[v7,7/8] drm/tidss: Update encoder/bridge chain connect model

Message ID 20230606082142.23760-8-a-bhatia1@ti.com
State New
Headers
Series drm/tidss: Use new connector model for tidss |

Commit Message

Aradhya Bhatia June 6, 2023, 8:21 a.m. UTC
  With the new encoder/bridge chain model, the display controller driver
is required to create a drm_connector entity instead of asking the
bridge to do so during drm_bridge_attach. Moreover, the controller
driver should create a drm_bridge entity to negotiate bus formats and a
'simple' drm_encoder entity to expose it to userspace.

Update the encoder/bridge initialization sequence in tidss as per the
new model.

Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
---

Notes:

    changes from v5:
    * Drop patches 5 and 6 from the original series.
    * Instead add this patch that addresses Boris Brezillon's comments
      of creating bridge, simple encoder and connector.

 drivers/gpu/drm/tidss/tidss_encoder.c | 140 ++++++++++++++++----------
 drivers/gpu/drm/tidss/tidss_encoder.h |   5 +-
 drivers/gpu/drm/tidss/tidss_kms.c     |  12 +--
 3 files changed, 94 insertions(+), 63 deletions(-)
  

Comments

Jan Kiszka Oct. 30, 2023, 9:25 a.m. UTC | #1
On 06.06.23 10:21, Aradhya Bhatia wrote:
> With the new encoder/bridge chain model, the display controller driver
> is required to create a drm_connector entity instead of asking the
> bridge to do so during drm_bridge_attach. Moreover, the controller
> driver should create a drm_bridge entity to negotiate bus formats and a
> 'simple' drm_encoder entity to expose it to userspace.
> 
> Update the encoder/bridge initialization sequence in tidss as per the
> new model.
> 
> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
> ---
> 
> Notes:
> 
>     changes from v5:
>     * Drop patches 5 and 6 from the original series.
>     * Instead add this patch that addresses Boris Brezillon's comments
>       of creating bridge, simple encoder and connector.
> 
>  drivers/gpu/drm/tidss/tidss_encoder.c | 140 ++++++++++++++++----------
>  drivers/gpu/drm/tidss/tidss_encoder.h |   5 +-
>  drivers/gpu/drm/tidss/tidss_kms.c     |  12 +--
>  3 files changed, 94 insertions(+), 63 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tidss/tidss_encoder.c b/drivers/gpu/drm/tidss/tidss_encoder.c
> index 0d4865e9c03d..17a86bed8054 100644
> --- a/drivers/gpu/drm/tidss/tidss_encoder.c
> +++ b/drivers/gpu/drm/tidss/tidss_encoder.c
> @@ -6,91 +6,125 @@
>  
>  #include <linux/export.h>
>  
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_bridge_connector.h>
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_modeset_helper_vtables.h>
>  #include <drm/drm_panel.h>
>  #include <drm/drm_of.h>
> +#include <drm/drm_simple_kms_helper.h>
>  
>  #include "tidss_crtc.h"
>  #include "tidss_drv.h"
>  #include "tidss_encoder.h"
>  
> -static int tidss_encoder_atomic_check(struct drm_encoder *encoder,
> -				      struct drm_crtc_state *crtc_state,
> -				      struct drm_connector_state *conn_state)
> +struct tidss_encoder {
> +	struct drm_bridge bridge;
> +	struct drm_encoder encoder;
> +	struct drm_connector *connector;
> +	struct drm_bridge *next_bridge;
> +	struct tidss_device *tidss;
> +};
> +
> +static inline struct tidss_encoder
> +*bridge_to_tidss_encoder(struct drm_bridge *b)
> +{
> +	return container_of(b, struct tidss_encoder, bridge);
> +}
> +
> +static int tidss_bridge_attach(struct drm_bridge *bridge,
> +			       enum drm_bridge_attach_flags flags)
> +{
> +	struct tidss_encoder *t_enc = bridge_to_tidss_encoder(bridge);
> +
> +	return drm_bridge_attach(bridge->encoder, t_enc->next_bridge,
> +				 bridge, flags);
> +}
> +
> +static int tidss_bridge_atomic_check(struct drm_bridge *bridge,
> +				     struct drm_bridge_state *bridge_state,
> +				     struct drm_crtc_state *crtc_state,
> +				     struct drm_connector_state *conn_state)
>  {
> -	struct drm_device *ddev = encoder->dev;
> +	struct tidss_encoder *t_enc = bridge_to_tidss_encoder(bridge);
> +	struct tidss_device *tidss = t_enc->tidss;
>  	struct tidss_crtc_state *tcrtc_state = to_tidss_crtc_state(crtc_state);
>  	struct drm_display_info *di = &conn_state->connector->display_info;
> -	struct drm_bridge *bridge;
> -	bool bus_flags_set = false;
> -
> -	dev_dbg(ddev->dev, "%s\n", __func__);
> -
> -	/*
> -	 * Take the bus_flags from the first bridge that defines
> -	 * bridge timings, or from the connector's display_info if no
> -	 * bridge defines the timings.
> -	 */
> -	drm_for_each_bridge_in_chain(encoder, bridge) {
> -		if (!bridge->timings)
> -			continue;
> -
> -		tcrtc_state->bus_flags = bridge->timings->input_bus_flags;
> -		bus_flags_set = true;
> -		break;
> -	}
> +	struct drm_bridge_state *next_bridge_state = NULL;
> +
> +	if (t_enc->next_bridge)
> +		next_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
> +								    t_enc->next_bridge);
>  
> -	if (!di->bus_formats || di->num_bus_formats == 0)  {
