 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
                         /* more bytes to be written */
                         dev->status |= STATUS_WRITE_IN_PROGRESS;
                         break;
-                } else {
+                } else
                         dev->status &= ~STATUS_WRITE_IN_PROGRESS;
-                        intr_mask &= ~DW_IC_INTR_TX_EMPTY;
-                }
         }
 
+        /*
+         * If i2c_msg index search is completed, we don't need TX_EMPTY
+         * interrupt any more.
+         */
+        if (dev->msg_write_idx == dev->msgs_num)
+                intr_mask &= ~DW_IC_INTR_TX_EMPTY;
+
         writel(intr_mask, dev->base + DW_IC_INTR_MASK);
 }