Use -Werror in hardware/libhardware

* Remove unused local variables and function.
* Fix unused return value warning.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I269eca76cda2222c7a0176e85e92df0bb0924a0e

Android.bp

@@ -29,7 +29,11 @@ cc_library_shared {
         "libdl",
         "libvndksupport",
     ],
-    cflags: ["-DQEMU_HARDWARE"],
+    cflags: [
+        "-DQEMU_HARDWARE",
+        "-Wall",
+        "-Werror",
+    ],
 
     header_libs: ["libhardware_headers"],
     export_header_lib_headers: ["libhardware_headers"],

modules/consumerir/Android.bp

@@ -17,6 +17,7 @@ cc_library_shared {
     relative_install_path: "hw",
     proprietary: true,
     srcs: ["consumerir.c"],
+    cflags: ["-Wall", "-Werror"],
     header_libs: ["libhardware_headers"],
     shared_libs: [
         "liblog",

modules/fingerprint/Android.bp

@@ -17,6 +17,7 @@ cc_library_shared {
     relative_install_path: "hw",
     proprietary: true,
     srcs: ["fingerprint.c"],
+    cflags: ["-Wall", "-Werror"],
     header_libs: ["libhardware_headers"],
     shared_libs: ["liblog"],
 }

modules/local_time/Android.bp

@@ -26,6 +26,7 @@ cc_library_shared {
     relative_install_path: "hw",
     proprietary: true,
     srcs: ["local_time_hw.c"],
+    cflags: ["-Wall", "-Werror"],
     header_libs: ["libhardware_headers"],
     shared_libs: [
         "liblog",

modules/local_time/local_time_hw.c

@@ -72,8 +72,6 @@ static int ltdev_open(const hw_module_t* module, const char* name,
                      hw_device_t** device)
 {
     struct stub_local_time_device *ltdev;
-    struct timespec ts;
-    int ret;
 
     if (strcmp(name, LOCAL_TIME_HARDWARE_INTERFACE) != 0)
         return -EINVAL;

modules/nfc-nci/Android.bp

@@ -21,4 +21,5 @@ cc_library_shared {
         "liblog",
         "libcutils",
     ],
+    cflags: ["-Wall", "-Werror"],
 }

modules/nfc/Android.bp

@@ -17,6 +17,7 @@ cc_library_shared {
     relative_install_path: "hw",
     proprietary: true,
     srcs: ["nfc_pn544_example.c"],
+    cflags: ["-Wall", "-Werror"],
     header_libs: ["libhardware_headers"],
     shared_libs: [
         "liblog",

modules/power/Android.bp

@@ -17,6 +17,7 @@ cc_library_shared {
     relative_install_path: "hw",
     proprietary: true,
     srcs: ["power.c"],
+    cflags: ["-Wall", "-Werror"],
     header_libs: [
         "libhardware_headers",
         "libutils_headers",

modules/sensors/Android.bp

@@ -12,4 +12,5 @@ cc_library_static {
         "libdl"
     ],
     export_include_dirs: ["."],
+    cflags: ["-Wall", "-Werror"],
 }

modules/sensors/multihal.cpp

@@ -515,6 +515,7 @@ static int device__close(struct hw_device_t *dev) {
     if (ctx != NULL) {
         int retval = ctx->close();
         delete ctx;
+        return retval;
     }
 
     if (sub_hw_modules != nullptr) {
@@ -586,15 +587,6 @@ static int device__config_direct_report(struct sensors_poll_device_1 *dev,
 static int open_sensors(const struct hw_module_t* module, const char* name,
         struct hw_device_t** device);
 
-static bool starts_with(const char* s, const char* prefix) {
-    if (s == NULL || prefix == NULL) {
-        return false;
-    }
-    size_t s_size = strlen(s);
-    size_t prefix_size = strlen(prefix);
-    return s_size >= prefix_size && strncmp(s, prefix, prefix_size) == 0;
-}
-
 /*
  * Adds valid paths from the config file to the vector passed in.
  * The vector must not be null.

modules/tv_input/Android.bp

@@ -22,4 +22,5 @@ cc_library_shared {
         "liblog",
     ],
     srcs: ["tv_input.cpp"],
+    cflags: ["-Wall", "-Werror"],
 }

modules/vibrator/Android.bp

@@ -21,5 +21,6 @@ cc_library_shared {
     proprietary: true,
     header_libs: ["libhardware_headers"],
     srcs: ["vibrator.c"],
+    cflags: ["-Wall", "-Werror"],
     shared_libs: ["liblog"],
 }

modules/vibrator/vibrator.c

@@ -108,7 +108,6 @@ static int write_led_file(const char *file, const char *value)
 
 static bool vibra_led_exists()
 {
-    int fd;
     char file_str[50];
 
     snprintf(file_str, sizeof(file_str), "%s/%s", LED_DEVICE, "activate");

tests/fingerprint/Android.bp

@@ -9,6 +9,7 @@ cc_test {
 
     cflags: [
         "-Wall",
+        "-Werror",
         "-Wextra",
     ],
 }

tests/nusensors/Android.bp

@@ -3,6 +3,8 @@ cc_binary {
 
     srcs: ["nusensors.cpp"],
 
+    cflags: ["-Wall", "-Werror"],
+
     shared_libs: [
         "libcutils",
         "libhardware",