Hi, On Thu, Jan 21, 2021 at 05:48:46PM +0800, Kyle Tso wrote: > On Thu, Jan 21, 2021 at 4:41 PM Heikki Krogerus > <heikki.krogerus@xxxxxxxxxxxxxxx> wrote: > > > > Hi Kyle, > > > > On Sat, Jan 16, 2021 at 12:33:11AM +0800, Kyle Tso wrote: > > > If the port partner is PD2, the PDOs of the local port should follow the > > > format defined in PD2 Spec. Dynamically modify the pre-defined PD3 PDOs > > > and transform them into PD2 format before sending them to the PD2 port > > > partner. > > > > I guess it's not possible for the system to supply separate static > > PDOs for each PD revision? > > > We can do that for sure. But a problem is that if there are more PD > revisions in the future, we will need to add more PDO arrays. > For backward compatibility, the new revision usually uses the > previously-reserved bits for the new features. > >From my perspective, the better way to achieve the backward > compatibility is to just clear the bits if those are reserved in the > previous revision. I was trying to think of something better for this, but I got nothing. I'm not completely comfortable with this, but never mind. Let's just go with this. > I can submit another patch which adds another PDO array for PD2 if you > think it is more appropriate. Not necessary. Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > > > Signed-off-by: Kyle Tso <kyletso@xxxxxxxxxx> > > > --- > > > drivers/usb/typec/tcpm/tcpm.c | 62 +++++++++++++++++++++++++++++------ > > > include/linux/usb/pd.h | 1 + > > > 2 files changed, 53 insertions(+), 10 deletions(-) > > > > > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > > > index 22a85b396f69..1220ab1ed47d 100644 > > > --- a/drivers/usb/typec/tcpm/tcpm.c > > > +++ b/drivers/usb/typec/tcpm/tcpm.c > > > @@ -911,13 +911,47 @@ static int tcpm_set_pwr_role(struct tcpm_port *port, enum typec_role role) > > > return 0; > > > } > > > > > > +/* > > > + * Transform the PDO to be compliant to PD rev2.0. > > > + * Return 0 if the PDO type is not defined in PD rev2.0. > > > + * Otherwise, return the converted PDO. > > > + */ > > > +static u32 tcpm_forge_legacy_pdo(struct tcpm_port *port, u32 pdo, enum typec_role role) > > > +{ > > > + switch (pdo_type(pdo)) { > > > + case PDO_TYPE_FIXED: > > > + if (role == TYPEC_SINK) > > > + return pdo & ~PDO_FIXED_FRS_CURR_MASK; > > > + else > > > + return pdo & ~PDO_FIXED_UNCHUNK_EXT; > > > + case PDO_TYPE_VAR: > > > + case PDO_TYPE_BATT: > > > + return pdo; > > > + case PDO_TYPE_APDO: > > > + default: > > > + return 0; > > > + } > > > +} > > > + > > > static int tcpm_pd_send_source_caps(struct tcpm_port *port) > > > { > > > struct pd_message msg; > > > - int i; > > > + u32 pdo; > > > + unsigned int i, nr_pdo = 0; > > > > Side note. I think this driver uses the "reverse christmas tree" > > style with the variables. > > I will change the order (if there is a next version) > > thanks, > Kyle -- heikki