diff mbox series

[v9,3/9] drm/display: Add Type-C switch helpers

Message ID 20230109084101.265664-4-treapking@chromium.org (mailing list archive)
State Superseded
Headers show
Series Register Type-C mode-switch in DP bridge endpoints | expand

Commit Message

Pin-yen Lin Jan. 9, 2023, 8:40 a.m. UTC
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@chromium.org>

---

(no changes since v8)

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 | 132 ++++++++++++++++++++++++
 include/drm/display/drm_dp_helper.h     |  16 +++
 2 files changed, 148 insertions(+)

Comments

Chen-Yu Tsai Jan. 9, 2023, 10:10 a.m. UTC | #1
On Mon, Jan 9, 2023 at 4:41 PM Pin-yen Lin <treapking@chromium.org> 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@chromium.org>

Tested-by: Chen-Yu Tsai <wenst@chromium.org>

on MT8192 based Hayato (ASUS Chromebook Flip CM3200).

> ---
>
> (no changes since v8)
>
> 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 | 132 ++++++++++++++++++++++++
>  include/drm/display/drm_dp_helper.h     |  16 +++
>  2 files changed, 148 insertions(+)
>
> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> index 16565a0a5da6..fb9e23744c08 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 +3893,133 @@ 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, void *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);
> +       if (num_lanes <= 0) {
> +               dev_err(dev, "Error on getting data lanes count: %d\n",
> +                       num_lanes);

Also printing out the full node name (endpoint@N) would be more helpful.

> +               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: %d\n",
> +                       ret);

Same here.

> +               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;
> +}
> +
> +/**
> + * 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, void *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_warn(dev, "No Type-C switches node found\n");

Maybe change this to dev_info or even dev_debug? A warning would be too
noisy if the bridge drivers are calling this helper unconditionally.

Otherwise,

Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Chen-Yu Tsai Jan. 9, 2023, 11:33 a.m. UTC | #2
On Mon, Jan 9, 2023 at 6:10 PM Chen-Yu Tsai <wenst@chromium.org> wrote:
>
> On Mon, Jan 9, 2023 at 4:41 PM Pin-yen Lin <treapking@chromium.org> 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@chromium.org>
>
> Tested-by: Chen-Yu Tsai <wenst@chromium.org>
>
> on MT8192 based Hayato (ASUS Chromebook Flip CM3200).
>
> > ---
> >
> > (no changes since v8)
> >
> > 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 | 132 ++++++++++++++++++++++++
> >  include/drm/display/drm_dp_helper.h     |  16 +++
> >  2 files changed, 148 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> > index 16565a0a5da6..fb9e23744c08 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 +3893,133 @@ 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, void *mux_set)

Using "typec_mux_set_fn_t" instead of "void *" for mux_set would be
more explicit. Same for all the other instances where this parameter
gets declared.

ChenYu


> > +{
> > +       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);
> > +       if (num_lanes <= 0) {
> > +               dev_err(dev, "Error on getting data lanes count: %d\n",
> > +                       num_lanes);
>
> Also printing out the full node name (endpoint@N) would be more helpful.
>
> > +               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: %d\n",
> > +                       ret);
>
> Same here.
>
> > +               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;
> > +}
> > +
> > +/**
> > + * 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, void *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_warn(dev, "No Type-C switches node found\n");
>
> Maybe change this to dev_info or even dev_debug? A warning would be too
> noisy if the bridge drivers are calling this helper unconditionally.
>
> Otherwise,
>
> Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
AngeloGioacchino Del Regno Jan. 9, 2023, 11:41 a.m. UTC | #3
Il 09/01/23 09:40, Pin-yen Lin ha scritto:
> 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@chromium.org>
> 
> ---
> 
> (no changes since v8)
> 
> 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 | 132 ++++++++++++++++++++++++
>   include/drm/display/drm_dp_helper.h     |  16 +++
>   2 files changed, 148 insertions(+)
> 
> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> index 16565a0a5da6..fb9e23744c08 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 +3893,133 @@ 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, void *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);
> +	if (num_lanes <= 0) {
> +		dev_err(dev, "Error on getting data lanes count: %d\n",
> +			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: %d\n",
> +			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)) {

I would propose, instead...

> +		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 ret;

	return 0;

> +}
> +

...but I don't have strong opinions, so regardless of that:

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index 16565a0a5da6..fb9e23744c08 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 +3893,133 @@  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, void *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);
+	if (num_lanes <= 0) {
+		dev_err(dev, "Error on getting data lanes count: %d\n",
+			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: %d\n",
+			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;
+}
+
+/**
+ * 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, void *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_warn(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, void *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..fef0a9a0d8ea 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -763,4 +763,20 @@  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, void *mux_set);
+
 #endif /* _DRM_DP_HELPER_H_ */