[v6,7/7] drm/bridge: it6505: Register Type C mode switches

Message ID 20221124102056.393220-8-treapking@chromium.org
State New
Headers
Series Register Type-C mode-switch in DP bridge endpoints |

Commit Message

Pin-yen Lin Nov. 24, 2022, 10:20 a.m. UTC
  Register USB Type-C mode switches when the "mode-switch" property and
relevant port are available in Device Tree. Configure the "lane_swap"
state based on the entered alternate mode for a specific Type-C
connector, which ends up updating the lane swap registers of the it6505
chip.

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

---

Changes in v6:
- Changed it6505_typec_mux_set callback function to accommodate with
  the latest drm-misc patches
- Changed the driver implementation to accommodate with the new binding
- Squashed to a single patch

 drivers/gpu/drm/bridge/Kconfig      |   1 +
 drivers/gpu/drm/bridge/ite-it6505.c | 205 +++++++++++++++++++++++++++-
 2 files changed, 202 insertions(+), 4 deletions(-)
  

Comments

Andy Shevchenko Nov. 24, 2022, 12:23 p.m. UTC | #1
On Thu, Nov 24, 2022 at 06:20:56PM +0800, Pin-yen Lin wrote:
> Register USB Type-C mode switches when the "mode-switch" property and
> relevant port are available in Device Tree. Configure the "lane_swap"
> state based on the entered alternate mode for a specific Type-C
> connector, which ends up updating the lane swap registers of the it6505
> chip.

...

>  config DRM_ITE_IT6505
>          tristate "ITE IT6505 DisplayPort bridge"
>          depends on OF
> +	depends on TYPEC || TYPEC=n
>  	select DRM_DISPLAY_DP_HELPER
>  	select DRM_DISPLAY_HDCP_HELPER
>  	select DRM_DISPLAY_HELPER

Something went wrong with the indentation. Perhaps you need to fix it first.

...

>  #include <drm/drm_edid.h>
>  #include <drm/drm_print.h>
>  #include <drm/drm_probe_helper.h>
> +#include <drm/drm_of.h>

Make it ordered?

...

> +struct it6505_port_data {

> +	bool dp_connected;

Perhaps make it last?

> +	struct typec_mux_dev *typec_mux;
> +	struct it6505 *it6505;
> +};

...

> +static void it6505_typec_ports_update(struct it6505 *it6505)
> +{
> +	usleep_range(3000, 4000);
> +
> +	if (it6505->typec_ports[0].dp_connected && it6505->typec_ports[1].dp_connected)
> +		/* Both ports available, do nothing to retain the current one. */
> +		return;
> +	else if (it6505->typec_ports[0].dp_connected)
> +		it6505->lane_swap = false;
> +	else if (it6505->typec_ports[1].dp_connected)
> +		it6505->lane_swap = true;
> +
> +	usleep_range(3000, 4000);
> +}

As per previous patch comments.

Also, comment out these long sleeps. Why they are needed.

...

> +		int ret = pm_runtime_get_sync(dev);
> +
> +		/*
> +		 * On system resume, mux_set can be triggered before
> +		 * pm_runtime_force_resume re-enables runtime power management.

We refer to the functions as func().

> +		 * Handling the error here to make sure the bridge is powered on.
> +		 */
> +		if (ret < 0)
> +			it6505_poweron(it6505);

This seems needed a bit more of explanation, esp. why you leave PM runtime
reference count bumped up.

...

> +	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;
> +	}
> +
> +	for (i = 0; i < num_lanes; i++) {
> +		if (port_num != -1 && port_num != dp_lanes[i] / 2) {
> +			dev_err(dev, "Invalid data lane numbers\n");
> +			return -EINVAL;
> +		}

As per previous patch comments.

> +		port_num = dp_lanes[i] / 2;
> +	}

The above seems like tons of duplicating code that drivers need to implement.
Can we shrink that burden by adding some library functions?
  
Pin-yen Lin Nov. 25, 2022, 6:55 a.m. UTC | #2
Hi Andy,

Thanks for reviewing the patch.

