Re: [PATCH] drm/bridge: sii902x: add support for DRM_BRIDGE_ATTACH_NO_CONNECTOR

[Neil Armstrong <narmstrong@xxxxxxxxxxxx>]

Hi Dmitry,

On 31/07/2022 22:07, Dmitry Osipenko wrote:
> 13.01.2022 17:43, Neil Armstrong пишет:
> > This adds support for DRM_BRIDGE_ATTACH_NO_CONNECTOR by adding the
> > bridge get_edid() and detect() callbacks after refactoring the connector
> > get_modes() and connector_detect() callbacks.
> >
> > In order to keep the bridge working, extra code in get_modes() has been
> > moved to more logical places.
> >
> > Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/bridge/sii902x.c | 129 ++++++++++++++++++++++++-------
> >   

1 file changed, 99 insertions(+), 30 deletions(-)
> > diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
> > index 89558e581530..65549fbfdc87 100644
> > --- a/drivers/gpu/drm/bridge/sii902x.c
> > +++ b/drivers/gpu/drm/bridge/sii902x.c
> > @@ -166,10 +166,12 @@ struct sii902x {
> >   	struct i2c_client *i2c;
> >   	struct regmap *regmap;
> >   	struct drm_bridge bridge;
> > +	struct drm_bridge *next_bridge;
> >   	struct drm_connector connector;
> >   	struct gpio_desc *reset_gpio;
> >   	struct i2c_mux_core *i2cmux;
> >   	struct regulator_bulk_data supplies[2];
> > +	bool sink_is_hdmi;
> >   	/*
> >   	 * Mutex protects audio and video functions from interfering
> >   	 * each other, by keeping their i2c command sequences atomic.
> > @@ -245,10 +247,8 @@ static void sii902x_reset(struct sii902x *sii902x)
> >   	gpiod_set_value(sii902x->reset_gpio, 0);
> >   }
> >   
> > -static enum drm_connector_status
> > -sii902x_connector_detect(struct drm_connector *connector, bool force)
> > +static enum drm_connector_status sii902x_detect(struct sii902x *sii902x)
> >   {
> > -	struct sii902x *sii902x = connector_to_sii902x(connector);
> >   	unsigned int status;
> >   
> >   	mutex_lock(&sii902x->mutex);
> > @@ -261,6 +261,14 @@ sii902x_connector_detect(struct drm_connector *connector, bool force)
> >   	       connector_status_connected : connector_status_disconnected;
> >   }
> >   
> > +static enum drm_connector_status
> > +sii902x_connector_detect(struct drm_connector *connector, bool force)
> > +{
> > +	struct sii902x *sii902x = connector_to_sii902x(connector);
> > +
> > +	return sii902x_detect(sii902x);
> > +}
> > +
> >   static const struct drm_connector_funcs sii902x_connector_funcs = {
> >   	.detect = sii902x_connector_detect,
> >   	.fill_modes = drm_helper_probe_single_connector_modes,
> > @@ -270,42 +278,40 @@ static const struct drm_connector_funcs sii902x_connector_funcs = {
> >   	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> >   };
> >   
> > -static int sii902x_get_modes(struct drm_connector *connector)
> > +static struct edid *sii902x_get_edid(struct sii902x *sii902x,
> > +				     struct drm_connector *connector)
> >   {
> > -	struct sii902x *sii902x = connector_to_sii902x(connector);
> > -	u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
> > -	u8 output_mode = SII902X_SYS_CTRL_OUTPUT_DVI;
> >   	struct edid *edid;
> > -	int num = 0, ret;
> >   
> >   	mutex_lock(&sii902x->mutex);
> >   
> >   	edid = drm_get_edid(connector, sii902x->i2cmux->adapter[0]);
> > -	drm_connector_update_edid_property(connector, edid);
> >   	if (edid) {
> >   		if (drm_detect_hdmi_monitor(edid))
> > -			output_mode = SII902X_SYS_CTRL_OUTPUT_HDMI;
