drm/mediatek: Introduce HDMI/DDC v2 for MT8195/MT8188

Add support for the newer HDMI-TX (Encoder) v2 and DDC v2 IPs
found in MediaTek's MT8195, MT8188 SoC and their variants, and
including support for display modes up to 4k60 and for HDMI
Audio, as per the HDMI 2.0 spec.

HDCP and CEC functionalities are also supported by this hardware,
but are not included in this commit and that also poses a slight
difference between the V2 and V1 controllers in how they handle
Hotplug Detection (HPD).

While the v1 controller was using the CEC controller to check
HDMI cable connection and disconnection, in this driver the v2
one does not.

This is due to the fact that on parts with v2 designs, like the
MT8195 SoC, there is one CEC controller shared between the HDMI
Transmitter (HDMI-TX) and Receiver (HDMI-RX): before eventually
adding support to use the CEC HW to wake up the HDMI controllers
it is necessary to have support for one TX, one RX *and* for both
at the same time.

Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20251023-mediatek-drm-hdmi-v2-v11-9-7873ec4a1edf@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

ddc_v2

ddc_v2

Author: AngeloGioacchino Del Regno

drivers/gpu/drm/mediatek/Kconfig

@@ -45,3 +45,15 @@ config DRM_MEDIATEK_HDMI
 	select DRM_MEDIATEK_HDMI_COMMON
 	help
 	  DRM/KMS HDMI driver for Mediatek SoCs
+
+config DRM_MEDIATEK_HDMI_V2
+	tristate "DRM HDMI v2 IP support for MediaTek SoCs"
+	depends on DRM_MEDIATEK
+	select DRM_MEDIATEK_HDMI_COMMON
+	help
+	  Say yes here to enable support for the HDMIv2 IP and related
+	  DDCv2 as found in the MediaTek MT8195, MT8188 SoCs and other
+	  variants.
+	  This driver can also be built as a module. If so, the HDMIv2
+	  module will be called "mtk_hdmi_v2", and the DDCv2 module
+	  will be called "mtk_hdmi_ddc_v2".

drivers/gpu/drm/mediatek/Makefile

@@ -25,5 +25,7 @@ obj-$(CONFIG_DRM_MEDIATEK_HDMI_COMMON) += mtk_hdmi_common.o
 obj-$(CONFIG_DRM_MEDIATEK_HDMI) += mtk_cec.o
 obj-$(CONFIG_DRM_MEDIATEK_HDMI) += mtk_hdmi.o
 obj-$(CONFIG_DRM_MEDIATEK_HDMI) += mtk_hdmi_ddc.o
+obj-$(CONFIG_DRM_MEDIATEK_HDMI_V2) += mtk_hdmi_v2.o
+obj-$(CONFIG_DRM_MEDIATEK_HDMI_V2) += mtk_hdmi_ddc_v2.o
 
 obj-$(CONFIG_DRM_MEDIATEK_DP) += mtk_dp.o

drivers/gpu/drm/mediatek/mtk_hdmi_common.c

@@ -302,6 +302,10 @@ static int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi, struct platform_device
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to get clocks\n");
 
+	hdmi->irq = platform_get_irq(pdev, 0);
+	if (!hdmi->irq)
+		return hdmi->irq;
+
 	hdmi->regs = device_node_to_regmap(dev->of_node);
 	if (IS_ERR(hdmi->regs))
 		return PTR_ERR(hdmi->regs);

drivers/gpu/drm/mediatek/mtk_hdmi_common.h

@@ -126,6 +126,12 @@ struct hdmi_audio_param {
 	struct hdmi_codec_params codec_params;
 };
 
+enum hdmi_hpd_state {
+	HDMI_PLUG_OUT = 0,
+	HDMI_PLUG_IN_AND_SINK_POWER_ON,
+	HDMI_PLUG_IN_ONLY,
+};
+
 struct mtk_hdmi_ver_conf {
 	const struct drm_bridge_funcs *bridge_funcs;
 	const struct hdmi_codec_ops *codec_ops;
@@ -139,6 +145,7 @@ struct mtk_hdmi_conf {
 	bool tz_disabled;
 	bool cea_modes_only;
 	unsigned long max_mode_clock;
+	u32 reg_hdmi_tx_cfg;
 };
 
 struct mtk_hdmi {
@@ -161,6 +168,8 @@ struct mtk_hdmi {
 	bool audio_enable;
 	bool powered;
 	bool enabled;
+	unsigned int irq;
+	enum hdmi_hpd_state hpd;
 	hdmi_codec_plugged_cb plugged_cb;
 	struct device *codec_dev;
 	struct mutex update_plugged_status_lock;