[PATCH v2] i3c: master: Improve initialization of numbered I2C adapters

[Defa Li <defa.li@mediatek.com>]

Add logic to initialize I2C adapters with a specific ID if available,
improving device identification and configuration.

For mixed buses, in addition to the i3c alias, an i2c alias can be added to
assign a fixed bus number to the i2c adapter.

This allows an alias node such as:
    aliases {
        i2c2 = &mixed_bus_a,
        i3c2 = &mixed_bus_a,
        i3c4 = &mixed_bus_b,
    };

    /* assigned "i3c-2" and "i2c-2" */
    mixed_bus_a: i3c-master {
    };

If there is no i2c alias for a mixed bus, the i2c adapter numbers will
remain as is and will be assigned starting after the highest fixed bus
number.

    /* assigned "i3c-4" and likely assigned "i2c-3" */
    mixed_bus_b: i3c-master {
    };

v2:
  - Modify commit message and code format issues

Signed-off-by: Defa Li <defa.li@mediatek.com>
---
 drivers/i3c/master.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 42310c9a00c2..92223e0b6e59 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2486,7 +2486,7 @@ static int i3c_master_i2c_adapter_init(struct i3c_master_controller *master)
 	struct i2c_adapter *adap = i3c_master_to_i2c_adapter(master);
 	struct i2c_dev_desc *i2cdev;
 	struct i2c_dev_boardinfo *i2cboardinfo;
-	int ret;
+	int ret, id = -ENODEV;
 
 	adap->dev.parent = master->dev.parent;
 	adap->owner = master->dev.parent->driver->owner;
@@ -2497,7 +2497,15 @@ static int i3c_master_i2c_adapter_init(struct i3c_master_controller *master)
 	adap->timeout = 1000;
 	adap->retries = 3;
 
-	ret = i2c_add_adapter(adap);
+	if (master->dev.of_node)
+		id = of_alias_get_id(master->dev.of_node, "i2c");
+
+	if (id >= 0) {
+		adap->nr = id;
+		ret = i2c_add_numbered_adapter(adap);
+	} else {
+		ret = i2c_add_adapter(adap);
+	}
 	if (ret)
 		return ret;
 
-- 
2.46.0