Initial commit

meta-google/recipes-google/gpio/gpio-ctrl/lib.sh

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+#!/bin/bash
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This is intended to be used as a library for managing gpio line values.
+# Executing this directly will do nothing.
+[ -n "${gpio_ctrl_init-}" ] && return
+
+# Map names of GPIOs to GPIO number
+# This maps a schematic name to a gpiochip and line at a specific offset
+declare -A GPIO_NAMES_TO_SCM=(
+  # Examples
+  #['SYS_RESET_N']='label=/pinctrl@f0800000/gpio@f0012000 21'
+  #['PWRBTN_N']='label=/pinctrl@f0800000/gpio@f0012000 23'
+  #['PCH_SLP_S5_R_N']='of_node=/ahb/apb/i2c@8e000/cpu_seq@6b 9'
+  #['PCH_PWRGOOD_R']='of_node=/ahb/apb/i2c@8e000/cpu_seq@6b 6'
+)
+
+# Load configurations from a known location in the filesystem to populate
+# named GPIOs
+shopt -s nullglob
+for conf in /usr/share/gpio-ctrl/conf.d/*.sh; do
+  # shellcheck source=/dev/null
+  source "$conf"
+done
+
+declare -A gpio_sysfs_lookup_cache=()
+declare -A gpio_lookup_cache=()
+
+declare -A gpio_init=()
+
+##################################################
+# Looks up the sysfs GPIO number
+# Arguments:
+#   $1: GPIO name
+# Return:
+#   0 if success, non-zero if error
+#   stdout: The GPIO number
+##################################################
+gpio_name_to_num() {
+  local name="$1"
+
+  if [ -n "${gpio_lookup_cache["$name"]+1}" ]; then
+    echo "${gpio_lookup_cache["$name"]}"
+    return 0
+  fi
+
+  local scm="${GPIO_NAMES_TO_SCM["$name"]-}"
+  if [ -z "$scm" ]; then
+    echo "Missing gpio definition: $name" >&2
+    return 1
+  fi
+  local id="${scm% *}"
+  local type="${id%=*}"
+  local val="${id#*=}"
+  local offset="${scm#* }"
+
+  local sysfs
+  if [ -n "${gpio_sysfs_lookup_cache["$id"]+1}" ]; then
+    sysfs="${gpio_sysfs_lookup_cache["$id"]}"
+  else
+    case "$type" in
+    label)
+      if ! sysfs="$(grep -xl "$val" /sys/class/gpio/gpiochip*/label)"; then
+        echo "Failed to find gpiochip: $val" >&2
+        return 1
+      fi
+      sysfs="${sysfs%/label}"
+      ;;
+    of_node)
+      for sysfs in $(echo /sys/class/gpio/gpiochip*); do
+        local link
+        # Ignore errors because not all devices have of_nodes
+        link="$(readlink -f "$sysfs/device/of_node" 2>/dev/null)" || continue
+        [ "${link#/sys/firmware/devicetree/base}" = "$val" ] && break
+        sysfs=
+      done
+      if [ -z "$sysfs" ]; then
+        echo "Failed to find gpiochip: $val" >&2
+        return 1
+      fi
+      ;;
+    *)
+      echo "Invalid GPIO type $type" >&2
+      return 1
+      ;;
+    esac
+    gpio_sysfs_lookup_cache["$id"]="$sysfs"
+  fi
+
+  local ngpio
+  ngpio=$(<"$sysfs"/ngpio)
+  if (( ngpio <= offset )); then
+    echo "$name with gpiochip $sysfs only has $ngpio but wants $offset" >&2
+    return 1
+  fi
+
+  gpio_lookup_cache["$name"]=$(( $(<"$sysfs"/base) + offset ))
+  echo "${gpio_lookup_cache["$name"]}"
+}
+
+
+##################################################
+# Populates the GPIO lookup cache
+# Most calls to gpio_name_to_num that would
+# normally cache the sysfs lookups for gpios run
+# inside subshells. This prevents them from
+# populating a global cache and greatly speeding
+# up future lookups. This call allows scripts to
+# populate the cache prior to looking up gpios.
+##################################################
+gpio_build_cache() {
+  local timeout="${1-0}"
+  shift
+  local gpios=("$@")
+
+  if (( ${#gpios[@]} == 0 )); then
+    gpios=("${!GPIO_NAMES_TO_SCM[@]}")
+  fi
+
