Re: [PATCH v3 06/21] drm/bridge: tc358767: add drm_panel_bridge support

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sam,

On Sun, Jul 19, 2020 at 03:06:56PM +0200, Sam Ravnborg wrote:
> On Sat, Jul 11, 2020 at 01:19:35AM +0300, Laurent Pinchart wrote:
> > On Fri, Jul 03, 2020 at 09:24:02PM +0200, Sam Ravnborg wrote:
> > > Prepare the bridge driver for use in a chained setup by
> > > replacing direct use of drm_panel with drm_panel_bridge support.
> > > 
> > > The bridge driver assume the panel is optional.
> > > The relevant tests are migrated over to check for the
> > > pnale bridge to keep the same functionality.
> > 
> > s/pnale/panel/
> > 
> > > Note: the bridge panel will use the connector type from the panel.
> > > 
> > > Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> > > Cc: Andrzej Hajda <a.hajda@samsung.com>
> > > Cc: Neil Armstrong <narmstrong@baylibre.com>
> > > Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
> > > Cc: Jonas Karlman <jonas@kwiboo.se>
> > > Cc: Jernej Skrabec <jernej.skrabec@siol.net>
> > > ---
> > >  drivers/gpu/drm/bridge/tc358767.c | 57 +++++++++++++++----------------
> > >  1 file changed, 27 insertions(+), 30 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> > > index c2777b226c75..08d483664258 100644
> > > --- a/drivers/gpu/drm/bridge/tc358767.c
> > > +++ b/drivers/gpu/drm/bridge/tc358767.c
> > > @@ -244,8 +244,8 @@ struct tc_data {
> > >  	struct drm_dp_aux	aux;
> > >  
> > >  	struct drm_bridge	bridge;
> > > +	struct drm_bridge	*panel_bridge;
> > >  	struct drm_connector	connector;
> > > -	struct drm_panel	*panel;
> > >  
> > >  	/* link settings */
> > >  	struct tc_edp_link	link;
> > > @@ -1236,13 +1236,6 @@ static int tc_stream_disable(struct tc_data *tc)
> > >  	return 0;
> > >  }
> > >  
> > > -static void tc_bridge_pre_enable(struct drm_bridge *bridge)
> > > -{
> > > -	struct tc_data *tc = bridge_to_tc(bridge);
> > > -
> > > -	drm_panel_prepare(tc->panel);
> > > -}
> > > -
> > >  static void tc_bridge_enable(struct drm_bridge *bridge)
> > >  {
> > >  	struct tc_data *tc = bridge_to_tc(bridge);
> > > @@ -1266,8 +1259,6 @@ static void tc_bridge_enable(struct drm_bridge *bridge)
> > >  		tc_main_link_disable(tc);
> > >  		return;
> > >  	}
> > > -
> > > -	drm_panel_enable(tc->panel);
> > >  }
> > >  
> > >  static void tc_bridge_disable(struct drm_bridge *bridge)
> > > @@ -1275,8 +1266,6 @@ static void tc_bridge_disable(struct drm_bridge *bridge)
> > >  	struct tc_data *tc = bridge_to_tc(bridge);
> > >  	int ret;
> > >  
> > > -	drm_panel_disable(tc->panel);
> > > -
> > >  	ret = tc_stream_disable(tc);
> > >  	if (ret < 0)
> > >  		dev_err(tc->dev, "main link stream stop error: %d\n", ret);
> > > @@ -1286,13 +1275,6 @@ static void tc_bridge_disable(struct drm_bridge *bridge)
> > >  		dev_err(tc->dev, "main link disable error: %d\n", ret);
> > >  }
> > >  
> > > -static void tc_bridge_post_disable(struct drm_bridge *bridge)
> > > -{
> > > -	struct tc_data *tc = bridge_to_tc(bridge);
> > > -
> > > -	drm_panel_unprepare(tc->panel);
> > > -}
> > > -
> > >  static bool tc_bridge_mode_fixup(struct drm_bridge *bridge,
> > >  				 const struct drm_display_mode *mode,
> > >  				 struct drm_display_mode *adj)
> > > @@ -1348,9 +1330,11 @@ static int tc_connector_get_modes(struct drm_connector *connector)
> > >  		return 0;
> > >  	}
> > >  
> > > -	count = drm_panel_get_modes(tc->panel, connector);
> > > -	if (count > 0)
> > > -		return count;
> > > +	if (tc->panel_bridge) {
> > > +		count = drm_bridge_get_modes(tc->panel_bridge, connector);
> > > +		if (count > 0)
> > > +			return count;
> > > +	}
> > >  
> > >  	edid = drm_get_edid(connector, &tc->aux.ddc);
> > >  
> > > @@ -1378,7 +1362,7 @@ static enum drm_connector_status tc_connector_detect(struct drm_connector *conne
> > >  	int ret;
> > >  
> > >  	if (tc->hpd_pin < 0) {
> > > -		if (tc->panel)
> > > +		if (tc->panel_bridge)
> > >  			return connector_status_connected;
> > >  		else
> > >  			return connector_status_unknown;
> > > @@ -1413,6 +1397,13 @@ static int tc_bridge_attach(struct drm_bridge *bridge,
> > >  	struct drm_device *drm = bridge->dev;
> > >  	int ret;
> > >  
> > > +	if (tc->panel_bridge) {
> > > +		ret = drm_bridge_attach(tc->bridge.encoder, tc->panel_bridge,
> > > +					&tc->bridge, flags);
> > > +		if (ret < 0)
> > > +			return ret;
> > > +	}
> > 
> > With this both this driver and the panel bridge driver will create a
> > connector. The simplest way to handle that is probably to pass
> > flags & ~DRM_BRIDGE_ATTACH_NO_CONNECTOR to drm_bridge_attach(). It's a
> > bit of a hack, but should go away once all users are converted to
> > !DRM_BRIDGE_ATTACH_NO_CONNECTOR.
> 
> I do not follow you here - sorry.
> 
> We have two situations:
> 
> display driver creates the connector - and passes DRM_BRIDGE_ATTACH_NO_CONNECTOR.
> - bridge driver shall not create connector
> - bridge panel shall not create connector
> 
> display driver expect bridge to create connector and passes 0
> - bridge driver shall not create connector
> - bridge panel shall create connector

