pw_gpio: Add new module and interfaces

NOTE: this module will be renamed `pw_digital_io` immediately in a
follow-up change.

The Digital IO interface represents individual GPIO lines that support
some combination of input, output, and/or interrupt functionality.
The choice of supported capability, and most other configuration details
are left up to the backend implementation.

Change-Id: I27437464ff918592e69a0bdbcbe005c68f2e9ef5
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/94100
Reviewed-by: Ewout van Bekkum <[email protected]>
Reviewed-by: Wyatt Hepler <[email protected]>
Commit-Queue: Anton Markov <[email protected]>

CMakeLists.txt

@@ -40,6 +40,7 @@ add_subdirectory(pw_cpu_exception EXCLUDE_FROM_ALL)
 add_subdirectory(pw_cpu_exception_cortex_m EXCLUDE_FROM_ALL)
 add_subdirectory(pw_file EXCLUDE_FROM_ALL)
 add_subdirectory(pw_function EXCLUDE_FROM_ALL)
+add_subdirectory(pw_gpio EXCLUDE_FROM_ALL)
 add_subdirectory(pw_hdlc EXCLUDE_FROM_ALL)
 add_subdirectory(pw_interrupt EXCLUDE_FROM_ALL)
 add_subdirectory(pw_interrupt_cortex_m EXCLUDE_FROM_ALL)

PIGWEED_MODULES

@@ -38,6 +38,7 @@ pw_env_setup
 pw_file
 pw_function
 pw_fuzzer
+pw_gpio
 pw_hdlc
 pw_hex_dump
 pw_i2c

pw_build/generated_pigweed_modules_lists.gni

@@ -68,6 +68,7 @@ declare_args() {
   dir_pw_file = get_path_info("../pw_file", "abspath")
   dir_pw_function = get_path_info("../pw_function", "abspath")
   dir_pw_fuzzer = get_path_info("../pw_fuzzer", "abspath")
+  dir_pw_gpio = get_path_info("../pw_gpio", "abspath")
   dir_pw_hdlc = get_path_info("../pw_hdlc", "abspath")
   dir_pw_hex_dump = get_path_info("../pw_hex_dump", "abspath")
   dir_pw_i2c = get_path_info("../pw_i2c", "abspath")
@@ -203,6 +204,7 @@ declare_args() {
     dir_pw_file,
     dir_pw_function,
     dir_pw_fuzzer,
+    dir_pw_gpio,
     dir_pw_hdlc,
     dir_pw_hex_dump,
     dir_pw_i2c,
@@ -304,6 +306,7 @@ declare_args() {
     "$dir_pw_file:tests",
     "$dir_pw_function:tests",
     "$dir_pw_fuzzer:tests",
+    "$dir_pw_gpio:tests",
     "$dir_pw_hdlc:tests",
     "$dir_pw_hex_dump:tests",
     "$dir_pw_i2c:tests",
@@ -395,6 +398,7 @@ declare_args() {
     "$dir_pw_file:docs",
     "$dir_pw_function:docs",
     "$dir_pw_fuzzer:docs",
+    "$dir_pw_gpio:docs",
     "$dir_pw_hdlc:docs",
     "$dir_pw_hex_dump:docs",
     "$dir_pw_i2c:docs",

pw_gpio/BUILD.bazel

@@ -0,0 +1,48 @@
+# Copyright 2020 The Pigweed Authors
+#
+# 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
+#
+#     https://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.
+
+load(
+    "//pw_build:pigweed.bzl",
+    "pw_cc_library",
+    "pw_cc_test",
+)
+
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+pw_cc_library(
+    name = "pw_gpio",
+    srcs = ["gpio.cc"],
+    hdrs = [
+        "public/pw_gpio/gpio.h",
+        "public/pw_gpio/internal/conversions.h",
+    ],
+    includes = ["public"],
+    deps = [
+        "//pw_assert",
+        "//pw_function",
+        "//pw_result",
+        "//pw_status",
+    ],
+)
+
+pw_cc_test(
+    name = "gpio_test",
+    srcs = ["gpio_test.cc"],
+    deps = [
+        ":pw_gpio",
+        "//pw_unit_test",
+    ],
+)

pw_gpio/BUILD.gn

@@ -0,0 +1,53 @@
+# Copyright 2020 The Pigweed Authors
+#
+# 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
+#
+#     https://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.
+
+import("//build_overrides/pigweed.gni")
+
+import("$dir_pw_build/target_types.gni")
+import("$dir_pw_docgen/docs.gni")
+import("$dir_pw_toolchain/generate_toolchain.gni")
+import("$dir_pw_unit_test/test.gni")
+
+config("public_include_path") {
+  include_dirs = [ "public" ]
+  visibility = [ ":*" ]
+}
+
+pw_source_set("pw_gpio") {
+  public_configs = [ ":public_include_path" ]
+  public = [
+    "public/pw_gpio/gpio.h",
+    "public/pw_gpio/internal/conversions.h",
+  ]
+  sources = [ "gpio.cc" ]
+  public_deps = [
+    dir_pw_assert,
+    dir_pw_function,
+    dir_pw_result,
+    dir_pw_status,
+  ]
+}
+
+pw_doc_group("docs") {
+  sources = [ "docs.rst" ]
+}
+
+pw_test_group("tests") {
+  tests = [ ":gpio_test" ]
+}
+
+pw_test("gpio_test") {
+  sources = [ "gpio_test.cc" ]
+  deps = [ ":pw_gpio" ]
+}

pw_gpio/CMakeLists.txt

@@ -0,0 +1,43 @@
+# Copyright 2020 The Pigweed Authors
+#
+# 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
+#
+#     https://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.
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+pw_add_module_library(pw_gpio
+  HEADERS
+    public/pw_gpio/gpio.h
+    public/pw_gpio/internal/conversions.h
+  PUBLIC_INCLUDES
+    public
+  SOURCES
+    gpio.cc
+  PUBLIC_DEPS
+    pw_assert
+    pw_function
+    pw_result
+    pw_status
+)
+if(Zephyr_FOUND AND CONFIG_PIGWEED_GPIO)
+  zephyr_link_libraries(pw_gpio)
+endif()
+
+pw_add_test(pw_gpio.stream_test
+  SOURCES
+    gpio_test.cc
+  DEPS
+    pw_gpio
+  GROUPS
+    modules
+    pw_gpio
+)

pw_gpio/OWNERS

@@ -0,0 +1 @@
+[email protected]

pw_gpio/README.md

@@ -0,0 +1,7 @@
+This directory contains the `pw` Digital IO Hardware Abstraction Layer (HAL).
+This HAL defines interfaces for working with Digital IO lines that provide
+different combinations of capabilities (input, output, and/or interrupts).
+Hardware specific backends provide implementations of these interfaces for
+different hardware platforms.
+
+Warning: This module is under construction and may not be ready for use.