[PATCH v9 12/16] drm/imx: dc-lb: Support getting secondary input selection

[Liu Ying]

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

Reviewed-by: Frank Li <Frank.Li at nxp.com>
Acked-by: Maxime Ripard <mripard at kernel.org>
Signed-off-by: Liu Ying <victor.liu at nxp.com>
---
v8:
- Fix dc_lb_pec_dynamic_sec_sel_get()'s return value when regmap_read() fails.
- Iterate over sec_sels[] to find the secondary input selection.

v7:
- Collect Maxime's A-b tag.
- Check regmap_read()'s return value.

v4:
- Rebase onto the latest drm-misc-next and resolve conflict.

v2:
- Collect Frank's R-b tag.
---
 drivers/gpu/drm/imx/dc/dc-lb.c | 25 +++++++++++++++++++++++++
 drivers/gpu/drm/imx/dc/dc-pe.h |  1 +
 2 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/imx/dc/dc-lb.c b/drivers/gpu/drm/imx/dc/dc-lb.c
index cb614f3c2f69..924a0de4b909 100644
--- a/drivers/gpu/drm/imx/dc/dc-lb.c
+++ b/drivers/gpu/drm/imx/dc/dc-lb.c
@@ -19,6 +19,8 @@
 #define  PIXENGCFG_DYNAMIC_SEC_SEL_MASK		GENMASK(13, 8)
 #define  PIXENGCFG_DYNAMIC_SEC_SEL(x)		\
 		FIELD_PREP(PIXENGCFG_DYNAMIC_SEC_SEL_MASK, (x))
+#define  PIXENGCFG_DYNAMIC_SEC_SEL_GET(x)	\
+		FIELD_GET(PIXENGCFG_DYNAMIC_SEC_SEL_MASK, (x))
 #define  PIXENGCFG_DYNAMIC_PRIM_SEL_MASK	GENMASK(5, 0)
 #define  PIXENGCFG_DYNAMIC_PRIM_SEL(x)		\
 		FIELD_PREP(PIXENGCFG_DYNAMIC_PRIM_SEL_MASK, (x))
@@ -181,6 +183,29 @@ void dc_lb_pec_dynamic_sec_sel(struct dc_lb *lb, enum dc_link_id sec)
 	dev_warn(lb->dev, "invalid secondary input selection:%d\n", sec);
 }
 
+int dc_lb_pec_dynamic_sec_sel_get(struct dc_lb *lb, enum dc_link_id *sec)
+{
+	u32 val;
+	int ret;
+	int i;
+
+	ret = regmap_read(lb->reg_pec, PIXENGCFG_DYNAMIC, &val);
+	if (ret)
+		return ret;
+
+	val = PIXENGCFG_DYNAMIC_SEC_SEL_GET(val);
+
+	for (i = 0; i < ARRAY_SIZE(sec_sels); i++) {
+		if (sec_sels[i] == val) {
+			dev_dbg(lb->dev, "get secondary input selection: 0x%02x\n", val);
+			*sec = val;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
 void dc_lb_pec_clken(struct dc_lb *lb, enum dc_pec_clken clken)
 {
 	regmap_write_bits(lb->reg_pec, PIXENGCFG_DYNAMIC, CLKEN_MASK,
diff --git a/drivers/gpu/drm/imx/dc/dc-pe.h b/drivers/gpu/drm/imx/dc/dc-pe.h
index 0b81dc6b251c..4e38aead69bc 100644
--- a/drivers/gpu/drm/imx/dc/dc-pe.h
+++ b/drivers/gpu/drm/imx/dc/dc-pe.h
@@ -93,6 +93,7 @@ void dc_ed_init(struct dc_ed *ed);
 enum dc_link_id dc_lb_get_link_id(struct dc_lb *lb);
 void dc_lb_pec_dynamic_prim_sel(struct dc_lb *lb, enum dc_link_id prim);
 void dc_lb_pec_dynamic_sec_sel(struct dc_lb *lb, enum dc_link_id sec);
+int dc_lb_pec_dynamic_sec_sel_get(struct dc_lb *lb, enum dc_link_id *sec);
 void dc_lb_pec_clken(struct dc_lb *lb, enum dc_pec_clken clken);
 void dc_lb_mode(struct dc_lb *lb, enum dc_lb_mode mode);
 void dc_lb_position(struct dc_lb *lb, int x, int y);

-- 
2.43.0