From 292a26d6ad420f123332622aac6bbd4a721d817d Mon Sep 17 00:00:00 2001
From: Iwan Timmer <irtimmer@gmail.com>
Date: Sat, 16 Feb 2019 16:12:06 +0100
Subject: [PATCH] Initial attempt to implement rumble for evdev

---
 src/input/evdev.c | 39 +++++++++++++++++++++++++++++++++++++++
 src/input/evdev.h |  1 +
 src/main.c        |  1 +
 3 files changed, 41 insertions(+)

diff --git a/src/input/evdev.c b/src/input/evdev.c
index 96f4c7c..51ba4f9 100644
--- a/src/input/evdev.c
+++ b/src/input/evdev.c
@@ -63,6 +63,7 @@ struct input_device {
   char modifiers;
   __s32 mouseDeltaX, mouseDeltaY, mouseScroll;
   short controllerId;
+  int haptic_effect_id;
   int buttonFlags;
   char leftTrigger, rightTrigger;
   short leftStickX, leftStickY;
@@ -547,6 +548,7 @@ void evdev_create(const char* device, struct mapping* mappings, bool verbose) {
   }
 
   devices[dev].controllerId = -1;
+  devices[dev].haptic_effect_id = -1;
 
   if (devices[dev].map != NULL) {
     bool valid = evdev_init_parms(&devices[dev], &(devices[dev].xParms), devices[dev].map->abs_leftx);
@@ -704,3 +706,40 @@ void evdev_stop() {
 void evdev_init() {
   handler = evdev_handle_event;
 }
+
+static struct input_device* evdev_get_input_device(unsigned short controller_id) {
+  for (int i=0; i<numDevices; i++)
+    if (devices[i].controllerId == controller_id)
+      return &devices[i];
+
+  return NULL;
+}
+
+void evdev_rumble(unsigned short controller_id, unsigned short low_freq_motor, unsigned short high_freq_motor) {
+  struct input_device* device = evdev_get_input_device(controller_id);
+  if (!device)
+    return;
+
+  if (device->haptic_effect_id >= 0) {
+    ioctl(device->fd, EVIOCRMFF, device->haptic_effect_id);
+    device->haptic_effect_id = -1;
+  }
+
+  if (low_freq_motor == 0 && high_freq_motor == 0)
+    return;
+
+  struct ff_effect effect = {0};
+  effect.type = FF_RUMBLE;
+  effect.id = -1;
+  effect.replay.length = USHRT_MAX;
+  effect.u.rumble.strong_magnitude = low_freq_motor;
+  effect.u.rumble.weak_magnitude = high_freq_motor;
+  if (ioctl(device->fd, EVIOCSFF, &effect) == -1)
+    return;
+
+  struct input_event event = {0};
+  event.type = EV_FF;
+  event.code = effect.id;
+  write(device->fd, (const void*) &event, sizeof(event));
+  device->haptic_effect_id = effect.id;
+}
diff --git a/src/input/evdev.h b/src/input/evdev.h
index 8583a27..7a2e453 100644
--- a/src/input/evdev.h
+++ b/src/input/evdev.h
@@ -28,3 +28,4 @@ void evdev_init();
 void evdev_start();
 void evdev_stop();
 void evdev_map(char* device);
+void evdev_rumble(unsigned short controller_id, unsigned short low_freq_motor, unsigned short high_freq_motor);
diff --git a/src/main.c b/src/main.c
index 5dc9fd9..8edfe84 100644
--- a/src/main.c
+++ b/src/main.c
@@ -311,6 +311,7 @@ int main(int argc, char* argv[]) {
 
       udev_init(!inputAdded, mappings, config.debug_level > 0);
       evdev_init();
+      rumble_handler = evdev_rumble;
       #ifdef HAVE_LIBCEC
       cec_init();
       #endif /* HAVE_LIBCEC */