V4L/DVB (11074): au0828: fix i2c enumeration bug

[karo-tx-linux.git] / drivers / media / video / au0828 / au0828-i2c.c

diff --git a/drivers/media/video/au0828/au0828-i2c.c b/drivers/media/video/au0828/au0828-i2c.c
index ee3e3040d54cddd3223a8945543c2d19be4f1571..d57a38f5c738a57679d8ff2411475159cb2774ce 100644 (file)
--- a/drivers/media/video/au0828/au0828-i2c.c
+++ b/drivers/media/video/au0828/au0828-i2c.c
@@ -156,6 +156,24 @@ static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
 
        dprintk(4, "SEND: %02x\n", msg->addr);
 
+       /* Deal with i2c_scan */
+       if (msg->len == 0) {
+               /* The analog tuner detection code makes use of the SMBUS_QUICK
+                  message (which involves a zero length i2c write).  To avoid
+                  checking the status register when we didn't strobe out any
+                  actual bytes to the bus, just do a read check.  This is
+                  consistent with how I saw i2c device checking done in the
+                  USB trace of the Windows driver */
+               au0828_write(dev, REG_200, 0x20);
+               if (!i2c_wait_done(i2c_adap))
+                       return -EIO;
+
+               if (i2c_wait_read_ack(i2c_adap))
+                       return -EIO;
+
+               return 0;
+       }
+
        for (i = 0; i < msg->len;) {
 
                dprintk(4, " %02x\n", msg->buf[i]);