[RFC 3/5] media: adv748x: Make lanes number depend on routing

[Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>]

Use the TXA routing information to configure the number of active CSI-2
data lanes. When routing AFE through TXA limit the number of data lanes
to 1, while in the canonical HDMI->TXA routing use all the physically
available ones.

The number of lanes collected from the 'data-lanes' DT property is now
used as a the number of physically available data lanes, while the
'num_lanes' variable contains the number of active ones.

Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
---
 drivers/media/i2c/adv748x/adv748x-core.c | 19 ++++++++++++++++++-
 drivers/media/i2c/adv748x/adv748x.h      |  1 +
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/media/i2c/adv748x/adv748x-core.c b/drivers/media/i2c/adv748x/adv748x-core.c
index 02135741b1a6..f91c7b83f1bf 100644
--- a/drivers/media/i2c/adv748x/adv748x-core.c
+++ b/drivers/media/i2c/adv748x/adv748x-core.c
@@ -350,6 +350,8 @@ static int adv748x_link_setup(struct media_entity *entity,
 	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
 	bool enable = flags & MEDIA_LNK_FL_ENABLED;
 	u8 csi4_in_sel = 0;
+	u8 num_lanes;
+	int ret;
 
 	/* Refuse to enable multiple links to the same TX at the same time. */
 	if (enable && tx->src)
@@ -373,10 +375,23 @@ static int adv748x_link_setup(struct media_entity *entity,
 			csi4_in_sel |= ADV748X_IO_10_CSI4_IN_SEL_AFE;
 		else
 			csi4_in_sel |= ADV748X_IO_10_CSI1_EN;
+
+		num_lanes = 1;
 	}
 
-	if (state->hdmi.tx)
+	if (state->hdmi.tx) {
 		csi4_in_sel |= ADV748X_IO_10_CSI4_EN;
+		num_lanes = tx->available_lanes;
+	}
+
+	/* Update the number of active lanes if it has changed. */
+	if (num_lanes != tx->num_lanes) {
+		tx->num_lanes = num_lanes;
+		ret = adv748x_write(state, tx->page, 0x00,
+				    0x80 | tx->num_lanes);
+		if (ret)
+			return ret;
+	}
 
 	state->csi4_in_sel = csi4_in_sel;
 
@@ -608,6 +623,7 @@ static int adv748x_parse_csi2_lanes(struct adv748x_state *state,
 		}
 
 		state->txa.num_lanes = num_lanes;
+		state->txa.available_lanes = num_lanes;
 		adv_dbg(state, "TXA: using %u lanes\n", state->txa.num_lanes);
 	}
 
@@ -619,6 +635,7 @@ static int adv748x_parse_csi2_lanes(struct adv748x_state *state,
 		}
 
 		state->txb.num_lanes = num_lanes;
+		state->txb.available_lanes = num_lanes;
 		adv_dbg(state, "TXB: using %u lanes\n", state->txb.num_lanes);
 	}
 
diff --git a/drivers/media/i2c/adv748x/adv748x.h b/drivers/media/i2c/adv748x/adv748x.h
index 27c116d09284..6e5c2cb421fe 100644
--- a/drivers/media/i2c/adv748x/adv748x.h
+++ b/drivers/media/i2c/adv748x/adv748x.h
@@ -80,6 +80,7 @@ struct adv748x_csi2 {
 	unsigned int page;
 	unsigned int port;
 	unsigned int num_lanes;
+	unsigned int available_lanes;
 
 	struct media_pad pads[ADV748X_CSI2_NR_PADS];
 	struct v4l2_ctrl_handler ctrl_hdl;
-- 
2.21.0