[v1,2/3] usb: typec: tcpci: Add support to report vSafe0V

This change adds vbus_vsafe0v which when set, makes TCPM
query for VSAFE0V by assigning the tcpc.is_vbus_vsafe0v callback.
Also enables ALERT.ExtendedStatus which is triggered when
status of EXTENDED_STATUS.vSafe0V changes.
EXTENDED_STATUS.vSafe0V is set when vbus is at vSafe0V and
cleared otherwise.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
 drivers/usb/typec/tcpm/tcpci.c | 55 ++++++++++++++++++++++++++--------
 drivers/usb/typec/tcpm/tcpci.h |  6 ++++
 2 files changed, 49 insertions(+), 12 deletions(-)

On Tue, Dec 1, 2020 at 5:27 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On Mon, Nov 30, 2020 at 05:32:45PM -0800, Badhri Jagan Sridharan wrote:
> > This change adds vbus_vsafe0v which when set, makes TCPM
> > query for VSAFE0V by assigning the tcpc.is_vbus_vsafe0v callback.
> > Also enables ALERT.ExtendedStatus which is triggered when
> > status of EXTENDED_STATUS.vSafe0V changes.
> > EXTENDED_STATUS.vSafe0V is set when vbus is at vSafe0V and
> > cleared otherwise.
> >
> > Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
> > ---
> >  drivers/usb/typec/tcpm/tcpci.c | 55 ++++++++++++++++++++++++++--------
> >  drivers/usb/typec/tcpm/tcpci.h |  6 ++++
> >  2 files changed, 49 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> > index 12d983a75510..e281b8bee4db 100644
> > --- a/drivers/usb/typec/tcpm/tcpci.c
> > +++ b/drivers/usb/typec/tcpm/tcpci.c
> > @@ -402,6 +402,19 @@ static int tcpci_get_vbus(struct tcpc_dev *tcpc)
> >       return !!(reg & TCPC_POWER_STATUS_VBUS_PRES);
> >  }
> >
> > +static int tcpci_is_vbus_vsafe0v(struct tcpc_dev *tcpc)
> > +{
> > +     struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
> > +     unsigned int reg;
> > +     int ret;
> > +
> > +     ret = regmap_read(tcpci->regmap, TCPC_EXTENDED_STATUS, &reg);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     return !!(reg & TCPC_EXTENDED_STATUS_VSAFE0V);
> > +}
> > +
> >  static int tcpci_set_vbus(struct tcpc_dev *tcpc, bool source, bool sink)
> >  {
> >       struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
> > @@ -554,12 +567,22 @@ static int tcpci_init(struct tcpc_dev *tcpc)
> >               TCPC_ALERT_RX_HARD_RST | TCPC_ALERT_CC_STATUS;
> >       if (tcpci->controls_vbus)
> >               reg |= TCPC_ALERT_POWER_STATUS;
> > +     /* Enable VSAFE0V status interrupt when detecting VSAFE0V is supported */
> > +     if (tcpci->data->vbus_vsafe0v) {
> > +             reg |= TCPC_ALERT_EXTENDED_STATUS;
> > +             ret = regmap_write(tcpci->regmap, TCPC_EXTENDED_STATUS_MASK,
> > +                                TCPC_EXTENDED_STATUS_VSAFE0V);
> > +             if (ret < 0)
> > +                     return ret;
> > +     }
> >       return tcpci_write16(tcpci, TCPC_ALERT_MASK, reg);
> >  }
> >
> >  irqreturn_t tcpci_irq(struct tcpci *tcpci)
> >  {
> >       u16 status;
> > +     int ret;
> > +     unsigned int raw;
> >
> >       tcpci_read16(tcpci, TCPC_ALERT, &status);
> >
> > @@ -575,18 +598,17 @@ irqreturn_t tcpci_irq(struct tcpci *tcpci)
> >               tcpm_cc_change(tcpci->port);
> >
> >       if (status & TCPC_ALERT_POWER_STATUS) {
> > -             unsigned int reg;
> > -
> > -             regmap_read(tcpci->regmap, TCPC_POWER_STATUS_MASK, &reg);
> > -
> > -             /*
> > -              * If power status mask has been reset, then the TCPC
> > -              * has reset.
> > -              */
> > -             if (reg == 0xff)
> > -                     tcpm_tcpc_reset(tcpci->port);
> > -             else
> > -                     tcpm_vbus_change(tcpci->port);
> > +             ret = regmap_read(tcpci->regmap, TCPC_POWER_STATUS_MASK, &raw);
> > +             if (ret >= 0) {
> > +                     /*
> > +                      * If power status mask has been reset, then the TCPC
> > +                      * has reset.
> > +                      */
> > +                     if (raw == 0xff)
> > +                             tcpm_tcpc_reset(tcpci->port);
> > +                     else
> > +                             tcpm_vbus_change(tcpci->port);
> > +             }
>
> This change seems unrelated to this patch. Besides that, are you sure that
> ignoring an error from regmap_read() is sensible here ?

