V4L/DVB (12778): tm6000: Fix SMBus Read Byte command

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

1 files changed, 27 insertions, 10 deletions

diff --git a/drivers/staging/tm6000/tm6000-i2c.c b/drivers/staging/tm6000/tm6000-i2c.c
index 5e165ed25eee..80252b746699 100644
--- a/drivers/staging/tm6000/tm6000-i2c.c
+++ b/drivers/staging/tm6000/tm6000-i2c.c
@@ -3,6 +3,9 @@
 
    Copyright (C) 2006-2007 Mauro Carvalho Chehab <mchehab@infradead.org>
 
+   Copyright (C) 2007 Michel Ludwig <michel.ludwig@gmail.com>
+        - Fix SMBus Read Byte command
+
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation version 2
@@ -92,6 +95,7 @@ static int tm6000_i2c_xfer(struct i2c_adapter *i2c_adap,
 {
         struct tm6000_core *dev = i2c_adap->algo_data;
         int addr, rc, i, byte;
+        u8 prev_reg = 0;
 
         if (num <= 0)
                 return 0;
@@ -100,25 +104,31 @@ static int tm6000_i2c_xfer(struct i2c_adapter *i2c_adap,
                 i2c_dprintk(2,"%s %s addr=0x%x len=%d:",
                          (msgs[i].flags & I2C_M_RD) ? "read" : "write",
                          i == num - 1 ? "stop" : "nonstop", addr, msgs[i].len);
-
                 if (!msgs[i].len) {
                         /* Do I2C scan */
                         rc=tm6000_i2c_scan(i2c_adap, addr);
                 } else if (msgs[i].flags & I2C_M_RD) {
-                        char buf[msgs[i].len];
-                        memcpy(buf,msgs[i].buf, msgs[i].len-1);
-                        buf[msgs[i].len-1]=0;
-
                         /* Read bytes */
         /* I2C is assumed to have always a subaddr at the first byte of the
            message bus. Also, the first i2c value of the answer is returned
            out of message data.
          */
-                        rc = tm6000_read_write_usb (dev,
-                                USB_DIR_IN | USB_TYPE_VENDOR,
-                                REQ_16_SET_GET_I2CSEQ,
-                                addr|(*msgs[i].buf)<<8, 0,
-                                msgs[i].buf, msgs[i].len);
+                        /* SMBus Read Byte command */
+                        if(msgs[i].len == 1) {
+                                // we use the previously used register to read from
+                                rc = tm6000_read_write_usb (dev,
+                                        USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+                                        REQ_16_SET_GET_I2CSEQ,
+                                        addr | prev_reg<<8, 0,
+                                        msgs[i].buf, msgs[i].len);
+                        }
+                        else {
+                                rc = tm6000_read_write_usb (dev,
+                                        USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+                                        REQ_16_SET_GET_I2CSEQ,
+                                        addr|(*msgs[i].buf)<<8, 0,
+                                        msgs[i].buf, msgs[i].len);
+                        }
                         if (i2c_debug>=2) {
                                 for (byte = 0; byte < msgs[i].len; byte++) {
                                         printk(" %02x", msgs[i].buf[byte]);
@@ -136,6 +146,13 @@ static int tm6000_i2c_xfer(struct i2c_adapter *i2c_adap,
                                 REQ_16_SET_GET_I2CSEQ,
                                 addr|(*msgs[i].buf)<<8, 0,
                                 msgs[i].buf+1, msgs[i].len-1);
+
+                        if(msgs[i].len >= 1) {
+                                prev_reg = msgs[i].buf[0];
+                        }
+                        else {
+                                prev_reg = 0;
+                        }
                 }
                 if (i2c_debug>=2)
                         printk("\n");