On Fri, Apr 09, 2021 at 02:49:05PM +0200, Hans de Goede wrote:
> 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.
It's API so we can change it later. Let's go with your function
first.
Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
thanks,
--
heikki
