evdev: use mtdev for multitouch devices

mtdev library translates all multitouch based devices to the slotted evdev
protocol. It provides an uniform interface for Weston, which eases mt
implementation when dealing with a big variety of devices.

Weston on drm now directly depends on such library.

Signed-off-by: Tiago Vignatti <tiago.vignatti@intel.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

configure.ac

@@ -73,7 +73,7 @@ AC_ARG_ENABLE(drm-compositor, [  --enable-drm-compositor],,
 AM_CONDITIONAL(ENABLE_DRM_COMPOSITOR, test x$enable_drm_compositor = xyes)
 if test x$enable_drm_compositor = xyes; then
   AC_DEFINE([BUILD_DRM_COMPOSITOR], [1], [Build the DRM compositor])
-  PKG_CHECK_MODULES(DRM_COMPOSITOR, [libudev >= 136 libdrm >= 2.4.30 gbm])
+  PKG_CHECK_MODULES(DRM_COMPOSITOR, [libudev >= 136 libdrm >= 2.4.30 gbm mtdev])
 fi
 
 

src/evdev.c

@@ -26,6 +26,7 @@
 #include <linux/input.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <mtdev.h>
 
 #include "compositor.h"
 #include "evdev.h"
@@ -57,6 +58,7 @@ struct evdev_input_device {
 		int32_t x[MAX_SLOTS];
 		int32_t y[MAX_SLOTS];
 	} mt;
+	struct mtdev *mtdev;
 
 	struct {
 		int dx, dy;
@@ -320,13 +322,14 @@ evdev_flush_motion(struct evdev_input_device *device, uint32_t time)
 		device->type &= ~EVDEV_ABSOLUTE_MOTION;
 	}
 }
+#define NUM_EVENTS 8
 
 static int
 evdev_input_device_data(int fd, uint32_t mask, void *data)
 {
 	struct weston_compositor *ec;
 	struct evdev_input_device *device = data;
-	struct input_event ev[8], *e, *end;
+	struct input_event ev[NUM_EVENTS], *e, *end;
 	int len;
 	uint32_t time = 0;
 
@@ -334,6 +337,10 @@ evdev_input_device_data(int fd, uint32_t mask, void *data)
 	if (!ec->focus)
 		return 1;
 
+	if (device->mtdev)
+		len = mtdev_get(device->mtdev, fd, ev, NUM_EVENTS) *
+		      sizeof (struct input_event);
+	else
 		len = read(fd, &ev, sizeof ev);
 	if (len < 0 || len % sizeof e[0] != 0) {
 		/* FIXME: call device_removed when errno is ENODEV. */;
@@ -450,18 +457,26 @@ evdev_input_device_create(struct evdev_input *master,
 	device->master = master;
 	device->is_touchpad = 0;
 	device->is_mt = 0;
+	device->mtdev = NULL;
 	device->devnode = strdup(path);
 	device->mt.slot = -1;
 	device->rel.dx = 0;
 	device->rel.dy = 0;
 
-	device->fd = open(path, O_RDONLY);
+	/* if O_NONBLOCK is not set, mtdev_get() blocks */
+	device->fd = open(path, O_RDONLY | O_NONBLOCK);
 	if (device->fd < 0)
 		goto err0;
 
 	if (evdev_configure_device(device) == -1)
 		goto err1;
 
+	if (device->is_mt) {
+		device->mtdev = mtdev_new_open(device->fd);
+		if (!device->mtdev)
+			fprintf(stderr, "mtdev failed to open for %s\n", path);
+	}
+
 	device->source = wl_event_loop_add_fd(ec->input_loop, device->fd,
 					      WL_EVENT_READABLE,
 					      evdev_input_device_data, device);
@@ -511,6 +526,8 @@ device_removed(struct udev_device *udev_device, struct evdev_input *master)
 		if (!strcmp(device->devnode, devnode)) {
 			wl_event_source_remove(device->source);
 			wl_list_remove(&device->link);
+			if (device->mtdev)
+				mtdev_close_delete(device->mtdev);
 			close(device->fd);
 			free(device->devnode);
 			free(device);