Hi,
On 4/9/21 12:54 PM, Heikki Krogerus wrote:
> Hi Hans,
>
> On Thu, Apr 08, 2021 at 10:31:27PM +0200, 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.
>>
>> Note there are is no devicetree bindings documentation for the altmodes
>> node, this is deliberate. ATM the fwnodes used to register the altmodes
>> are only used internally to pass platform info from a drivers/platform/x86
>> driver to the type-c subsystem.
>>
>> When a devicetree user of this functionally comes up and the dt-bindings
>> have been hashed out the internal use can be adjusted to match the
>> dt-bindings.
>>
>> Currently the typec_port_register_altmodes_from_fwnode() function expects
>> an "altmodes" child fwnode on port->dev with this "altmodes" fwnode having
>> child fwnodes itself with each child containing 2 integer properties:
>>
>> 1. A "svid" property, which sets the id of the altmode, e.g. displayport
>> altmode has a svid of 0xff01.
>>
>> 2. A "vdo" property, typically used as a bitmask describing the
>> capabilities of the altmode, the bits in the vdo are specified in the
>> specification of the altmode.
>>
>> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
>> ---
>> Changes in v2:
>> - Drop the unnecessary fwnode parameter from
>> typec_port_register_altmodes_from_fwnode()
>> - Document the expected "altmodes" fwnode in the commit message for now
>> as v2 of the patch-set drops the dt-bindings since there are not DT
>> users for this yet
>> ---
>> drivers/usb/typec/class.c | 55 +++++++++++++++++++++++++++++++++++++++
>> include/linux/usb/typec.h | 6 +++++
>> 2 files changed, 61 insertions(+)
>>
>> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
>> index 45f0bf65e9ab..a82344fe1650 100644
>> --- a/drivers/usb/typec/class.c
>> +++ b/drivers/usb/typec/class.c
>> @@ -1978,6 +1978,61 @@ 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)
>
> Couldn't we just call this typec_port_register_altmodes()?
Ack, will fix for v3.
>> +{
>> + 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 = device_get_named_child_node(&port->dev, "altmodes");
>> + if (!altmodes_node)
>> + return; /* No altmodes specified */
>> +
>> + child = NULL;
>> + while ((child = fwnode_get_next_child_node(altmodes_node, child))) {
>
> fwnode_for_each_child_node()?
Ack, will fix for v3.
>
>> + 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;
>> + }
>> +
>> + 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;
>> + }
>> +
>> + 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;
>> + }
>> +
>> + alt->ops = ops;
>> + typec_altmode_set_drvdata(alt, drvdata);
>> + altmodes[index] = alt;
>> + index++;
>> + }
>> +}
>> +EXPORT_SYMBOL_GPL(typec_port_register_altmodes_from_fwnode);
>
> This is OK by me, but I've been wondering if it would be more clear to
> just have a function fwnode_for_each_altmode() (I don't know if the
> name is good enough).
>
> int fwnode_for_each_altmode(struct fwnode_handle *fwnode,
> int (*fn)(struct typec_altmode_desc *, void *),
> void *data)
> {
> struct fwnode_handle *altmodes_node, *child;
> struct typec_altmode_desc desc;
> u32 svid, vdo;
> int ret;
>
> altmodes_node = fwnode_get_named_child_node(fwnode, "altmodes");
> if (!altmodes_node)
> return 0; /* No altmodes specified */
>
> fwnode_for_each_child_node(altmodes_node, child) {
> ...
> /* read the properties */
> ...
>
> desc.svid = svid;
> desc.vdo = vdo;
> desc.mode = index + 1;
>
> /* We need to add this member to struct typec_altmode_desc! */
> desc.fwnode = client;
>
> ret = fn(&desc, data);
> if (ret)
> return ret;
> }
>
> return 0;
> }
>
> Something like that. It would leave the registration of the alternate
> modes to the drivers, which I think would actually be better.
>
> If there ever is need, this can be also used for other things besides
> mode registration.
>
> What do you think?
I think adding such a helper might make sense once we actually have
a need for the doing "other things" for all altmodes in a fwnode beside
registering them.
And even then I think it would still make sense to have a
typec_port_register_altmodes() helper for drivers to use, but that
could then be a wrapper around fwnode_for_each_altmode().
Since ATM we have only 1 user for a fwnode_for_each_altmode()
helper adding it now seems premature to me.
But if you have a strong preference for adding it now, then I can
do that for v3.
If you let me know which way you want to go on this, then I'll
prepare a v3.
Regards,
Hans
