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 v14:
- Introduce a new Kconfig becuase it didn't build when CONFIG_TYPEC=m
- Add comments about devm_* usage
- Fix style issues
Changes in v13:
- Add typec_mode_switch_node_count helper
- Fix style issues
Changes in v12:
- Add fwnode_for_each_typec_mode_switch macro
- Remove a duplicated dmesg in the helper
- Used IS_REACHABLE instead to guard the function signatures
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/Kconfig | 8 ++
drivers/gpu/drm/display/Makefile | 2 +
drivers/gpu/drm/display/drm_dp_typec_helper.c | 105 ++++++++++++++++++
include/drm/display/drm_dp_helper.h | 46 ++++++++
4 files changed, 161 insertions(+)
create mode 100644 drivers/gpu/drm/display/drm_dp_typec_helper.c
diff --git a/drivers/gpu/drm/display/Kconfig b/drivers/gpu/drm/display/Kconfig
index 09712b88a5b8..d61076947a1c 100644
--- a/drivers/gpu/drm/display/Kconfig
+++ b/drivers/gpu/drm/display/Kconfig
@@ -29,6 +29,14 @@ config DRM_DISPLAY_HDMI_HELPER
help
DRM display helpers for HDMI.
+config DRM_DISPLAY_DP_TYPEC_HELPER
+ bool
+ default y
+ depends on DRM_DISPLAY_HELPER
+ depends on DRM_DISPLAY_HELPER=TYPEC || TYPEC=y
+ help
+ DRM display helpers for USB Type-C Displayport Alternate mode.
+
config DRM_DP_AUX_CHARDEV
bool "DRM DP AUX Interface"
depends on DRM && DRM_DISPLAY_HELPER
diff --git a/drivers/gpu/drm/display/Makefile b/drivers/gpu/drm/display/Makefile
index 17ac4a1006a8..2202a6aea38e 100644
--- a/drivers/gpu/drm/display/Makefile
+++ b/drivers/gpu/drm/display/Makefile
@@ -8,6 +8,8 @@ drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_HELPER) += \
drm_dp_helper.o \
drm_dp_mst_topology.o \
drm_dsc_helper.o
+drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER) += \
+ drm_dp_typec_helper.o
drm_display_helper-$(CONFIG_DRM_DISPLAY_HDCP_HELPER) += drm_hdcp_helper.o
drm_display_helper-$(CONFIG_DRM_DISPLAY_HDMI_HELPER) += \
drm_hdmi_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..1562a9ccdaf2
--- /dev/null
+++ b/drivers/gpu/drm/display/drm_dp_typec_helper.c
@@ -0,0 +1,105 @@
+// 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);
+ ret = PTR_ERR_OR_ZERO(port_data->typec_mux);
+ if (ret)
+ 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. This function uses devm_kcalloc
+ * to allocate memory, so it is expected to only call this in the driver probe
+ * functions.
+ *
+ * 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;
+
+ switch_desc->num_typec_switches = typec_mode_switch_node_count(port);
+ 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_typec_mode_switch_node(port, sw) {
+ 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);
+ 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)
+{
+ unsigned 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..0fe56586d7bc 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 +764,49 @@ 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;
+};
+
+#define for_each_typec_mode_switch_node(port, sw) \
+ fwnode_for_each_child_node((port), (sw)) \
+ for_each_if(fwnode_property_present((sw), "mode-switch"))
+
+static inline unsigned int typec_mode_switch_node_count(struct fwnode_handle *port)
+{
+ struct fwnode_handle *sw;
+ unsigned int count = 0;
+
+ for_each_typec_mode_switch_node(port, sw)
+ count++;
+
+ return count;
+}
+
+#ifdef CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER
+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_ */
--
2.40.0.rc1.284.g88254d51c5-googOn Wed, 22 Mar 2023 at 12:47, 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 "reg" properties are available in Device Tree.
