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    Subject[PATCH v11 3/9] drm/display: Add Type-C switch helpers
    Date
    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 "reg" properties are available in Device Tree.

    Signed-off-by: Pin-yen Lin <treapking@chromium.org>

    ---

    Changes in v11:
    - Use fwnode helpers instead of DT
    - Moved the helpers to a new file
    - Use "reg" instead of "data-lanes" to determine the port number
    - Dropped collected tags due to new changes

    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/Makefile | 1 +
    drivers/gpu/drm/display/drm_dp_typec_helper.c | 114 ++++++++++++++++++
    include/drm/display/drm_dp_helper.h | 31 +++++
    3 files changed, 146 insertions(+)
    create mode 100644 drivers/gpu/drm/display/drm_dp_typec_helper.c

    diff --git a/drivers/gpu/drm/display/Makefile b/drivers/gpu/drm/display/Makefile
    index 17ac4a1006a8..ef80b9fde615 100644
    --- a/drivers/gpu/drm/display/Makefile
    +++ b/drivers/gpu/drm/display/Makefile
    @@ -14,5 +14,6 @@ drm_display_helper-$(CONFIG_DRM_DISPLAY_HDMI_HELPER) += \
    drm_scdc_helper.o
    drm_display_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o
    drm_display_helper-$(CONFIG_DRM_DP_CEC) += drm_dp_cec.o
    +drm_display_helper-$(CONFIG_TYPEC) += drm_dp_typec_helper.o

    obj-$(CONFIG_DRM_DISPLAY_HELPER) += drm_display_helper.o
    diff --git a/drivers/gpu/drm/display/drm_dp_typec_helper.c b/drivers/gpu/drm/display/drm_dp_typec_helper.c
    new file mode 100644
    index 000000000000..b11a268da57f
    --- /dev/null
    +++ b/drivers/gpu/drm/display/drm_dp_typec_helper.c
    @@ -0,0 +1,114 @@
    +// SPDX-License-Identifier: GPL-2.0
    +
    +#include <linux/usb/typec_mux.h>
    +#include <drm/display/drm_dp_helper.h>
    +
    +static int drm_dp_register_mode_switch(struct device *dev,
    + struct fwnode_handle *fwnode,
    + 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 port_num;
    + int ret;
    +
    + ret = fwnode_property_read_u32(fwnode, "reg", &port_num);
    + if (ret) {
    + dev_err(dev, "Failed to read reg property: %d\n", ret);
    + return ret;
    + }
    +
    + port_data = &switch_desc->typec_ports[port_num];
    + port_data->data = data;
    + port_data->port_num = port_num;
    + port_data->fwnode = fwnode;
    + mux_desc.fwnode = fwnode;
    + mux_desc.drvdata = port_data;
    + snprintf(name, sizeof(name), "%pfwP-%u", fwnode, 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.
    + * The port number is determined by the "reg" property of the endpoint.
    + */
    +int drm_dp_register_typec_switches(struct device *dev, struct fwnode_handle *port,
    + struct drm_dp_typec_switch_desc *switch_desc,
    + void *data, typec_mux_set_fn_t mux_set)
    +{
    + struct fwnode_handle *sw;
    + int ret;
    +
    + fwnode_for_each_child_node(port, sw) {
    + if (fwnode_property_present(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. */
    + fwnode_for_each_child_node(port, sw) {
    + if (!fwnode_property_present(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:
    + fwnode_handle_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);
    diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
    index ab55453f2d2c..d9213739de72 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 +764,34 @@ 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;
    + int port_num;
    + struct fwnode_handle *fwnode;
    + void *data;
    +};
    +
    +struct drm_dp_typec_switch_desc {
    + int num_typec_switches;
    + struct drm_dp_typec_port_data *typec_ports;
    +};
    +
    +#ifdef CONFIG_TYPEC
    +void drm_dp_unregister_typec_switches(struct drm_dp_typec_switch_desc *switch_desc);
    +int drm_dp_register_typec_switches(struct device *dev, struct fwnode_handle *port,
    + struct drm_dp_typec_switch_desc *switch_desc,
    + void *data, typec_mux_set_fn_t mux_set);
    +#else
    +static inline void drm_dp_unregister_typec_switches(struct drm_dp_typec_switch_desc *switch_desc)
    +{
    +}
    +static inline int drm_dp_register_typec_switches(
    + struct device *dev, struct fwnode_handle *port,
    + struct drm_dp_typec_switch_desc *switch_desc, void *data,
    + typec_mux_set_fn_t mux_set)
    +{
    + return -EOPNOTSUPP;
    +}
    +#endif
    +
    #endif /* _DRM_DP_HELPER_H_ */
    --
    2.39.1.519.gcb327c4b5f-goog
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