[PATCH v3 2/3] Subject: [PATCH] drm/mediatek/dp: Add HDCP2.x feature for DisplayPort

[CK Hu (胡俊光)]

Hi, Mac:

On Sat, 2024-06-08 at 20:01 +0800, mac.shen wrote:
> Changes in v3:
> - refine the function to get system time
> - refine the flow to do HDCP with content type and
>   protection value which set by user space
> - refine the flow to update content protection
> - refine the flow to do HDCP2.x authentication
> per suggestion from the previous thread:
> https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek__;!!CTRNKA9wMg0ARbw!md6xUiYN88D2YmETs8FQgaExM2zH8S1SmAEU9GRchwpNsXOyDFul3ziVKhRpCJaj8Rcn-gvM-801runjwA$ 
> /patch/20240205055055.25340-3-mac.shen at mediatek.com/
> 
> Signed-off-by: mac.shen <mac.shen at mediatek.com>
> ---

[snip]

> +
> +static int dp_tx_hdcp2x_write_ake_no_stored_km(struct mtk_hdcp_info *hdcp_info)
> +{
> +	struct mtk_dp *mtk_dp = container_of(hdcp_info, struct mtk_dp, hdcp_info);
> +	ssize_t ret;
> +
> +	dev_dbg(mtk_dp->dev, "[HDCP2.X] HDCP_2_2_AKE_NO_STORED_KM\n");
> +
> +	ret = drm_dp_dpcd_write(&mtk_dp->aux, DP_HDCP_2_2_AKE_NO_STORED_KM_OFFSET,
> +				hdcp_info->hdcp2_info.hdcp_tx.no_stored_km.e_kpub_km,
> +		HDCP_2_2_E_KPUB_KM_LEN);
> +	if (ret < 0)

Directly return ret here.

> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int dp_tx_hdcp2x_write_ake_stored_km(struct mtk_hdcp_info *hdcp_info)
> +{
> +	struct mtk_dp *mtk_dp = container_of(hdcp_info, struct mtk_dp, hdcp_info);
> +	ssize_t ret;
> +
> +	dev_dbg(mtk_dp->dev, "[HDCP2.X] HDCP_2_2_AKE_STORED_KM\n");
> +
> +	ret = drm_dp_dpcd_write(&mtk_dp->aux, DP_HDCP_2_2_AKE_STORED_KM_OFFSET,
> +				hdcp_info->hdcp2_info.ake_stored_km.e_kh_km_m,
> +		HDCP_2_2_E_KH_KM_LEN);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = drm_dp_dpcd_write(&mtk_dp->aux, DP_HDCP_2_2_REG_M_OFFSET,
> +				hdcp_info->hdcp2_info.ake_stored_km.e_kh_km_m +
> +		HDCP_2_2_E_KH_KM_LEN,
> +		HDCP_2_2_E_KH_KM_M_LEN - HDCP_2_2_E_KH_KM_LEN);
> +	if (ret < 0)

Ditto.

Regards,
CK

> +		return ret;
> +
> +	return 0;
> +}
> +