>
> Signed-off-by: Pin-yen Lin <treapking@chromium.org>
>
> ---
>
> Changes in v14:
> - Introduce a new Kconfig becuase it didn't build when CONFIG_TYPEC=m
> - Add comments about devm_* usage
> - Fix style issues
>
> Changes in v13:
> - Add typec_mode_switch_node_count helper
> - Fix style issues
>
> Changes in v12:
> - Add fwnode_for_each_typec_mode_switch macro
> - Remove a duplicated dmesg in the helper
> - Used IS_REACHABLE instead to guard the function signatures
>
> 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/Kconfig | 8 ++
> drivers/gpu/drm/display/Makefile | 2 +
> drivers/gpu/drm/display/drm_dp_typec_helper.c | 105 ++++++++++++++++++
> include/drm/display/drm_dp_helper.h | 46 ++++++++
> 4 files changed, 161 insertions(+)
> create mode 100644 drivers/gpu/drm/display/drm_dp_typec_helper.c
>
> diff --git a/drivers/gpu/drm/display/Kconfig b/drivers/gpu/drm/display/Kconfig
> index 09712b88a5b8..d61076947a1c 100644
> --- a/drivers/gpu/drm/display/Kconfig
> +++ b/drivers/gpu/drm/display/Kconfig
> @@ -29,6 +29,14 @@ config DRM_DISPLAY_HDMI_HELPER
> help
> DRM display helpers for HDMI.
>
> +config DRM_DISPLAY_DP_TYPEC_HELPER
> + bool
> + default y
> + depends on DRM_DISPLAY_HELPER
> + depends on DRM_DISPLAY_HELPER=TYPEC || TYPEC=y
If it is a select'able option, it doesn't make sense to use "depends"
here. Select will override depends.
> + help
> + DRM display helpers for USB Type-C Displayport Alternate mode.
> +
> config DRM_DP_AUX_CHARDEV
> bool "DRM DP AUX Interface"
> depends on DRM && DRM_DISPLAY_HELPER
> diff --git a/drivers/gpu/drm/display/Makefile b/drivers/gpu/drm/display/Makefile
> index 17ac4a1006a8..2202a6aea38e 100644
> --- a/drivers/gpu/drm/display/Makefile
> +++ b/drivers/gpu/drm/display/Makefile
> @@ -8,6 +8,8 @@ drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_HELPER) += \
> drm_dp_helper.o \
> drm_dp_mst_topology.o \
> drm_dsc_helper.o
> +drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER) += \
> + drm_dp_typec_helper.o
> drm_display_helper-$(CONFIG_DRM_DISPLAY_HDCP_HELPER) += drm_hdcp_helper.o
> drm_display_helper-$(CONFIG_DRM_DISPLAY_HDMI_HELPER) += \
> drm_hdmi_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..1562a9ccdaf2
> --- /dev/null
> +++ b/drivers/gpu/drm/display/drm_dp_typec_helper.c
> @@ -0,0 +1,105 @@
> +// 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];
Why 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);
I think it makes more sense to use dev_name here instead of fwnode.
> + mux_desc.name = name;
> + mux_desc.set = mux_set;
> +
> + port_data->typec_mux = typec_mux_register(dev, &mux_desc);
> + ret = PTR_ERR_OR_ZERO(port_data->typec_mux);
> + if (ret)
> + 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. This function uses devm_kcalloc
> + * to allocate memory, so it is expected to only call this in the driver probe
> + * functions.
> + *
> + * 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;
> +
> + switch_desc->num_typec_switches = typec_mode_switch_node_count(port);
> + 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_typec_mode_switch_node(port, sw) {
> + 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);
> + 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)
> +{
> + unsigned 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..0fe56586d7bc 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 +764,49 @@ 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;
> +};
> +
> +#define for_each_typec_mode_switch_node(port, sw) \
> + fwnode_for_each_child_node((port), (sw)) \
> + for_each_if(fwnode_property_present((sw), "mode-switch"))
> +
> +static inline unsigned int typec_mode_switch_node_count(struct fwnode_handle *port)
> +{
> + struct fwnode_handle *sw;
> + unsigned int count = 0;
> +
> + for_each_typec_mode_switch_node(port, sw)
> + count++;
> +
> + return count;
> +}
> +
> +#ifdef CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER
> +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_ */
> --
> 2.40.0.rc1.284.g88254d51c5-goog
>
--
With best wishes
Dmitry
Hi Dmitry,
Thanks for the review.
On Thu, Mar 23, 2023 at 7:39 AM Dmitry Baryshkov
<dmitry.baryshkov@linaro.org> wrote:
>
> On Wed, 22 Mar 2023 at 12:47, 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 "reg" properties are available in Device Tree.
