[S] Change in flashrom[master]: buspirate_spi: Add 'aux' programmer option to control AUX pin.

[David Norris (Code Review)]

David Norris has uploaded this change for review. ( https://review.coreboot.org/c/flashrom/+/72198 )

Change subject: buspirate_spi: Add 'aux' programmer option to control AUX pin.
......................................................................

buspirate_spi: Add 'aux' programmer option to control AUX pin.

Set aux=0 to drive AUX to GND.
Set aux=1 to drive AUX to +3.3 V (the previous behavior).

It is often convenient to use the AUX pin to control something on the
target board like a reset pin. This option allows for cases when AUX
should be driven to GND instead of +3.3 V as was the previous behavior.
Unfortunately the Bus Pirate's raw SPI mode does not appear to easily
support a High-Z mode for AUX but if I'm mistaken, "aux=z" should be
added to this patch accordingly.

Change-Id: I463ff7c57a67a3132d2fb3608f1d8408b84febd7
Signed-off-by: David A Norris 
---
M buspirate_spi.c
1 file changed, 36 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/98/72198/1

diff --git a/buspirate_spi.c b/buspirate_spi.c
index a40fb70..3aa13d4 100644
--- a/buspirate_spi.c
+++ b/buspirate_spi.c
@@ -331,6 +331,7 @@
    bool psu = false;
    unsigned char *bp_commbuf;
    int bp_commbufsize;
+	int aux = 1;

dev = extract_programmer_param_str(cfg, "dev");
    if (dev && !strlen(dev)) {
@@ -391,6 +392,17 @@
    }
    free(tmp);

+	tmp = extract_programmer_param_str(cfg, "aux");
+	if (aux) {
+		if (strcmp("1", tmp) == 0)
+			aux = 1;
+		else if (strcmp("0", tmp) == 0)
+			aux = 0;
+		else
+			msg_perr("Invalid aux state, leaving high (the default).\n");
+	}
+	free(tmp);
+
    /* Default buffer size is 19: 16 bytes data, 3 bytes control. */
 #define DEFAULT_BUFSIZE (16 + 3)
    bp_commbuf = malloc(DEFAULT_BUFSIZE);
@@ -650,6 +662,10 @@
    	bp_commbuf[0] |= (1 << 2);
    	msg_pdbg("Enabling pull-up resistors.\n");
    }
+	if (aux == 0) {
+		bp_commbuf[0] &= ~(1 << 1);
+		msg_pdbg("Setting AUX low.\n");
+	}
    if (psu) {
    	bp_commbuf[0] |= (1 << 3);
    	msg_pdbg("Enabling PSUs.\n");