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From: Kyle Tso <kyletso@google.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: heikki.krogerus@linux.intel.com, gregkh@linuxfoundation.org,
	robh+dt@kernel.org, badhri@google.com, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Subject: Re: [PATCH v2 2/2] usb: typec: tcpm: Support non-PD mode
Date: Wed, 28 Jul 2021 10:11:26 +0800	[thread overview]
Message-ID: <CAGZ6i=0CQy7sMvwT3e47w-3SFWgTXr-5kA2pOn1oLhH=GJJE0A@mail.gmail.com> (raw)
In-Reply-To: <cbc4bdd6-de34-08a8-7968-9d3b0276e347@roeck-us.net>

On Wed, Jul 28, 2021 at 6:46 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On 7/27/21 8:13 AM, Kyle Tso wrote:
> > Even if the Type-C controller supports PD, it is doable to disable PD
> > capabilities with the current state machine in TCPM. Without enabling RX
> > in low-level drivers and with skipping the power negotiation, the port
> > is eligible to be a non-PD Type-C port. Use new flags whose values are
> > populated from the device tree to decide the port PD capability. Adding
> > "pd-supported" property in device tree indicates that the port supports
> > PD. If "pd-supported" is not found, "typec-power-opmode" shall be added
> > to specify the advertised Rp value if the port supports SRC role.
> >
> > Signed-off-by: Kyle Tso <kyletso@google.com>
> > ---
> > changes since v1:
> > - Revised the patch to use dt properties
> > - Added back the checks of callbacks set_pd_rx and pd_transmit
> > - Added src_rp to indicate which Rp value should be used in SRC. This
> >    variable is derived from dt property "typec-power-opmode"
> >
> >   drivers/usb/typec/tcpm/tcpm.c | 108 +++++++++++++++++++++++++---------
> >   1 file changed, 79 insertions(+), 29 deletions(-)
> >
> > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> > index 5b22a1c931a9..4cf77c787f54 100644
> > --- a/drivers/usb/typec/tcpm/tcpm.c
> > +++ b/drivers/usb/typec/tcpm/tcpm.c
> > @@ -316,6 +316,7 @@ struct tcpm_port {
> >       struct typec_partner *partner;
> >
> >       enum typec_cc_status cc_req;
> > +     enum typec_cc_status src_rp;    /* work only if pd_supported == false */
> >
> >       enum typec_cc_status cc1;
> >       enum typec_cc_status cc2;
> > @@ -323,6 +324,7 @@ struct tcpm_port {
> >
> >       bool attached;
> >       bool connected;
> > +     bool pd_supported;
> >       enum typec_port_type port_type;
> >
> >       /*
> > @@ -804,6 +806,7 @@ static void tcpm_apply_rc(struct tcpm_port *port)
> >       }
> >   }
> >
> > +
> >   /*
> >    * Determine RP value to set based on maximum current supported
> >    * by a port if configured as source.
> > @@ -815,6 +818,9 @@ static enum typec_cc_status tcpm_rp_cc(struct tcpm_port *port)
> >       int nr_pdo = port->nr_src_pdo;
> >       int i;
> >
> > +     if (!port->pd_supported)
> > +             return port->src_rp;
> > +
> >       /*
> >        * Search for first entry with matching voltage.
> >        * It should report the maximum supported current.
> > @@ -3568,9 +3574,11 @@ static int tcpm_src_attach(struct tcpm_port *port)
> >       if (ret < 0)
> >               return ret;
> >
> > -     ret = port->tcpc->set_pd_rx(port->tcpc, true);
> > -     if (ret < 0)
> > -             goto out_disable_mux;
> > +     if (port->pd_supported) {
> > +             ret = port->tcpc->set_pd_rx(port->tcpc, true);
> > +             if (ret < 0)
> > +                     goto out_disable_mux;
> > +     }
> >
> >       /*
> >        * USB Type-C specification, version 1.2,
