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authorDoug Anderson <dianders@chromium.org>2014-10-28 14:09:47 -0700
committerPatrick Georgi <pgeorgi@google.com>2015-04-10 20:49:39 +0200
commitf3d5736c8f079321af3cc8dc7210dc0b1a05a327 (patch)
tree7ca19f0d437062ddf959e0babb6d3c47e06b66ac
parentb262c726252dc870b373c1e2736699ce172788b1 (diff)
veyron: Change eMMC enable pin to be pulled (not driven) high
The eMMC enable pin is in a 3.3V IO domain. Unfortunately the eMMC expects this pin to be 1.8V. The way we were driving this pin would cause the eMMC to pull power through this pin and that was causing current leaks. In future revisions of hardware we should move this pin somewhere more legit. However, in the current hardware we can get things working pretty well by using a pullup to "drive" this pin. This will work in conjunction with the external 100K pullup to give a somewhat reasonable voltage. The eMMC will also not be able to pull much current through this pin, so it can't leak too badly. BRANCH=none BUG=chrome-os-partner:33319 TEST=Boot a kernel that doesn't touch the mux/pulls and see no leak: dut-control --port=${SERVO} vcc_flash_ma -t 5 Change-Id: Ibc25cd090d826c8215be24a0b5c11d97b5281700 Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Original-Commit-Id: 26e7a9d7e067ed4dd859387ee63bf654ab9dc529 Original-Change-Id: Iadfc1477cd478773cc9d159e3fbc22b66b8f0f78 Original-Signed-off-by: Doug Anderson <dianders@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/226039 Original-Reviewed-by: Julius Werner <jwerner@chromium.org> Reviewed-on: http://review.coreboot.org/9545 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
-rw-r--r--src/mainboard/google/veyron_jerry/mainboard.c7
-rw-r--r--src/mainboard/google/veyron_pinky/mainboard.c7
2 files changed, 12 insertions, 2 deletions
diff --git a/src/mainboard/google/veyron_jerry/mainboard.c b/src/mainboard/google/veyron_jerry/mainboard.c
index 2442472b67..0166796b9e 100644
--- a/src/mainboard/google/veyron_jerry/mainboard.c
+++ b/src/mainboard/google/veyron_jerry/mainboard.c
@@ -79,7 +79,12 @@ static void configure_emmc(void)
writel(IOMUX_EMMCPWREN, &rk3288_grf->iomux_emmcpwren);
writel(IOMUX_EMMCCMD, &rk3288_grf->iomux_emmccmd);
- gpio_output(GPIO(7, B, 4), 1); /* EMMC_RST_L */
+ /*
+ * Use a pullup instead of a drive since the output is 3.3V and
+ * really should be 1.8V (oops). The external pulldown will help
+ * bring the voltage down if we only drive with a pullup here.
+ */
+ gpio_input_pullup(GPIO(7, B, 4)); /* EMMC_RST_L */
}
static void configure_codec(void)
diff --git a/src/mainboard/google/veyron_pinky/mainboard.c b/src/mainboard/google/veyron_pinky/mainboard.c
index 2442472b67..0166796b9e 100644
--- a/src/mainboard/google/veyron_pinky/mainboard.c
+++ b/src/mainboard/google/veyron_pinky/mainboard.c
@@ -79,7 +79,12 @@ static void configure_emmc(void)
writel(IOMUX_EMMCPWREN, &rk3288_grf->iomux_emmcpwren);
writel(IOMUX_EMMCCMD, &rk3288_grf->iomux_emmccmd);
- gpio_output(GPIO(7, B, 4), 1); /* EMMC_RST_L */
+ /*
+ * Use a pullup instead of a drive since the output is 3.3V and
+ * really should be 1.8V (oops). The external pulldown will help
+ * bring the voltage down if we only drive with a pullup here.
+ */
+ gpio_input_pullup(GPIO(7, B, 4)); /* EMMC_RST_L */
}
static void configure_codec(void)