Re: [PATCH 2/4] usb: typec: Add typec_port_register_altmodes_from_fwnode()

[Guenter Roeck <linux@roeck-us.net>]

On 7/14/20 4:36 AM, Hans de Goede wrote:
> This can be used by Type-C controller drivers which use a standard
> usb-connector fwnode, with altmodes sub-node, to describe the available
> altmodes.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/usb/typec/class.c | 56 +++++++++++++++++++++++++++++++++++++++
>  include/linux/usb/typec.h |  7 +++++
>  2 files changed, 63 insertions(+)
> 
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index c9234748537a..47de2b2e3d54 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -1607,6 +1607,62 @@ typec_port_register_altmode(struct typec_port *port,
>  }
>  EXPORT_SYMBOL_GPL(typec_port_register_altmode);
>  
> +void typec_port_register_altmodes_from_fwnode(struct typec_port *port,
> +	const struct typec_altmode_ops *ops, void *drvdata,
> +	struct typec_altmode **altmodes, size_t n,
> +	struct fwnode_handle *fwnode)
> +{
> +	struct fwnode_handle *altmodes_node, *child;
> +	struct typec_altmode_desc desc;
> +	struct typec_altmode *alt;
> +	size_t index = 0;
> +	u32 svid, vdo;
> +	int ret;
> +
> +	altmodes_node = fwnode_get_named_child_node(fwnode, "altmodes");
> +	if (!altmodes_node)
> +		return;
> +
> +	child = NULL;
> +	while ((child = fwnode_get_next_child_node(altmodes_node, child))) {
> +		ret = fwnode_property_read_u32(child, "svid", &svid);
> +		if (ret) {
> +			dev_err(&port->dev, "Error reading svid for altmode %s\n",
> +				fwnode_get_name(child));
> +			continue;

The properties are mandatory. I think the errors should not be ignored.

> +		}
> +
> +		ret = fwnode_property_read_u32(child, "vdo", &vdo);
> +		if (ret) {
> +			dev_err(&port->dev, "Error reading vdo for altmode %s\n",
> +				fwnode_get_name(child));
> +			continue;
> +		}
> +
> +		if (index >= n) {
> +			dev_err(&port->dev, "Error not enough space for altmode %s\n",
> +				fwnode_get_name(child));
> +			continue;

Seems to be pointless to continue here.

> +		}
> +
> +		desc.svid = svid;
> +		desc.vdo = vdo;
> +		desc.mode = index + 1;
> +		alt = typec_port_register_altmode(port, &desc);
> +		if (IS_ERR(alt)) {
> +			dev_err(&port->dev, "Error registering altmode %s\n",
> +				fwnode_get_name(child));
> +			continue;

Maybe there is a reason to ignore all those errors. If so,
that should be explained.

> +		}
> +
> +		alt->ops = ops;
> +		typec_altmode_set_drvdata(alt, drvdata);
> +		altmodes[index] = alt;
> +		index++;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(typec_port_register_altmodes_from_fwnode);
> +
>  /**
>   * typec_register_port - Register a USB Type-C Port
>   * @parent: Parent device
> diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
> index 5daa1c49761c..fbe4bccb3a98 100644
> --- a/include/linux/usb/typec.h
> +++ b/include/linux/usb/typec.h
> @@ -17,6 +17,7 @@ struct typec_partner;
>  struct typec_cable;
>  struct typec_plug;
>  struct typec_port;
> +struct typec_altmode_ops;
>  
>  struct fwnode_handle;
>  struct device;
> @@ -121,6 +122,12 @@ struct typec_altmode
>  struct typec_altmode
>  *typec_port_register_altmode(struct typec_port *port,
>  			     const struct typec_altmode_desc *desc);
> +
> +void typec_port_register_altmodes_from_fwnode(struct typec_port *port,
> +	const struct typec_altmode_ops *ops, void *drvdata,
> +	struct typec_altmode **altmodes, size_t n,
> +	struct fwnode_handle *fwnode);
> +
>  void typec_unregister_altmode(struct typec_altmode *altmode);
>  
>  struct typec_port *typec_altmode2port(struct typec_altmode *alt);
>