Sorry should have split that into a separate patch. I was actually intending
to do the following where tcpm calls are not made if TCPC_POWER_STATUS_MASK
read returns error. The code was previously ignoring the error.

               if (!ret) {
                        /*
                         * If power status mask has been reset, then the TCPC
                         * has reset.
                         */
                        if (raw == 0xff)
                                tcpm_tcpc_reset(tcpci->port);
                        else
                                tcpm_vbus_change(tcpci->port);
             }

This is reasonable right ?

                }

>
> Overall, it may make sense to improve error handling in this driver, but I think
> it should be done in a separate patch.
>
> >       }
> >
> >       if (status & TCPC_ALERT_RX_STATUS) {
> > @@ -622,6 +644,12 @@ irqreturn_t tcpci_irq(struct tcpci *tcpci)
> >               tcpm_pd_receive(tcpci->port, &msg);
> >       }
> >
> > +     if (status & TCPC_ALERT_EXTENDED_STATUS) {
> > +             ret = regmap_read(tcpci->regmap, TCPC_EXTENDED_STATUS, &raw);
> > +             if (ret >= 0 && (raw & TCPC_EXTENDED_STATUS_VSAFE0V))
> > +                     tcpm_vbus_change(tcpci->port);
> > +     }
> > +
> >       if (status & TCPC_ALERT_RX_HARD_RST)
> >               tcpm_pd_hard_reset(tcpci->port);
> >
> > @@ -699,6 +727,9 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
> >                       tcpci_set_auto_vbus_discharge_threshold;
> >       }
> >
> > +     if (tcpci->data->vbus_vsafe0v)
> > +             tcpci->tcpc.is_vbus_vsafe0v = tcpci_is_vbus_vsafe0v;
> > +
> >       err = tcpci_parse_config(tcpci);
> >       if (err < 0)
> >               return ERR_PTR(err);
> > diff --git a/drivers/usb/typec/tcpm/tcpci.h b/drivers/usb/typec/tcpm/tcpci.h
> > index 3fe313655f0c..116a69c85e38 100644
> > --- a/drivers/usb/typec/tcpm/tcpci.h
> > +++ b/drivers/usb/typec/tcpm/tcpci.h
> > @@ -49,6 +49,9 @@
> >  #define TCPC_TCPC_CTRL_ORIENTATION   BIT(0)
> >  #define TCPC_TCPC_CTRL_BIST_TM               BIT(1)
> >
> > +#define TCPC_EXTENDED_STATUS         0x20
> > +#define TCPC_EXTENDED_STATUS_VSAFE0V BIT(0)
> > +
> >  #define TCPC_ROLE_CTRL                       0x1a
> >  #define TCPC_ROLE_CTRL_DRP           BIT(6)
> >  #define TCPC_ROLE_CTRL_RP_VAL_SHIFT  4
> > @@ -155,11 +158,14 @@ struct tcpci;
> >   *           is sourcing vbus.
> >   * @auto_discharge_disconnect:
> >   *           Optional; Enables TCPC to autonously discharge vbus on disconnect.
> > + * @vbus_vsafe0v:
> > + *           optional; Set when TCPC can detect whether vbus is at VSAFE0V.
> >   */
> >  struct tcpci_data {
> >       struct regmap *regmap;
> >       unsigned char TX_BUF_BYTE_x_hidden:1;
> >       unsigned char auto_discharge_disconnect:1;
> > +     unsigned char vbus_vsafe0v:1;
> >
> >       int (*init)(struct tcpci *tcpci, struct tcpci_data *data);
> >       int (*set_vconn)(struct tcpci *tcpci, struct tcpci_data *data,
> > --
> > 2.29.2.454.gaff20da3a2-goog
> >