> -		dev_err(ddev->dev, "%s: No bus_formats in connected display\n",
> +	if (next_bridge_state) {
> +		tcrtc_state->bus_flags = next_bridge_state->input_bus_cfg.flags;
> +		tcrtc_state->bus_format = next_bridge_state->input_bus_cfg.format;
> +	} else if (di->num_bus_formats) {
> +		tcrtc_state->bus_format = di->bus_formats[0];
> +		tcrtc_state->bus_flags = di->bus_flags;
> +	} else {
> +		dev_err(tidss->dev, "%s: No bus_formats in connected display\n",
>  			__func__);
>  		return -EINVAL;
>  	}
>  
> -	// XXX any cleaner way to set bus format and flags?
> -	tcrtc_state->bus_format = di->bus_formats[0];
> -	if (!bus_flags_set)
> -		tcrtc_state->bus_flags = di->bus_flags;
> -
>  	return 0;
>  }
>  
> -static void tidss_encoder_destroy(struct drm_encoder *encoder)
> -{
> -	drm_encoder_cleanup(encoder);
> -	kfree(encoder);
> -}
> -
> -static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
> -	.atomic_check = tidss_encoder_atomic_check,
> -};
> -
> -static const struct drm_encoder_funcs encoder_funcs = {
> -	.destroy = tidss_encoder_destroy,
> +static const struct drm_bridge_funcs tidss_bridge_funcs = {
> +	.attach				= tidss_bridge_attach,
> +	.atomic_check			= tidss_bridge_atomic_check,
> +	.atomic_reset			= drm_atomic_helper_bridge_reset,
> +	.atomic_duplicate_state		= drm_atomic_helper_bridge_duplicate_state,
> +	.atomic_destroy_state		= drm_atomic_helper_bridge_destroy_state,
>  };
>  
> -struct drm_encoder *tidss_encoder_create(struct tidss_device *tidss,
> -					 u32 encoder_type, u32 possible_crtcs)
> +int tidss_encoder_create(struct tidss_device *tidss,
> +			 struct drm_bridge *next_bridge,
> +			 u32 encoder_type, u32 possible_crtcs)
>  {
> +	struct tidss_encoder *t_enc;
>  	struct drm_encoder *enc;
> +	struct drm_connector *connector;
>  	int ret;
>  
> -	enc = kzalloc(sizeof(*enc), GFP_KERNEL);
> -	if (!enc)
> -		return ERR_PTR(-ENOMEM);
> +	t_enc = drmm_simple_encoder_alloc(&tidss->ddev, struct tidss_encoder,
> +					  encoder, encoder_type);
> +	if (IS_ERR(t_enc))
> +		return PTR_ERR(t_enc);
> +
> +	t_enc->tidss = tidss;
> +	t_enc->next_bridge = next_bridge;
> +	t_enc->bridge.funcs = &tidss_bridge_funcs;
>  
> +	enc = &t_enc->encoder;
>  	enc->possible_crtcs = possible_crtcs;
>  
> -	ret = drm_encoder_init(&tidss->ddev, enc, &encoder_funcs,
> -			       encoder_type, NULL);
> -	if (ret < 0) {
> -		kfree(enc);
> -		return ERR_PTR(ret);
> +	/* Attaching first bridge to the encoder */
> +	ret = drm_bridge_attach(enc, &t_enc->bridge, NULL,
> +				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +	if (ret) {
> +		dev_err(tidss->dev, "bridge attach failed: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* Initializing the connector at the end of bridge-chain */
> +	connector = drm_bridge_connector_init(&tidss->ddev, enc);
> +	if (IS_ERR(connector)) {
> +		dev_err(tidss->dev, "bridge_connector create failed\n");
> +		return PTR_ERR(connector);
> +	}
> +
> +	ret = drm_connector_attach_encoder(connector, enc);
> +	if (ret) {
> +		dev_err(tidss->dev, "attaching encoder to connector failed\n");
> +		return ret;
>  	}
>  
> -	drm_encoder_helper_add(enc, &encoder_helper_funcs);
> +	t_enc->connector = connector;
>  
>  	dev_dbg(tidss->dev, "Encoder create done\n");
>  
> -	return enc;
> +	return ret;
>  }
> diff --git a/drivers/gpu/drm/tidss/tidss_encoder.h b/drivers/gpu/drm/tidss/tidss_encoder.h
> index ace877c0e0fd..3e561d6b1e83 100644
> --- a/drivers/gpu/drm/tidss/tidss_encoder.h
> +++ b/drivers/gpu/drm/tidss/tidss_encoder.h
> @@ -11,7 +11,8 @@
>  
>  struct tidss_device;
>  
> -struct drm_encoder *tidss_encoder_create(struct tidss_device *tidss,
> -					 u32 encoder_type, u32 possible_crtcs);
> +int tidss_encoder_create(struct tidss_device *tidss,
> +			 struct drm_bridge *next_bridge,
> +			 u32 encoder_type, u32 possible_crtcs);
>  
>  #endif
> diff --git a/drivers/gpu/drm/tidss/tidss_kms.c b/drivers/gpu/drm/tidss/tidss_kms.c
> index ad2fa3c3d4a7..c979ad1af236 100644
> --- a/drivers/gpu/drm/tidss/tidss_kms.c
> +++ b/drivers/gpu/drm/tidss/tidss_kms.c
> @@ -193,7 +193,6 @@ static int tidss_dispc_modeset_init(struct tidss_device *tidss)
>  	for (i = 0; i < num_pipes; ++i) {
>  		struct tidss_plane *tplane;
>  		struct tidss_crtc *tcrtc;
> -		struct drm_encoder *enc;
>  		u32 hw_plane_id = feat->vid_order[tidss->num_planes];
>  		int ret;
>  
> @@ -216,16 +215,13 @@ static int tidss_dispc_modeset_init(struct tidss_device *tidss)
>  
>  		tidss->crtcs[tidss->num_crtcs++] = &tcrtc->crtc;
>  
> -		enc = tidss_encoder_create(tidss, pipes[i].enc_type,
> +		ret = tidss_encoder_create(tidss, pipes[i].bridge,
> +					   pipes[i].enc_type,
>  					   1 << tcrtc->crtc.index);
> -		if (IS_ERR(enc)) {
> +		if (ret) {
>  			dev_err(tidss->dev, "encoder create failed\n");
> -			return PTR_ERR(enc);
> -		}
> -
> -		ret = drm_bridge_attach(enc, pipes[i].bridge, NULL, 0);
> -		if (ret)
>  			return ret;
> +		}
>  	}
>  
>  	/* create overlay planes of the leftover planes */

