Support DRM bridges on NVIDIA Tegra
Subsystems (5)
v6 cover Support DRM bridges on NVIDIA Tegra
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:
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 | 85 +++++++++++++++++++++------------- drivers/of/property.c | 32 +++++++++---- include/linux/of_graph.h | 7 +++ 6 files changed, 114 insertions(+), 46 deletions(-)
Signature · 1 line
2.26.0
PATCH v6 1/6 of_graph: add of_graph_get_local_port()
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.
--- drivers/of/property.c | 32 +++++++++++++++++++++++--------- include/linux/of_graph.h | 7 +++++++ 2 files changed, 30 insertions(+), 9 deletions(-)
drivers/of/property.c +23 -9
@@ -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;
include/linux/of_graph.h +7 -0
@@ -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 */
Signature · 1 line
2.26.0
PATCH v6 2/6 drm/of: Make drm_of_find_panel_or_bridge() to check graph's presence
In reply to Dmitry OsipenkoWhen 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.
--- drivers/gpu/drm/drm_of.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
drivers/gpu/drm/drm_of.c +12 -1
@@ -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 ;
Signature · 1 line
2.26.0
PATCH v6 3/6 drm/tegra: output: Don't leak OF node on error
In reply to Dmitry OsipenkoThe OF node should be put before returning error in tegra_output_probe(), otherwise node's refcount will be leaked.
--- drivers/gpu/drm/tegra/output.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
drivers/gpu/drm/tegra/output.c +4 -5
@@ -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,
Signature · 1 line
2.26.0
PATCH v6 4/6 drm/tegra: output: Support DRM bridges
In reply to Dmitry OsipenkoNewer 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.
--- drivers/gpu/drm/tegra/drm.h | 2 ++ drivers/gpu/drm/tegra/output.c | 12 ++++++++++++ 2 files changed, 14 insertions(+)
drivers/gpu/drm/tegra/drm.h +2 -0
@@ -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;
drivers/gpu/drm/tegra/output.c +12 -0
@@ -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);
Signature · 1 line
2.26.0
PATCH v6 5/6 drm/tegra: output: rgb: Support LVDS encoder bridge
In reply to Dmitry OsipenkoNewer 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.
--- drivers/gpu/drm/tegra/rgb.c | 58 +++++++++++++++++++++++++++++++------ 1 file changed, 49 insertions(+), 9 deletions(-)
drivers/gpu/drm/tegra/rgb.c +49 -9
@@ -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 ) {
Signature · 1 line
2.26.0
PATCH v6 6/6 drm/tegra: output: rgb: Wrap directly-connected panel into DRM bridge
In reply to Dmitry OsipenkoCurrently 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.
--- drivers/gpu/drm/tegra/rgb.c | 53 +++++++++++++------------------------ 1 file changed, 18 insertions(+), 35 deletions(-)
drivers/gpu/drm/tegra/rgb.c +18 -35
@@ -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"
@@ -86,15 +85,6 @@ 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)
@@ -117,14 +107,8 @@ 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 +117,6 @@ 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 +138,6 @@ 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 +256,23 @@ 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 +287,7 @@ 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 +307,6 @@ 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);
Signature · 1 line
2.26.0
kernel test robot
build botRe: [PATCH v6 6/6] drm/tegra: output: rgb: Wrap directly-connected panel into DRM bridge
I love your patch! Perhaps something to improve:
Hi Dmitry,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on next-20200612]
[cannot apply to tegra/for-next robh/for-next v5.7]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Dmitry-Osipenko/Support-DRM-bridges-on-NVIDIA-Tegra/20200609-213026 base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git abfbb29297c27e3f101f348dc9e467b0fe70f919 config: arm64-randconfig-r026-20200612 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 3b43f006294971b8049d4807110032169780e5b8)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# install arm64 cross compiling tool for clang build
# apt-get install binutils-aarch64-linux-gnu
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64
If you fix the issue, kindly add following tag as appropriate
All warnings (new ones prefixed by >>, old ones prefixed by <<):
>> drivers/gpu/drm/tegra/rgb.c:100:48: warning: unused variable 'tegra_rgb_connector_helper_funcs' [-Wunused-const-variable]
static const struct drm_connector_helper_funcs tegra_rgb_connector_helper_funcs = { ^
1 warning generated.
vim +/tegra_rgb_connector_helper_funcs +100 drivers/gpu/drm/tegra/rgb.c
3b0e58554873d1 Thierry Reding 2014-12-16 99
3b0e58554873d1 Thierry Reding 2014-12-16 @100 static const struct drm_connector_helper_funcs tegra_rgb_connector_helper_funcs = {
3b0e58554873d1 Thierry Reding 2014-12-16 101 .get_modes = tegra_output_connector_get_modes,
3b0e58554873d1 Thierry Reding 2014-12-16 102 .mode_valid = tegra_rgb_connector_mode_valid,
3b0e58554873d1 Thierry Reding 2014-12-16 103 };3b0e58554873d1 Thierry Reding 2014-12-16 104
:::::: The code at line 100 was first introduced by commit :::::: 3b0e58554873d1034beef737f15c7aa46492ff98 drm/tegra: rgb: Demidlayer
:::::: TO: Thierry Reding <[email protected]> :::::: CC: Thierry Reding <[email protected]>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Re: [PATCH v6 6/6] drm/tegra: output: rgb: Wrap directly-connected panel into DRM bridge
13.06.2020 00:23, kernel test robot пишет:
Quoted 11 lines
Hi Dmitry,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on next-20200612]
[cannot apply to tegra/for-next robh/for-next v5.7]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
Quoted 4 lines
url: https://github.com/0day-ci/linux/commits/Dmitry-Osipenko/Support-DRM-bridges-on-NVIDIA-Tegra/20200609-213026 base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git abfbb29297c27e3f101f348dc9e467b0fe70f919 config: arm64-randconfig-r026-20200612 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 3b43f006294971b8049d4807110032169780e5b8)
Interestingly, GCC doesn't report this warning.
Quoted 9 lines
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# install arm64 cross compiling tool for clang build
# apt-get install binutils-aarch64-linux-gnu
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64If you fix the issue, kindly add following tag as appropriate
Quoted 8 lines
Reported-by kernel test robot <[email protected]>All warnings (new ones prefixed by >>, old ones prefixed by <<):
Quoted 1 line
Quoted 1 line
drivers/gpu/drm/tegra/rgb.c:100:48: warning: unused variable 'tegra_rgb_connector_helper_funcs' [-Wunused-const-variable]static const struct
drm_connector_helper_funcstegra_rgb_connector_helper_funcs= { ^
1 warning generated.
There are two unused structs in the code and one is referenced by the other, I'll remove the unused structs in v7.