> > @@ -3600,7 +3608,8 @@ static int tcpm_src_attach(struct tcpm_port *port)
> >   out_disable_vconn:
> >       tcpm_set_vconn(port, false);
> >   out_disable_pd:
> > -     port->tcpc->set_pd_rx(port->tcpc, false);
> > +     if (port->pd_supported)
> > +             port->tcpc->set_pd_rx(port->tcpc, false);
> >   out_disable_mux:
> >       tcpm_mux_set(port, TYPEC_STATE_SAFE, USB_ROLE_NONE,
> >                    TYPEC_ORIENTATION_NONE);
> > @@ -3804,6 +3813,20 @@ static enum typec_pwr_opmode tcpm_get_pwr_opmode(enum typec_cc_status cc)
> >       }
> >   }
> >
> > +static enum typec_cc_status tcpm_pwr_opmode_to_rp(enum typec_pwr_opmode opmode)
> > +{
> > +     switch (opmode) {
> > +     case TYPEC_PWR_MODE_USB:
> > +             return TYPEC_CC_RP_DEF;
> > +     case TYPEC_PWR_MODE_1_5A:
> > +             return TYPEC_CC_RP_1_5;
> > +     case TYPEC_PWR_MODE_3_0A:
> > +     case TYPEC_PWR_MODE_PD:
> > +     default:
> > +             return TYPEC_CC_RP_3_0;
> > +     }
> > +}
> > +
> >   static void run_state_machine(struct tcpm_port *port)
> >   {
> >       int ret;
> > @@ -3914,6 +3937,10 @@ static void run_state_machine(struct tcpm_port *port)
> >               if (port->ams == POWER_ROLE_SWAP ||
> >                   port->ams == FAST_ROLE_SWAP)
> >                       tcpm_ams_finish(port);
> > +             if (!port->pd_supported) {
> > +                     tcpm_set_state(port, SRC_READY, 0);
> > +                     break;
> > +             }
> >               port->upcoming_state = SRC_SEND_CAPABILITIES;
> >               tcpm_ams_start(port, POWER_NEGOTIATION);
> >               break;
> > @@ -4161,7 +4188,10 @@ static void run_state_machine(struct tcpm_port *port)
> >                               current_lim = PD_P_SNK_STDBY_MW / 5;
> >                       tcpm_set_current_limit(port, current_lim, 5000);
> >                       tcpm_set_charge(port, true);
> > -                     tcpm_set_state(port, SNK_WAIT_CAPABILITIES, 0);
> > +                     if (!port->pd_supported)
> > +                             tcpm_set_state(port, SNK_READY, 0);
> > +                     else
> > +                             tcpm_set_state(port, SNK_WAIT_CAPABILITIES, 0);
> >                       break;
> >               }
> >               /*
> > @@ -4389,7 +4419,8 @@ static void run_state_machine(struct tcpm_port *port)
> >               tcpm_set_vbus(port, true);
> >               if (port->ams == HARD_RESET)
> >                       tcpm_ams_finish(port);
> > -             port->tcpc->set_pd_rx(port->tcpc, true);
> > +             if (port->pd_supported)
> > +                     port->tcpc->set_pd_rx(port->tcpc, true);
> >               tcpm_set_attached_state(port, true);
> >               tcpm_set_state(port, SRC_UNATTACHED, PD_T_PS_SOURCE_ON);
> >               break;
> > @@ -5898,6 +5929,7 @@ EXPORT_SYMBOL_GPL(tcpm_tcpc_reset);
> >   static int tcpm_fw_get_caps(struct tcpm_port *port,
> >                           struct fwnode_handle *fwnode)
> >   {
> > +     const char *opmode_str;
> >       const char *cap_str;
> >       int ret;
> >       u32 mw, frs_current;
> > @@ -5932,22 +5964,36 @@ static int tcpm_fw_get_caps(struct tcpm_port *port,
> >               return ret;
> >       port->typec_caps.type = ret;
> >       port->port_type = port->typec_caps.type;
> > +     port->pd_supported = fwnode_property_read_bool(fwnode, "pd-supported");
> >
>
> As mentioned in the other patch, I think this needs to be negated.
> Not the variable itself, but the meaning of the property.
>