This breaks the IOT2050 devices over 6.6, just bisected to it:

[    3.435153] [drm] Initialized tidss 1.0.0 20180215 for 4a00000.dss on minor 0
[    3.491246] tidss 4a00000.dss: [drm] Cannot find any crtc or sizes

vs.

[    3.436116] [drm] Initialized tidss 1.0.0 20180215 for 4a00000.dss on minor 0
[    3.910574] Console: switching to colour frame buffer device 80x30
[    3.937614] tidss 4a00000.dss: [drm] fb0: tidssdrmfb frame buffer device

Do we need to adjust its device tree to anything, or what may be the 
reason?

Jan
  
Aradhya Bhatia Oct. 30, 2023, 7:38 p.m. UTC | #2
On 30-Oct-23 14:55, Jan Kiszka wrote:
> On 06.06.23 10:21, Aradhya Bhatia wrote:
>> With the new encoder/bridge chain model, the display controller driver
>> is required to create a drm_connector entity instead of asking the
>> bridge to do so during drm_bridge_attach. Moreover, the controller
>> driver should create a drm_bridge entity to negotiate bus formats and a
>> 'simple' drm_encoder entity to expose it to userspace.
>>
>> Update the encoder/bridge initialization sequence in tidss as per the
>> new model.
>>
>> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
>> ---
>>
>> Notes:
>>
>>     changes from v5:
>>     * Drop patches 5 and 6 from the original series.
>>     * Instead add this patch that addresses Boris Brezillon's comments
>>       of creating bridge, simple encoder and connector.
>>
>>  drivers/gpu/drm/tidss/tidss_encoder.c | 140 ++++++++++++++++----------
>>  drivers/gpu/drm/tidss/tidss_encoder.h |   5 +-
>>  drivers/gpu/drm/tidss/tidss_kms.c     |  12 +--
>>  3 files changed, 94 insertions(+), 63 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/tidss/tidss_encoder.c b/drivers/gpu/drm/tidss/tidss_encoder.c
>> index 0d4865e9c03d..17a86bed8054 100644
>> --- a/drivers/gpu/drm/tidss/tidss_encoder.c
>> +++ b/drivers/gpu/drm/tidss/tidss_encoder.c
>> @@ -6,91 +6,125 @@
>>  
>>  #include <linux/export.h>
>>  
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_bridge_connector.h>
>>  #include <drm/drm_crtc.h>
>>  #include <drm/drm_modeset_helper_vtables.h>
>>  #include <drm/drm_panel.h>
>>  #include <drm/drm_of.h>
>> +#include <drm/drm_simple_kms_helper.h>
>>  
>>  #include "tidss_crtc.h"
>>  #include "tidss_drv.h"
>>  #include "tidss_encoder.h"
>>  
>> -static int tidss_encoder_atomic_check(struct drm_encoder *encoder,
>> -				      struct drm_crtc_state *crtc_state,
>> -				      struct drm_connector_state *conn_state)
>> +struct tidss_encoder {
>> +	struct drm_bridge bridge;
>> +	struct drm_encoder encoder;
>> +	struct drm_connector *connector;
>> +	struct drm_bridge *next_bridge;
>> +	struct tidss_device *tidss;
>> +};
>> +
>> +static inline struct tidss_encoder
>> +*bridge_to_tidss_encoder(struct drm_bridge *b)
>> +{
>> +	return container_of(b, struct tidss_encoder, bridge);
>> +}
>> +
>> +static int tidss_bridge_attach(struct drm_bridge *bridge,
>> +			       enum drm_bridge_attach_flags flags)
>> +{
>> +	struct tidss_encoder *t_enc = bridge_to_tidss_encoder(bridge);
>> +
>> +	return drm_bridge_attach(bridge->encoder, t_enc->next_bridge,
>> +				 bridge, flags);
>> +}
>> +
>> +static int tidss_bridge_atomic_check(struct drm_bridge *bridge,
>> +				     struct drm_bridge_state *bridge_state,
>> +				     struct drm_crtc_state *crtc_state,
>> +				     struct drm_connector_state *conn_state)
>>  {