+  local deadline=$(( timeout + SECONDS ))
+  local name
+  for name in "${gpios[@]}"; do
+    while true; do
+      gpio_name_to_num "$name" >/dev/null && break
+      if (( deadline <= SECONDS )); then
+        echo "Timed out building gpio cache" >&2
+        return 1
+      fi
+    done
+  done
+}
+
+##################################################
+# Initializes the gpio state
+# This operation is idempotent and can be applied
+# repeatedly to the same gpio. It will make sure the
+# gpio ends up in the initialized state even if it
+# was.
+# Arguments:
+#   $1: GPIO name
+# Return:
+#   0 if success, non-zero if error
+##################################################
+gpio_init_() {
+  local name="$1"
+  local num="$2"
+
+  if [ -n "${gpio_init["$name"]+1}" ]; then
+    return 0
+  fi
+
+  if [ ! -e "/sys/class/gpio/gpio$num" ]; then
+    if ! echo "$num" >'/sys/class/gpio/export'; then
+      echo "Failed to export $name gpio$num" >&2
+      return 1
+    fi
+  fi
+  local active_low=0
+  if [[ "${name%_N}" != "$name" ]]; then
+    active_low=1
+  fi
+  if ! echo "$active_low" >"/sys/class/gpio/gpio$num/active_low"; then
+    echo "Failed to set active_low for $name gpio$num" >&2
+    return 1
+  fi
+  gpio_init["$name"]=1
+}
+gpio_init() {
+  local name="$1"
+
+  # Ensure the cache is updated by not running in a subshell
+  gpio_name_to_num "$name" >/dev/null || return
+
+  gpio_init_ "$name" "$(gpio_name_to_num "$name")"
+}
+
+##################################################
+# Sets the output GPIO value.
+# Arguments:
+#   $1: GPIO name
+#   $2: GPIO value, "1" or "0"
+# Return:
+#   0 if success, non-zero if error
+##################################################
+gpio_set_value_() {
+  local name="$1"
+  local num="$2"
+  local val="$3"
+
+  gpio_init_ "$name" "$num" || return
+  if ! echo out >"/sys/class/gpio/gpio$num/direction"; then
+    echo "Failed to set output for $name gpio$num" >&2
+    return 1
+  fi
+  if ! echo "$val" >"/sys/class/gpio/gpio$num/value"; then
+    echo "Failed to set $name gpio$num = $val" >&2
+    return 1
+  fi
+}
+gpio_set_value() {
+  local name="$1"
+  local val="$2"
+
+  # Ensure the cache is updated by not running in a subshell
+  gpio_name_to_num "$name" >/dev/null || return
+
+  gpio_set_value_ "$name" "$(gpio_name_to_num "$name")" "$val"
+}
+
+##################################################
+# Get GPIO value
+# Arguments:
+#   $1: GPIO name
+# Return:
+#   0 if success, non-zero if error
+#   stdout: The value of the gpio
+##################################################
+gpio_get_value_() {
+  local name="$1"
+  local num="$2"
+
+  gpio_init_ "$name" "$num" || return
+  if ! cat "/sys/class/gpio/gpio$num/value"; then
+    echo "Failed to get $name gpio$num value" >&2
+    return 1
+  fi
+}
+gpio_get_value() {
+  local name="$1"
+
+  # Ensure the cache is updated by not running in a subshell
+  gpio_name_to_num "$name" >/dev/null || return
+
+  gpio_get_value_ "$name" "$(gpio_name_to_num "$name")"
+}
+
+gpio_ctrl_init=1

meta-google/recipes-google/gpio/gpio-ctrl_git.bb

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+SUMMARY = "GPIO control library for bash scripts"
+DESCRIPTION = "GPIO control library for bash scripts."
+LICENSE = "Apache-2.0"
+LIC_FILES_CHKSUM = "file://${COREBASE}/meta/files/common-licenses/Apache-2.0;md5=89aea4e17d99a7cacdbeed46a0096b10"
+PR = "r1"
+
+SRC_URI += "file://lib.sh"
+
+RDEPENDS:${PN} = "bash"
+
+do_install() {
+    install -d ${D}${datadir}/gpio-ctrl
+    install -m 0755 ${WORKDIR}/lib.sh ${D}${datadir}/gpio-ctrl/
+}