Makes sense. I will send another patch.

> >       port->slow_charger_loop = fwnode_property_read_bool(fwnode, "slow-charger-loop");
>
> It might make sense to move the properties needed with !pd_supported to here
> and return immediately after they are read. This would reduce the number of
> required changes and avoid trying to read irrelevant properties.
> Something like
>
>         if (port->port_type != TYPEC_PORT_SRC)
>                 port->self_powered = fwnode_property_read_bool(fwnode, "self-powered");
>
>         if (!port->pd_supported)
>                 return 0;
>

I will try to modify the flow control as well.

thanks,
Kyle

> >       if (port->port_type == TYPEC_PORT_SNK)
> >               goto sink;
> >
> >       /* Get source pdos */
> > -     ret = fwnode_property_count_u32(fwnode, "source-pdos");
> > -     if (ret <= 0)
> > -             return -EINVAL;
> > +     if (port->pd_supported) {
> > +             ret = fwnode_property_count_u32(fwnode, "source-pdos");
> > +             if (ret <= 0)
> > +                     return -EINVAL;
> >
> > -     port->nr_src_pdo = min(ret, PDO_MAX_OBJECTS);
> > -     ret = fwnode_property_read_u32_array(fwnode, "source-pdos",
> > -                                          port->src_pdo, port->nr_src_pdo);
> > -     if ((ret < 0) || tcpm_validate_caps(port, port->src_pdo,
> > -                                         port->nr_src_pdo))
> > -             return -EINVAL;
> > +             port->nr_src_pdo = min(ret, PDO_MAX_OBJECTS);
> > +             ret = fwnode_property_read_u32_array(fwnode, "source-pdos",
> > +                                                  port->src_pdo, port->nr_src_pdo);
> > +             if ((ret < 0) || tcpm_validate_caps(port, port->src_pdo,
> > +                                                 port->nr_src_pdo))
> > +                     return -EINVAL;
> > +     } else {
> > +             port->nr_src_pdo = 0;
> > +             ret = fwnode_property_read_string(fwnode, "typec-power-opmode", &opmode_str);
> > +             if (ret == 0) {
> > +                     ret = typec_find_pwr_opmode(opmode_str);
> > +                     if (ret < 0)
> > +                             return ret;
> > +                     port->src_rp = tcpm_pwr_opmode_to_rp(ret);
> > +             } else {
> > +                     return ret;
> > +             }
> > +     }
> >
> >       if (port->port_type == TYPEC_PORT_SRC)
> >               return 0;
> > @@ -5962,25 +6008,29 @@ static int tcpm_fw_get_caps(struct tcpm_port *port,
> >               return -EINVAL;
> >   sink:
> >       /* Get sink pdos */
> > -     ret = fwnode_property_count_u32(fwnode, "sink-pdos");
> > -     if (ret <= 0)
> > -             return -EINVAL;
> > +     if (port->pd_supported) {
> > +             ret = fwnode_property_count_u32(fwnode, "sink-pdos");
> > +             if (ret <= 0)
> > +                     return -EINVAL;
> >
> > -     port->nr_snk_pdo = min(ret, PDO_MAX_OBJECTS);
> > -     ret = fwnode_property_read_u32_array(fwnode, "sink-pdos",
> > -                                          port->snk_pdo, port->nr_snk_pdo);
> > -     if ((ret < 0) || tcpm_validate_caps(port, port->snk_pdo,
> > -                                         port->nr_snk_pdo))
> > -             return -EINVAL;
> > +             port->nr_snk_pdo = min(ret, PDO_MAX_OBJECTS);
> > +             ret = fwnode_property_read_u32_array(fwnode, "sink-pdos",
> > +                                                  port->snk_pdo, port->nr_snk_pdo);
> > +             if ((ret < 0) || tcpm_validate_caps(port, port->snk_pdo,
> > +                                                 port->nr_snk_pdo))
> > +                     return -EINVAL;
> >
> > -     if (fwnode_property_read_u32(fwnode, "op-sink-microwatt", &mw) < 0)
> > -             return -EINVAL;
> > -     port->operating_snk_mw = mw / 1000;
> > +             if (fwnode_property_read_u32(fwnode, "op-sink-microwatt", &mw) < 0)
> > +                     return -EINVAL;
> > +             port->operating_snk_mw = mw / 1000;
> > +     } else {
> > +             port->nr_snk_pdo = 0;
> > +     }
> >
> >       port->self_powered = fwnode_property_read_bool(fwnode, "self-powered");
> >
> > -     /* FRS can only be supported byb DRP ports */
> > -     if (port->port_type == TYPEC_PORT_DRP) {
> > +     /* FRS can only be supported by DRP ports */
> > +     if (port->port_type == TYPEC_PORT_DRP && port->pd_supported) {
> >               ret = fwnode_property_read_u32(fwnode, "new-source-frs-typec-current",
> >                                              &frs_current);
> >               if (ret >= 0 && frs_current <= FRS_5V_3A)
> >
>

      reply	other threads:[~2021-07-28  2:11 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-27 15:13 [PATCH v2 0/2] TCPM non-pd mode Kyle Tso
2021-07-27 15:13 ` [PATCH v2 1/2] dt-bindings: connector: Add pd-supported property Kyle Tso
2021-07-27 16:29   ` Guenter Roeck
2021-07-27 15:13 ` [PATCH v2 2/2] usb: typec: tcpm: Support non-PD mode Kyle Tso
2021-07-27 22:46   ` Guenter Roeck
2021-07-28  2:11     ` Kyle Tso [this message]

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