Re: [PATCH 2/2] drm/msm/dpu: add display port support in DPU

From: Jordan Crouse <jcrouse@codeaurora.org>
To: Jeykumar Sankaran <jsanka@codeaurora.org>
Cc: seanpaul@chromium.org, linux-arm-msm@vger.kernel.org,
	hoegsberg@google.com, freedreno@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 2/2] drm/msm/dpu: add display port support in DPU
Date: Fri, 16 Nov 2018 13:33:30 -0700	[thread overview]
Message-ID: <20181116203330.GD6285@jcrouse-lnx.qualcomm.com> (raw)
In-Reply-To: <1542396142-19534-2-git-send-email-jsanka@codeaurora.org>

On Fri, Nov 16, 2018 at 11:22:22AM -0800, Jeykumar Sankaran wrote:
> Add display port support in DPU by creating hooks
> for DP encoder enumeration and encoder mode
> initialization.
> 
> This change is based on the SDM845 Display port
> driver changes[1].
> 
> [1] https://lwn.net/Articles/768265/
> 
> Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c |  3 ++
>  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c     | 49 +++++++++++++++++++++++++----
>  2 files changed, 46 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index b253165..e9c7edc6 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -2048,6 +2048,9 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc,
>  	case DRM_MODE_ENCODER_DSI:
>  		intf_type = INTF_DSI;
>  		break;
> +	case DRM_MODE_ENCODER_TMDS:
> +		intf_type = INTF_DP;
> +		break;
>  	default:
>  		DPU_ERROR_ENC(dpu_enc, "unsupported display interface type\n");
>  		return -EINVAL;
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> index 985c855..b823a37 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> @@ -473,6 +473,31 @@ static void _dpu_kms_initialize_dsi(struct drm_device *dev,
>  	}
>  }
>  
> +static void _dpu_kms_initialize_displayport(struct drm_device *dev,
> +					    struct msm_drm_private *priv,
> +					    struct dpu_kms *dpu_kms)
> +{
> +	struct drm_encoder *encoder = NULL;
> +	int rc;
> +
> +	if (!priv->dp)
> +		return;
> +
> +	encoder = dpu_encoder_init(dev, DRM_MODE_ENCODER_TMDS);
> +	if (IS_ERR_OR_NULL(encoder)) {

dpu_encoder_init() only returns valid pointer or ERR_PTR() so a Only IS_ERR() is
needed.

> +		DPU_ERROR("encoder init failed for dsi display\n");
> +		return;
> +	}
> +
> +	priv->encoders[priv->num_encoders++] = encoder;
> +
> +	rc = msm_dp_modeset_init(priv->dp, dev, encoder);
> +	if (rc) {
> +		DPU_ERROR("modeset_init failed for DP, rc = %d\n", rc);
> +		dpu_encoder_uninit(encoder);
> +	}
> +}
> +
>  /**
>   * _dpu_kms_setup_displays - create encoders, bridges and connectors
>   *                           for underlying displays
> @@ -487,6 +512,8 @@ static void _dpu_kms_setup_displays(struct drm_device *dev,
>  {
>  	_dpu_kms_initialize_dsi(dev, priv, dpu_kms);
>  
> +	_dpu_kms_initialize_displayport(dev, priv, dpu_kms);
> +
>  	/**
>  	 * Extend this function to initialize other
>  	 * types of displays
> @@ -723,13 +750,23 @@ static void _dpu_kms_set_encoder_mode(struct msm_kms *kms,
>  	info.capabilities = cmd_mode ? MSM_DISPLAY_CAP_CMD_MODE :
>  			MSM_DISPLAY_CAP_VID_MODE;
>  
> -	/* TODO: No support for DSI swap */
> -	for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
> -		if (priv->dsi[i]) {
> -			info.h_tile_instance[info.num_of_h_tiles] = i;
> -			info.num_of_h_tiles++;
> +	switch (info.intf_type) {
> +	case DRM_MODE_ENCODER_DSI:
> +		/* TODO: No support for DSI swap */
> +		for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
> +			if (priv->dsi[i]) {
> +				info.h_tile_instance[info.num_of_h_tiles] = i;
> +				info.num_of_h_tiles++;
> +			}
>  		}
> -	}
> +		break;
> +	case DRM_MODE_ENCODER_TMDS:
> +		info.num_of_h_tiles = 1;
> +		break;
> +	default:
> +		DPU_ERROR("Invalid connector type\n");
> +		return;
> +	};

This is still going to be one of two options, a simple if/else can suffice here
and you don't need a log message and a default path.
>  
>  	rc = dpu_encoder_setup(encoder->dev, encoder, &info);
>  	if (rc)

Jordan
-- 
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
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