>> -	struct drm_device *ddev = encoder->dev;
>> +	struct tidss_encoder *t_enc = bridge_to_tidss_encoder(bridge);
>> +	struct tidss_device *tidss = t_enc->tidss;
>>  	struct tidss_crtc_state *tcrtc_state = to_tidss_crtc_state(crtc_state);
>>  	struct drm_display_info *di = &conn_state->connector->display_info;
>> -	struct drm_bridge *bridge;
>> -	bool bus_flags_set = false;
>> -
>> -	dev_dbg(ddev->dev, "%s\n", __func__);
>> -
>> -	/*
>> -	 * Take the bus_flags from the first bridge that defines
>> -	 * bridge timings, or from the connector's display_info if no
>> -	 * bridge defines the timings.
>> -	 */
>> -	drm_for_each_bridge_in_chain(encoder, bridge) {
>> -		if (!bridge->timings)
>> -			continue;
>> -
>> -		tcrtc_state->bus_flags = bridge->timings->input_bus_flags;
>> -		bus_flags_set = true;
>> -		break;
>> -	}
>> +	struct drm_bridge_state *next_bridge_state = NULL;
>> +
>> +	if (t_enc->next_bridge)
>> +		next_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
>> +								    t_enc->next_bridge);
>>  
>> -	if (!di->bus_formats || di->num_bus_formats == 0)  {
>> -		dev_err(ddev->dev, "%s: No bus_formats in connected display\n",
>> +	if (next_bridge_state) {
>> +		tcrtc_state->bus_flags = next_bridge_state->input_bus_cfg.flags;
>> +		tcrtc_state->bus_format = next_bridge_state->input_bus_cfg.format;
>> +	} else if (di->num_bus_formats) {
>> +		tcrtc_state->bus_format = di->bus_formats[0];
>> +		tcrtc_state->bus_flags = di->bus_flags;
>> +	} else {
>> +		dev_err(tidss->dev, "%s: No bus_formats in connected display\n",
>>  			__func__);
>>  		return -EINVAL;
>>  	}
>>  
>> -	// XXX any cleaner way to set bus format and flags?
>> -	tcrtc_state->bus_format = di->bus_formats[0];
>> -	if (!bus_flags_set)
>> -		tcrtc_state->bus_flags = di->bus_flags;
>> -
>>  	return 0;
>>  }
>>  
>> -static void tidss_encoder_destroy(struct drm_encoder *encoder)
>> -{
>> -	drm_encoder_cleanup(encoder);
>> -	kfree(encoder);
>> -}
>> -
>> -static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
>> -	.atomic_check = tidss_encoder_atomic_check,
>> -};
>> -
>> -static const struct drm_encoder_funcs encoder_funcs = {
>> -	.destroy = tidss_encoder_destroy,
>> +static const struct drm_bridge_funcs tidss_bridge_funcs = {
>> +	.attach				= tidss_bridge_attach,
>> +	.atomic_check			= tidss_bridge_atomic_check,
>> +	.atomic_reset			= drm_atomic_helper_bridge_reset,
>> +	.atomic_duplicate_state		= drm_atomic_helper_bridge_duplicate_state,
>> +	.atomic_destroy_state		= drm_atomic_helper_bridge_destroy_state,
>>  };
>>  
>> -struct drm_encoder *tidss_encoder_create(struct tidss_device *tidss,
>> -					 u32 encoder_type, u32 possible_crtcs)
>> +int tidss_encoder_create(struct tidss_device *tidss,
>> +			 struct drm_bridge *next_bridge,
>> +			 u32 encoder_type, u32 possible_crtcs)
>>  {
>> +	struct tidss_encoder *t_enc;
>>  	struct drm_encoder *enc;
>> +	struct drm_connector *connector;
>>  	int ret;
>>  
>> -	enc = kzalloc(sizeof(*enc), GFP_KERNEL);
>> -	if (!enc)
>> -		return ERR_PTR(-ENOMEM);
>> +	t_enc = drmm_simple_encoder_alloc(&tidss->ddev, struct tidss_encoder,
>> +					  encoder, encoder_type);
>> +	if (IS_ERR(t_enc))
>> +		return PTR_ERR(t_enc);
>> +
>> +	t_enc->tidss = tidss;
>> +	t_enc->next_bridge = next_bridge;
>> +	t_enc->bridge.funcs = &tidss_bridge_funcs;
>>  
>> +	enc = &t_enc->encoder;
>>  	enc->possible_crtcs = possible_crtcs;
>>  
