[PATCH 1/4] drm/exynos: add display-mode-check operation to exynos_mixer_ops struct

[Rahul Sharma]

This patch adds the display mode check operation to exynos_mixer_ops
in drm-common-hdmi. In Exynos SoCs, mixer IP can put certain restrictions
on the proposed display modes. These restriction needs to be considered
during mode negotiation, which happens immediately after edid parsing.

Both, mixer check-mode and hdmi check-timing callbacks are called one after
another and ANDed result is returned back.

Signed-off-by: Rahul Sharma <rahul.sharma at samsung.com>
---
 drivers/gpu/drm/exynos/exynos_drm_hdmi.c | 12 ++++++++++++
 drivers/gpu/drm/exynos/exynos_drm_hdmi.h |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_hdmi.c b/drivers/gpu/drm/exynos/exynos_drm_hdmi.c
index 55793c4..3a8eea6 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_hdmi.c
@@ -125,9 +125,21 @@ static int drm_hdmi_get_edid(struct device *dev,
 static int drm_hdmi_check_timing(struct device *dev, void *timing)
 {
 	struct drm_hdmi_context *ctx = to_context(dev);
+	int ret = 0;
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
+	/*
+	* Both, mixer and hdmi should be able to handle the requested mode.
+	* If any of the two fails, return mode as BAD.
+	*/
+
+	if (mixer_ops && mixer_ops->check_mode)
+		ret = mixer_ops->check_mode(ctx->mixer_ctx->ctx, timing);
+
+	if (ret)
+		return ret;
+
 	if (hdmi_ops && hdmi_ops->check_timing)
 		return hdmi_ops->check_timing(ctx->hdmi_ctx->ctx, timing);
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_hdmi.h b/drivers/gpu/drm/exynos/exynos_drm_hdmi.h
index 784a7e9..ae4b6ae 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_hdmi.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_hdmi.h
@@ -58,6 +58,9 @@ struct exynos_mixer_ops {
 	void (*win_mode_set)(void *ctx, struct exynos_drm_overlay *overlay);
 	void (*win_commit)(void *ctx, int zpos);
 	void (*win_disable)(void *ctx, int zpos);
+
+	/* display */
+	int (*check_mode)(void *ctx, void *mode);
 };
 
 void exynos_hdmi_drv_attach(struct exynos_drm_hdmi_context *ctx);
-- 
1.8.0