diff mbox series

[v12,03/10] drm/display: Add Type-C switch helpers

Message ID 20230221095054.1868277-4-treapking@chromium.org (mailing list archive)
State New, archived
Headers show
Series Register Type-C mode-switch in DP bridge endpoints | expand

Commit Message

Pin-yen Lin Feb. 21, 2023, 9:50 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 "reg" properties are available in Device Tree.

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

---

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/Makefile              |   1 +
 drivers/gpu/drm/display/drm_dp_typec_helper.c | 108 ++++++++++++++++++
 include/drm/display/drm_dp_helper.h           |  35 ++++++
 3 files changed, 144 insertions(+)
 create mode 100644 drivers/gpu/drm/display/drm_dp_typec_helper.c

Comments

Andy Shevchenko Feb. 21, 2023, 11:48 a.m. UTC | #1 
On Tue, Feb 21, 2023 at 05:50:47PM +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.
> 
> Signed-off-by: Pin-yen Lin <treapking@chromium.org>

...

> +	fwnode_for_each_typec_mode_switch(port, sw)
> +		switch_desc->num_typec_switches++;
> +
> +	if (!switch_desc->num_typec_switches) {
> +		dev_dbg(dev, "No Type-C switches node found\n");
> +		return 0;
> +	}

What about

static inline unsigned int typec_mode_switch_node_count(... *port)
{
	... *sw;
	unsigned int count = 0;

	for_each_typec_mode_switch_node(port, sw)
		count++;

	return count;
}


And then it seems something like

	unsigned int count;

	count = typec_mode_switch_node_count(port);
	if (!count) {
		...
	}

	_switches = count;

...

> +	switch_desc->typec_ports = devm_kcalloc(
> +		dev, switch_desc->num_typec_switches,

Strange indentation.

> +		sizeof(struct drm_dp_typec_port_data), GFP_KERNEL);

> +

Redundant blank line.

> +	if (!switch_desc->typec_ports)
> +		return -ENOMEM;

...

> +void drm_dp_unregister_typec_switches(struct drm_dp_typec_switch_desc *switch_desc)
> +{
> +	int i;

unsigned?

> +	for (i = 0; i < switch_desc->num_typec_switches; i++)
> +		typec_mux_unregister(switch_desc->typec_ports[i].typec_mux);
> +}

...

>  #include <linux/delay.h>
>  #include <linux/i2c.h>
> +#include <linux/usb/typec_mux.h>

I don't see users of this.
But a few forward declarations are missing.

>  #include <drm/display/drm_dp.h>
>  #include <drm/drm_connector.h>

...

> +#define fwnode_for_each_typec_mode_switch(port, sw)	\
> +	fwnode_for_each_child_node((port), (sw))	\
> +		for_each_if(fwnode_property_present((sw), "mode-switch"))

Please don't use fwnode namespace (see above), something like

#define for_each_typec_mode_switch_node(port, sw)	\
	...
Pin-yen Lin Feb. 22, 2023, 8:53 a.m. UTC | #2 
Hi Andy,

Thanks for the review.

On Tue, Feb 21, 2023 at 7:48 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Tue, Feb 21, 2023 at 05:50:47PM +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.
> >
> > Signed-off-by: Pin-yen Lin <treapking@chromium.org>
>
> ...
>
> > +     fwnode_for_each_typec_mode_switch(port, sw)
> > +             switch_desc->num_typec_switches++;
> > +
> > +     if (!switch_desc->num_typec_switches) {
> > +             dev_dbg(dev, "No Type-C switches node found\n");
> > +             return 0;
> > +     }
>
> What about
>
> static inline unsigned int typec_mode_switch_node_count(... *port)
> {
>         ... *sw;
>         unsigned int count = 0;
>
>         for_each_typec_mode_switch_node(port, sw)
>                 count++;
>
>         return count;
> }
>
>
> And then it seems something like
>
>         unsigned int count;
>
>         count = typec_mode_switch_node_count(port);
>         if (!count) {
>                 ...
>         }
>
>         _switches = count;
>
> ...
>
> > +     switch_desc->typec_ports = devm_kcalloc(
> > +             dev, switch_desc->num_typec_switches,
>
> Strange indentation.
>
> > +             sizeof(struct drm_dp_typec_port_data), GFP_KERNEL);
>
> > +
>
> Redundant blank line.
>
> > +     if (!switch_desc->typec_ports)
> > +             return -ENOMEM;
>
> ...
>
> > +void drm_dp_unregister_typec_switches(struct drm_dp_typec_switch_desc *switch_desc)
> > +{
> > +     int i;
>
> unsigned?
>
> > +     for (i = 0; i < switch_desc->num_typec_switches; i++)
> > +             typec_mux_unregister(switch_desc->typec_ports[i].typec_mux);
> > +}
>
> ...
>
> >  #include <linux/delay.h>
> >  #include <linux/i2c.h>
> > +#include <linux/usb/typec_mux.h>
>
> I don't see users of this.
> But a few forward declarations are missing.

I can put a `struct typec_mux_dev;` here, but there is also a usage of
typec_mux_set_fn_t.

Should I add the typedef into this header file as well?

Regards,
Pin-yen
>
> >  #include <drm/display/drm_dp.h>
> >  #include <drm/drm_connector.h>
>
> ...
>
> > +#define fwnode_for_each_typec_mode_switch(port, sw)  \
> > +     fwnode_for_each_child_node((port), (sw))        \
> > +             for_each_if(fwnode_property_present((sw), "mode-switch"))
>
> Please don't use fwnode namespace (see above), something like
>
> #define for_each_typec_mode_switch_node(port, sw)       \
>         ...
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
Andy Shevchenko Feb. 22, 2023, 2:08 p.m. UTC | #3 
On Wed, Feb 22, 2023 at 04:53:41PM +0800, Pin-yen Lin wrote:
> On Tue, Feb 21, 2023 at 7:48 PM Andy Shevchenko
> > On Tue, Feb 21, 2023 at 05:50:47PM +0800, Pin-yen Lin wrote:

...

> > >  #include <linux/delay.h>
> > >  #include <linux/i2c.h>
> > > +#include <linux/usb/typec_mux.h>
> >
> > I don't see users of this.
> > But a few forward declarations are missing.
> 
> I can put a `struct typec_mux_dev;` here, but there is also a usage of
> typec_mux_set_fn_t.
> 
> Should I add the typedef into this header file as well?

No, inclusion is fine, it's me who didn't notice the type in use.
diff mbox series

Patch

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..161e4110f6b9
--- /dev/null
+++ b/drivers/gpu/drm/display/drm_dp_typec_helper.c
@@ -0,0 +1,108 @@ 
+// 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_typec_mode_switch(port, sw)
+		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_typec_mode_switch(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)
+{
+	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..d2ac4be09c8e 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 +764,38 @@  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 fwnode_for_each_typec_mode_switch(port, sw)	\
+	fwnode_for_each_child_node((port), (sw))	\
+		for_each_if(fwnode_property_present((sw), "mode-switch"))
+
+#if IS_REACHABLE(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_ */