On Thu, Nov 24, 2022 at 8:23 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Thu, Nov 24, 2022 at 06:20:56PM +0800, Pin-yen Lin wrote:
> > Register USB Type-C mode switches when the "mode-switch" property and
> > relevant port are available in Device Tree. Configure the "lane_swap"
> > state based on the entered alternate mode for a specific Type-C
> > connector, which ends up updating the lane swap registers of the it6505
> > chip.
>
> ...
>
> >  config DRM_ITE_IT6505
> >          tristate "ITE IT6505 DisplayPort bridge"
> >          depends on OF
> > +     depends on TYPEC || TYPEC=n
> >       select DRM_DISPLAY_DP_HELPER
> >       select DRM_DISPLAY_HDCP_HELPER
> >       select DRM_DISPLAY_HELPER
>
> Something went wrong with the indentation. Perhaps you need to fix it first.
>
> ...
>
> >  #include <drm/drm_edid.h>
> >  #include <drm/drm_print.h>
> >  #include <drm/drm_probe_helper.h>
> > +#include <drm/drm_of.h>
>
> Make it ordered?

Will fix it in v7.

>
> ...
>
> > +struct it6505_port_data {
>
> > +     bool dp_connected;
>
> Perhaps make it last?

Will fix it in v7.

>
> > +     struct typec_mux_dev *typec_mux;
> > +     struct it6505 *it6505;
> > +};
>
> ...
>
> > +static void it6505_typec_ports_update(struct it6505 *it6505)
> > +{
> > +     usleep_range(3000, 4000);
> > +
> > +     if (it6505->typec_ports[0].dp_connected && it6505->typec_ports[1].dp_connected)
> > +             /* Both ports available, do nothing to retain the current one. */
> > +             return;
> > +     else if (it6505->typec_ports[0].dp_connected)
> > +             it6505->lane_swap = false;
> > +     else if (it6505->typec_ports[1].dp_connected)
> > +             it6505->lane_swap = true;
> > +
> > +     usleep_range(3000, 4000);
> > +}
>
> As per previous patch comments.

Will update it in v7.

>
> Also, comment out these long sleeps. Why they are needed.

Actually, it turns out that these sleeps are not needed. I'll remove it in v7.

>
> ...
>
> > +             int ret = pm_runtime_get_sync(dev);
> > +
> > +             /*
> > +              * On system resume, mux_set can be triggered before
> > +              * pm_runtime_force_resume re-enables runtime power management.
>
> We refer to the functions as func().

Will fix this in v7.

>
> > +              * Handling the error here to make sure the bridge is powered on.
> > +              */
> > +             if (ret < 0)
> > +                     it6505_poweron(it6505);
>
> This seems needed a bit more of explanation, esp. why you leave PM runtime
> reference count bumped up.

pm_runtime_force_suspend() disables runtime PM when the device enters
suspend, and sometime it6505_typec_mux_set() is called before
pm_runtime_force_resume brings runtime PM back. We force power up the
bridge in this case and leave the ref count incremented to make the
future pm_runtime_(get|put)_sync() calls balanced.

I'll include more explanations around this in v7.

>
> ...
>
> > +     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;
> > +     }
> > +
> > +     for (i = 0; i < num_lanes; i++) {
> > +             if (port_num != -1 && port_num != dp_lanes[i] / 2) {
> > +                     dev_err(dev, "Invalid data lane numbers\n");
> > +                     return -EINVAL;
> > +             }
>
> As per previous patch comments.

I'll remove this part in v7 and try to figure out how to do similar
checking with schemas.
>
> > +             port_num = dp_lanes[i] / 2;
> > +     }
>
> The above seems like tons of duplicating code that drivers need to implement.
> Can we shrink that burden by adding some library functions?

Could you advise where this lib file should go, and what the namings
can be? The "port-switching" logic is specific to some of the DP
bridges, and I'm not sure what kinds of naming/structure fit into this
case.

