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Message-ID: <ccea730e-c5cb-4225-8d1e-97a0a7cb2e34@linaro.org>
Date: Thu, 12 Jan 2023 06:40:01 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Pin-yen Lin <treapking@...omium.org>,
Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>,
Robert Foss <robert.foss@...aro.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>,
Jernej Skrabec <jernej.skrabec@...il.com>,
David Airlie <airlied@...il.com>,
Daniel Vetter <daniel@...ll.ch>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Daniel Scally <djrscally@...il.com>,
Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
Sakari Ailus <sakari.ailus@...ux.intel.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J . Wysocki" <rafael@...nel.org>,
Prashant Malani <pmalani@...omium.org>,
Benson Leung <bleung@...omium.org>,
Guenter Roeck <groeck@...omium.org>
Cc: Stephen Boyd <swboyd@...omium.org>,
Nícolas F . R . A . Prado
<nfraprado@...labora.com>, Marek Vasut <marex@...x.de>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>,
devicetree@...r.kernel.org, dri-devel@...ts.freedesktop.org,
Javier Martinez Canillas <javierm@...hat.com>,
Lyude Paul <lyude@...hat.com>, chrome-platform@...ts.linux.dev,
Xin Ji <xji@...logixsemi.com>,
Thomas Zimmermann <tzimmermann@...e.de>,
linux-kernel@...r.kernel.org, Allen Chen <allen.chen@....com.tw>,
linux-acpi@...r.kernel.org, Hsin-Yi Wang <hsinyi@...omium.org>,
Chen-Yu Tsai <wenst@...omium.org>,
Douglas Anderson <dianders@...omium.org>,
Imre Deak <imre.deak@...el.com>,
Jani Nikula <jani.nikula@...el.com>,
Kees Cook <keescook@...omium.org>,
Ville Syrjälä <ville.syrjala@...ux.intel.com>,
shaomin Deng <dengshaomin@...rlc.com>
Subject: Re: [PATCH v10 3/9] drm/display: Add Type-C switch helpers
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@...omium.org>
> Tested-by: Chen-Yu Tsai <wenst@...omium.org>
> Reviewed-by: Chen-Yu Tsai <wenst@...omium.org>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
>
> ---
>
> 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
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