Change in coreboot[master]: Snappy: hack Melfas kernel driver to prevent VTSP power drop

[Kevin Chiu (Code Review)]

Kevin Chiu has uploaded this change for review. ( https://review.coreboot.org/22858

Change subject: Snappy: hack Melfas kernel driver to prevent VTSP power drop
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Snappy: hack Melfas kernel driver to prevent VTSP power drop

Melfas kernel TS driver (melfas_mip4.c) will look up "ce"
GPIO during driver probe in ACPI _DSD.
But FW does not report "ce-gpios" but "enable-gpios" in _DSD.
Kernel will obtain GPIO from _CRS by index "0" without ID.

Melfas driver does not have separate condition
for MIT-410 so driver will set TS IC power off in probe.

FW now may need to add back "reset" pin in order to hack
this condition to let Melfas driver get "useless" GPIO
so TS IC power (VTSP) will not drop during driver probe.

BUG=b:70149336
BRANCH=reef
TEST=emerge-snappy coreboot
Change-Id: Icf0451ff0c3df97cb2474e30542a2f46ba67d82a
Signed-off-by: Kevin Chiu 
---
M src/mainboard/google/reef/variants/snappy/devicetree.cb
1 file changed, 2 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/58/22858/1

diff --git a/src/mainboard/google/reef/variants/snappy/devicetree.cb b/src/mainboard/google/reef/variants/snappy/devicetree.cb
index f40c330..4b0981e 100644
--- a/src/mainboard/google/reef/variants/snappy/devicetree.cb
+++ b/src/mainboard/google/reef/variants/snappy/devicetree.cb
@@ -198,6 +198,8 @@
    			register "desc" = ""Melfas Touchscreen""
    			register "irq" = "ACPI_IRQ_EDGE_LOW(GPIO_21_IRQ)"
    			register "probed" = "1"
+				register "reset_gpio" = "ACPI_GPIO_OUTPUT_ACTIVE_HIGH(GPIO_36)"
+				register "reset_delay_ms" = "1"
    			register "enable_gpio" = "ACPI_GPIO_OUTPUT_ACTIVE_HIGH(GPIO_152)"
    			register "enable_delay_ms" = "5"
    			register "has_power_resource" = "1"