base-files: gpio switch: add named GPIO support

Previously, gpio_switch only accepts GPIO pin number as input. Once a
GPIO pin is exported and named by device tree, its pin state cannot be
configured and saved across reboots by UCI.

This patch adds support for named GPIO pins. Thus GPIO pin can be
exported by device tree with active high/low correctly configured,
having human-readable name in /sys/class/gpio/ is also now possible.

More importantly, GPIO pins which are referenced by name will be immune
from pin mapping breakage while unintentional pin number changes are
introduced by kernel or driver updates.

Signed-off-by: Kuan-Yi Li <kyli@abysm.org>
This commit is contained in:
Kuan-Yi Li 2019-08-11 03:23:28 +08:00 committed by Jo-Philipp Wich
parent a4c0767fbc
commit c5bf9a8ced
3 changed files with 32 additions and 14 deletions

View File

@ -12,7 +12,7 @@ include $(INCLUDE_DIR)/version.mk
include $(INCLUDE_DIR)/feeds.mk
PKG_NAME:=base-files
PKG_RELEASE:=222
PKG_RELEASE:=223
PKG_FLAGS:=nonshared
PKG_FILE_DEPENDS:=$(PLATFORM_DIR)/ $(GENERIC_PLATFORM_DIR)/base-files/

View File

@ -16,21 +16,39 @@ load_gpio_switch()
config_get name "$1" name
config_get value "$1" value 0
local gpio_path="/sys/class/gpio/gpio${gpio_pin}"
# export GPIO pin for access
[ -d "$gpio_path" ] || {
echo "$gpio_pin" >/sys/class/gpio/export
# we need to wait a bit until the GPIO appears
[ -d "$gpio_path" ] || sleep 1
[ -z "$gpio_pin" ] && {
echo >&2 "Skipping gpio_switch '$name' due to missing gpio_pin"
return 1
}
# direction attribute only exists if the kernel supports changing the
# direction of a GPIO
if [ -e "${gpio_path}/direction" ]; then
# set the pin to output with high or low pin value
{ [ "$value" = "0" ] && echo "low" || echo "high"; } >"$gpio_path/direction"
local gpio_path
if [ -n "$(echo "$gpio_pin" | grep -E "^[0-9]+$")" ]; then
gpio_path="/sys/class/gpio/gpio${gpio_pin}"
# export GPIO pin for access
[ -d "$gpio_path" ] || {
echo "$gpio_pin" >/sys/class/gpio/export
# we need to wait a bit until the GPIO appears
[ -d "$gpio_path" ] || sleep 1
}
# direction attribute only exists if the kernel supports changing the
# direction of a GPIO
if [ -e "${gpio_path}/direction" ]; then
# set the pin to output with high or low pin value
{ [ "$value" = "0" ] && echo "low" || echo "high"; } \
>"$gpio_path/direction"
else
{ [ "$value" = "0" ] && echo "0" || echo "1"; } \
>"$gpio_path/value"
fi
else
{ [ "$value" = "0" ] && echo "0" || echo "1"; } >"$gpio_path/value"
gpio_path="/sys/class/gpio/${gpio_pin}"
[ -d "$gpio_path" ] && {
{ [ "$value" = "0" ] && echo "0" || echo "1"; } \
>"$gpio_path/value"
}
fi
}

View File

@ -573,7 +573,7 @@ ucidef_add_gpio_switch() {
json_select_object gpioswitch
json_select_object "$cfg"
json_add_string name "$name"
json_add_int pin "$pin"
json_add_string pin "$pin"
json_add_int default "$default"
json_select ..
json_select ..