Patrick Georgi (pgeorgi@google.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/9545
-gerrit
commit 18b8c2bfb31188f025e7d3f93fd3883e9c6bc175 Author: Doug Anderson dianders@chromium.org Date: Tue Oct 28 14:09:47 2014 -0700
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 --- src/mainboard/google/veyron_jerry/mainboard.c | 7 ++++++- src/mainboard/google/veyron_pinky/mainboard.c | 7 ++++++- 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 2442472..0166796 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 2442472..0166796 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)