drm/dp/mst: Provide defines for ACK vs. NAK reply type

Make the code a bit easier to read by providing symbolic names
for the reply_type (ACK vs. NAK). Also clean up some brace stuff
while at it.

v2: s/DP_REPLY/DP_SIDEBAND_REPLY/ (DK)
    Fix some checkpatch issues
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190122200301.18633-1-ville.syrjala@linux.intel.com

drivers/gpu/drm/drm_dp_mst_topology.c

@@ -568,7 +568,7 @@ static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
 	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
 	msg->req_type = (raw->msg[0] & 0x7f);
 
-	if (msg->reply_type) {
+	if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
 		memcpy(msg->u.nak.guid, &raw->msg[1], 16);
 		msg->u.nak.reason = raw->msg[17];
 		msg->u.nak.nak_data = raw->msg[18];
@@ -1969,9 +1969,9 @@ static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
 	if (ret > 0) {
 		int i;
 
-		if (txmsg->reply.reply_type == 1)
+		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
 			DRM_DEBUG_KMS("link address nak received\n");
-		else {
+		} else {
 			DRM_DEBUG_KMS("link address reply: %d\n", txmsg->reply.u.link_addr.nports);
 			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
 				DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n", i,
@@ -2020,9 +2020,9 @@ static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
 
 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
 	if (ret > 0) {
-		if (txmsg->reply.reply_type == 1)
+		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
 			DRM_DEBUG_KMS("enum path resources nak received\n");
-		else {
+		} else {
 			if (port->port_num != txmsg->reply.u.path_resources.port_number)
 				DRM_ERROR("got incorrect port in response\n");
 			DRM_DEBUG_KMS("enum path resources %d: %d %d\n", txmsg->reply.u.path_resources.port_number, txmsg->reply.u.path_resources.full_payload_bw_number,
@@ -2132,7 +2132,7 @@ static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
 	 */
 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
 	if (ret > 0) {
-		if (txmsg->reply.reply_type == 1)
+		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
 			ret = -EINVAL;
 		else
 			ret = 0;
@@ -2165,7 +2165,7 @@ int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
 
 	ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
 	if (ret > 0) {
-		if (txmsg->reply.reply_type == 1)
+		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
 			ret = -EINVAL;
 		else
 			ret = 0;
@@ -2423,9 +2423,9 @@ static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
 
 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
 	if (ret > 0) {
-		if (txmsg->reply.reply_type == 1) {
+		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
 			ret = -EINVAL;
-		} else
+		else
 			ret = 0;
 	}
 	kfree(txmsg);
@@ -2438,7 +2438,7 @@ static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req
 {
 	struct drm_dp_sideband_msg_reply_body reply;
 
-	reply.reply_type = 0;
+	reply.reply_type = DP_SIDEBAND_REPLY_ACK;
 	reply.req_type = req_type;
 	drm_dp_encode_sideband_reply(&reply, msg);
 	return 0;
@@ -2745,9 +2745,9 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 		}
 
 		drm_dp_sideband_parse_reply(&mgr->down_rep_recv, &txmsg->reply);
-		if (txmsg->reply.reply_type == 1) {
+
+		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
 			DRM_DEBUG_KMS("Got NAK reply: req 0x%02x, reason 0x%02x, nak data 0x%02x\n", txmsg->reply.req_type, txmsg->reply.u.nak.reason, txmsg->reply.u.nak.nak_data);
-		}
 
 		memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
 		drm_dp_mst_topology_put_mstb(mstb);
@@ -3893,7 +3893,7 @@ static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs
 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
 	if (ret > 0) {
 
-		if (txmsg->reply.reply_type == 1) { /* got a NAK back */
+		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
 			ret = -EREMOTEIO;
 			goto out;
 		}

include/drm/drm_dp_helper.h

@@ -992,6 +992,10 @@
 #define DP_SINK_EVENT_NOTIFY		0x30
 #define DP_QUERY_STREAM_ENC_STATUS	0x38
 
+/* DP 1.2 MST sideband reply types */
+#define DP_SIDEBAND_REPLY_ACK		0x00
+#define DP_SIDEBAND_REPLY_NAK		0x01
+
 /* DP 1.2 MST sideband nak reasons - table 2.84 */
 #define DP_NAK_WRITE_FAILURE		0x01
 #define DP_NAK_INVALID_READ		0x02