[flashrom] Bus Pirate pull-up resistors patch.

[Brian Salcedo]

When working with some flash chips using the Bus Pirate programmer, the
use of the Bus Pirate's on-board pull-up resistors is sometimes
necessary.

Use of said pull-up resistors requires the user to apply a voltage to
the VPU pin of the Bus Pirate, and then command it to use them.

Included is a patch to initialize the Bus Pirate's pull-up resistors
with a 'pullups=1' at the command line:

e.g. flashrom -p buspirate_spi:dev=/dev/buspirate,pullups=1

Here is a link to information pertaining to what this patch does.
http://dangerousprototypes.com/docs/SPI_(binary)#0100wxyz_-_Configure_periph...

Currently, flashrom sends 0x4b, which does not set the "pull-ups" bit
high. Optionally sending 0x4f instead will enable them.

--- trunk/buspirate_spi.c	2013-01-01 04:03:42.507602657 -0500
+++ src/flashrom/buspirate_spi.c	2013-01-01 04:02:25.847578106
-0500 @@ -204,11 +204,13 @@
    char *dev = NULL;
    char *speed = NULL;
    char *tmp;
+	char *pullups = NULL;
    unsigned int fw_version_major = 0;
    unsigned int fw_version_minor = 0;
    int spispeed = 0x7;
    int ret = 0;
    int i;
+	int ipullup = 0;

dev = extract_programmer_param("dev");
    if (dev && !strlen(dev)) {
@@ -220,6 +222,16 @@
    	return 1;
    }

+	/* enable pull-up resistors? */
+	pullups = extract_programmer_param("pullups");
+	if(pullups) {
+		ipullup = atoi(pullups);
+
+		if(ipullup == 1) {
+			msg_pinfo("Enabled Bus Pirate pull-up
resistors.\n");
+		}
+	}
+
    speed = extract_programmer_param("spispeed");
    if (speed) {
    	for (i = 0; spispeeds[i].name; i++)
@@ -395,7 +407,7 @@
    }

/* Initial setup (SPI peripherals config): Enable power, CS
high, AUX */
-	bp_commbuf[0] = 0x40 | 0xb;
+	bp_commbuf[0] = 0x40 | ((ipullup == 1) ? 0xf : 0xb);
    ret = buspirate_sendrecv(bp_commbuf, 1, 1);
    if (ret)
    	return 1;

Happy New Year!
Signed-off-by: Brian Salcedo