>> -	ret = drm_encoder_init(&tidss->ddev, enc, &encoder_funcs,
>> -			       encoder_type, NULL);
>> -	if (ret < 0) {
>> -		kfree(enc);
>> -		return ERR_PTR(ret);
>> +	/* Attaching first bridge to the encoder */
>> +	ret = drm_bridge_attach(enc, &t_enc->bridge, NULL,
>> +				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
>> +	if (ret) {
>> +		dev_err(tidss->dev, "bridge attach failed: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	/* Initializing the connector at the end of bridge-chain */
>> +	connector = drm_bridge_connector_init(&tidss->ddev, enc);
>> +	if (IS_ERR(connector)) {
>> +		dev_err(tidss->dev, "bridge_connector create failed\n");
>> +		return PTR_ERR(connector);
>> +	}
>> +
>> +	ret = drm_connector_attach_encoder(connector, enc);
>> +	if (ret) {
>> +		dev_err(tidss->dev, "attaching encoder to connector failed\n");
>> +		return ret;
>>  	}
>>  
>> -	drm_encoder_helper_add(enc, &encoder_helper_funcs);
>> +	t_enc->connector = connector;
>>  
>>  	dev_dbg(tidss->dev, "Encoder create done\n");
>>  
>> -	return enc;
>> +	return ret;
>>  }
>> diff --git a/drivers/gpu/drm/tidss/tidss_encoder.h b/drivers/gpu/drm/tidss/tidss_encoder.h
>> index ace877c0e0fd..3e561d6b1e83 100644
>> --- a/drivers/gpu/drm/tidss/tidss_encoder.h
>> +++ b/drivers/gpu/drm/tidss/tidss_encoder.h
>> @@ -11,7 +11,8 @@
>>  
>>  struct tidss_device;
>>  
>> -struct drm_encoder *tidss_encoder_create(struct tidss_device *tidss,
>> -					 u32 encoder_type, u32 possible_crtcs);
>> +int tidss_encoder_create(struct tidss_device *tidss,
>> +			 struct drm_bridge *next_bridge,
>> +			 u32 encoder_type, u32 possible_crtcs);
>>  
>>  #endif
>> diff --git a/drivers/gpu/drm/tidss/tidss_kms.c b/drivers/gpu/drm/tidss/tidss_kms.c
>> index ad2fa3c3d4a7..c979ad1af236 100644
>> --- a/drivers/gpu/drm/tidss/tidss_kms.c
>> +++ b/drivers/gpu/drm/tidss/tidss_kms.c
>> @@ -193,7 +193,6 @@ static int tidss_dispc_modeset_init(struct tidss_device *tidss)
>>  	for (i = 0; i < num_pipes; ++i) {
>>  		struct tidss_plane *tplane;
>>  		struct tidss_crtc *tcrtc;
>> -		struct drm_encoder *enc;
>>  		u32 hw_plane_id = feat->vid_order[tidss->num_planes];
>>  		int ret;
>>  
>> @@ -216,16 +215,13 @@ static int tidss_dispc_modeset_init(struct tidss_device *tidss)
>>  
>>  		tidss->crtcs[tidss->num_crtcs++] = &tcrtc->crtc;
>>  
>> -		enc = tidss_encoder_create(tidss, pipes[i].enc_type,
>> +		ret = tidss_encoder_create(tidss, pipes[i].bridge,
>> +					   pipes[i].enc_type,
>>  					   1 << tcrtc->crtc.index);
>> -		if (IS_ERR(enc)) {
>> +		if (ret) {
>>  			dev_err(tidss->dev, "encoder create failed\n");
>> -			return PTR_ERR(enc);
>> -		}
>> -
>> -		ret = drm_bridge_attach(enc, pipes[i].bridge, NULL, 0);
>> -		if (ret)
>>  			return ret;
>> +		}
>>  	}
>>  
>>  	/* create overlay planes of the leftover planes */
> 
> This breaks the IOT2050 devices over 6.6, just bisected to it:
> 
> [    3.435153] [drm] Initialized tidss 1.0.0 20180215 for 4a00000.dss on minor 0
> [    3.491246] tidss 4a00000.dss: [drm] Cannot find any crtc or sizes
> 
> vs.
> 
> [    3.436116] [drm] Initialized tidss 1.0.0 20180215 for 4a00000.dss on minor 0
> [    3.910574] Console: switching to colour frame buffer device 80x30
> [    3.937614] tidss 4a00000.dss: [drm] fb0: tidssdrmfb frame buffer device
> 
> Do we need to adjust its device tree to anything, or what may be the 
> reason?
> 

