[PATCH V3 05/13] drm: bridge: icn6211: Add DSI lane count DT property parsing

[Marek Vasut]

The driver currently hard-codes DSI lane count to two, however the chip
is capable of operating in 1..4 DSI lanes mode. Parse 'data-lanes' DT
property and program the result into DSI_CTRL register.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Jagan Teki <jagan at amarulasolutions.com>
Cc: Maxime Ripard <maxime at cerno.tech>
Cc: Robert Foss <robert.foss at linaro.org>
Cc: Sam Ravnborg <sam at ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
To: dri-devel at lists.freedesktop.org
---
V2: Rebase on next-20220214
V3: Default to 4 data lanes unless specified otherwise
---
 drivers/gpu/drm/bridge/chipone-icn6211.c | 45 +++++++++++++++++++++---
 1 file changed, 41 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/bridge/chipone-icn6211.c b/drivers/gpu/drm/bridge/chipone-icn6211.c
index 2ac8eb7e25f52..df8e75a068ad0 100644
--- a/drivers/gpu/drm/bridge/chipone-icn6211.c
+++ b/drivers/gpu/drm/bridge/chipone-icn6211.c
@@ -136,10 +136,12 @@ struct chipone {
 	struct drm_bridge bridge;
 	struct drm_display_mode mode;
 	struct drm_bridge *panel_bridge;
+	struct device_node *host_node;
 	struct gpio_desc *enable_gpio;
 	struct regulator *vdd1;
 	struct regulator *vdd2;
 	struct regulator *vdd3;
+	int dsi_lanes;
 };
 
 static inline struct chipone *bridge_to_chipone(struct drm_bridge *bridge)
@@ -212,6 +214,11 @@ static void chipone_atomic_enable(struct drm_bridge *bridge,
 	/* dsi specific sequence */
 	ICN6211_DSI(icn, SYNC_EVENT_DLY, 0x80);
 	ICN6211_DSI(icn, HFP_MIN, hfp & 0xff);
+
+	/* DSI data lane count */
+	ICN6211_DSI(icn, DSI_CTRL,
+		    DSI_CTRL_UNKNOWN | DSI_CTRL_DSI_LANES(icn->dsi_lanes - 1));
+
 	ICN6211_DSI(icn, MIPI_PD_CK_LANE, 0xa0);
 	ICN6211_DSI(icn, PLL_CTRL(12), 0xff);
 
@@ -314,7 +321,9 @@ static const struct drm_bridge_funcs chipone_bridge_funcs = {
 static int chipone_parse_dt(struct chipone *icn)
 {
 	struct device *dev = icn->dev;
+	struct device_node *endpoint;
 	struct drm_panel *panel;
+	int dsi_lanes;
 	int ret;
 
 	icn->vdd1 = devm_regulator_get_optional(dev, "vdd1");
@@ -350,15 +359,42 @@ static int chipone_parse_dt(struct chipone *icn)
 		return PTR_ERR(icn->enable_gpio);
 	}
 
+	endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, 0);
+	dsi_lanes = of_property_count_u32_elems(endpoint, "data-lanes");
+	icn->host_node = of_graph_get_remote_port_parent(endpoint);
+	of_node_put(endpoint);
+
+	if (!icn->host_node)
+		return -ENODEV;
+
+	/*
+	 * If the 'data-lanes' property does not exist in DT or is invalid,
+	 * default to previously hard-coded behavior, which was 4 data lanes.
+	 */
+	if (dsi_lanes < 0) {
+		icn->dsi_lanes = 4;
+	} else if (dsi_lanes > 4) {
+		ret = -EINVAL;
+		goto err_data_lanes;
+	} else {
+		icn->dsi_lanes = dsi_lanes;
+	}
+
 	ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 0, &panel, NULL);
 	if (ret)
-		return ret;
+		goto err_data_lanes;
 
 	icn->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
-	if (IS_ERR(icn->panel_bridge))
-		return PTR_ERR(icn->panel_bridge);
+	if (IS_ERR(icn->panel_bridge)) {
+		ret = PTR_ERR(icn->panel_bridge);
+		goto err_data_lanes;
+	}
 
 	return 0;
+
+err_data_lanes:
+	of_node_put(icn->host_node);
+	return ret;
 }
 
 static int chipone_probe(struct mipi_dsi_device *dsi)
@@ -384,7 +420,7 @@ static int chipone_probe(struct mipi_dsi_device *dsi)
 
 	drm_bridge_add(&icn->bridge);
 
-	dsi->lanes = 4;
+	dsi->lanes = icn->dsi_lanes;
 	dsi->format = MIPI_DSI_FMT_RGB888;
 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO_SYNC_PULSE;
 
@@ -403,6 +439,7 @@ static int chipone_remove(struct mipi_dsi_device *dsi)
 
 	mipi_dsi_detach(dsi);
 	drm_bridge_remove(&icn->bridge);
+	of_node_put(icn->host_node);
 
 	return 0;
 }
-- 
2.34.1