linux-stable/drivers/gpu/drm/tilcdc/tilcdc_external.c
Laurent Pinchart a25b988ff8 drm/bridge: Extend bridge API to disable connector creation
Most bridge drivers create a DRM connector to model the connector at the
output of the bridge. This model is historical and has worked pretty
well so far, but causes several issues:

- It prevents supporting more complex display pipelines where DRM
connector operations are split over multiple components. For instance a
pipeline with a bridge connected to the DDC signals to read EDID data,
and another one connected to the HPD signal to detect connection and
disconnection, will not be possible to support through this model.

- It requires every bridge driver to implement similar connector
handling code, resulting in code duplication.

- It assumes that a bridge will either be wired to a connector or to
another bridge, but doesn't support bridges that can be used in both
positions very well (although there is some ad-hoc support for this in
the analogix_dp bridge driver).

In order to solve these issues, ownership of the connector should be
moved to the display controller driver (where it can be implemented
using helpers provided by the core).

Extend the bridge API to allow disabling connector creation in bridge
drivers as a first step towards the new model. The new flags argument to
the bridge .attach() operation allows instructing the bridge driver to
skip creating a connector. Unconditionally set the new flags argument to
0 for now to keep the existing behaviour, and modify all existing bridge
drivers to return an error when connector creation is not requested as
they don't support this feature yet.

The change is based on the following semantic patch, with manual review
and edits.

@ rule1 @
identifier funcs;
identifier fn;
@@
 struct drm_bridge_funcs funcs = {
 	...,
 	.attach = fn
 };

@ depends on rule1 @
identifier rule1.fn;
identifier bridge;
statement S, S1;
@@
 int fn(
 	struct drm_bridge *bridge
+	, enum drm_bridge_attach_flags flags
 )
 {
 	... when != S
+	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
+		DRM_ERROR("Fix bridge driver to make connector optional!");
+		return -EINVAL;
+	}
+
 	S1
 	...
 }

@ depends on rule1 @
identifier rule1.fn;
identifier bridge, flags;
expression E1, E2, E3;
@@
 int fn(
 	struct drm_bridge *bridge,
 	enum drm_bridge_attach_flags flags
 ) {
 <...
 drm_bridge_attach(E1, E2, E3
+	, flags
 )
 ...>
 }

@@
expression E1, E2, E3;
@@
 drm_bridge_attach(E1, E2, E3
+	, 0
 )

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200226112514.12455-10-laurent.pinchart@ideasonboard.com
2020-02-26 13:31:23 +02:00

183 lines
4.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2015 Texas Instruments
* Author: Jyri Sarha <jsarha@ti.com>
*/
#include <linux/component.h>
#include <linux/of_graph.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_of.h>
#include "tilcdc_drv.h"
#include "tilcdc_external.h"
static const struct tilcdc_panel_info panel_info_tda998x = {
.ac_bias = 255,
.ac_bias_intrpt = 0,
.dma_burst_sz = 16,
.bpp = 16,
.fdd = 0x80,
.tft_alt_mode = 0,
.invert_pxl_clk = 1,
.sync_edge = 1,
.sync_ctrl = 1,
.raster_order = 0,
};
static const struct tilcdc_panel_info panel_info_default = {
.ac_bias = 255,
.ac_bias_intrpt = 0,
.dma_burst_sz = 16,
.bpp = 16,
.fdd = 0x80,
.tft_alt_mode = 0,
.sync_edge = 0,
.sync_ctrl = 1,
.raster_order = 0,
};
static
struct drm_connector *tilcdc_encoder_find_connector(struct drm_device *ddev,
struct drm_encoder *encoder)
{
struct drm_connector *connector;
list_for_each_entry(connector, &ddev->mode_config.connector_list, head) {
if (drm_connector_has_possible_encoder(connector, encoder))
return connector;
}
dev_err(ddev->dev, "No connector found for %s encoder (id %d)\n",
encoder->name, encoder->base.id);
return NULL;
}
int tilcdc_add_component_encoder(struct drm_device *ddev)
{
struct tilcdc_drm_private *priv = ddev->dev_private;
struct drm_encoder *encoder;
list_for_each_entry(encoder, &ddev->mode_config.encoder_list, head)
if (encoder->possible_crtcs & (1 << priv->crtc->index))
break;
if (!encoder) {
dev_err(ddev->dev, "%s: No suitable encoder found\n", __func__);
return -ENODEV;
}
priv->external_connector =
tilcdc_encoder_find_connector(ddev, encoder);
if (!priv->external_connector)
return -ENODEV;
/* Only tda998x is supported at the moment. */
tilcdc_crtc_set_simulate_vesa_sync(priv->crtc, true);
tilcdc_crtc_set_panel_info(priv->crtc, &panel_info_tda998x);
return 0;
}
static const struct drm_encoder_funcs tilcdc_external_encoder_funcs = {
.destroy = drm_encoder_cleanup,
};
static
int tilcdc_attach_bridge(struct drm_device *ddev, struct drm_bridge *bridge)
{
struct tilcdc_drm_private *priv = ddev->dev_private;
int ret;
priv->external_encoder->possible_crtcs = BIT(0);
ret = drm_bridge_attach(priv->external_encoder, bridge, NULL, 0);
if (ret) {
dev_err(ddev->dev, "drm_bridge_attach() failed %d\n", ret);
return ret;
}
tilcdc_crtc_set_panel_info(priv->crtc, &panel_info_default);
priv->external_connector =
tilcdc_encoder_find_connector(ddev, priv->external_encoder);
if (!priv->external_connector)
return -ENODEV;
return 0;
}
int tilcdc_attach_external_device(struct drm_device *ddev)
{
struct tilcdc_drm_private *priv = ddev->dev_private;
struct drm_bridge *bridge;
struct drm_panel *panel;
int ret;
ret = drm_of_find_panel_or_bridge(ddev->dev->of_node, 0, 0,
&panel, &bridge);
if (ret == -ENODEV)
return 0;
else if (ret)
return ret;
priv->external_encoder = devm_kzalloc(ddev->dev,
sizeof(*priv->external_encoder),
GFP_KERNEL);
if (!priv->external_encoder)
return -ENOMEM;
ret = drm_encoder_init(ddev, priv->external_encoder,
&tilcdc_external_encoder_funcs,
DRM_MODE_ENCODER_NONE, NULL);
if (ret) {
dev_err(ddev->dev, "drm_encoder_init() failed %d\n", ret);
return ret;
}
if (panel) {
bridge = devm_drm_panel_bridge_add_typed(ddev->dev, panel,
DRM_MODE_CONNECTOR_DPI);
if (IS_ERR(bridge)) {
ret = PTR_ERR(bridge);
goto err_encoder_cleanup;
}
}
ret = tilcdc_attach_bridge(ddev, bridge);
if (ret)
goto err_encoder_cleanup;
return 0;
err_encoder_cleanup:
drm_encoder_cleanup(priv->external_encoder);
return ret;
}
static int dev_match_of(struct device *dev, void *data)
{
return dev->of_node == data;
}
int tilcdc_get_external_components(struct device *dev,
struct component_match **match)
{
struct device_node *node;
node = of_graph_get_remote_node(dev->of_node, 0, 0);
if (!of_device_is_compatible(node, "nxp,tda998x")) {
of_node_put(node);
return 0;
}
if (match)
drm_of_component_match_add(dev, match, dev_match_of, node);
of_node_put(node);
return 1;
}