drm/sun4i: Add support for H6 DW HDMI controller

H6 has DW HDMI 2.0b controller v2.12a.

It supports 4K at 60 Hz and HDCP 2.2.
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181104182705.18047-20-jernej.skrabec@siol.net

drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c

@@ -44,6 +44,17 @@ sun8i_dw_hdmi_mode_valid_a83t(struct drm_connector *connector,
 	return MODE_OK;
 }
 
+static enum drm_mode_status
+sun8i_dw_hdmi_mode_valid_h6(struct drm_connector *connector,
+			    const struct drm_display_mode *mode)
+{
+	/* This is max for HDMI 2.0b (4K@60Hz) */
+	if (mode->clock > 594000)
+		return MODE_CLOCK_HIGH;
+
+	return MODE_OK;
+}
+
 static bool sun8i_dw_hdmi_node_is_tcon_top(struct device_node *node)
 {
 	return IS_ENABLED(CONFIG_DRM_SUN8I_TCON_TOP) &&
@@ -239,11 +250,19 @@ static const struct sun8i_dw_hdmi_quirks sun8i_a83t_quirks = {
 	.set_rate = true,
 };
 
+static const struct sun8i_dw_hdmi_quirks sun50i_h6_quirks = {
+	.mode_valid = sun8i_dw_hdmi_mode_valid_h6,
+};
+
 static const struct of_device_id sun8i_dw_hdmi_dt_ids[] = {
 	{
 		.compatible = "allwinner,sun8i-a83t-dw-hdmi",
 		.data = &sun8i_a83t_quirks,
 	},
+	{
+		.compatible = "allwinner,sun50i-h6-dw-hdmi",
+		.data = &sun50i_h6_quirks,
+	},
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, sun8i_dw_hdmi_dt_ids);