> >
> > Signed-off-by: Pin-yen Lin <treapking@chromium.org>
> >
> > ---
> >
> > Changes in v14:
> > - Introduce a new Kconfig becuase it didn't build when CONFIG_TYPEC=m
> > - Add comments about devm_* usage
> > - Fix style issues
> >
> > Changes in v13:
> > - Add typec_mode_switch_node_count helper
> > - Fix style issues
> >
> > Changes in v12:
> > - Add fwnode_for_each_typec_mode_switch macro
> > - Remove a duplicated dmesg in the helper
> > - Used IS_REACHABLE instead to guard the function signatures
> >
> > 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/Kconfig | 8 ++
> > drivers/gpu/drm/display/Makefile | 2 +
> > drivers/gpu/drm/display/drm_dp_typec_helper.c | 105 ++++++++++++++++++
> > include/drm/display/drm_dp_helper.h | 46 ++++++++
> > 4 files changed, 161 insertions(+)
> > create mode 100644 drivers/gpu/drm/display/drm_dp_typec_helper.c
> >
> > diff --git a/drivers/gpu/drm/display/Kconfig b/drivers/gpu/drm/display/Kconfig
> > index 09712b88a5b8..d61076947a1c 100644
> > --- a/drivers/gpu/drm/display/Kconfig
> > +++ b/drivers/gpu/drm/display/Kconfig
> > @@ -29,6 +29,14 @@ config DRM_DISPLAY_HDMI_HELPER
> > help
> > DRM display helpers for HDMI.
> >
> > +config DRM_DISPLAY_DP_TYPEC_HELPER
> > + bool
> > + default y
> > + depends on DRM_DISPLAY_HELPER
> > + depends on DRM_DISPLAY_HELPER=TYPEC || TYPEC=y
>
> If it is a select'able option, it doesn't make sense to use "depends"
> here. Select will override depends.
>
I'm not very familiar with the practices of Kconfigs, but I'll keep
this in the next version per Andy's comment.
> > + help
> > + DRM display helpers for USB Type-C Displayport Alternate mode.
> > +
> > config DRM_DP_AUX_CHARDEV
> > bool "DRM DP AUX Interface"
> > depends on DRM && DRM_DISPLAY_HELPER
> > diff --git a/drivers/gpu/drm/display/Makefile b/drivers/gpu/drm/display/Makefile
> > index 17ac4a1006a8..2202a6aea38e 100644
> > --- a/drivers/gpu/drm/display/Makefile
> > +++ b/drivers/gpu/drm/display/Makefile
> > @@ -8,6 +8,8 @@ drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_HELPER) += \
> > drm_dp_helper.o \
> > drm_dp_mst_topology.o \
> > drm_dsc_helper.o
> > +drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER) += \
> > + drm_dp_typec_helper.o
> > drm_display_helper-$(CONFIG_DRM_DISPLAY_HDCP_HELPER) += drm_hdcp_helper.o
> > drm_display_helper-$(CONFIG_DRM_DISPLAY_HDMI_HELPER) += \
> > drm_hdmi_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..1562a9ccdaf2
> > --- /dev/null
> > +++ b/drivers/gpu/drm/display/drm_dp_typec_helper.c
> > @@ -0,0 +1,105 @@
> > +// 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];
>
> Why 32?
This is just a random length that is probably sufficiently large. I
see other users use the pointer from `fwnode_get_name` directly, but
we want to append the port number to ensure the names are unique.
>
> > + 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);
>
> I think it makes more sense to use dev_name here instead of fwnode.
Thanks for the suggestions. I'll update this in the next version.
>
> > + mux_desc.name = name;
> > + mux_desc.set = mux_set;
> > +
> > + port_data->typec_mux = typec_mux_register(dev, &mux_desc);
> > + ret = PTR_ERR_OR_ZERO(port_data->typec_mux);
> > + if (ret)
> > + 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. This function uses devm_kcalloc
> > + * to allocate memory, so it is expected to only call this in the driver probe
> > + * functions.
