soundwire: mipi-disco: add support for DP0/DPn 'lane-list' property

The SoundWire specification did not clearly require that ports could
use all Lanes. Some SoundWire/SDCA peripheral adopters added
restrictions on which lanes can be used by what port, and the DisCo
for SoundWire 2.1 specification added a 'lane-list' property to model
this hardware limitation.

When not specified, the ports can use all Lanes. Otherwise, the
'lane-list' indicates which Lanes can be used, sorted by order of
preference (most-preferred-first).

This patch only reads the properties, the use of this property will
come at a later time with multi-lane support.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20241003070650.62787-15-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/soundwire/mipi_disco.c b/drivers/soundwire/mipi_disco.c
index 36e734751225..9d59f486edbe 100644
--- a/drivers/soundwire/mipi_disco.c
+++ b/drivers/soundwire/mipi_disco.c
@@ -197,6 +197,22 @@ static int sdw_slave_read_dp0(struct sdw_slave *slave,
 	dp0->imp_def_interrupts = mipi_fwnode_property_read_bool(port,
 				"mipi-sdw-imp-def-dp0-interrupts-supported");
 
+	nval = fwnode_property_count_u32(port, "mipi-sdw-lane-list");
+	if (nval > 0) {
+		dp0->num_lanes = nval;
+		dp0->lane_list = devm_kcalloc(&slave->dev,
+					      dp0->num_lanes, sizeof(*dp0->lane_list),
+					      GFP_KERNEL);
+		if (!dp0->lane_list)
+			return -ENOMEM;
+
+		ret = fwnode_property_read_u32_array(port,
+					       "mipi-sdw-lane-list",
+					       dp0->lane_list, dp0->num_lanes);
+		if (ret < 0)
+			return ret;
+	}
+
 	return 0;
 }
 
@@ -326,6 +342,22 @@ static int sdw_slave_read_dpn(struct sdw_slave *slave,
 		fwnode_property_read_u32(node, "mipi-sdw-port-encoding-type",
 					 &dpn[i].port_encoding);
 
+		nval = fwnode_property_count_u32(node, "mipi-sdw-lane-list");
+		if (nval > 0) {
+			dpn[i].num_lanes = nval;
+			dpn[i].lane_list = devm_kcalloc(&slave->dev,
+							dpn[i].num_lanes, sizeof(*dpn[i].lane_list),
+							GFP_KERNEL);
+			if (!dpn[i].lane_list)
+				return -ENOMEM;
+
+			ret = fwnode_property_read_u32_array(node,
+						       "mipi-sdw-lane-list",
+						       dpn[i].lane_list, dpn[i].num_lanes);
+			if (ret < 0)
+				return ret;
+		}
+
 		fwnode_handle_put(node);
 
 		i++;