> > -
> > -		num = drm_add_edid_modes(connector, edid);
> > -		kfree(edid);
> > +			sii902x->sink_is_hdmi = true;
> > +		else
> > +			sii902x->sink_is_hdmi = false;
> >   	}
> >   
> > -	ret = drm_display_info_set_bus_formats(&connector->display_info,
> > -					       &bus_format, 1);
> > -	if (ret)
> > -		goto error_out;
> > +	mutex_unlock(&sii902x->mutex);
> >   
> > -	ret = regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,
> > -				 SII902X_SYS_CTRL_OUTPUT_MODE, output_mode);
> > -	if (ret)
> > -		goto error_out;
> > +	return edid;
> > +}
> >   
> > -	ret = num;
> > +static int sii902x_get_modes(struct drm_connector *connector)
> > +{
> > +	struct sii902x *sii902x = connector_to_sii902x(connector);
> > +	struct edid *edid;
> > +	int num = 0;
> >   
> > -error_out:
> > -	mutex_unlock(&sii902x->mutex);
> > +	edid = sii902x_get_edid(sii902x, connector);
> > +	drm_connector_update_edid_property(connector, edid);
> > +	if (edid) {
> > +		num = drm_add_edid_modes(connector, edid);
> > +		kfree(edid);
> > +	}
> >   
> > -	return ret;
> > +	return num;
> >   }
> >   
> >   static enum drm_mode_status sii902x_mode_valid(struct drm_connector *connector,
> > @@ -354,12 +360,16 @@ static void sii902x_bridge_mode_set(struct drm_bridge *bridge,
> >   				    const struct drm_display_mode *adj)
> >   {
> >   	struct sii902x *sii902x = bridge_to_sii902x(bridge);
> > +	u8 output_mode = SII902X_SYS_CTRL_OUTPUT_DVI;
> >   	struct regmap *regmap = sii902x->regmap;
> >   	u8 buf[HDMI_INFOFRAME_SIZE(AVI)];
> >   	struct hdmi_avi_infoframe frame;
> >   	u16 pixel_clock_10kHz = adj->clock / 10;
> >   	int ret;
> >   
> > +	if (sii902x->sink_is_hdmi)
> > +		output_mode = SII902X_SYS_CTRL_OUTPUT_HDMI;
> > +
> >   	buf[0] = pixel_clock_10kHz & 0xff;
> >   	buf[1] = pixel_clock_10kHz >> 8;
> >   	buf[2] = drm_mode_vrefresh(adj);
> > @@ -375,6 +385,11 @@ static void sii902x_bridge_mode_set(struct drm_bridge *bridge,
> >   
> >   	mutex_lock(&sii902x->mutex);
> >   
> > +	ret = regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,
> > +				 SII902X_SYS_CTRL_OUTPUT_MODE, output_mode);
> > +	if (ret)
> > +		goto out;
> > +
> >   	ret = regmap_bulk_write(regmap, SII902X_TPI_VIDEO_DATA, buf, 10);
> >   	if (ret)
> >   		goto out;
> > @@ -405,13 +420,13 @@ static int sii902x_bridge_attach(struct drm_bridge *bridge,
> >   				 enum drm_bridge_attach_flags flags)
> >   {
> >   	struct sii902x *sii902x = bridge_to_sii902x(bridge);
> > +	u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
> >   	struct drm_device *drm = bridge->dev;
> >   	int ret;
> >   
> > -	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
> > -		DRM_ERROR("Fix bridge driver to make connector optional!");
> > -		return -EINVAL;
> > -	}
> > +	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
> > +		return drm_bridge_attach(bridge->encoder, sii902x->next_bridge,
> > +					 bridge, flags);
> >   
> >   	drm_connector_helper_add(&sii902x->connector,
> >   				 &sii902x_connector_helper_funcs);
> > @@ -433,16 +448,38 @@ static int sii902x_bridge_attach(struct drm_bridge *bridge,
> >   	else
> >   		sii902x->connector.polled = DRM_CONNECTOR_POLL_CONNECT;
> >   
> > +	ret = drm_display_info_set_bus_formats(&sii902x->connector.display_info,
> > +					       &bus_format, 1);
> > +	if (ret)
> > +		return ret;
