Re: [PATCH 0/3] usb: typec: report a current limit for non-PD Rp-def sources

[Heikki Krogerus]

On Fri, Oct 09, 2026 at 01:19:44PM +0200, Heikki Krogerus wrote:
> On Thu, Oct 01, 2026 at 10:51:12PM +0000, Amit Sunil Dhamne via B4 Relay wrote:
> > As per Sec. 4.6.2.1 of the Type-C cable & connector spec when the
> > source advertises Rp-default, the current limit is set as per the
> > USB 2.0/USB 3.2 specification, BC1.2 specification as applicable or the
> > PD negotiation.
> > 
> > Reset value for the Input Current Limit register for the MAX77759
> > charger is 500 mA. Prior to the max77759_charger driver, the battery
> > would always charge at that limit since it wasn't re-programmed. Since
> > the driver was introduced, for any non-PD source advertising Rp-default,
> > the charger turns off as tcpm reports the current limit to be 0. The
> > max77759_charger driver reads POWER_SUPPLY_PROP_CURRENT_MAX from the
> > "tcpm-source" power supply that tcpm_set_current_limit() updates, and
> > programs its input current limit from it. The limit is 0 because the
> > tcpm doesn't have visibility on the USB data speed or BC1.2 detection.
> > As a workaround for the Rp-default case, let the Type-C stack report a
> > USB 2.0 current limit of 500 mA so that the behavior is at parity with
> > what was before. This is until we implement a conduit for USB core to
> > communicate with the Type-C stack.
> > 
> > Signed-off-by: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
> > ---
> > Amit Sunil Dhamne (3):
> >       usb: typec: tcpm: only call get_current_limit() for cc=Rp-def
> >       usb: typec: tcpci: implement get_current_limit
> >       usb: typec: tcpci_maxim: implement get_current_limit
> > 
> >  drivers/usb/typec/tcpm/tcpci.c            | 14 ++++++++++++++
> >  drivers/usb/typec/tcpm/tcpci_maxim_core.c | 15 +++++++++++++++
> >  drivers/usb/typec/tcpm/tcpm.c             |  7 +++----
> >  include/linux/usb/tcpci.h                 |  6 ++++++
> >  4 files changed, 38 insertions(+), 4 deletions(-)
> > ---
> > base-commit: 551c722f40809618230001baccf219193e22fc5a
> > change-id: 20260918-max77759-icl-typec-8dfb9f83d712
> > 
> > Best regards,
> > -- 
> > Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
> 
> For the series:
> 
> Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

Sorry, there's v2. Please ignore this ACK.

-- 
heikki