From a091b418d9a3c07adb7f2d7719ed3976dd35ee3e Mon Sep 17 00:00:00 2001
From: Mike Choi <mikechoi@meta.com>
Date: Mon, 16 Sep 2024 15:09:08 -0700
Subject: [PATCH] fan_service : Fan_service control logic to use either sysfs
 path or gpio, for detecting fan presence

Summary: [FBOSS/Platform] fan_service : Fan_service control logic to use either sysfs path or gpio, for detecting fan presence

Reviewed By: alandau, kimdo8736

Differential Revision: D62211922

fbshipit-source-id: d0fb8322da74a76ed47bf2e446096afeff88dddc
---
 cmake/PlatformFanService.cmake              |  3 ++
 fboss/platform/fan_service/BUCK             |  4 +++
 fboss/platform/fan_service/ControlLogic.cpp | 40 ++++++++++++++++-----
 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/cmake/PlatformFanService.cmake b/cmake/PlatformFanService.cmake
index c8a38b9efe8d8..9b7db3618b773 100644
--- a/cmake/PlatformFanService.cmake
+++ b/cmake/PlatformFanService.cmake
@@ -41,6 +41,7 @@ target_link_libraries(fan_service_lib
   platform_name_lib
   platform_utils
   fan_service_config_types_cpp2
+  gpiod_line
   sensor_service_cpp2
   fan_service_cpp2
   Folly::folly
@@ -72,6 +73,8 @@ add_executable(fan_service_sw_test
 target_link_libraries(fan_service_sw_test
   fan_service_lib
   Folly::folly
+  ${LIBGPIOD}
+  gpiod_line
   ${GTEST}
   ${LIBGMOCK_LIBRARIES}
 )
diff --git a/fboss/platform/fan_service/BUCK b/fboss/platform/fan_service/BUCK
index c9f13837f24f0..e836676810549 100644
--- a/fboss/platform/fan_service/BUCK
+++ b/fboss/platform/fan_service/BUCK
@@ -85,6 +85,7 @@ cpp_library(
         "//fboss/fsdb/if:fsdb_model",
         "//fboss/fsdb/if:fsdb_oper-cpp2-types",
         "//fboss/lib:common_file_utils",
+        "//fboss/lib:gpiod_line",
         "//fboss/platform/fan_service/if:fan_service-cpp2-services",
         "//fboss/platform/fan_service/if:fan_service-cpp2-types",
         "//fboss/platform/helpers:platform_utils",
@@ -104,6 +105,9 @@ cpp_library(
         "//security/ca/lib:cert_path_picker",
         "//thrift/lib/cpp2/protocol:protocol",
     ],
+    exported_external_deps = [
+        ("libgpiod", None, "gpiod"),
+    ],
 )
 
 custom_unittest(
diff --git a/fboss/platform/fan_service/ControlLogic.cpp b/fboss/platform/fan_service/ControlLogic.cpp
index d701b2cefb27e..9a511615e546f 100644
--- a/fboss/platform/fan_service/ControlLogic.cpp
+++ b/fboss/platform/fan_service/ControlLogic.cpp
@@ -6,8 +6,10 @@
 #include "fboss/platform/fan_service/ControlLogic.h"
 
 #include <folly/logging/xlog.h>
+#include <gpiod.h>
 
 #include "common/time/Time.h"
+#include "fboss/lib/GpiodLine.h"
 #include "fboss/platform/fan_service/SensorData.h"
 #include "fboss/platform/fan_service/if/gen-cpp2/fan_service_config_constants.h"
 #include "fboss/platform/fan_service/if/gen-cpp2/fan_service_config_types.h"
@@ -349,15 +351,35 @@ void ControlLogic::getOpticsUpdate() {
 bool ControlLogic::isFanPresentInDevice(const Fan& fan) {
   unsigned int readVal;
   bool readSuccessful = false;
-  try {
-    readVal = static_cast<unsigned>(pBsp_->readSysfs(*fan.presenceSysfsPath()));
-    readSuccessful = true;
-  } catch (std::exception&) {
-    XLOG(ERR) << "Failed to read sysfs " << *fan.presenceSysfsPath();
-  }
-  auto fanPresent = (readSuccessful && readVal == *fan.fanPresentVal());
-  if (!fanPresent) {
-    XLOG(INFO) << fmt::format("{}: is absent in the host", *fan.fanName());
+  bool fanPresent = false;
+  if (fan.presenceSysfsPath()) {
+    try {
+      readVal =
+          static_cast<unsigned>(pBsp_->readSysfs(*fan.presenceSysfsPath()));
+      readSuccessful = true;
+    } catch (std::exception&) {
+      XLOG(ERR) << "Failed to read sysfs " << *fan.presenceSysfsPath();
+    }
+    fanPresent = (readSuccessful && readVal == *fan.fanPresentVal());
+    if (fanPresent) {
+      XLOG(INFO) << fmt::format(
+          "{}: is present in the host (through sysfs)", *fan.fanName());
+    } else {
+      XLOG(INFO) << fmt::format(
+          "{}: is absent in the host (through sysfs)", *fan.fanName());
+    }
+  } else if (fan.presenceGpio()) {
+    struct gpiod_chip* chip =
+        gpiod_chip_open(fan.presenceGpio()->path()->c_str());
+    GpiodLine line(chip, *fan.presenceGpio()->lineIndex(), "gpioline");
+    int16_t value = line.getValue();
+    gpiod_chip_close(chip);
+    if (value == *fan.presenceGpio()->desiredValue()) {
+      fanPresent = true;
+    } else {
+      XLOG(INFO) << fmt::format(
+          "{}: is absent in the host (through gpio)", *fan.fanName());
+    }
   }
   fb303::fbData->setCounter(
       fmt::format(kFanAbsent, *fan.fanName()), !fanPresent);