> > +
> >   	drm_connector_attach_encoder(&sii902x->connector, bridge->encoder);
> >   
> >   	return 0;
> >   }
> >   
> > +static enum drm_connector_status sii902x_bridge_detect(struct drm_bridge *bridge)
> > +{
> > +	struct sii902x *sii902x = bridge_to_sii902x(bridge);
> > +
> > +	return sii902x_detect(sii902x);
> > +}
> > +
> > +static struct edid *sii902x_bridge_get_edid(struct drm_bridge *bridge,
> > +					    struct drm_connector *connector)
> > +{
> > +	struct sii902x *sii902x = bridge_to_sii902x(bridge);
> > +
> > +	return sii902x_get_edid(sii902x, connector);
> > +}
> > +
> >   static const struct drm_bridge_funcs sii902x_bridge_funcs = {
> >   	.attach = sii902x_bridge_attach,
> >   	.mode_set = sii902x_bridge_mode_set,
> >   	.disable = sii902x_bridge_disable,
> >   	.enable = sii902x_bridge_enable,
> > +	.detect = sii902x_bridge_detect,
> > +	.get_edid = sii902x_bridge_get_edid,
> >   };
> >   
> >   static int sii902x_mute(struct sii902x *sii902x, bool mute)
> > @@ -829,8 +866,12 @@ static irqreturn_t sii902x_interrupt(int irq, void *data)
> >   
> >   	mutex_unlock(&sii902x->mutex);
> >   
> > -	if ((status & SII902X_HOTPLUG_EVENT) && sii902x->bridge.dev)
> > +	if ((status & SII902X_HOTPLUG_EVENT) && sii902x->bridge.dev) {
> >   		drm_helper_hpd_irq_event(sii902x->bridge.dev);
> > +		drm_bridge_hpd_notify(&sii902x->bridge, (status & SII902X_PLUGGED_STATUS)
> > +								? connector_status_connected
> > +								: connector_status_disconnected);
> > +	}
> >   
> >   	return IRQ_HANDLED;
> >   }
> > @@ -1001,6 +1042,11 @@ static int sii902x_init(struct sii902x *sii902x)
> >   	sii902x->bridge.funcs = &sii902x_bridge_funcs;
> >   	sii902x->bridge.of_node = dev->of_node;
> >   	sii902x->bridge.timings = &default_sii902x_timings;
> > +	sii902x->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID;
> > +
> > +	if (sii902x->i2c->irq > 0)
> > +		sii902x->bridge.ops |= DRM_BRIDGE_OP_HPD;
> > +
> >   	drm_bridge_add(&sii902x->bridge);
> >   
> >   	sii902x_audio_codec_init(sii902x, dev);
> > @@ -1022,6 +1068,7 @@ static int sii902x_probe(struct i2c_client *client,
> >   			 const struct i2c_device_id *id)
> >   {
> >   	struct device *dev = &client->dev;
> > +	struct device_node *endpoint;
> >   	struct sii902x *sii902x;
> >   	int ret;
> >   
> > @@ -1049,6 +1096,28 @@ static int sii902x_probe(struct i2c_client *client,
> >   		return PTR_ERR(sii902x->reset_gpio);
> >   	}
> >   
> > +	endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1);
> > +	if (endpoint) {
> > +		struct device_node *remote = of_graph_get_remote_port_parent(endpoint);
> > +
> > +		of_node_put(endpoint);
> > +		if (!remote) {
> > +			dev_err(dev, "Endpoint in port@1 unconnected\n");
> > +			return -ENODEV;
> > +		}
> > +
> > +		if (!of_device_is_available(remote)) {
> > +			dev_err(dev, "port@1 remote device is disabled\n");
> > +			of_node_put(remote);
> > +			return -ENODEV;
> > +		}
> > +
> > +		sii902x->next_bridge = of_drm_find_bridge(remote);
> > +		of_node_put(remote);
> > +		if (!sii902x->next_bridge)
> > +			return -EPROBE_DEFER;
>
> Hi,
>
> This patch broke ARM/QEMU vexpress display because of_drm_find_bridge()
> always fail with -EPROBE_DEFER. Reverting this patch returns display
> back. Please fix or revert, thanks in advance.

Can you share a QEMU cmdline to reproduce ?

Neil