[PATCH v8 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 at nxp.com>
Acked-by: Maxime Ripard <mripard at kernel.org>
Reviewed-by: Alexander Stein <alexander.stein at ew.tq-group.com>
Signed-off-by: Liu Ying <victor.liu at nxp.com>
---
v8:
- Collect Alexander's R-b tag.
- Fix dc_ed_pec_src_sel_get()'s return value when regmap_read() fails.
  (Alexander)
- Iterate over src_sels[] to find the source selection.  (Sashiko AI bot)

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 | 21 +++++++++++++++++++++
 drivers/gpu/drm/imx/dc/dc-pe.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/imx/dc/dc-ed.c b/drivers/gpu/drm/imx/dc/dc-ed.c
index de1b71315eab..a4a21d0affb6 100644
--- a/drivers/gpu/drm/imx/dc/dc-ed.c
+++ b/drivers/gpu/drm/imx/dc/dc-ed.c
@@ -149,6 +149,27 @@ 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;
+	int i;
+
+	ret = regmap_read(ed->reg_pec, PIXENGCFG_DYNAMIC, &val);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < ARRAY_SIZE(src_sels); i++) {
+		if (src_sels[i] == val) {
+			dev_dbg(ed->dev, "get source selection: 0x%02x\n", val);
+			*src = val;
+			return 0;
+		}
+	}
+
+	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