[PATCH v2] drm/bridge: ti-sn65dsi83: Add reversed lvds lanes support

[Wojciech Dubowik]

From: Wojciech Dubowik <Wojciech.Dubowik@xxxxxx>

The chip supports output lvds lanes in two orders, default <1 2 3 4>
and <4 3 2 1>. Add parsing of an optional output lvds data-lanes
property so we can inform chip that the lanes have been reversed.

Signed-off-by: Wojciech Dubowik <Wojciech.Dubowik@xxxxxx>
---
Changes in v2:
- Parse existing data-lanes property instead of ading new DT
  bindings
---
 drivers/gpu/drm/bridge/ti-sn65dsi83.c | 50 +++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
index 42b451432bbb..4945d4c960c4 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
@@ -148,6 +148,18 @@ enum sn65dsi83_lvds_term {
 	OHM_200
 };
 
+enum {
+	NORMAL_LANE_MAPPING,
+	REVERSE_LANE_MAPPING,
+};
+
+#define DATA_LANES_COUNT	4
+
+static const int supported_data_lane_mapping[][DATA_LANES_COUNT] = {
+	[NORMAL_LANE_MAPPING] = { 1, 2, 3, 4 },
+	[REVERSE_LANE_MAPPING] = { 4, 3, 2, 1},
+};
+
 enum sn65dsi83_model {
 	MODEL_SN65DSI83,
 	MODEL_SN65DSI84,
@@ -163,6 +175,7 @@ struct sn65dsi83 {
 	struct regulator		*vcc;
 	bool				lvds_dual_link;
 	bool				lvds_dual_link_even_odd_swap;
+	bool				lvds_reverse_lanes_conf[2];
 	int				lvds_vod_swing_conf[2];
 	int				lvds_term_conf[2];
 	int				irq;
@@ -644,6 +657,10 @@ static void sn65dsi83_atomic_pre_enable(struct drm_bridge *bridge,
 	regmap_write(ctx->regmap, REG_LVDS_LANE,
 		     (ctx->lvds_dual_link_even_odd_swap ?
 		      REG_LVDS_LANE_EVEN_ODD_SWAP : 0) |
+		     (ctx->lvds_reverse_lanes_conf[CHANNEL_A] ?
+		      REG_LVDS_LANE_CHA_REVERSE_LVDS : 0) |
+		     (ctx->lvds_reverse_lanes_conf[CHANNEL_B] ?
+		      REG_LVDS_LANE_CHB_REVERSE_LVDS : 0) |
 		     (ctx->lvds_term_conf[CHANNEL_A] ?
 			  REG_LVDS_LANE_CHA_LVDS_TERM : 0) |
 		     (ctx->lvds_term_conf[CHANNEL_B] ?
@@ -832,10 +849,12 @@ static int sn65dsi83_parse_lvds_endpoint(struct sn65dsi83 *ctx, int channel)
 	u32 lvds_vod_swing_clk[2] = { 0, 1000000 };
 	/* Set default near end terminataion to 200 Ohm */
 	u32 lvds_term = 200;
+	u32 data_lanes[DATA_LANES_COUNT];
 	int lvds_vod_swing_conf;
 	int ret = 0;
 	int ret_data;
 	int ret_clock;
+	int i, j;
 
 	if (channel == CHANNEL_A)
 		endpoint_reg = 2;
@@ -854,6 +873,37 @@ static int sn65dsi83_parse_lvds_endpoint(struct sn65dsi83 *ctx, int channel)
 		goto exit;
 	}
 
+	ret_data = of_property_read_u32_array(endpoint, "data-lanes", data_lanes,
+			ARRAY_SIZE(data_lanes));
+	if (ret_data != 0 && ret_data != -EINVAL) {
+		ret = ret_data;
+		goto exit;
+	}
+
+	if (!ret_data) {
+		for (i = 0; i < ARRAY_SIZE(supported_data_lane_mapping); i++) {
+			for (j = 0; j < DATA_LANES_COUNT; j++) {
+				if (data_lanes[j] != supported_data_lane_mapping[i][j])
+					break;
+			}
+
+			if (j == DATA_LANES_COUNT)
+				break;
+		}
+
+		switch (i) {
+		case NORMAL_LANE_MAPPING:
+			break;
+		case REVERSE_LANE_MAPPING:
+			ctx->lvds_reverse_lanes_conf[channel] = true;
+			break;
+		default:
+			dev_err(dev, "invalid data lanes mapping\n");
+			ret = -EINVAL;
+			goto exit;
+		}
+	}
+
 	ret_data = of_property_read_u32_array(endpoint, "ti,lvds-vod-swing-data-microvolt",
 					lvds_vod_swing_data, ARRAY_SIZE(lvds_vod_swing_data));
 	if (ret_data != 0 && ret_data != -EINVAL) {
-- 
2.47.3