dediprog: fix SPI clock setting

Avoid setting SPI speed on firmware versions < 5.0.0 and note this
limitation in the man page.
Use the correct offset of the "12M" element in the spispeeds array to
match our manpage and the default of Dediprog's dpcmd.

Corresponding to flashrom svn r1674.
Signed-off-by: Patrick Georgi <patrick.georgi@secunet.com>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

dediprog.c

@@ -184,12 +184,15 @@ static const struct dediprog_spispeeds spispeeds[] = {
  */
 static int dediprog_set_spi_speed(unsigned int spispeed_idx)
 {
-	int ret;
+	if (dediprog_firmwareversion < FIRMWARE_VERSION(5, 0, 0)) {
+		msg_pwarn("Skipping to set SPI speed because firmware is too old.\n");
+		return 0;
+	}
 
-	msg_pdbg("SPI speed is %sHz\n", spispeeds[spispeed_idx].name);
+	msg_pdbg("SPI speed is %s Hz\n", spispeeds[spispeed_idx].name);
 
-	ret = usb_control_msg(dediprog_handle, 0x42, 0x61, spispeeds[spispeed_idx].speed, 0xff,
-			      NULL, 0x0, DEFAULT_TIMEOUT);
+	int ret = usb_control_msg(dediprog_handle, 0x42, 0x61, spispeeds[spispeed_idx].speed, 0xff,
+				  NULL, 0x0, DEFAULT_TIMEOUT);
 	if (ret != 0x0) {
 		msg_perr("Command Set SPI Speed 0x%x failed!\n", spispeeds[spispeed_idx].speed);
 		return 1;
@@ -789,7 +792,7 @@ int dediprog_init(void)
 {
 	struct usb_device *dev;
 	char *voltage, *device, *spispeed, *target_str;
-	int spispeed_idx = 2;
+	int spispeed_idx = 1;
 	int millivolt = 3500;
 	long usedevice = 0;
 	long target = 1;
@@ -806,7 +809,7 @@ int dediprog_init(void)
 			}
 		}
 		if (!spispeeds[i].name) {
-			msg_perr("Error: Invalid 'spispeed' value.\n");
+			msg_perr("Error: Invalid spispeed value: '%s'.\n", spispeed);
 			free(spispeed);
 			return 1;
 		}

flashrom.8

@@ -683,7 +683,8 @@ Usage example to select the second device:
 .sp
 An optional
 .B spispeed
-parameter specifies the frequency of the SPI bus. Syntax is
+parameter specifies the frequency of the SPI bus. The firmware on the device needs to be 5.0.0 or newer.
+Syntax is
 .sp
 .B "  flashrom \-p dediprog:spispeed=frequency"
 .sp