V4L/DVB (12780): tm6000: Improve handling of SMBus Write Byte commands followed by...

SMBus Write Byte commands followed by a read command on the same I2C
address are not sent out to the chip as they wouldn't have any effect.

Signed-off-by: Michel Ludwig <michel.ludwig@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/staging/tm6000/tm6000-i2c.c b/drivers/staging/tm6000/tm6000-i2c.c
index 80252b74669996f16690c2185586b48ef1030625..2a8c169cf07f49436e8eaaaef6128beed578dcb5 100644 (file)
--- a/drivers/staging/tm6000/tm6000-i2c.c
+++ b/drivers/staging/tm6000/tm6000-i2c.c
@@ -141,6 +141,13 @@ static int tm6000_i2c_xfer(struct i2c_adapter *i2c_adap,
                                        printk(" %02x", msgs[i].buf[byte]);
                        }
 
+                       /* SMBus Write Byte command followed by a read command */
+                       if(msgs[i].len == 1 && i+1 < num && msgs[i+1].flags & I2C_M_RD
+                                           && msgs[i+1].addr == msgs[i].addr) {
+                               prev_reg = msgs[i].buf[0];
+                               continue;
+                       }
+
                        rc = tm6000_read_write_usb (dev,
                                USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                                REQ_16_SET_GET_I2CSEQ,