staging: greybus: vibrator: use proper API for vibrator devices

The correct user/kernel api for vibrator devices is the Input rumble
api, not a random sysfs file like the greybus vibrator driver currently
uses.

Add support for the correct input api to the vibrator driver so that it
hooks up to the kernel and userspace correctly.

Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/vibrator.c

@@ -13,13 +13,18 @@
 #include <linux/kdev_t.h>
 #include <linux/idr.h>
 #include <linux/pm_runtime.h>
+#include <linux/input.h>
 #include <linux/greybus.h>
 
 struct gb_vibrator_device {
 	struct gb_connection	*connection;
+	struct input_dev	*input;
 	struct device		*dev;
 	int			minor;		/* vibrator minor number */
 	struct delayed_work     delayed_work;
+	bool			running;
+	bool			on;
+	struct work_struct	play_work;
 };
 
 /* Greybus Vibrator operation types */
@@ -36,6 +41,7 @@ static int turn_off(struct gb_vibrator_device *vib)
 
 	gb_pm_runtime_put_autosuspend(bundle);
 
+	vib->on = false;
 	return ret;
 }
 
@@ -59,11 +65,48 @@ static int turn_on(struct gb_vibrator_device *vib, u16 timeout_ms)
 		return ret;
 	}
 
+	vib->on = true;
 	schedule_delayed_work(&vib->delayed_work, msecs_to_jiffies(timeout_ms));
 
 	return 0;
 }
 
+static void gb_vibrator_play_work(struct work_struct *work)
+{
+	struct gb_vibrator_device *vib =
+		container_of(work, struct gb_vibrator_device, play_work);
+
+	if (vib->running)
+		turn_off(vib);
+	else
+		turn_on(vib, 100);
+}
+
+static int gb_vibrator_play_effect(struct input_dev *input, void *data,
+				   struct ff_effect *effect)
+{
+	struct gb_vibrator_device *vib = input_get_drvdata(input);
+	int level;
+
+	level = effect->u.rumble.strong_magnitude;
+	if (!level)
+		level = effect->u.rumble.weak_magnitude;
+
+	vib->running = level;
+	schedule_work(&vib->play_work);
+	return 0;
+}
+
+static void gb_vibrator_close(struct input_dev *input)
+{
+	struct gb_vibrator_device *vib = input_get_drvdata(input);
+
+	cancel_delayed_work_sync(&vib->delayed_work);
+	cancel_work_sync(&vib->play_work);
+	turn_off(vib);
+	vib->running = false;
+}
+
 static void gb_vibrator_worker(struct work_struct *work)
 {
 	struct delayed_work *delayed_work = to_delayed_work(work);
@@ -169,10 +212,26 @@ static int gb_vibrator_probe(struct gb_bundle *bundle,
 
 	INIT_DELAYED_WORK(&vib->delayed_work, gb_vibrator_worker);
 
+	INIT_WORK(&vib->play_work, gb_vibrator_play_work);
+	vib->input->name = "greybus-vibrator";
+	vib->input->close = gb_vibrator_close;
+	vib->input->dev.parent = &bundle->dev;
+	vib->input->id.bustype = BUS_HOST;
+
+	input_set_drvdata(vib->input, vib);
+	input_set_capability(vib->input, EV_FF, FF_RUMBLE);
+
+	retval = input_ff_create_memless(vib->input, NULL,
+					 gb_vibrator_play_effect);
+	if (retval)
+		goto err_device_remove;
+
 	gb_pm_runtime_put_autosuspend(bundle);
 
 	return 0;
 
+err_device_remove:
+	device_unregister(vib->dev);
 err_ida_remove:
 	ida_simple_remove(&minors, vib->minor);
 err_connection_disable: