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authorKevin Chiu <Kevin.Chiu@quantatw.com>2017-12-14 07:27:37 +0800
committerAaron Durbin <adurbin@chromium.org>2017-12-15 16:11:38 +0000
commitea0aa33ea3be908b54a07984dd8072ab1b284e90 (patch)
tree7de285b4e9aacc01b07070bd637c8b81dcc2092e /src
parent91ea9f0b90546c6c085eec2e3dcfe78032dc1ad8 (diff)
downloadcoreboot-ea0aa33ea3be908b54a07984dd8072ab1b284e90.tar.xz
mb/google/snappy: add reset pin for Melfas touch controller
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 be not off during driver probe by itself. BUG=b:70149336 BRANCH=reef TEST=emerge-snappy coreboot Change-Id: Icf0451ff0c3df97cb2474e30542a2f46ba67d82a Signed-off-by: Kevin Chiu <Kevin.Chiu@quantatw.com> Reviewed-on: https://review.coreboot.org/22858 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Diffstat (limited to 'src')
-rw-r--r--src/mainboard/google/reef/variants/snappy/devicetree.cb11
1 files changed, 11 insertions, 0 deletions
diff --git a/src/mainboard/google/reef/variants/snappy/devicetree.cb b/src/mainboard/google/reef/variants/snappy/devicetree.cb
index f40c3307c6..6adf94c1b3 100644
--- a/src/mainboard/google/reef/variants/snappy/devicetree.cb
+++ b/src/mainboard/google/reef/variants/snappy/devicetree.cb
@@ -198,6 +198,17 @@ chip soc/intel/apollolake
register "desc" = ""Melfas Touchscreen""
register "irq" = "ACPI_IRQ_EDGE_LOW(GPIO_21_IRQ)"
register "probed" = "1"
+ # Melfas TS IC doesn't have reset pin design, current FW also not
+ # declare "ce-gpios" in ACPI _DSD to let Melfas TS driver to know
+ # "enable gpio#152 (VTSP) but because of kernel bug & Melfas TS driver
+ # is unable to separate clear power sequence path for certain
+ # TS IC (ex: MIT-410) and kernel will still obstain GPIO from _CRS
+ # by index "0" since no matched "gpio" in ACPI _DSD.
+ # coreboot needs to have "dummy pin" as workaround in order to let
+ # kernel driver grab "useless" GPIO to prevent Melfas TS driver cut
+ # power by driver itself.
+ 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"