[PATCH] drm: rcar-du: Use drmm_encoder_alloc() to manage encoder

[Kieran Bingham]

Hi Laurent,

On 13/01/2021 22:45, Laurent Pinchart wrote:
> Hi Kieran,
> 
> Thank you for the patch.
> 
> On Wed, Jan 13, 2021 at 05:02:53PM +0000, Kieran Bingham wrote:
>> The encoder allocation was converted to a DRM managed resource at the
>> same time as the addition of a new helper drmm_encoder_alloc() which
>> simplifies the same process.
>>
>> Convert the custom drm managed resource allocation of the encoder
>> with the helper to simplify the implementation, and prevent hitting a
>> WARN_ON() due to the handling the drm_encoder_init() call directly
>> without registering a .destroy() function op.
>>
>> Fixes: f5f16725edbc ("drm: rcar-du: Use DRM-managed allocation for encoders")
> 
> We could equally point to the patch that has added drmm_encoder_alloc(),
> but I'm fine taking the blame :-)

Perhaps, we could point there indeed, I'm surprised that patch/series
didn't seem to add any users of drmm_encoder_alloc() as far as I can see.

I don't think this is a "blame" though. Just a reference to the most
relevant change.

> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> 

Thanks.

Kieran


>> Reported-by: Geert Uytterhoeven <geert+renesas at glider.be>
>> Signed-off-by: Kieran Bingham <kieran.bingham+renesas at ideasonboard.com>
>> ---
>>  drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 31 +++++------------------
>>  1 file changed, 6 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
>> index ba8c6038cd63..ca3761772211 100644
>> --- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
>> +++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
>> @@ -48,21 +48,12 @@ static unsigned int rcar_du_encoder_count_ports(struct device_node *node)
>>  static const struct drm_encoder_funcs rcar_du_encoder_funcs = {
>>  };
>>  
>> -static void rcar_du_encoder_release(struct drm_device *dev, void *res)
>> -{
>> -	struct rcar_du_encoder *renc = res;
>> -
>> -	drm_encoder_cleanup(&renc->base);
>> -	kfree(renc);
>> -}
>> -
>>  int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>>  			 enum rcar_du_output output,
>>  			 struct device_node *enc_node)
>>  {
>>  	struct rcar_du_encoder *renc;
>>  	struct drm_bridge *bridge;
>> -	int ret;
>>  
>>  	/*
>>  	 * Locate the DRM bridge from the DT node. For the DPAD outputs, if the
>> @@ -101,26 +92,16 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>>  			return -ENOLINK;
>>  	}
>>  
>> -	renc = kzalloc(sizeof(*renc), GFP_KERNEL);
>> -	if (renc == NULL)
>> -		return -ENOMEM;
>> -
>> -	renc->output = output;
>> -
>>  	dev_dbg(rcdu->dev, "initializing encoder %pOF for output %u\n",
>>  		enc_node, output);
>>  
>> -	ret = drm_encoder_init(&rcdu->ddev, &renc->base, &rcar_du_encoder_funcs,
>> -			       DRM_MODE_ENCODER_NONE, NULL);
>> -	if (ret < 0) {
>> -		kfree(renc);
>> -		return ret;
>> -	}
>> +	renc = drmm_encoder_alloc(&rcdu->ddev, struct rcar_du_encoder, base,
>> +				  &rcar_du_encoder_funcs, DRM_MODE_ENCODER_NONE,
>> +				  NULL);
>> +	if (!renc)
>> +		return -ENOMEM;
>>  
>> -	ret = drmm_add_action_or_reset(&rcdu->ddev, rcar_du_encoder_release,
>> -				       renc);
>> -	if (ret)
>> -		return ret;
>> +	renc->output = output;
>>  
>>  	/*
>>  	 * Attach the bridge to the encoder. The bridge will create the
>