On 12/01/2023 06:20, Pin-yen Lin wrote:
Add helpers to register and unregister Type-C "switches" for bridges
capable of switching their output between two downstream devices.
The helper registers USB Type-C mode switches when the "mode-switch"
and the "data-lanes" properties are available in Device Tree.
Signed-off-by: Pin-yen Lin <treapking@xxxxxxxxxxxx>
Tested-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
Reviewed-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
Changes in v10:
- Collected Reviewed-by and Tested-by tags
- Replaced "void *" with "typec_mux_set_fn_t" for mux_set callbacks
- Print out the node name when errors on parsing DT
- Use dev_dbg instead of dev_warn when no Type-C switch nodes available
- Made the return path of drm_dp_register_mode_switch clearer
Changes in v8:
- Fixed the build issue when CONFIG_TYPEC=m
- Fixed some style issues
Changes in v7:
- Extracted the common codes to a helper function
- New in v7
drivers/gpu/drm/display/drm_dp_helper.c | 134 ++++++++++++++++++++++++
include/drm/display/drm_dp_helper.h | 17 +++
2 files changed, 151 insertions(+)
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index 16565a0a5da6..a2ec40a621cb 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -30,11 +30,13 @@
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/string_helpers.h>
+#include <linux/usb/typec_mux.h>
#include <linux/dynamic_debug.h>
#include <drm/display/drm_dp_helper.h>
#include <drm/display/drm_dp_mst_helper.h>
#include <drm/drm_edid.h>
+#include <drm/drm_of.h>
#include <drm/drm_print.h>
#include <drm/drm_vblank.h>
#include <drm/drm_panel.h>
@@ -3891,3 +3893,135 @@ int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux)
EXPORT_SYMBOL(drm_panel_dp_aux_backlight);
#endif
+
+#if IS_REACHABLE(CONFIG_TYPEC)
+static int drm_dp_register_mode_switch(struct device *dev, struct device_node *node,
+ struct drm_dp_typec_switch_desc *switch_desc,
+ void *data, typec_mux_set_fn_t mux_set)
+{
+ struct drm_dp_typec_port_data *port_data;
+ struct typec_mux_desc mux_desc = {};
+ char name[32];
+ u32 dp_lanes[2];
+ int ret, num_lanes, port_num = -1;
+
+ num_lanes = drm_of_get_data_lanes_count(node, 0, 2);
2 looks incorrect. IIRC DP altmode can support up to 4 lanes.
+ if (num_lanes <= 0) {
+ dev_err(dev, "Error on getting data lanes count from %s: %d\n",
+ node->name, num_lanes);
+ return num_lanes;
+ }
+
+ ret = of_property_read_u32_array(node, "data-lanes", dp_lanes, num_lanes);
+ if (ret) {
+ dev_err(dev, "Failed to read the data-lanes variable from %s: %d\n",
+ node->name, ret);
+ return ret;
+ }
+
+ port_num = dp_lanes[0] / 2;
+
+ port_data = &switch_desc->typec_ports[port_num];
+ port_data->data = data;
+ mux_desc.fwnode = &node->fwnode;
+ mux_desc.drvdata = port_data;
+ snprintf(name, sizeof(name), "%s-%u", node->name, port_num);
+ mux_desc.name = name;
+ mux_desc.set = mux_set;
+
+ port_data->typec_mux = typec_mux_register(dev, &mux_desc);
+ if (IS_ERR(port_data->typec_mux)) {
+ ret = PTR_ERR(port_data->typec_mux);
+ dev_err(dev, "Mode switch register for port %d failed: %d\n",
+ port_num, ret);
+
+ return ret;
+ }
+
+ return 0;
+}
+
+/**
+ * drm_dp_register_typec_switches() - register Type-C switches
+ * @dev: Device that registers Type-C switches
+ * @port: Device node for the switch
+ * @switch_desc: A Type-C switch descriptor
+ * @data: Private data for the switches
+ * @mux_set: Callback function for typec_mux_set
+ *
+ * This function registers USB Type-C switches for DP bridges that can switch
+ * the output signal between their output pins.
+ *
+ * Currently only mode switches are implemented, and the function assumes the
+ * given @port device node has endpoints with "mode-switch" property.
