Input: gamecon - add rumble support for N64 pads

Add force-feedback support for N64 pads with rumble pak accessory installed.
Actually we do not check for the presence of rumble pad but simply assume it
is installed and expect the device to ignore FF commands if rumble pak is
missing.
Signed-off-by: Scott Moreau <oreaus@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/joystick/Kconfig

@@ -221,6 +221,7 @@ config JOYSTICK_DB9
 config JOYSTICK_GAMECON
 	tristate "Multisystem, NES, SNES, N64, PSX joysticks and gamepads"
 	depends on PARPORT
+	select INPUT_FF_MEMLESS
 	---help---
 	  Say Y here if you have a Nintendo Entertainment System gamepad,
 	  Super Nintendo Entertainment System gamepad, Nintendo 64 gamepad,

drivers/input/joystick/gamecon.c

@@ -85,6 +85,10 @@ struct gc {
 	char phys[GC_MAX_DEVICES][32];
 };
 
+struct gc_subdev {
+	unsigned int idx;
+};
+
 static struct gc *gc_base[3];
 
 static int gc_status_bit[] = { 0x40, 0x80, 0x20, 0x10, 0x08 };
@@ -100,9 +104,16 @@ static unsigned char gc_n64_bytes[] = { 0, 1, 13, 15, 14, 12, 10, 11, 2, 3 };
 static short gc_n64_btn[] = { BTN_A, BTN_B, BTN_C, BTN_X, BTN_Y, BTN_Z, BTN_TL, BTN_TR, BTN_TRIGGER, BTN_START };
 
 #define GC_N64_LENGTH		32		/* N64 bit length, not including stop bit */
-#define GC_N64_REQUEST_LENGTH	37		/* transmit request sequence is 9 bits long */
+#define GC_N64_STOP_LENGTH	5		/* Length of encoded stop bit */
+#define GC_N64_CMD_00		0x11111111UL
+#define GC_N64_CMD_01		0xd1111111UL
+#define GC_N64_CMD_03		0xdd111111UL
+#define GC_N64_CMD_1b		0xdd1dd111UL
+#define GC_N64_CMD_c0		0x111111ddUL
+#define GC_N64_CMD_80		0x1111111dUL
+#define GC_N64_STOP_BIT		0x1d		/* Encoded stop bit */
+#define GC_N64_REQUEST_DATA	GC_N64_CMD_01	/* the request data command */
 #define GC_N64_DELAY		133		/* delay between transmit request, and response ready (us) */
-#define GC_N64_REQUEST		0x1dd1111111ULL /* the request data command (encoded for 000000011) */
 #define GC_N64_DWS		3		/* delay between write segments (required for sound playback because of ISA DMA) */
 						/* GC_N64_DWS > 24 is known to fail */
 #define GC_N64_POWER_W		0xe2		/* power during write (transmit request) */
@@ -113,6 +124,37 @@ static short gc_n64_btn[] = { BTN_A, BTN_B, BTN_C, BTN_X, BTN_Y, BTN_Z, BTN_TL,
 						/* than 123 us */
 #define GC_N64_CLOCK		0x02		/* clock bits for read */
 
+/*
+ * Used for rumble code.
+ */
+
+/* Send encoded command */
+static void gc_n64_send_command(struct gc *gc, unsigned long cmd,
+				unsigned char target)
+{
+	struct parport *port = gc->pd->port;
+	int i;
+
+	for (i = 0; i < GC_N64_LENGTH; i++) {
+		unsigned char data = (cmd >> i) & 1 ? target : 0;
+		parport_write_data(port, GC_N64_POWER_W | data);
+		udelay(GC_N64_DWS);
+	}
+}
+
+/* Send stop bit */
+static void gc_n64_send_stop_bit(struct gc *gc, unsigned char target)
+{
+	struct parport *port = gc->pd->port;
+	int i;
+
+	for (i = 0; i < GC_N64_STOP_LENGTH; i++) {
+		unsigned char data = (GC_N64_STOP_BIT >> i) & 1 ? target : 0;
+		parport_write_data(port, GC_N64_POWER_W | data);
+		udelay(GC_N64_DWS);
+	}
+}
+
 /*
  * gc_n64_read_packet() reads an N64 packet.
  * Each pad uses one bit per byte. So all pads connected to this port are read in parallel.
@@ -128,10 +170,8 @@ static void gc_n64_read_packet(struct gc *gc, unsigned char *data)
  */
 
 	local_irq_save(flags);
-	for (i = 0; i < GC_N64_REQUEST_LENGTH; i++) {
-		parport_write_data(gc->pd->port, GC_N64_POWER_W | ((GC_N64_REQUEST >> i) & 1 ? GC_N64_OUT : 0));
-		udelay(GC_N64_DWS);
-	}
+	gc_n64_send_command(gc, GC_N64_REQUEST_DATA, GC_N64_OUT);
+	gc_n64_send_stop_bit(gc, GC_N64_OUT);
 	local_irq_restore(flags);
 
