linux-kernel - Re: [PATCH v6 4/8] drm/bridge: mhdp8546: Set input_bus_flags from atomic

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Message-ID: <1b95b75d-1b81-806b-7b7f-34cd93c9d0ec@ti.com>
Date:   Wed, 17 May 2023 11:18:52 +0530
From:   Aradhya Bhatia <a-bhatia1@...com>
To:     <neil.armstrong@...aro.org>, Tomi Valkeinen <tomba@...nel.org>,
        Jyri Sarha <jyri.sarha@....fi>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Robert Foss <rfoss@...nel.org>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Rahul T R <r-ravikumar@...com>,
        Swapnil Jakhade <sjakhade@...ence.com>,
        Boris Brezillon <boris.brezillon@...labora.com>,
        Francesco Dolcini <francesco@...cini.it>
CC:     DRI Development List <dri-devel@...ts.freedesktop.org>,
        Linux Kernel List <linux-kernel@...r.kernel.org>,
        Nishanth Menon <nm@...com>,
        Vignesh Raghavendra <vigneshr@...com>,
        Devarsh Thakkar <devarsht@...com>,
        Jayesh Choudhary <j-choudhary@...com>
Subject: Re: [PATCH v6 4/8] drm/bridge: mhdp8546: Set input_bus_flags from
 atomic_check

Hi Neil,

On 16-May-23 12:54, Neil Armstrong wrote:
> On 09/05/2023 11:30, Aradhya Bhatia wrote:
>> From: Nikhil Devshatwar <nikhil.nd@...com>
>>
>> input_bus_flags are specified in drm_bridge_timings (legacy) as well
>> as drm_bridge_state->input_bus_cfg.flags
>>
>> The flags from the timings will be deprecated. Bridges are supposed
>> to validate and set the bridge state flags from atomic_check.
>>
>> Signed-off-by: Nikhil Devshatwar <nikhil.nd@...com>
>> [a-bhatia1: replace timings in cdns_mhdp_platform_info by
>> input_bus_flags]
>> Signed-off-by: Aradhya Bhatia <a-bhatia1@...com>
>> ---
>>
>> Notes:
>>
>>      changes from v5:
>>      * removed the wrongly addded return statement in tfp410 driver.
>>      * replaced the timings field in cdns_mhdp_platform_info by
>>        input_bus_flags field, in order to get rid of bridge->timings
>>        altogether.
>>
>>   drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c  | 11 ++++++++---
>>   drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h  |  2 +-
>>   drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.c |  9 ++++-----
>>   drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.h |  2 +-
>>   4 files changed, 14 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> index 623e4235c94f..a677b1267525 100644
>> --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> @@ -2189,6 +2189,13 @@ static int cdns_mhdp_atomic_check(struct
>> drm_bridge *bridge,
>>           return -EINVAL;
>>       }
>>   +    /*
>> +     * There might be flags negotiation supported in future.
>> +     * Set the bus flags in atomic_check statically for now.
>> +     */
>> +    if (mhdp->info)
>> +        bridge_state->input_bus_cfg.flags =
>> *mhdp->info->input_bus_flags;
>> +
>>       mutex_unlock(&mhdp->link_mutex);
>>       return 0;
>>   }
>> @@ -2554,8 +2561,6 @@ static int cdns_mhdp_probe(struct
>> platform_device *pdev)
>>       mhdp->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID |
>>                  DRM_BRIDGE_OP_HPD;
>>       mhdp->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
>> -    if (mhdp->info)
>> -        mhdp->bridge.timings = mhdp->info->timings;
> 
> Won't this cause a breakage because at this point in time
> bridge.timings->input_bus_flags
> seems to be still used by tidss right ?
> 

tidss was using the bridge.timings->input_bus_flags before the 7th
patch[1] in this series.

After the patch, it only relies on bridge_state and display_info for bus
flags and formats.


Regards
Aradhya

[1]: https://lore.kernel.org/all/20230509093036.3303-8-a-bhatia1@ti.com/


> 
>>         ret = phy_init(mhdp->phy);
>>       if (ret) {
>> @@ -2642,7 +2647,7 @@ static const struct of_device_id mhdp_ids[] = {
>>   #ifdef CONFIG_DRM_CDNS_MHDP8546_J721E
>>       { .compatible = "ti,j721e-mhdp8546",
>>         .data = &(const struct cdns_mhdp_platform_info) {
>> -          .timings = &mhdp_ti_j721e_bridge_timings,
>> +          .input_bus_flags = &mhdp_ti_j721e_bridge_input_bus_flags,
>>             .ops = &mhdp_ti_j721e_ops,
>>         },
>>       },
>> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
>> b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
>> index bedddd510d17..bad2fc0c7306 100644
>> --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
>> +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
>> @@ -336,7 +336,7 @@ struct cdns_mhdp_bridge_state {
>>   };
>>     struct cdns_mhdp_platform_info {
>> -    const struct drm_bridge_timings *timings;
>> +    const u32 *input_bus_flags;
>>       const struct mhdp_platform_ops *ops;
>>   };
>>   diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.c
>> b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.c
>> index dfe1b59514f7..12d04be4e242 100644
>> --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.c
>> +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.c
>> @@ -71,8 +71,7 @@ const struct mhdp_platform_ops mhdp_ti_j721e_ops = {
>>       .disable = cdns_mhdp_j721e_disable,
>>   };
>>   -const struct drm_bridge_timings mhdp_ti_j721e_bridge_timings = {
>> -    .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE |
>> -               DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE |
>> -               DRM_BUS_FLAG_DE_HIGH,
>> -};
>> +const u32
>> +mhdp_ti_j721e_bridge_input_bus_flags =
>> DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE |
>> +                       DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE |
>> +                       DRM_BUS_FLAG_DE_HIGH;
>> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.h
>> b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.h
>> index 97d20d115a24..5ddca07a4255 100644
>> --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.h
>> +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-j721e.h
>> @@ -14,6 +14,6 @@
>>   struct mhdp_platform_ops;
>>     extern const struct mhdp_platform_ops mhdp_ti_j721e_ops;
>> -extern const struct drm_bridge_timings mhdp_ti_j721e_bridge_timings;
>> +extern const u32 mhdp_ti_j721e_bridge_input_bus_flags;
>>     #endif /* !CDNS_MHDP8546_J721E_H */
>