From 2099c648b929cd36c500202089ef4b7a8c14680f Mon Sep 17 00:00:00 2001 From: Maxime Vincent Date: Fri, 24 Nov 2017 13:04:08 +0100 Subject: buspirate_spi: Tristate IOs when using using pullup=on Avoid putting 3.3V on IO pins when pullup=on to avoid damage to 1.8V chips. Signed-off-by: David Hendricks Change-Id: I9ac4c6b7a0079bb1022f2d70030a6eb29996108f Reviewed-on: https://review.coreboot.org/23864 Tested-by: build bot (Jenkins) --- buspirate_spi.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/buspirate_spi.c b/buspirate_spi.c index db8b310b..fad309f9 100644 --- a/buspirate_spi.c +++ b/buspirate_spi.c @@ -543,6 +543,10 @@ int buspirate_spi_init(void) /* Set SPI config: output type, idle, clock edge, sample */ bp_commbuf[0] = 0x80 | 0xa; + if (pullup == 1) { + bp_commbuf[0] &= ~(1 << 3); + msg_pdbg("Pull-ups enabled, so using HiZ pin output! (Open-Drain mode)\n"); + } ret = buspirate_sendrecv(bp_commbuf, 1, 1); if (ret) return 1; -- cgit v1.2.3