Thanks and regards,
Pin-yen

>
> --
> With Best Regards,
> Andy Shevchenko
>
>
  

Patch

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 57946d80b02d..9b1240ef3981 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -87,6 +87,7 @@  config DRM_FSL_LDB
 config DRM_ITE_IT6505
         tristate "ITE IT6505 DisplayPort bridge"
         depends on OF
+	depends on TYPEC || TYPEC=n
 	select DRM_DISPLAY_DP_HELPER
 	select DRM_DISPLAY_HDCP_HELPER
 	select DRM_DISPLAY_HELPER
diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 21a9b8422bda..37e2bd8d8d79 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -17,6 +17,8 @@ 
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/types.h>
+#include <linux/usb/typec_dp.h>
+#include <linux/usb/typec_mux.h>
 #include <linux/wait.h>
 
 #include <crypto/hash.h>
@@ -30,6 +32,7 @@ 
 #include <drm/drm_edid.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
+#include <drm/drm_of.h>
 
 #include <sound/hdmi-codec.h>
 
@@ -402,6 +405,12 @@  struct debugfs_entries {
 	const struct file_operations *fops;
 };
 
+struct it6505_port_data {
+	bool dp_connected;
+	struct typec_mux_dev *typec_mux;
+	struct it6505 *it6505;
+};
+
 struct it6505 {
 	struct drm_dp_aux aux;
 	struct drm_bridge bridge;
@@ -454,6 +463,8 @@  struct it6505 {
 	struct delayed_work delayed_audio;
 	struct it6505_audio_data audio;
 	struct dentry *debugfs;
+	int num_typec_switches;
+	struct it6505_port_data *typec_ports;
 
 	/* it6505 driver hold option */
 	bool enable_drv_hold;
@@ -3265,13 +3276,185 @@  static void it6505_shutdown(struct i2c_client *client)
 		it6505_lane_off(it6505);
 }
 
+static void it6505_typec_ports_update(struct it6505 *it6505)
+{
+	usleep_range(3000, 4000);
+
+	if (it6505->typec_ports[0].dp_connected && it6505->typec_ports[1].dp_connected)
+		/* Both ports available, do nothing to retain the current one. */
+		return;
+	else if (it6505->typec_ports[0].dp_connected)
+		it6505->lane_swap = false;
+	else if (it6505->typec_ports[1].dp_connected)
+		it6505->lane_swap = true;
+
+	usleep_range(3000, 4000);
+}
+
+static int it6505_typec_mux_set(struct typec_mux_dev *mux,
+				struct typec_mux_state *state)
+{
+	struct it6505_port_data *data = typec_mux_get_drvdata(mux);
+	struct it6505 *it6505 = data->it6505;
+	struct device *dev = &it6505->client->dev;
+	bool old_dp_connected, new_dp_connected;
+
+	if (it6505->num_typec_switches == 1)
+		return 0;
+
+	mutex_lock(&it6505->extcon_lock);
+
+	old_dp_connected = it6505->typec_ports[0].dp_connected ||
+			   it6505->typec_ports[1].dp_connected;
+
+	data->dp_connected = (state->alt && state->alt->svid == USB_TYPEC_DP_SID &&
+			      state->alt->mode == USB_TYPEC_DP_MODE);
+
+	dev_dbg(dev, "mux_set dp_connected: c0=%d, c1=%d\n",
+		it6505->typec_ports[0].dp_connected, it6505->typec_ports[1].dp_connected);
+
+	new_dp_connected = it6505->typec_ports[0].dp_connected ||
+			   it6505->typec_ports[1].dp_connected;
+
+	if (it6505->enable_drv_hold) {
+		dev_dbg(dev, "enable driver hold\n");
+		goto unlock;
+	}
+
+	it6505_typec_ports_update(it6505);
+
+	if (!old_dp_connected && new_dp_connected) {
+		int ret = pm_runtime_get_sync(dev);
+
+		/*
+		 * On system resume, mux_set can be triggered before
+		 * pm_runtime_force_resume re-enables runtime power management.
+		 * Handling the error here to make sure the bridge is powered on.
+		 */
+		if (ret < 0)
+			it6505_poweron(it6505);
+
+		complete_all(&it6505->extcon_completion);
+	}
+
+	if (old_dp_connected && !new_dp_connected) {
+		reinit_completion(&it6505->extcon_completion);
+		pm_runtime_put_sync(dev);
+		if (it6505->bridge.dev)
+			drm_helper_hpd_irq_event(it6505->bridge.dev);
+		memset(it6505->dpcd, 0, sizeof(it6505->dpcd));
+	}
+
+unlock:
+	mutex_unlock(&it6505->extcon_lock);
+	return 0;
+}
+
+static int it6505_register_mode_switch(struct device *dev, struct device_node *node,
+				       struct it6505 *it6505)
+{
+	struct it6505_port_data *port_data;
+	struct typec_mux_desc mux_desc = {};
+	char name[32];
+	u32 dp_lanes[2];
+	int ret, num_lanes, i, 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;
+	}
+
+	for (i = 0; i < num_lanes; i++) {
+		if (port_num != -1 && port_num != dp_lanes[i] / 2) {
+			dev_err(dev, "Invalid data lane numbers\n");
+			return -EINVAL;
+		}
+		port_num = dp_lanes[i] / 2;
+	}
+
+	port_data = &it6505->typec_ports[port_num];
+	port_data->it6505 = it6505;
+	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 = it6505_typec_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;
+}
+
+static void it6505_unregister_typec_switches(struct it6505 *it6505)
+{
+	int i;
+
+	for (i = 0; i < it6505->num_typec_switches; i++)
+		typec_mux_unregister(it6505->typec_ports[i].typec_mux);
+}
+
+static int it6505_register_typec_switches(struct device *dev, struct it6505 *it6505)
+{
+	struct device_node *port, *sw;
+	int ret = 0;
+
+	port = of_graph_get_port_by_id(dev->of_node, 1);
+
+	for_each_child_of_node(port, sw) {
+		if (of_property_read_bool(sw, "mode-switch"))
+			it6505->num_typec_switches++;
+	}
+
+	if (!it6505->num_typec_switches) {
+		dev_warn(dev, "No Type-C switches node found\n");
+		return ret;
+	}
+
+	it6505->typec_ports = devm_kzalloc(
+		dev, it6505->num_typec_switches * sizeof(struct it6505_port_data),
+		GFP_KERNEL);
+	if (!it6505->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 = it6505_register_mode_switch(dev, sw, it6505);
+		if (ret) {
+			dev_err(dev, "Failed to register mode switch: %d\n", ret);
+			of_node_put(sw);
+			break;
+		}
+	}
+
+	if (ret)
+		it6505_unregister_typec_switches(it6505);
+
+	return ret;
+}
+
 static int it6505_i2c_probe(struct i2c_client *client,
 			    const struct i2c_device_id *id)
 {
 	struct it6505 *it6505;
 	struct device *dev = &client->dev;
 	struct extcon_dev *extcon;
-	int err, intp_irq;
+	int err, intp_irq, ret;
 