Hey Jan,

This patch series added support for the DRM_BRIDGE_ATTACH_NO_CONNECTOR
flag, for tidss, and for a few of the bridges.

Upon a quick look at the devicetree files, I see that the IOT-2050
platform is using Toshiba's TC358767 DPI to DP bridge, and it appears
that the TC358767 driver does not support the get_input_bus_fmt hook.

I have sent a patch for it[0].

Since I do not have hardware with me, I would appreciate it if you could
test and review it. The patch has only been build tested.


Regards
Aradhya


[0]: Patch Link:
https://lore.kernel.org/all/20231030192846.27934-1-a-bhatia1@ti.com/
  

Patch

diff --git a/drivers/gpu/drm/tidss/tidss_encoder.c b/drivers/gpu/drm/tidss/tidss_encoder.c
index 0d4865e9c03d..17a86bed8054 100644
--- a/drivers/gpu/drm/tidss/tidss_encoder.c
+++ b/drivers/gpu/drm/tidss/tidss_encoder.c
@@ -6,91 +6,125 @@ 
 
 #include <linux/export.h>
 
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_bridge_connector.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_modeset_helper_vtables.h>
 #include <drm/drm_panel.h>
 #include <drm/drm_of.h>
+#include <drm/drm_simple_kms_helper.h>
 