+ * Register the endpoint as port 0 if the "data-lanes" property falls in 0/1,
+ * and register it as port 1 if "data-lanes" falls in 2/3.
+ */
+int drm_dp_register_typec_switches(struct device *dev, struct device_node *port,
+ struct drm_dp_typec_switch_desc *switch_desc,
+ void *data, typec_mux_set_fn_t mux_set)
+{
+ struct device_node *sw;
+ int ret;
+
+ for_each_child_of_node(port, sw) {
+ if (of_property_read_bool(sw, "mode-switch"))
+ switch_desc->num_typec_switches++;
+ }
+
+ if (!switch_desc->num_typec_switches) {
+ dev_dbg(dev, "No Type-C switches node found\n");
+ return 0;
+ }
+
+ switch_desc->typec_ports = devm_kcalloc(
+ dev, switch_desc->num_typec_switches,
+ sizeof(struct drm_dp_typec_port_data), GFP_KERNEL);
+
+ if (!switch_desc->typec_ports)
+ return -ENOMEM;
+
+ /* Register switches for each connector. */
+ for_each_child_of_node(port, sw) {
+ if (!of_property_read_bool(sw, "mode-switch"))
+ continue;
+ ret = drm_dp_register_mode_switch(dev, sw, switch_desc, data, mux_set);
+ if (ret)
+ goto err_unregister_typec_switches;
+ }
+
+ return 0;
+
+err_unregister_typec_switches:
+ of_node_put(sw);
+ drm_dp_unregister_typec_switches(switch_desc);
+ dev_err(dev, "Failed to register mode switch: %d\n", ret);
+ return ret;
+}
+EXPORT_SYMBOL(drm_dp_register_typec_switches);
+
+/**
+ * drm_dp_unregister_typec_switches() - unregister Type-C switches
+ * @switch_desc: A Type-C switch descriptor
+ */
+void drm_dp_unregister_typec_switches(struct drm_dp_typec_switch_desc *switch_desc)
+{
+ int i;
+
+ for (i = 0; i < switch_desc->num_typec_switches; i++)
+ typec_mux_unregister(switch_desc->typec_ports[i].typec_mux);
+}
+EXPORT_SYMBOL(drm_dp_unregister_typec_switches);
+#else
+void drm_dp_unregister_typec_switches(struct drm_dp_typec_switch_desc *switch_desc)
+{
+}
+EXPORT_SYMBOL(drm_dp_register_typec_switches);
+int drm_dp_register_typec_switches(struct device *dev, struct device_node *port,
+ struct drm_dp_typec_switch_desc *switch_desc,
+ void *data, typec_mux_set_fn_t mux_set)
+{
+ return 0;
+}
+EXPORT_SYMBOL(drm_dp_unregister_typec_switches);
+#endif
diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
index ab55453f2d2c..5a3824f13b4e 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -25,6 +25,7 @@
#include <linux/delay.h>
#include <linux/i2c.h>
+#include <linux/usb/typec_mux.h>
#include <drm/display/drm_dp.h>
#include <drm/drm_connector.h>
@@ -763,4 +764,20 @@ bool drm_dp_downstream_rgb_to_ycbcr_conversion(const u8 dpcd[DP_RECEIVER_CAP_SIZ
const u8 port_cap[4], u8 color_spc);
int drm_dp_pcon_convert_rgb_to_ycbcr(struct drm_dp_aux *aux, u8 color_spc);
+struct drm_dp_typec_port_data {
+ struct typec_mux_dev *typec_mux;
+ void *data;
+ bool dp_connected;
+};
+
+struct drm_dp_typec_switch_desc {
+ int num_typec_switches;
+ struct drm_dp_typec_port_data *typec_ports;
+};
+
+void drm_dp_unregister_typec_switches(struct drm_dp_typec_switch_desc *switch_desc);
+int drm_dp_register_typec_switches(struct device *dev, struct device_node *port,
+ struct drm_dp_typec_switch_desc *switch_desc,
+ void *data, typec_mux_set_fn_t mux_set);
+
#endif /* _DRM_DP_HELPER_H_ */
--
With best wishes
Dmitry