 	it6505 = devm_kzalloc(&client->dev, sizeof(*it6505), GFP_KERNEL);
 	if (!it6505)
@@ -3292,11 +3475,24 @@  static int it6505_i2c_probe(struct i2c_client *client,
 	if (PTR_ERR(extcon) == -EPROBE_DEFER)
 		return -EPROBE_DEFER;
 	if (IS_ERR(extcon)) {
-		dev_err(dev, "can not get extcon device!");
-		return PTR_ERR(extcon);
+		if (PTR_ERR(extcon) != -ENODEV)
+			dev_warn(dev, "Cannot get extcon device: %ld\n",
+				 PTR_ERR(extcon));
+		it6505->extcon = NULL;
+	} else {
+		it6505->extcon = extcon;
 	}
 
-	it6505->extcon = extcon;
+	ret = it6505_register_typec_switches(dev, it6505);
+	if (ret) {
+		if (ret != -ENODEV)
+			dev_warn(dev, "Didn't register Type-C switches, err: %d\n",
+				 ret);
+		if (!it6505->extcon) {
+			dev_err(dev, "Both extcon and typec-switch are not registered.\n");
+			return -EINVAL;
+		}
+	}
 
 	it6505->regmap = devm_regmap_init_i2c(client, &it6505_regmap_config);
 	if (IS_ERR(it6505->regmap)) {
@@ -3367,6 +3563,7 @@  static void it6505_i2c_remove(struct i2c_client *client)
 	drm_dp_aux_unregister(&it6505->aux);
 	it6505_debugfs_remove(it6505);
 	it6505_poweroff(it6505);
+	it6505_unregister_typec_switches(it6505);
 }
 
 static const struct i2c_device_id it6505_id[] = {