 #include "tidss_crtc.h"
 #include "tidss_drv.h"
 #include "tidss_encoder.h"
 
-static int tidss_encoder_atomic_check(struct drm_encoder *encoder,
-				      struct drm_crtc_state *crtc_state,
-				      struct drm_connector_state *conn_state)
+struct tidss_encoder {
+	struct drm_bridge bridge;
+	struct drm_encoder encoder;
+	struct drm_connector *connector;
+	struct drm_bridge *next_bridge;
+	struct tidss_device *tidss;
+};
+
+static inline struct tidss_encoder
+*bridge_to_tidss_encoder(struct drm_bridge *b)
+{
+	return container_of(b, struct tidss_encoder, bridge);
+}
+
+static int tidss_bridge_attach(struct drm_bridge *bridge,
+			       enum drm_bridge_attach_flags flags)
+{
+	struct tidss_encoder *t_enc = bridge_to_tidss_encoder(bridge);
+
+	return drm_bridge_attach(bridge->encoder, t_enc->next_bridge,
+				 bridge, flags);
+}
+
+static int tidss_bridge_atomic_check(struct drm_bridge *bridge,
+				     struct drm_bridge_state *bridge_state,
+				     struct drm_crtc_state *crtc_state,
+				     struct drm_connector_state *conn_state)
 {
-	struct drm_device *ddev = encoder->dev;
+	struct tidss_encoder *t_enc = bridge_to_tidss_encoder(bridge);
+	struct tidss_device *tidss = t_enc->tidss;
 	struct tidss_crtc_state *tcrtc_state = to_tidss_crtc_state(crtc_state);
 	struct drm_display_info *di = &conn_state->connector->display_info;
-	struct drm_bridge *bridge;
-	bool bus_flags_set = false;
-
-	dev_dbg(ddev->dev, "%s\n", __func__);
-
-	/*
-	 * Take the bus_flags from the first bridge that defines
-	 * bridge timings, or from the connector's display_info if no
-	 * bridge defines the timings.
-	 */
-	drm_for_each_bridge_in_chain(encoder, bridge) {
-		if (!bridge->timings)
-			continue;
-
-		tcrtc_state->bus_flags = bridge->timings->input_bus_flags;
-		bus_flags_set = true;
-		break;
-	}
+	struct drm_bridge_state *next_bridge_state = NULL;
+
+	if (t_enc->next_bridge)
+		next_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
+								    t_enc->next_bridge);
 
-	if (!di->bus_formats || di->num_bus_formats == 0)  {
-		dev_err(ddev->dev, "%s: No bus_formats in connected display\n",
+	if (next_bridge_state) {
+		tcrtc_state->bus_flags = next_bridge_state->input_bus_cfg.flags;
+		tcrtc_state->bus_format = next_bridge_state->input_bus_cfg.format;
+	} else if (di->num_bus_formats) {
+		tcrtc_state->bus_format = di->bus_formats[0];
+		tcrtc_state->bus_flags = di->bus_flags;
+	} else {
+		dev_err(tidss->dev, "%s: No bus_formats in connected display\n",
 			__func__);
 		return -EINVAL;
 	}
 
-	// XXX any cleaner way to set bus format and flags?
-	tcrtc_state->bus_format = di->bus_formats[0];
-	if (!bus_flags_set)
-		tcrtc_state->bus_flags = di->bus_flags;
-
 	return 0;
 }
 
-static void tidss_encoder_destroy(struct drm_encoder *encoder)
-{
-	drm_encoder_cleanup(encoder);
-	kfree(encoder);
-}
-
-static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
-	.atomic_check = tidss_encoder_atomic_check,
-};
-
-static const struct drm_encoder_funcs encoder_funcs = {
-	.destroy = tidss_encoder_destroy,
+static const struct drm_bridge_funcs tidss_bridge_funcs = {
+	.attach				= tidss_bridge_attach,
+	.atomic_check			= tidss_bridge_atomic_check,
+	.atomic_reset			= drm_atomic_helper_bridge_reset,
+	.atomic_duplicate_state		= drm_atomic_helper_bridge_duplicate_state,
+	.atomic_destroy_state		= drm_atomic_helper_bridge_destroy_state,
 };
 
