Detect touchpad

4 files changed, 69 insertions, 21 deletions

diff --git a/PCM.cpp b/PCM.cpp
index b8510b5..205b1cd 100644
--- a/PCM.cpp
+++ b/PCM.cpp
@@ -41,7 +41,7 @@ PCM::PCM(Config& config):
   if (0 > snd_pcm_start(handle))
   {
     // On raspberry, this results in error. However, seems to generally work without
-    log_cout << "PCM could not be started" << std::endl;
+    log_cout << "PCM could not be started. Ignoring. Will be done implicitly." << std::endl;
   }
 
   if (npfd != 1) {
diff --git a/PIDFile.cpp b/PIDFile.cpp
index 85f30d3..6bfaa3a 100644
--- a/PIDFile.cpp
+++ b/PIDFile.cpp
@@ -32,7 +32,7 @@ PIDFile::PIDFile(const std::string& programname): m_programname{programname}
   try {
     Reichwein::File::setFile(filename, contents);
   } catch (const std::exception& ex) {
-    log_cout << fmt::format("Warning: Not able to write to file{}, ignoring.\n", filename.string());
+    log_cout << fmt::format("Warning: Not able to write to file {}, ignoring.\n", filename.string());
   }
 }
 
diff --git a/Touchpad.cpp b/Touchpad.cpp
index 3989df7..9d3fe22 100644
--- a/Touchpad.cpp
+++ b/Touchpad.cpp
@@ -1,34 +1,82 @@
 #include "Touchpad.h"
 
+#include <filesystem>
 #include <fmt/format.h>
 #include <sys/poll.h>
 #include <fcntl.h>
 
 #include "log.h"
 
-Touchpad::Touchpad(): m_valid{}, m_ev{}
-{
-  m_fd = open("/dev/input/event0", O_RDONLY | O_NONBLOCK);
-  int rc = libevdev_new_from_fd(m_fd, &m_dev);
-  if (rc < 0) {
-    log_cout << fmt::format("Failed to init libevdev ({})\n", strerror(-rc));
-    return;
+namespace fs = std::filesystem;
+
+namespace {
+  fs::path eventfile_from_index(int i)
+  {
+    fs::path result{"/dev/input/event"};
+    result += fs::path{std::to_string(i)};
+    return result;
+  }
+
+  libevdev* get_evdev(int& result_fd)
+  {
+    for (int i = 0; ; ++i) {
+      fs::path filename = eventfile_from_index(i);
+      if (!fs::exists(filename)) {
+        log_cout << "Warning: No suitable evdev device found.\n";
+        return nullptr;
+      }
+
+      int fd = open(filename.string().c_str(), O_RDONLY | O_NONBLOCK);
+      if (fd < 0) {
+        log_cout << fmt::format("Warning: evdev open() failed for {}", filename.string()) << std::endl;
+        continue;
+      }
+      libevdev* result{};
+      int rc = libevdev_new_from_fd(fd, &result);
+      if (rc < 0) {
+        log_cout << fmt::format("Warning: Failed to init libevdev ({})\n", strerror(-rc));
+        continue;
+      }
+
+      if (!libevdev_has_event_type(result, EV_REL) ||
+        !libevdev_has_event_code(result, EV_KEY, BTN_LEFT) ||
+        !libevdev_has_event_code(result, EV_KEY, BTN_RIGHT))
+      {
+        // Not the correct device
+        continue;
+      }
+      log_cout << fmt::format("evdev using: Input device name: \"{}\"\n", libevdev_get_name(result));
+      log_cout << fmt::format("evdev using: Input device ID: bus {:x} vendor {:x} product {:x}\n",
+        libevdev_get_id_bustype(result),
+        libevdev_get_id_vendor(result),
+        libevdev_get_id_product(result));
+      result_fd = fd;
+      return result;
+    }
   }
 
-  log_cout << fmt::format("Input device name: \"{}\"\n", libevdev_get_name(m_dev));
-  log_cout << fmt::format("Input device ID: bus {:x} vendor {:x} product {:x}\n",
-       libevdev_get_id_bustype(m_dev),
-       libevdev_get_id_vendor(m_dev),
-       libevdev_get_id_product(m_dev));
-  if (!libevdev_has_event_type(m_dev, EV_REL) ||
-      !libevdev_has_event_code(m_dev, EV_KEY, BTN_LEFT) ||
-      !libevdev_has_event_code(m_dev, EV_KEY, BTN_RIGHT)) {
-    log_cout << fmt::format("Not the correct device, ignoring.\n");
-  } else {
+  void free_evdev(libevdev* evdev, int fd)
+  {
+    if (evdev) {
+      libevdev_free(evdev);
+      close(fd);
+    }
+  }
+}
+
+Touchpad::Touchpad(): m_fd{}, m_dev{}, m_valid{}, m_ev{}
+{
+  m_dev = get_evdev(m_fd);
+  if (m_dev != nullptr) {
     m_valid = true;
   }
 }
 
+Touchpad::~Touchpad()
+{
+  free_evdev(m_dev, m_fd);
+}
+
 bool Touchpad::is_valid()
 {
   return m_valid;
diff --git a/Touchpad.h b/Touchpad.h
index 0474d04..b5945fe 100644
--- a/Touchpad.h
+++ b/Touchpad.h
@@ -8,6 +8,7 @@ class Touchpad
 {
 public:
   Touchpad();
+  ~Touchpad();
 
   bool is_valid();
 
@@ -19,10 +20,9 @@ public:
   bool event_is_button2(const input_event& ev);
 
 private:
-  libevdev* m_dev = nullptr;
   int m_fd;
+  libevdev* m_dev;
   bool m_valid;
-
   std::optional<input_event> m_ev;
 };