All lanes in data-lanes and clock-lanes properties should be unique. Add
a check for this in v4l2_of_parse_csi_bus() and print a warning if
duplicated lanes are found.

Signed-off-by: Niklas Söderlund <niklas.soderlund+rene...@ragnatech.se>
---

Changes since v1:

- Do not return -EINVAL if a duplicate is found. Sakari pointed out 
  there are drivers where the number of lanes matter but not the actual 
  lane numbers. Updated commit message to highlight that only a warning 
  is printed.
- Switched to a bitmask to track lanes used instead of a nested loop, 
  thanks Laurent for the suggestion.


 drivers/media/v4l2-core/v4l2-of.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-of.c 
b/drivers/media/v4l2-core/v4l2-of.c
index 93b33681776ca427..4f59f442dd0a64c9 100644
--- a/drivers/media/v4l2-core/v4l2-of.c
+++ b/drivers/media/v4l2-core/v4l2-of.c
@@ -26,7 +26,7 @@ static int v4l2_of_parse_csi_bus(const struct device_node 
*node,
        struct v4l2_of_bus_mipi_csi2 *bus = &endpoint->bus.mipi_csi2;
        struct property *prop;
        bool have_clk_lane = false;
-       unsigned int flags = 0;
+       unsigned int flags = 0, lanes_used = 0;
        u32 v;
 
        prop = of_find_property(node, "data-lanes", NULL);
@@ -38,6 +38,12 @@ static int v4l2_of_parse_csi_bus(const struct device_node 
*node,
                        lane = of_prop_next_u32(prop, lane, &v);
                        if (!lane)
                                break;
+
+                       if (lanes_used & BIT(v))
+                               pr_warn("%s: duplicated lane %u in 
data-lanes\n",
+                                       node->full_name, v);
+                       lanes_used |= BIT(v);
+
                        bus->data_lanes[i] = v;
                }
                bus->num_data_lanes = i;
@@ -63,6 +69,11 @@ static int v4l2_of_parse_csi_bus(const struct device_node 
*node,
        }
 
        if (!of_property_read_u32(node, "clock-lanes", &v)) {
+               if (lanes_used & BIT(v))
+                       pr_warn("%s: duplicated lane %u in clock-lanes\n",
+                               node->full_name, v);
+               lanes_used |= BIT(v);
+
                bus->clock_lane = v;
                have_clk_lane = true;
        }
-- 
2.11.0

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