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

[Frank Li]

On Thu, Dec 12, 2024 at 05:17:53PM +0800, Defa Li wrote:
> 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

v2: ...
 should be after "---"

>
> Signed-off-by: Defa Li <defa.li at mediatek.com>

Reviewed-by: Frank Li <Frank.Li at nxp.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
>
>
> --
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