Re: [PATCH 3/8] drm/bridge: fsl-ldb: Get the next non-panel bridge

[Liu Ying <victor.liu@nxp.com>]

On 07/11/2025, Frank Li wrote:
> On Wed, Jul 09, 2025 at 03:23:22PM +0300, Laurentiu Palcu wrote:
>> From: Liu Ying <victor.liu@nxp.com>
>>
>> The next bridge in bridge chain could be a panel bridge or a non-panel
>> bridge.  Use devm_drm_of_get_bridge() to replace the combination
>          ^ extra space.

It's intentional for readers to be aware of the start of a next sentence
easily.  It's not uncommon in kernel commit messages.

> 
>> function calls of of_drm_find_panel() and devm_drm_panel_bridge_add()
>> to get either a panel bridge or a non-panel bridge, instead of getting
>> a panel bridge only.
> 
> According to code change, devm_drm_of_get_bridge() replace
> devm_drm_panel_bridge_add(of_drm_find_panel()).
> 
> what relationship with panel bridge or a non-panel bridge?

Here, the former represents a panel with only video sink, and the latter
represents a bridge with both video sink and video source.

> 
> Frank
> 
>>
>> Signed-off-by: Liu Ying <victor.liu@nxp.com>
>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>> Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>
>> ---
>>  drivers/gpu/drm/bridge/fsl-ldb.c | 31 +++++++++++--------------------
>>  1 file changed, 11 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/fsl-ldb.c b/drivers/gpu/drm/bridge/fsl-ldb.c
>> index 5c3cf37200bce..665053d0cb79d 100644
>> --- a/drivers/gpu/drm/bridge/fsl-ldb.c
>> +++ b/drivers/gpu/drm/bridge/fsl-ldb.c
>> @@ -15,7 +15,6 @@
>>  #include <drm/drm_atomic_helper.h>
>>  #include <drm/drm_bridge.h>
>>  #include <drm/drm_of.h>
>> -#include <drm/drm_panel.h>
>>
>>  #define LDB_CTRL_CH0_ENABLE			BIT(0)
>>  #define LDB_CTRL_CH0_DI_SELECT			BIT(1)
>> @@ -86,7 +85,7 @@ static const struct fsl_ldb_devdata fsl_ldb_devdata[] = {
>>  struct fsl_ldb {
>>  	struct device *dev;
>>  	struct drm_bridge bridge;
>> -	struct drm_bridge *panel_bridge;
>> +	struct drm_bridge *next_bridge;
>>  	struct clk *clk;
>>  	struct regmap *regmap;
>>  	const struct fsl_ldb_devdata *devdata;
>> @@ -118,7 +117,7 @@ static int fsl_ldb_attach(struct drm_bridge *bridge,
>>  {
>>  	struct fsl_ldb *fsl_ldb = to_fsl_ldb(bridge);
>>
>> -	return drm_bridge_attach(encoder, fsl_ldb->panel_bridge,
>> +	return drm_bridge_attach(encoder, fsl_ldb->next_bridge,
>>  				 bridge, flags);
>>  }
>>
>> @@ -292,9 +291,7 @@ static const struct drm_bridge_funcs funcs = {
>>  static int fsl_ldb_probe(struct platform_device *pdev)
>>  {
>>  	struct device *dev = &pdev->dev;
>> -	struct device_node *panel_node;
>>  	struct device_node *remote1, *remote2;
>> -	struct drm_panel *panel;
>>  	struct fsl_ldb *fsl_ldb;
>>  	int dual_link;
>>
>> @@ -317,33 +314,27 @@ static int fsl_ldb_probe(struct platform_device *pdev)
>>  	if (IS_ERR(fsl_ldb->regmap))
>>  		return PTR_ERR(fsl_ldb->regmap);
>>
>> -	/* Locate the remote ports and the panel node */
>> +	/* Locate the remote ports. */
>>  	remote1 = of_graph_get_remote_node(dev->of_node, 1, 0);
>>  	remote2 = of_graph_get_remote_node(dev->of_node, 2, 0);
>>  	fsl_ldb->ch0_enabled = (remote1 != NULL);
>>  	fsl_ldb->ch1_enabled = (remote2 != NULL);
>> -	panel_node = of_node_get(remote1 ? remote1 : remote2);
>>  	of_node_put(remote1);
>>  	of_node_put(remote2);
>>
>> -	if (!fsl_ldb->ch0_enabled && !fsl_ldb->ch1_enabled) {
>> -		of_node_put(panel_node);
>> -		return dev_err_probe(dev, -ENXIO, "No panel node found");
>> -	}
>> +	if (!fsl_ldb->ch0_enabled && !fsl_ldb->ch1_enabled)
>> +		return dev_err_probe(dev, -ENXIO, "No next bridge node found");
>>
>>  	dev_dbg(dev, "Using %s\n",
>>  		fsl_ldb_is_dual(fsl_ldb) ? "dual-link mode" :
>>  		fsl_ldb->ch0_enabled ? "channel 0" : "channel 1");
>>
>> -	panel = of_drm_find_panel(panel_node);
>> -	of_node_put(panel_node);
>> -	if (IS_ERR(panel))
>> -		return PTR_ERR(panel);
>> -
>> -	fsl_ldb->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
>> -	if (IS_ERR(fsl_ldb->panel_bridge))
>> -		return PTR_ERR(fsl_ldb->panel_bridge);
>> -
>> +	fsl_ldb->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node,
>> +						      fsl_ldb->ch0_enabled ? 1 : 2,
>> +						      0);
>> +	if (IS_ERR(fsl_ldb->next_bridge))
>> +		return dev_err_probe(dev, PTR_ERR(fsl_ldb->next_bridge),
>> +				     "failed to get next bridge\n");
>>
>>  	if (fsl_ldb_is_dual(fsl_ldb)) {
>>  		struct device_node *port1, *port2;
>> --
>> 2.46.1
>>

-- 
Regards,
Liu Ying