[PATCH] scx200_acb: Fix the state machine
Thomas Andrews [Sat, 1 Jul 2006 15:05:12 +0000 (17:05 +0200)]
Fix the scx200_acb state machine:

* Nack was sent one byte too late on reads >= 2 bytes.
* Stop bit was set one byte too late on reads.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/i2c/busses/scx200_acb.c

index 22a3eda..454086a 100644 (file)
@@ -184,21 +184,21 @@ static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
                break;
 
        case state_read:
-               /* Set ACK if receiving the last byte */
-               if (iface->len == 1)
+               /* Set ACK if _next_ byte will be the last one */
+               if (iface->len == 2)
                        outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
                else
                        outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 
-               *iface->ptr++ = inb(ACBSDA);
-               --iface->len;
-
-               if (iface->len == 0) {
+               if (iface->len == 1) {
                        iface->result = 0;
                        iface->state = state_idle;
                        outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
                }
 
+               *iface->ptr++ = inb(ACBSDA);
+               --iface->len;
+
                break;
 
        case state_write: