Re: [PATCH 3/4] usb: typec: add typec orientation switch support via mux controller

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Wed, May 19, 2021 at 03:14:49PM +0800, Li Jun wrote:
> Some dedicated mux block can use existing mux controller as a
> mux provider, typec port as a consumer to select channel for
> orientation switch, this can be an alternate way to current
> typec_switch interface.
> 
> Signed-off-by: Li Jun <jun.li@nxp.com>
> ---
>  drivers/usb/typec/class.c     | 26 +++++++++++++++++++++++++-
>  drivers/usb/typec/class.h     |  2 ++
>  drivers/usb/typec/mux.c       | 34 ++++++++++++++++++++++++++++++++++
>  include/linux/usb/typec_mux.h |  4 ++++
>  4 files changed, 65 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index a29bf2c32233..1bb0275e6204 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -1601,6 +1601,7 @@ static void typec_release(struct device *dev)
>  	ida_simple_remove(&typec_index_ida, port->id);
>  	ida_destroy(&port->mode_ids);
>  	typec_switch_put(port->sw);
> +	typec_mux_control_switch_put(port->mux_control_switch);
>  	typec_mux_put(port->mux);
>  	kfree(port->cap);
>  	kfree(port);
> @@ -1816,6 +1817,13 @@ int typec_set_orientation(struct typec_port *port,
>  	if (ret)
>  		return ret;
>  
> +	if (!port->sw) {
> +		ret = typec_mux_control_switch_set(port->mux_control_switch,
> +				port->mux_control_switch_states[orientation]);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	port->orientation = orientation;
>  	sysfs_notify(&port->dev.kobj, NULL, "orientation");
>  	kobject_uevent(&port->dev.kobj, KOBJ_CHANGE);
> @@ -1991,7 +1999,7 @@ struct typec_port *typec_register_port(struct device *parent,
>  				       const struct typec_capability *cap)
>  {
>  	struct typec_port *port;
> -	int ret;
> +	int ret = 0;
>  	int id;
>  
>  	port = kzalloc(sizeof(*port), GFP_KERNEL);
> @@ -2068,6 +2076,22 @@ struct typec_port *typec_register_port(struct device *parent,
>  		return ERR_PTR(ret);
>  	}
>  
> +	if (!port->sw) {
> +		/* Try to get typec switch via general mux controller */
> +		port->mux_control_switch = typec_mux_control_switch_get(&port->dev);
> +		if (IS_ERR(port->mux_control_switch))
> +			ret = PTR_ERR(port->mux_control_switch);
> +		else if (port->mux_control_switch)
> +			ret = device_property_read_u32_array(&port->dev,
> +					"mux-control-switch-states",
> +					port->mux_control_switch_states,
> +					3);
> +		if (ret) {
> +			put_device(&port->dev);
> +			return ERR_PTR(ret);
> +		}
> +	}

Why not just do that inside fwnode_typec_switch_get() and handle the
whole thing in drivers/usb/typec/mux.c (or in its own file if you
prefer)?

You'll just need to register a "wrapper" Type-C switch object for the
OF mux controller, but that should not be a problem. That way you
don't need to export any new functions, touch this file or anything
else.


thanks,

-- 
heikki