buspirate: Add psus option
This change adds a 'psus=<on|off>' option, to control the external Vcc
state of the bus pirate, allowing hardware where the SPI flash chip is
powered by the 3V3/5V lines directly.
Change-Id: I8a7d4b40c0f7f04f6976f6757f05b61f2c9958f9
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/54887
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/flashrom.8.tmpl b/flashrom.8.tmpl
index e67cdea..9ec4d77 100644
--- a/flashrom.8.tmpl
+++ b/flashrom.8.tmpl
@@ -890,7 +890,21 @@
More information about the Bus Pirate pull-up resistors and their purpose is available
.URLB "http://dangerousprototypes.com/docs/Practical_guide_to_Bus_Pirate_pull-up_resistors" \
"in a guide by dangerousprototypes" .
-Only the external supply voltage (Vpu) is supported as of this writing.
+.sp
+The state of the Bus Pirate power supply pins is controllable through an optional
+.B psus
+parameter. Syntax is
+.sp
+.B " flashrom -p buspirate_spi:psus=state"
+.sp
+where
+.B state
+can be
+.BR on " or " off .
+This allows the bus pirate to power the ROM chip directly. This may also be used to provide the
+required pullup voltage (when using the
+.B pullups
+option), by connecting the Bus Pirate's Vpu input to the appropriate Vcc pin.
.SS
.BR "pickit2_spi " programmer
.IP