Re: [PATCH net-next] net: phy: micrel: Add support for PTP_PF_EXTTS for lan8814

[Vadim Fedorenko]

On 24/04/2024 20:12, Horatiu Vultur wrote:
> The 04/24/2024 11:57, Vadim Fedorenko wrote:
>
> Hi Vadim,
>
> > On 23/04/2024 20:57, Horatiu Vultur wrote:
> > > Extend the PTP programmable gpios to implement also PTP_PF_EXTTS
> > > function. The pins can be configured to capture both of rising
> > > and falling edge. Once the event is seen, then an interrupt is
> > > generated and the LTC is saved in the registers.
> > > On lan8814 only GPIO 3 can be configured for this.
> > >
> > > This was tested using:
> > > ts2phc -m -l 7 -s generic -f ts2phc.cfg
> > >
> > > Where the configuration was the following:
> > > ---
> > > [global]
> > > ts2phc.pin_index  3
> > >
> > > [eth0]
> > > ---
> > >
> > > Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
> >
> > I'm not sure what happened to (fac63186f116 net: phy: micrel: Add
> > support for PTP_PF_EXTTS for lan8841), looks like this patch is the
> > rework previous with the limit to GPIO 3 only. In this case comments
> > below are applicable.
>
> These are two different PHYs:
> 1. lan8814 which is a quad PHY and the patch is this PHY
> 2. lan8841 which is a single PHY. And the commit that you mention it was
>     for that PHY.
> So this commit is not rework of the commit that you mention.

Ah, I see, sorry for the mess..

> ...
>
> > > +static int lan8814_ptp_extts(struct ptp_clock_info *ptpci,
> > > +                          struct ptp_clock_request *rq, int on)
> > > +{
> > > +     struct lan8814_shared_priv *shared = container_of(ptpci, struct lan8814_shared_priv,
> > > +                                                       ptp_clock_info);
> > > +     struct phy_device *phydev = shared->phydev;
> > > +     int pin;
> > > +
> > > +     if (rq->extts.flags & ~(PTP_ENABLE_FEATURE |
> > > +                             PTP_EXTTS_EDGES |
> > > +                             PTP_STRICT_FLAGS))
> > > +             return -EOPNOTSUPP;
> > > +
> > > +     pin = ptp_find_pin(shared->ptp_clock, PTP_PF_EXTTS,
> > > +                        rq->extts.index);
> > > +     if (pin == -1 || pin != LAN8814_PTP_EXTTS_NUM)
> > > +             return -EINVAL;
> >
> > I'm not sure how will enable request pass this check?
> > In lan8814_ptp_probe_once pins are initialized with PTP_PF_NONE,
> > and ptp_find_pin will always return -1, which will end up with
> > -EINVAL here and never hit lan8814_ptp_extts_on/lan8814_ptp_extts_off
>
> Why ptp_find_pin will always return -1? Because we can set the function
> of the pin.

ah, I see, PTP_PIN_SETFUNC + PTP_EXTTS_REQUEST ioctls will do the
configuration. Maybe make GPIO 3 as PTP_PF_EXTTS function by default?

> ...
>
>   >       }
> > > @@ -3148,6 +3263,10 @@ static int lan8814_ptpci_verify(struct ptp_clock_info *ptp, unsigned int pin,
> > >                if (pin >= LAN8814_PTP_PEROUT_NUM || pin != chan)
> > >                        return -1;
> > >                break;
> > > +     case PTP_PF_EXTTS:
> > > +             if (pin != LAN8814_PTP_EXTTS_NUM)
> >
> > Here the check states that exactly GPIO 3 can have EXTTS function, but
> > later in the config...
>
> ...
> > > +                     return -1;
> > > +             break;
> > >        default:
> > >                return -1;
> > >        }
> > >
> > > @@ -3541,7 +3721,7 @@ static int lan8814_ptp_probe_once(struct phy_device *phydev)
> > >        snprintf(shared->ptp_clock_info.name, 30, "%s", phydev->drv->name);
> > >        shared->ptp_clock_info.max_adj = 31249999;
> > >        shared->ptp_clock_info.n_alarm = 0;
> > > -     shared->ptp_clock_info.n_ext_ts = 0;
> > > +     shared->ptp_clock_info.n_ext_ts = LAN8814_PTP_EXTTS_NUM;
> >
> > Here ptp_clock is configured to have 3 pins supporting EXTTS.
> > Looks like it should be n_ext_ts = 1;
>
> Good point, let me have a look at this.

I have checked it while checking enable part. Conditions in ptp_ioctl
give no options to limit lowest number of pin which supports EXTTS.

I think that the ptp_clock_info documentation is misleading here:

* @n_ext_ts:  The number of external time stamp channels.

should be replaced to something like "max index of external time
stamp channel".

With all above the patch LGTM!

Reviewed-by: Vadim Fedorenko <vadim.fedorenko@xxxxxxxxx>

> > >        shared->ptp_clock_info.n_pins = LAN8814_PTP_GPIO_NUM;
> > >        shared->ptp_clock_info.pps = 0;
> > >        shared->ptp_clock_info.pin_config = shared->pin_config;