 /*
@@ -146,6 +186,7 @@ static void gc_n64_read_packet(struct gc *gc, unsigned char *data)
 
 	for (i = 0; i < GC_N64_LENGTH; i++) {
 		parport_write_data(gc->pd->port, GC_N64_POWER_R);
+		udelay(2);
 		data[i] = parport_read_status(gc->pd->port);
 		parport_write_data(gc->pd->port, GC_N64_POWER_R | GC_N64_CLOCK);
 	 }
@@ -199,6 +240,70 @@ static void gc_n64_process_packet(struct gc *gc)
 	}
 }
 
+static int gc_n64_play_effect(struct input_dev *dev, void *data,
+			      struct ff_effect *effect)
+{
+	int i;
+	unsigned long flags;
+	struct gc *gc = input_get_drvdata(dev);
+	struct gc_subdev *sdev = data;
+	unsigned char target = 1 << sdev->idx; /* select desired pin */
+
+	if (effect->type == FF_RUMBLE) {
+		struct ff_rumble_effect *rumble = &effect->u.rumble;
+		unsigned int cmd =
+			rumble->strong_magnitude || rumble->weak_magnitude ?
+			GC_N64_CMD_01 : GC_N64_CMD_00;
+
+		local_irq_save(flags);
+
+		/* Init Rumble - 0x03, 0x80, 0x01, (34)0x80 */
+		gc_n64_send_command(gc, GC_N64_CMD_03, target);
+		gc_n64_send_command(gc, GC_N64_CMD_80, target);
+		gc_n64_send_command(gc, GC_N64_CMD_01, target);
+		for (i = 0; i < 32; i++)
+			gc_n64_send_command(gc, GC_N64_CMD_80, target);
+		gc_n64_send_stop_bit(gc, target);
+
+		udelay(GC_N64_DELAY);
+
+		/* Now start or stop it - 0x03, 0xc0, 0zx1b, (32)0x01/0x00 */
+		gc_n64_send_command(gc, GC_N64_CMD_03, target);
+		gc_n64_send_command(gc, GC_N64_CMD_c0, target);
+		gc_n64_send_command(gc, GC_N64_CMD_1b, target);
+		for (i = 0; i < 32; i++)
+			gc_n64_send_command(gc, cmd, target);
+		gc_n64_send_stop_bit(gc, target);
+
+		local_irq_restore(flags);
+
+	}
+
+	return 0;
+}
+
+static int __init gc_n64_init_ff(struct input_dev *dev, int i)
+{
+	struct gc_subdev *sdev;
+	int err;
+
+	sdev = kmalloc(sizeof(*sdev), GFP_KERNEL);
+	if (!sdev)
+		return -ENOMEM;
+
+	sdev->idx = i;
+
+	input_set_capability(dev, EV_FF, FF_RUMBLE);
+
+	err = input_ff_create_memless(dev, sdev, gc_n64_play_effect);
+	if (err) {
+		kfree(sdev);
+		return err;
+	}
+
+	return 0;
+}
+
 /*
  * NES/SNES support.
  */
@@ -624,6 +729,7 @@ static int __init gc_setup_pad(struct gc *gc, int idx, int pad_type)
 {
 	struct input_dev *input_dev;
 	int i;
+	int err;
 
 	if (!pad_type)
 		return 0;
@@ -673,6 +779,13 @@ static int __init gc_setup_pad(struct gc *gc, int idx, int pad_type)
 				input_set_abs_params(input_dev, ABS_HAT0X + i, -1, 1, 0, 0);
 			}
 
+			err = gc_n64_init_ff(input_dev, idx);
+			if (err) {
+				printk(KERN_WARNING "gamecon.c: Failed to initiate rumble for N64 device %d\n", idx);
+				input_free_device(input_dev);
+				return err;
+			}
+
 			break;
 
 		case GC_SNESMOUSE: