Hello,
This series adds initial support for the DRM bridges to NVIDIA Tegra DRM driver. This is required by newer device-trees where we model the LVDS encoder bridge properly.
Changelog:
v7: - Removed the obscure unused structs (which GCC doesn't detect, but CLANG does) in the patch "Wrap directly-connected panel into DRM bridge", which was reported by kernel test robot for v6.
v6: - Added r-b and acks from Rob Herring and Sam Ravnborg.
- Rebased on a recent linux-next, patches now apply without fuzz.
v5: - Added new patches that make drm_of_find_panel_or_bridge() more usable if graph isn't defined in a device-tree:
of_graph: add of_graph_get_local_port() drm/of: Make drm_of_find_panel_or_bridge() to check graph's presence
- Updated "Support DRM bridges" patch to use drm_of_find_panel_or_bridge() directly and added WARN_ON(output->panel || output->bridge) sanity-check.
- Added new "Wrap directly-connected panel into DRM bridge" patch, as was suggested by Laurent Pinchart.
v4: - Following review comments that were made by Laurent Pinchart to the v3, we now create and use the "bridge connector".
v3: - Following recommendation from Sam Ravnborg, the new bridge attachment model is now being used, i.e. we ask bridge to *not* create a connector using the DRM_BRIDGE_ATTACH_NO_CONNECTOR flag.
- The bridge is now created only for the RGB (LVDS) output, and only when necessary. For now we don't need bridges for HDMI or DSI outputs.
- I noticed that we're leaking OF node in the panel's error code path, this is fixed now by the new patch "Don't leak OF node on error".
v2: - Added the new "rgb: Don't register connector if bridge is used" patch, which hides the unused connector provided by the Tegra DRM driver when bridge is used, since bridge provides its own connector to us.
Dmitry Osipenko (6): of_graph: add of_graph_get_local_port() drm/of: Make drm_of_find_panel_or_bridge() to check graph's presence drm/tegra: output: Don't leak OF node on error drm/tegra: output: Support DRM bridges drm/tegra: output: rgb: Support LVDS encoder bridge drm/tegra: output: rgb: Wrap directly-connected panel into DRM bridge
drivers/gpu/drm/drm_of.c | 13 ++++- drivers/gpu/drm/tegra/drm.h | 2 + drivers/gpu/drm/tegra/output.c | 21 +++++-- drivers/gpu/drm/tegra/rgb.c | 102 +++++++++++++++++---------------- drivers/of/property.c | 32 ++++++++--- include/linux/of_graph.h | 7 +++ 6 files changed, 114 insertions(+), 63 deletions(-)
In some case, like a DRM display code for example, it's useful to silently check whether port node exists at all in a device-tree before proceeding with parsing the graph.
This patch adds of_graph_get_local_port() which returns pointer to a local port node, or NULL if graph isn't specified in a device-tree for a given device node.
Reviewed-by: Rob Herring robh@kernel.org Reviewed-by: Sam Ravnborg sam@ravnborg.org Signed-off-by: Dmitry Osipenko digetx@gmail.com --- drivers/of/property.c | 32 +++++++++++++++++++++++--------- include/linux/of_graph.h | 7 +++++++ 2 files changed, 30 insertions(+), 9 deletions(-)
diff --git a/drivers/of/property.c b/drivers/of/property.c index 1f2086f4e7ce..05c5f619b8bb 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -608,15 +608,7 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent, * parent port node. */ if (!prev) { - struct device_node *node; - - node = of_get_child_by_name(parent, "ports"); - if (node) - parent = node; - - port = of_get_child_by_name(parent, "port"); - of_node_put(node); - + port = of_graph_get_local_port(parent); if (!port) { pr_err("graph: no port node found in %pOF\n", parent); return NULL; @@ -765,6 +757,28 @@ struct device_node *of_graph_get_remote_port(const struct device_node *node) } EXPORT_SYMBOL(of_graph_get_remote_port);
+/** + * of_graph_get_local_port() - get local port node + * @node: pointer to a local endpoint device_node + * + * Return: First local port node associated with local endpoint node linked + * to @node. Use of_node_put() on it when done. + */ +struct device_node *of_graph_get_local_port(const struct device_node *node) +{ + struct device_node *ports, *port; + + ports = of_get_child_by_name(node, "ports"); + if (ports) + node = ports; + + port = of_get_child_by_name(node, "port"); + of_node_put(ports); + + return port; +} +EXPORT_SYMBOL(of_graph_get_local_port); + int of_graph_get_endpoint_count(const struct device_node *np) { struct device_node *endpoint; diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h index 01038a6aade0..1fdeb72c7765 100644 --- a/include/linux/of_graph.h +++ b/include/linux/of_graph.h @@ -54,6 +54,7 @@ struct device_node *of_graph_get_remote_port_parent( struct device_node *of_graph_get_remote_port(const struct device_node *node); struct device_node *of_graph_get_remote_node(const struct device_node *node, u32 port, u32 endpoint); +struct device_node *of_graph_get_local_port(const struct device_node *node); #else
static inline int of_graph_parse_endpoint(const struct device_node *node, @@ -116,6 +117,12 @@ static inline struct device_node *of_graph_get_remote_node( return NULL; }
+static inline struct device_node *of_graph_get_local_port( + const struct device_node *node) +{ + return NULL; +} + #endif /* CONFIG_OF */
#endif /* __LINUX_OF_GRAPH_H */
Hi Dmitry,
Thank you for the patch.
On Sun, Jun 14, 2020 at 08:22:29PM +0300, Dmitry Osipenko wrote:
The implementation doesn't seem to match the documentation. If node is a pointer to an endpoint, it should not have any ports child.
On Tue, Jun 16, 2020 at 04:21:12AM +0300, Laurent Pinchart wrote:
I forgot to mention that, given that there could be multiple 'port' nodes, this function would be better named of_graph_get_first_local_port(). 'first' here would refer to the nodes order in the device tree, which I believe may not match the port number. For instance, in the following case
ports { #address-cells = <1>; #size-cells = <1>; port@1 { reg = <1>; }; port@0 { reg = <0>; }; };
the function would I believe return port@1. It may be a good idea to explain this in the documentation. Depending on how you use this function, if your only use case is to test for the presence of port nodes, it may be best to return a bool and name it of_graph_has_port() or something similar.
16.06.2020 04:25, Laurent Pinchart пишет:
Hello Laurent,
It's correct that the port@1 will be returned in yours example.
I'll improve the doc and the function's name in the next revision, thank you for the suggestions!
Right, I'll reword the doc in v8. This function doesn't differentiate between start / end points. It's up to a user of this function to check whether node is endpoint or something else if needed.
Thank you very much for the comments!
16.06.2020 16:56, Dmitry Osipenko пишет:
Although, I re-read the doc comment and compared it to the wording of the other of_graph_*() functions and it's already good as-is to me because the doc explicitly says the "Return: First local port associated with local endpoint...", which is exactly what this function does.
But still the function name and it's brief description could be improved.
When graph isn't defined in a device-tree, the of_graph_get_remote_node() prints a noisy error message, telling that port node is not found. This is undesirable behaviour in our case because absence of a panel/bridge graph is a valid case. Let's check presence of the local port in a device-tree before proceeding with parsing the graph.
Reviewed-by: Sam Ravnborg sam@ravnborg.org Signed-off-by: Dmitry Osipenko digetx@gmail.com --- drivers/gpu/drm/drm_of.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index b50b44e76279..e0652c38f357 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -239,13 +239,24 @@ int drm_of_find_panel_or_bridge(const struct device_node *np, struct drm_bridge **bridge) { int ret = -EPROBE_DEFER; - struct device_node *remote; + struct device_node *local, *remote;
if (!panel && !bridge) return -EINVAL; if (panel) *panel = NULL;
+ /* + * of_graph_get_remote_node() produces a noisy error message if port + * node isn't found and the absence of the port is a legit case here, + * so at first we silently check presence of the local port. + */ + local = of_graph_get_local_port(np); + if (!local) + return -ENODEV; + + of_node_put(local); + remote = of_graph_get_remote_node(np, port, endpoint); if (!remote) return -ENODEV;
Hi Dmitry,
Thank you for the patch.
On Sun, Jun 14, 2020 at 08:22:30PM +0300, Dmitry Osipenko wrote:
The code looks fine, but you may want to take into account my proposal in 1/7 to instead create a of_graph_has_port() function. The could would be simpler here.
