[PATCH v7 10/15] drm/imx: dc-ed: Support getting source selection

[Liu Ying]

Add a helper to get ExtDst source selection.  This is needed by
disabling CRTC at boot in an upcoming commit which tries to get
the source selection.

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
Acked-by: Maxime Ripard <mripard@xxxxxxxxxx>
Signed-off-by: Liu Ying <victor.liu@xxxxxxx>
--
v7:
- Collect Maxime's A-b tag.
- Check regmap_read()'s return valure.  (Sashiko AI bot)

v2:
- Collect Frank's R-b tag.
---
 drivers/gpu/drm/imx/dc/dc-ed.c | 29 +++++++++++++++++++++++++++++
 drivers/gpu/drm/imx/dc/dc-pe.h |  1 +
 2 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/imx/dc/dc-ed.c b/drivers/gpu/drm/imx/dc/dc-ed.c
index de1b71315eab..67163dca1363 100644
--- a/drivers/gpu/drm/imx/dc/dc-ed.c
+++ b/drivers/gpu/drm/imx/dc/dc-ed.c
@@ -149,6 +149,35 @@ void dc_ed_pec_src_sel(struct dc_ed *ed, enum dc_link_id src)
 	}
 }
 
+int dc_ed_pec_src_sel_get(struct dc_ed *ed, enum dc_link_id *src)
+{
+	u32 val;
+	int ret;
+
+	ret = regmap_read(ed->reg_pec, PIXENGCFG_DYNAMIC, &val);
+	if (ret)
+		return -EINVAL;
+
+	switch (val) {
+	case LINK_ID_NONE:
+	case LINK_ID_CONSTFRAME0:
+	case LINK_ID_CONSTFRAME4:
+	case LINK_ID_CONSTFRAME1:
+	case LINK_ID_CONSTFRAME5:
+	case LINK_ID_FETCHWARP2:
+	case LINK_ID_FETCHLAYER0:
+	case LINK_ID_LAYERBLEND0:
+	case LINK_ID_LAYERBLEND1:
+	case LINK_ID_LAYERBLEND2:
+	case LINK_ID_LAYERBLEND3:
+		*src = val;
+		dev_dbg(ed->dev, "get source selection: 0x%02x\n", val);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
 void dc_ed_pec_sync_trigger(struct dc_ed *ed)
 {
 	regmap_write(ed->reg_pec, PIXENGCFG_TRIGGER, SYNC_TRIGGER);
diff --git a/drivers/gpu/drm/imx/dc/dc-pe.h b/drivers/gpu/drm/imx/dc/dc-pe.h
index f5e01a6eb9e9..0b81dc6b251c 100644
--- a/drivers/gpu/drm/imx/dc/dc-pe.h
+++ b/drivers/gpu/drm/imx/dc/dc-pe.h
@@ -85,6 +85,7 @@ void dc_cf_init(struct dc_cf *cf);
 
 /* External Destination Unit */
 void dc_ed_pec_src_sel(struct dc_ed *ed, enum dc_link_id src);
+int dc_ed_pec_src_sel_get(struct dc_ed *ed, enum dc_link_id *src);
 void dc_ed_pec_sync_trigger(struct dc_ed *ed);
 void dc_ed_init(struct dc_ed *ed);
 

-- 
2.43.0