linux-kernel - [PATCH 1/5] Input: xpad - use a packet array to start Xbox One pads

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Date:   Sat,  4 Feb 2017 16:29:58 -0800
From:   Cameron Gutman <aicommander@...il.com>
To:     dmitry.torokhov@...il.com, rojtberg@...il.com
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        Cameron Gutman <aicommander@...il.com>
Subject: [PATCH 1/5] Input: xpad - use a packet array to start Xbox One pads

This is preparatory work for supporting some 3rd party
pads that need more initialization packets than just
one. No initialization behavior change expected.

Signed-off-by: Cameron Gutman <aicommander@...il.com>
---
 drivers/input/joystick/xpad.c | 40 +++++++++++++++++++++++++++-------------
 1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
index 247fd3a..6f07b5b 100644
--- a/drivers/input/joystick/xpad.c
+++ b/drivers/input/joystick/xpad.c
@@ -343,6 +343,15 @@ struct xpad_output_packet {
 	bool pending;
 };
 
+/* Sequence numbers will be added before the packets are sent */
+static const struct xpad_output_packet xone_init_pkt[] = {
+	/*
+	 * This packet is required for all Xbox One pads with 2015
+	 * or later firmware installed (or present from the factory).
+	 */
+	{{0x05, 0x20, 0x00, 0x01, 0x00}, 5, true},
+};
+
 #define XPAD_OUT_CMD_IDX	0
 #define XPAD_OUT_FF_IDX		1
 #define XPAD_OUT_LED_IDX	(1 + IS_ENABLED(CONFIG_JOYSTICK_XPAD_FF))
@@ -373,6 +382,7 @@ struct usb_xpad {
 
 	struct xpad_output_packet out_packets[XPAD_NUM_OUT_PACKETS];
 	int last_out_packet;
+	int init_seq;
 
 #if defined(CONFIG_JOYSTICK_XPAD_LEDS)
 	struct xpad_led *led;
@@ -742,8 +752,19 @@ static void xpad_irq_in(struct urb *urb)
 static bool xpad_prepare_next_out_packet(struct usb_xpad *xpad)
 {
 	struct xpad_output_packet *pkt, *packet = NULL;
+	const struct xpad_output_packet *init_packet;
 	int i;
 
+	if (xpad->xtype == XTYPE_XBOXONE && xpad->init_seq < ARRAY_SIZE(xone_init_pkt)) {
+		init_packet = &xone_init_pkt[xpad->init_seq++];
+		memcpy(xpad->odata, init_packet->data, init_packet->len);
+		xpad->irq_out->transfer_buffer_length = init_packet->len;
+
+		/* Update packet with current sequence number */
+		xpad->odata[2] = xpad->odata_serial++;
+		return true;
+	}
+
 	for (i = 0; i < XPAD_NUM_OUT_PACKETS; i++) {
 		if (++xpad->last_out_packet >= XPAD_NUM_OUT_PACKETS)
 			xpad->last_out_packet = 0;
@@ -929,24 +950,17 @@ static int xpad_inquiry_pad_presence(struct usb_xpad *xpad)
 
 static int xpad_start_xbox_one(struct usb_xpad *xpad)
 {
-	struct xpad_output_packet *packet =
-			&xpad->out_packets[XPAD_OUT_CMD_IDX];
 	unsigned long flags;
 	int retval;
 
 	spin_lock_irqsave(&xpad->odata_lock, flags);
 
-	/* Xbox one controller needs to be initialized. */
-	packet->data[0] = 0x05;
-	packet->data[1] = 0x20;
-	packet->data[2] = xpad->odata_serial++; /* packet serial */
-	packet->data[3] = 0x01; /* rumble bit enable?  */
-	packet->data[4] = 0x00;
-	packet->len = 5;
-	packet->pending = true;
-
-	/* Reset the sequence so we send out start packet first */
-	xpad->last_out_packet = -1;
+	/*
+	 * Begin the init sequence by attempting to send a packet.
+	 * We will cycle through the init packet sequence before
+	 * sending any packets from the output ring.
+	 */
+	xpad->init_seq = 0;
 	retval = xpad_try_sending_next_out_packet(xpad);
 
 	spin_unlock_irqrestore(&xpad->odata_lock, flags);
-- 
2.9.3