The OF node should be put before returning error in tegra_output_probe(), otherwise node's refcount will be leaked.
Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Reviewed-by: Sam Ravnborg sam@ravnborg.org Signed-off-by: Dmitry Osipenko digetx@gmail.com --- drivers/gpu/drm/tegra/output.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/tegra/output.c b/drivers/gpu/drm/tegra/output.c index e36e5e7c2f69..a6a711d54e88 100644 --- a/drivers/gpu/drm/tegra/output.c +++ b/drivers/gpu/drm/tegra/output.c @@ -102,10 +102,10 @@ int tegra_output_probe(struct tegra_output *output) panel = of_parse_phandle(output->of_node, "nvidia,panel", 0); if (panel) { output->panel = of_drm_find_panel(panel); + of_node_put(panel); + if (IS_ERR(output->panel)) return PTR_ERR(output->panel); - - of_node_put(panel); }
output->edid = of_get_property(output->of_node, "nvidia,edid", &size); @@ -113,13 +113,12 @@ int tegra_output_probe(struct tegra_output *output) ddc = of_parse_phandle(output->of_node, "nvidia,ddc-i2c-bus", 0); if (ddc) { output->ddc = of_find_i2c_adapter_by_node(ddc); + of_node_put(ddc); + if (!output->ddc) { err = -EPROBE_DEFER; - of_node_put(ddc); return err; } - - of_node_put(ddc); }
output->hpd_gpio = devm_gpiod_get_from_of_node(output->dev,
Newer Tegra device-trees will specify a video output graph which involves a bridge. This patch adds initial support for the DRM bridges to the Tegra DRM output.
Acked-by: Sam Ravnborg sam@ravnborg.org Signed-off-by: Dmitry Osipenko digetx@gmail.com --- drivers/gpu/drm/tegra/drm.h | 2 ++ drivers/gpu/drm/tegra/output.c | 12 ++++++++++++ 2 files changed, 14 insertions(+)
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h index b25443255be6..f38de08e0c95 100644 --- a/drivers/gpu/drm/tegra/drm.h +++ b/drivers/gpu/drm/tegra/drm.h @@ -12,6 +12,7 @@ #include <linux/gpio/consumer.h>
#include <drm/drm_atomic.h> +#include <drm/drm_bridge.h> #include <drm/drm_edid.h> #include <drm/drm_encoder.h> #include <drm/drm_fb_helper.h> @@ -116,6 +117,7 @@ struct tegra_output { struct device_node *of_node; struct device *dev;
+ struct drm_bridge *bridge; struct drm_panel *panel; struct i2c_adapter *ddc; const struct edid *edid; diff --git a/drivers/gpu/drm/tegra/output.c b/drivers/gpu/drm/tegra/output.c index a6a711d54e88..ccd1421f1b24 100644 --- a/drivers/gpu/drm/tegra/output.c +++ b/drivers/gpu/drm/tegra/output.c @@ -5,6 +5,7 @@ */
#include <drm/drm_atomic_helper.h> +#include <drm/drm_of.h> #include <drm/drm_panel.h> #include <drm/drm_simple_kms_helper.h>
@@ -99,8 +100,19 @@ int tegra_output_probe(struct tegra_output *output) if (!output->of_node) output->of_node = output->dev->of_node;
+ err = drm_of_find_panel_or_bridge(output->of_node, -1, -1, + &output->panel, &output->bridge); + if (err && err != -ENODEV) + return err; + panel = of_parse_phandle(output->of_node, "nvidia,panel", 0); if (panel) { + /* + * Don't mix nvidia,panel phandle with the graph in a + * device-tree. + */ + WARN_ON(output->panel || output->bridge); + output->panel = of_drm_find_panel(panel); of_node_put(panel);
Newer Tegra device-trees will specify a video output graph, which involves LVDS encoder bridge. This patch adds support for the LVDS encoder bridge to the RGB output, allowing us to model the display hardware properly.
Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Acked-by: Sam Ravnborg sam@ravnborg.org Signed-off-by: Dmitry Osipenko digetx@gmail.com --- drivers/gpu/drm/tegra/rgb.c | 58 +++++++++++++++++++++++++++++++------ 1 file changed, 49 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/tegra/rgb.c b/drivers/gpu/drm/tegra/rgb.c index 0562a7eb793f..9a7024ec96bc 100644 --- a/drivers/gpu/drm/tegra/rgb.c +++ b/drivers/gpu/drm/tegra/rgb.c @@ -7,6 +7,7 @@ #include <linux/clk.h>
#include <drm/drm_atomic_helper.h> +#include <drm/drm_bridge_connector.h> #include <drm/drm_panel.h> #include <drm/drm_simple_kms_helper.h>
@@ -267,24 +268,63 @@ int tegra_dc_rgb_remove(struct tegra_dc *dc) int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc) { struct tegra_output *output = dc->rgb; + struct drm_connector *connector; int err;
if (!dc->rgb) return -ENODEV;
- drm_connector_init(drm, &output->connector, &tegra_rgb_connector_funcs, - DRM_MODE_CONNECTOR_LVDS); - drm_connector_helper_add(&output->connector, - &tegra_rgb_connector_helper_funcs); - output->connector.dpms = DRM_MODE_DPMS_OFF; - drm_simple_encoder_init(drm, &output->encoder, DRM_MODE_ENCODER_LVDS); drm_encoder_helper_add(&output->encoder, &tegra_rgb_encoder_helper_funcs);
- drm_connector_attach_encoder(&output->connector, - &output->encoder); - drm_connector_register(&output->connector); + /* + * Tegra devices that have LVDS panel utilize LVDS encoder bridge + * for converting up to 28 LCD LVTTL lanes into 5/4 LVDS lanes that + * go to display panel's receiver. + * + * Encoder usually have a power-down control which needs to be enabled + * in order to transmit data to the panel. Historically devices that + * use an older device-tree version didn't model the bridge, assuming + * that encoder is turned ON by default, while today's DRM allows us + * to model LVDS encoder properly. + * + * Newer device-trees utilize LVDS encoder bridge, which provides + * us with a connector and handles the display panel. + * + * For older device-trees we fall back to our own connector and use + * nvidia,panel phandle. + */ + if (output->bridge) { + err = drm_bridge_attach(&output->encoder, output->bridge, + NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR); + if (err) { + dev_err(output->dev, "failed to attach bridge: %d\n", + err); + return err; + } + + connector = drm_bridge_connector_init(drm, &output->encoder); + if (IS_ERR(connector)) { + dev_err(output->dev, + "failed to initialize bridge connector: %pe\n", + connector); + return PTR_ERR(connector); + } + + drm_connector_attach_encoder(connector, &output->encoder); + } else { + drm_connector_init(drm, &output->connector, + &tegra_rgb_connector_funcs, + DRM_MODE_CONNECTOR_LVDS); + drm_connector_helper_add(&output->connector, + &tegra_rgb_connector_helper_funcs); + output->connector.dpms = DRM_MODE_DPMS_OFF; + + drm_connector_attach_encoder(&output->connector, + &output->encoder); + drm_connector_register(&output->connector); + }
err = tegra_output_init(drm, output); if (err < 0) {
Currently Tegra DRM driver manually manages display panel, but this management could be moved out into DRM core if we'll wrap panel into DRM bridge. This patch wraps RGB panel into a DRM bridge and removes manual handling of the panel from the RGB output code.
