[PATCH v4 07/18] drm/bridge: dp_typec: Support USB Type-C orientation

[Stephen Boyd]

Register an orientation switch for each type-c output node to support
flipping the lane mapping when the port is in reverse orientation. Only
do this when the orientation-switch property is present. This is mostly
useful for the case where the DP lanes are directly connected to the
usb-c-connector and the device doesn't have an orientation switch wired
down on the board between the connector and the DP controller.

Cc: Prashant Malani <pmalani at chromium.org>
Cc: Benson Leung <bleung at chromium.org>
Cc: Tzung-Bi Shih <tzungbi at kernel.org>
Cc: <chrome-platform at lists.linux.dev>
Cc: Pin-yen Lin <treapking at chromium.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
Signed-off-by: Stephen Boyd <swboyd at chromium.org>
---
 drivers/gpu/drm/bridge/aux-hpd-bridge.c | 77 +++++++++++++++++++++----
 1 file changed, 66 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/bridge/aux-hpd-bridge.c b/drivers/gpu/drm/bridge/aux-hpd-bridge.c
index 32565f88ade7..d2832e6481d7 100644
--- a/drivers/gpu/drm/bridge/aux-hpd-bridge.c
+++ b/drivers/gpu/drm/bridge/aux-hpd-bridge.c
@@ -47,12 +47,16 @@ struct drm_dp_typec_bridge_data;
 /**
  * struct drm_dp_typec_bridge_typec_port - USB type-c port associated with DP bridge
  * @lane_mapping: Physical (array index) to logical (array value) USB type-C lane mapping
+ * @orientation: Orientation of USB type-c port
  * @mode_switch: DP altmode switch
+ * @orientation_switch: USB type-c orientation switch
  * @typec_data: Back pointer to type-c bridge data
  */
 struct drm_dp_typec_bridge_typec_port {
 	u32 lane_mapping[NUM_USB_SS];
+	enum typec_orientation orientation;
 	struct typec_mux_dev *mode_switch;
+	struct typec_switch_dev *orientation_switch;
 	struct drm_dp_typec_bridge_data *typec_data;
 };
 
@@ -378,17 +382,35 @@ static int dp_lane_to_typec_lane(enum dp_lane lane)
 	return -EINVAL;
 }
 
-static int typec_to_dp_lane(enum usb_ss_lane lane)
+static int typec_to_dp_lane(enum usb_ss_lane lane,
+			    enum typec_orientation orientation)
 {
-	switch (lane) {
-	case USB_SSRX1:
-		return DP_ML3;
-	case USB_SSTX1:
-		return DP_ML2;
-	case USB_SSTX2:
-		return DP_ML0;
-	case USB_SSRX2:
-		return DP_ML1;
+	switch (orientation) {
+	case TYPEC_ORIENTATION_NONE:
+	case TYPEC_ORIENTATION_NORMAL:
+		switch (lane) {
+		case USB_SSRX1:
+			return DP_ML3;
+		case USB_SSTX1:
+			return DP_ML2;
+		case USB_SSTX2:
+			return DP_ML0;
+		case USB_SSRX2:
+			return DP_ML1;
+		}
+		break;
+	case TYPEC_ORIENTATION_REVERSE:
+		switch (lane) {
+		case USB_SSRX1:
+			return DP_ML0;
+		case USB_SSTX1:
+			return DP_ML1;
+		case USB_SSTX2:
+			return DP_ML3;
+		case USB_SSRX2:
+			return DP_ML2;
+		}
+		break;
 	}
 
 	return -EINVAL;
@@ -413,6 +435,7 @@ drm_dp_typec_bridge_assign_pins(struct drm_dp_typec_bridge_dev *typec_bridge_dev
 				u32 conf,
 				struct drm_dp_typec_bridge_typec_port *port)
 {
+	enum typec_orientation orientation = port->orientation;
 	enum usb_ss_lane *lane_mapping = port->lane_mapping;
 	struct auxiliary_device *adev = &typec_bridge_dev->adev;
 	struct drm_aux_hpd_bridge_data *hpd_data = auxiliary_get_drvdata(adev);
@@ -448,7 +471,7 @@ drm_dp_typec_bridge_assign_pins(struct drm_dp_typec_bridge_dev *typec_bridge_dev
 		typec_lane = lane_mapping[typec_lane];
 
 		/* Map logical type-c lane to logical DP lane */
-		dp_lanes[i] = typec_to_dp_lane(typec_lane);
+		dp_lanes[i] = typec_to_dp_lane(typec_lane, orientation);
 	}
 
 	return 0;
@@ -496,6 +519,23 @@ static const struct drm_bridge_funcs drm_dp_typec_bridge_funcs = {
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
 };
 
+static int drm_dp_typec_bridge_orientation_set(struct typec_switch_dev *sw,
+					       enum typec_orientation orientation)
+{
+	struct drm_dp_typec_bridge_typec_port *port;
+
+	/*
+	 * Lane remapping is in drm_dp_typec_bridge_mode_switch_set(). Whenever
+	 * an orientation changes the mode will switch in and out of DP mode,
+	 * HPD will deassert and reassert so that
+	 * drm_dp_typec_bridge_atomic_check() sees the proper state.
+	 */
+	port = typec_switch_get_drvdata(sw);
+	port->orientation = orientation;
+
+	return 0;
+}
+
 static int
 drm_dp_typec_bridge_mode_switch_set(struct typec_mux_dev *mode_switch,
 				    struct typec_mux_state *state)
@@ -544,7 +584,9 @@ drm_dp_typec_bridge_probe_typec_ports(struct drm_dp_typec_bridge_data *typec_dat
 	struct drm_dp_typec_bridge_typec_port *port;
 	size_t num_ports = typec_bridge_dev->num_typec_ports;
 	struct typec_mux_desc mode_switch_desc = { };
+	struct typec_switch_desc orientation_switch_desc = { };
 	struct fwnode_handle *fwnode;
+	bool orientation = of_property_read_bool(np, "orientation-switch");
 	const char *name;
 
 	port = devm_kcalloc(dev, num_ports, sizeof(*port), GFP_KERNEL);
@@ -587,6 +629,19 @@ drm_dp_typec_bridge_probe_typec_ports(struct drm_dp_typec_bridge_data *typec_dat
 			return PTR_ERR(port->mode_switch);
 		}
 
+		if (orientation) {
+			orientation_switch_desc.set = drm_dp_typec_bridge_orientation_set,
+			orientation_switch_desc.fwnode = fwnode;
+			orientation_switch_desc.drvdata = port;
+			orientation_switch_desc.name = name;
+			port->orientation_switch = typec_switch_register(dev,
+									 &orientation_switch_desc);
+			if (IS_ERR(port->orientation_switch)) {
+				kfree(name);
+				return PTR_ERR(port->orientation_switch);
+			}
+		}
+
 		kfree(name);
 		port++;
 	}
-- 
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