I meant the other way around, creating a connector here and skipping it
in the bridge panel driver. Which of the two (this driver and the bridge
panel driver) has the most information to implement a connector ?

> So the correct logic seems to be:
> - if there is a bridge panel do not create a connector in the bridge
> - otherwise just follow the flags
> 
> I will try to implement this.
> 
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > 
> > > +
> > >  	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
> > >  		DRM_ERROR("Fix bridge driver to make connector optional!");
> > >  		return -EINVAL;
> > > @@ -1421,7 +1412,7 @@ static int tc_bridge_attach(struct drm_bridge *bridge,
> > >  	/* Create DP/eDP connector */
> > >  	drm_connector_helper_add(&tc->connector, &tc_connector_helper_funcs);
> > >  	ret = drm_connector_init(drm, &tc->connector, &tc_connector_funcs,
> > > -				 tc->panel ? DRM_MODE_CONNECTOR_eDP :
> > > +				 tc->panel_bridge ? DRM_MODE_CONNECTOR_eDP :
> > >  				 DRM_MODE_CONNECTOR_DisplayPort);
> > >  	if (ret)
> > >  		return ret;
> > > @@ -1435,9 +1426,6 @@ static int tc_bridge_attach(struct drm_bridge *bridge,
> > >  					       DRM_CONNECTOR_POLL_DISCONNECT;
> > >  	}
> > >  
> > > -	if (tc->panel)
> > > -		drm_panel_attach(tc->panel, &tc->connector);
> > > -
> > >  	drm_display_info_set_bus_formats(&tc->connector.display_info,
> > >  					 &bus_format, 1);
> > >  	tc->connector.display_info.bus_flags =
> > > @@ -1453,10 +1441,8 @@ static const struct drm_bridge_funcs tc_bridge_funcs = {
> > >  	.attach = tc_bridge_attach,
> > >  	.mode_valid = tc_mode_valid,
> > >  	.mode_set = tc_bridge_mode_set,
> > > -	.pre_enable = tc_bridge_pre_enable,
> > >  	.enable = tc_bridge_enable,
> > >  	.disable = tc_bridge_disable,
> > > -	.post_disable = tc_bridge_post_disable,
> > >  	.mode_fixup = tc_bridge_mode_fixup,
> > >  };
> > >  
> > > @@ -1547,6 +1533,7 @@ static irqreturn_t tc_irq_handler(int irq, void *arg)
> > >  static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
> > >  {
> > >  	struct device *dev = &client->dev;
> > > +	struct drm_panel *panel;
> > >  	struct tc_data *tc;
> > >  	int ret;
> > >  
> > > @@ -1557,10 +1544,20 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
> > >  	tc->dev = dev;
> > >  
> > >  	/* port@2 is the output port */
> > > -	ret = drm_of_find_panel_or_bridge(dev->of_node, 2, 0, &tc->panel, NULL);
> > > +	ret = drm_of_find_panel_or_bridge(dev->of_node, 2, 0, &panel, NULL);
> > >  	if (ret && ret != -ENODEV)
> > >  		return ret;
> > >  
> > > +	if (panel) {
> > > +		struct drm_bridge *pbridge;
> > > +
> > > +		pbridge = devm_drm_panel_bridge_add(dev, panel);
> > > +		if (IS_ERR(pbridge))
> > > +			return PTR_ERR(pbridge);
> > > +
> > > +		tc->panel_bridge = pbridge;
> > > +	}
> > > +
> > >  	/* Shut down GPIO is optional */
> > >  	tc->sd_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_HIGH);
> > >  	if (IS_ERR(tc->sd_gpio))

-- 
Regards,

Laurent Pinchart
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