Suggested-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Acked-by: Sam Ravnborg sam@ravnborg.org Signed-off-by: Dmitry Osipenko digetx@gmail.com --- drivers/gpu/drm/tegra/rgb.c | 70 ++++++++++--------------------------- 1 file changed, 18 insertions(+), 52 deletions(-)
diff --git a/drivers/gpu/drm/tegra/rgb.c b/drivers/gpu/drm/tegra/rgb.c index 9a7024ec96bc..4142a56ca764 100644 --- a/drivers/gpu/drm/tegra/rgb.c +++ b/drivers/gpu/drm/tegra/rgb.c @@ -8,7 +8,6 @@
#include <drm/drm_atomic_helper.h> #include <drm/drm_bridge_connector.h> -#include <drm/drm_panel.h> #include <drm/drm_simple_kms_helper.h>
#include "drm.h" @@ -86,45 +85,13 @@ static void tegra_dc_write_regs(struct tegra_dc *dc, tegra_dc_writel(dc, table[i].value, table[i].offset); }
-static const struct drm_connector_funcs tegra_rgb_connector_funcs = { - .reset = drm_atomic_helper_connector_reset, - .detect = tegra_output_connector_detect, - .fill_modes = drm_helper_probe_single_connector_modes, - .destroy = tegra_output_connector_destroy, - .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, - .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, -}; - -static enum drm_mode_status -tegra_rgb_connector_mode_valid(struct drm_connector *connector, - struct drm_display_mode *mode) -{ - /* - * FIXME: For now, always assume that the mode is okay. There are - * unresolved issues with clk_round_rate(), which doesn't always - * reliably report whether a frequency can be set or not. - */ - return MODE_OK; -} - -static const struct drm_connector_helper_funcs tegra_rgb_connector_helper_funcs = { - .get_modes = tegra_output_connector_get_modes, - .mode_valid = tegra_rgb_connector_mode_valid, -}; - static void tegra_rgb_encoder_disable(struct drm_encoder *encoder) { struct tegra_output *output = encoder_to_output(encoder); struct tegra_rgb *rgb = to_rgb(output);
- if (output->panel) - drm_panel_disable(output->panel); - tegra_dc_write_regs(rgb->dc, rgb_disable, ARRAY_SIZE(rgb_disable)); tegra_dc_commit(rgb->dc); - - if (output->panel) - drm_panel_unprepare(output->panel); }
static void tegra_rgb_encoder_enable(struct drm_encoder *encoder) @@ -133,9 +100,6 @@ static void tegra_rgb_encoder_enable(struct drm_encoder *encoder) struct tegra_rgb *rgb = to_rgb(output); u32 value;
- if (output->panel) - drm_panel_prepare(output->panel); - tegra_dc_write_regs(rgb->dc, rgb_enable, ARRAY_SIZE(rgb_enable));
value = DE_SELECT_ACTIVE | DE_CONTROL_NORMAL; @@ -157,9 +121,6 @@ static void tegra_rgb_encoder_enable(struct drm_encoder *encoder) tegra_dc_writel(rgb->dc, value, DC_DISP_SHIFT_CLOCK_OPTIONS);
tegra_dc_commit(rgb->dc); - - if (output->panel) - drm_panel_enable(output->panel); }
static int @@ -278,6 +239,23 @@ int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc) drm_encoder_helper_add(&output->encoder, &tegra_rgb_encoder_helper_funcs);
+ /* + * Wrap directly-connected panel into DRM bridge in order to let + * DRM core to handle panel for us. + */ + if (output->panel) { + output->bridge = devm_drm_panel_bridge_add(output->dev, + output->panel); + if (IS_ERR(output->bridge)) { + dev_err(output->dev, + "failed to wrap panel into bridge: %pe\n", + output->bridge); + return PTR_ERR(output->bridge); + } + + output->panel = NULL; + } + /* * Tegra devices that have LVDS panel utilize LVDS encoder bridge * for converting up to 28 LCD LVTTL lanes into 5/4 LVDS lanes that @@ -292,8 +270,7 @@ int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc) * Newer device-trees utilize LVDS encoder bridge, which provides * us with a connector and handles the display panel. * - * For older device-trees we fall back to our own connector and use - * nvidia,panel phandle. + * For older device-trees we wrapped panel into the panel-bridge. */ if (output->bridge) { err = drm_bridge_attach(&output->encoder, output->bridge, @@ -313,17 +290,6 @@ int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc) }
drm_connector_attach_encoder(connector, &output->encoder); - } else { - drm_connector_init(drm, &output->connector, - &tegra_rgb_connector_funcs, - DRM_MODE_CONNECTOR_LVDS); - drm_connector_helper_add(&output->connector, - &tegra_rgb_connector_helper_funcs); - output->connector.dpms = DRM_MODE_DPMS_OFF; - - drm_connector_attach_encoder(&output->connector, - &output->encoder); - drm_connector_register(&output->connector); }
err = tegra_output_init(drm, output);
dri-devel@lists.freedesktop.org
-
Dmitry Osipenko -
Laurent Pinchart