> > + *
> > + * 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;
> > +
> > + switch_desc->num_typec_switches = typec_mode_switch_node_count(port);
> > + 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_typec_mode_switch_node(port, sw) {
> > + 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);
> > + 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)
> > +{
> > + unsigned 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..0fe56586d7bc 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 +764,49 @@ 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;
> > +};
> > +
> > +#define for_each_typec_mode_switch_node(port, sw) \
> > + fwnode_for_each_child_node((port), (sw)) \
> > + for_each_if(fwnode_property_present((sw), "mode-switch"))
> > +
> > +static inline unsigned int typec_mode_switch_node_count(struct fwnode_handle *port)
> > +{
> > + struct fwnode_handle *sw;
> > + unsigned int count = 0;
> > +
> > + for_each_typec_mode_switch_node(port, sw)
> > + count++;
> > +
> > + return count;
> > +}
> > +
> > +#ifdef CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER
> > +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_ */
> > --
> > 2.40.0.rc1.284.g88254d51c5-goog
> >
>
>
> --
> With best wishes
> Dmitry
Best regards,
Pin-yen
On Thu, Mar 23, 2023 at 12:38:49AM +0200, Dmitry Baryshkov wrote: > On Wed, 22 Mar 2023 at 12:47, Pin-yen Lin <treapking@chromium.org> wrote: ... > > +config DRM_DISPLAY_DP_TYPEC_HELPER > > + bool > > + default y > > + depends on DRM_DISPLAY_HELPER > > + depends on DRM_DISPLAY_HELPER=TYPEC || TYPEC=y > > If it is a select'able option, it doesn't make sense to use "depends" > here. Select will override depends. He-he, not so easy. This will help to find configurations that miss these dependencies. Arnd taught me that. IIRC the ASoC subsystem has a lot of such cases. > > + help > > + DRM display helpers for USB Type-C Displayport Alternate mode. -- With Best Regards, Andy Shevchenko
On Wed, Mar 22, 2023 at 06:46:32PM +0800, 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 "reg" properties are available in Device Tree.
...
> +config DRM_DISPLAY_DP_TYPEC_HELPER
> + bool
> + default y
def_bool y
> + depends on DRM_DISPLAY_HELPER
> + depends on DRM_DISPLAY_HELPER=TYPEC || TYPEC=y
> + help
> + DRM display helpers for USB Type-C Displayport Alternate mode.
Hmm... Dunno if this help is enough.
...
> + snprintf(name, sizeof(name), "%pfwP-%u", fwnode, port_num);
Would it be possible to have a dup in name and would it be a problem if so?
...
> +/**
> + * 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. This function uses devm_kcalloc
> + * to allocate memory, so it is expected to only call this in the driver probe
> + * functions.
> + *
> + * 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.
`kernel-doc -v ...` should complain on absence of "Return" section.
> + */
...
> + switch_desc->typec_ports = devm_kcalloc(dev, switch_desc->num_typec_switches,
> + sizeof(struct drm_dp_typec_port_data),
sizeof(*switch_desc_typec_ports),
?
> + GFP_KERNEL);
> + if (!switch_desc->typec_ports)
> + return -ENOMEM;
...
> +#ifdef CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER
Ah, maybe this should use IS_REACHABLE() ?
> +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
--
With Best Regards,
Andy Shevchenko
Hi Andy,
Thanks for the review.
On Wed, Mar 22, 2023 at 8:01 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Wed, Mar 22, 2023 at 06:46:32PM +0800, 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 "reg" properties are available in Device Tree.
>
> ...
>
> > +config DRM_DISPLAY_DP_TYPEC_HELPER
>
> > + bool
> > + default y
>
> def_bool y
>
> > + depends on DRM_DISPLAY_HELPER
> > + depends on DRM_DISPLAY_HELPER=TYPEC || TYPEC=y
> > + help
> > + DRM display helpers for USB Type-C Displayport Alternate mode.
>
> Hmm... Dunno if this help is enough.
Okay I'll add more detail in the next version.
>
> ...
>
> > + snprintf(name, sizeof(name), "%pfwP-%u", fwnode, port_num);
>
> Would it be possible to have a dup in name and would it be a problem if so?
>
The port_num is included in the name, so the names should be unique.
Also, the fwnode name actually contains the reg property, so this name
looks like "endpoint@0-1" now... I'll change the name from fwnode name
to dev_name() per Dmitry's comment.
> ...
>
> > +/**
> > + * 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. This function uses devm_kcalloc
> > + * to allocate memory, so it is expected to only call this in the driver probe
> > + * functions.
> > + *
> > + * 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.
>
> `kernel-doc -v ...` should complain on absence of "Return" section.
>
> > + */
>
> ...
>
> > + switch_desc->typec_ports = devm_kcalloc(dev, switch_desc->num_typec_switches,
> > + sizeof(struct drm_dp_typec_port_data),
>
> sizeof(*switch_desc_typec_ports),
>
> ?
>
> > + GFP_KERNEL);
> > + if (!switch_desc->typec_ports)
> > + return -ENOMEM;
>
> ...
>
> > +#ifdef CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER
>
> Ah, maybe this should use IS_REACHABLE() ?
CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER is a boolean. Is there any
difference between IS_REACHABLE and ifdef when the given config is a
boolean?
>
> > +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
>
> --
> With Best Regards,
> Andy Shevchenko
>
Best regards,
Pin-yen
>
On Fri, Mar 31, 2023 at 11:36 AM Pin-yen Lin <treapking@chromium.org> wrote:
>
> Hi Andy,
>
> Thanks for the review.
>
> On Wed, Mar 22, 2023 at 8:01 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> >
> > On Wed, Mar 22, 2023 at 06:46:32PM +0800, 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 "reg" properties are available in Device Tree.
> >
> > ...
> >
> > > +config DRM_DISPLAY_DP_TYPEC_HELPER
> >
> > > + bool
> > > + default y
> >
> > def_bool y
> >
> > > + depends on DRM_DISPLAY_HELPER
> > > + depends on DRM_DISPLAY_HELPER=TYPEC || TYPEC=y
> > > + help
> > > + DRM display helpers for USB Type-C Displayport Alternate mode.
> >
> > Hmm... Dunno if this help is enough.
>
> Okay I'll add more detail in the next version.
> >
> > ...
> >
> > > + snprintf(name, sizeof(name), "%pfwP-%u", fwnode, port_num);
> >
> > Would it be possible to have a dup in name and would it be a problem if so?
> >
> The port_num is included in the name, so the names should be unique.
> Also, the fwnode name actually contains the reg property, so this name
> looks like "endpoint@0-1" now... I'll change the name from fwnode name
This should be "endpoint@0-0", or "endpoint@1-1@. The `port_num` value
has the same number as the `reg` property
> to dev_name() per Dmitry's comment.
> > ...
> >
> > > +/**
> > > + * 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. This function uses devm_kcalloc
> > > + * to allocate memory, so it is expected to only call this in the driver probe
> > > + * functions.
> > > + *
> > > + * 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.
> >
> > `kernel-doc -v ...` should complain on absence of "Return" section.
> >
> > > + */
> >
> > ...
> >
> > > + switch_desc->typec_ports = devm_kcalloc(dev, switch_desc->num_typec_switches,
> > > + sizeof(struct drm_dp_typec_port_data),
> >
> > sizeof(*switch_desc_typec_ports),
> >
> > ?
> >
> > > + GFP_KERNEL);
> > > + if (!switch_desc->typec_ports)
> > > + return -ENOMEM;
> >
> > ...
> >
> > > +#ifdef CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER
> >
> > Ah, maybe this should use IS_REACHABLE() ?
>
> CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER is a boolean. Is there any
> difference between IS_REACHABLE and ifdef when the given config is a
> boolean?
> >
> > > +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
> >
> > --
> > With Best Regards,
> > Andy Shevchenko
> >
>
> Best regards,
> Pin-yen
> >
On Wed, 22 Mar 2023, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > On Wed, Mar 22, 2023 at 06:46:32PM +0800, Pin-yen Lin wrote: >> +#ifdef CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER > > Ah, maybe this should use IS_REACHABLE() ? Personally, I think IS_REACHABLE() is a build-time band-aid solution to a problem that should be solved in Kconfig. :p I think it always means there's a configuration combo that shouldn't exist, and it's a surprise to the user when they've configured something, Kconfig has deemed it a valid configuration, but they don't get the feature they want. As a user, how would they even debug that case? Double check configs, don't see anything wrong. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center
On Wed, Mar 22, 2023 at 06:27:56PM +0200, Jani Nikula wrote: > On Wed, 22 Mar 2023, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > > On Wed, Mar 22, 2023 at 06:46:32PM +0800, Pin-yen Lin wrote: > >> +#ifdef CONFIG_DRM_DISPLAY_DP_TYPEC_HELPER > > > > Ah, maybe this should use IS_REACHABLE() ? > > Personally, I think IS_REACHABLE() is a build-time band-aid solution to > a problem that should be solved in Kconfig. :p > > I think it always means there's a configuration combo that shouldn't > exist, and it's a surprise to the user when they've configured > something, Kconfig has deemed it a valid configuration, but they don't > get the feature they want. > > As a user, how would they even debug that case? Double check configs, > don't see anything wrong. Usual pairing is 'imply FOO' in Kconfig & 'IS_REACHEABLE(CONFIG_FOO)' in the code. And I believe it's not an abnormal. -- With Best Regards, Andy Shevchenko
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