-struct drm_encoder *tidss_encoder_create(struct tidss_device *tidss,
-					 u32 encoder_type, u32 possible_crtcs)
+int tidss_encoder_create(struct tidss_device *tidss,
+			 struct drm_bridge *next_bridge,
+			 u32 encoder_type, u32 possible_crtcs)
 {
+	struct tidss_encoder *t_enc;
 	struct drm_encoder *enc;
+	struct drm_connector *connector;
 	int ret;
 
-	enc = kzalloc(sizeof(*enc), GFP_KERNEL);
-	if (!enc)
-		return ERR_PTR(-ENOMEM);
+	t_enc = drmm_simple_encoder_alloc(&tidss->ddev, struct tidss_encoder,
+					  encoder, encoder_type);
+	if (IS_ERR(t_enc))
+		return PTR_ERR(t_enc);
+
+	t_enc->tidss = tidss;
+	t_enc->next_bridge = next_bridge;
+	t_enc->bridge.funcs = &tidss_bridge_funcs;
 
+	enc = &t_enc->encoder;
 	enc->possible_crtcs = possible_crtcs;
 
-	ret = drm_encoder_init(&tidss->ddev, enc, &encoder_funcs,
-			       encoder_type, NULL);
-	if (ret < 0) {
-		kfree(enc);
-		return ERR_PTR(ret);
+	/* Attaching first bridge to the encoder */
+	ret = drm_bridge_attach(enc, &t_enc->bridge, NULL,
+				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+	if (ret) {
+		dev_err(tidss->dev, "bridge attach failed: %d\n", ret);
+		return ret;
+	}
+
+	/* Initializing the connector at the end of bridge-chain */
+	connector = drm_bridge_connector_init(&tidss->ddev, enc);
+	if (IS_ERR(connector)) {
+		dev_err(tidss->dev, "bridge_connector create failed\n");
+		return PTR_ERR(connector);
+	}
+
+	ret = drm_connector_attach_encoder(connector, enc);
+	if (ret) {
+		dev_err(tidss->dev, "attaching encoder to connector failed\n");
+		return ret;
 	}
 
-	drm_encoder_helper_add(enc, &encoder_helper_funcs);
+	t_enc->connector = connector;
 
 	dev_dbg(tidss->dev, "Encoder create done\n");
 
-	return enc;
+	return ret;
 }
diff --git a/drivers/gpu/drm/tidss/tidss_encoder.h b/drivers/gpu/drm/tidss/tidss_encoder.h
index ace877c0e0fd..3e561d6b1e83 100644
--- a/drivers/gpu/drm/tidss/tidss_encoder.h
+++ b/drivers/gpu/drm/tidss/tidss_encoder.h
@@ -11,7 +11,8 @@ 
 
 struct tidss_device;
 
-struct drm_encoder *tidss_encoder_create(struct tidss_device *tidss,
-					 u32 encoder_type, u32 possible_crtcs);
+int tidss_encoder_create(struct tidss_device *tidss,
+			 struct drm_bridge *next_bridge,
+			 u32 encoder_type, u32 possible_crtcs);
 
 #endif
diff --git a/drivers/gpu/drm/tidss/tidss_kms.c b/drivers/gpu/drm/tidss/tidss_kms.c
index ad2fa3c3d4a7..c979ad1af236 100644
--- a/drivers/gpu/drm/tidss/tidss_kms.c
+++ b/drivers/gpu/drm/tidss/tidss_kms.c
@@ -193,7 +193,6 @@  static int tidss_dispc_modeset_init(struct tidss_device *tidss)
 	for (i = 0; i < num_pipes; ++i) {
 		struct tidss_plane *tplane;
 		struct tidss_crtc *tcrtc;
-		struct drm_encoder *enc;
 		u32 hw_plane_id = feat->vid_order[tidss->num_planes];
 		int ret;
 
@@ -216,16 +215,13 @@  static int tidss_dispc_modeset_init(struct tidss_device *tidss)
 
 		tidss->crtcs[tidss->num_crtcs++] = &tcrtc->crtc;
 
-		enc = tidss_encoder_create(tidss, pipes[i].enc_type,
+		ret = tidss_encoder_create(tidss, pipes[i].bridge,
+					   pipes[i].enc_type,
 					   1 << tcrtc->crtc.index);
-		if (IS_ERR(enc)) {
+		if (ret) {
 			dev_err(tidss->dev, "encoder create failed\n");
-			return PTR_ERR(enc);
-		}
-
-		ret = drm_bridge_attach(enc, pipes[i].bridge, NULL, 0);
-		if (ret)
 			return ret;
+		}
 	}
 
 	/* create overlay planes of the leftover planes */