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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Tue, 6 Feb 2024 15:27:16 +0100
Message-ID: <CAMuHMdU=G0eYTf+n9Bv+Bwke4W8isRrh-B6zHD1=hD8yksxedw@mail.gmail.com>
Subject: Re: [PATCH net-next v8 2/2] ptp: add FemtoClock3 Wireless as ptp
 hardware clock
To: Min Li <lnimi@hotmail.com>
Cc: richardcochran@gmail.com, lee@kernel.org, linux-kernel@vger.kernel.org, 
	netdev@vger.kernel.org, Min Li <min.li.xe@renesas.com>
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Hi Min,

On Mon, Jan 15, 2024 at 9:22=E2=80=AFPM Min Li <lnimi@hotmail.com> wrote:
> From: Min Li <min.li.xe@renesas.com>
>
> The RENESAS FemtoClock3 Wireless is a high-performance jitter attenuator,
> frequency translator, and clock synthesizer. The device is comprised of 3
> digital PLLs (DPLL) to track CLKIN inputs and three independent low phase
> noise fractional output dividers (FOD) that output low phase noise clocks=
.
>
> FemtoClock3 supports one Time Synchronization (Time Sync) channel to enab=
le
> an external processor to control the phase and frequency of the Time Sync
> channel and to take phase measurements using the TDC. Intended applicatio=
ns
> are synchronization using the precision time protocol (PTP) and
> synchronization with 0.5 Hz and 1 Hz signals from GNSS.
>
> Signed-off-by: Min Li <min.li.xe@renesas.com>

Thanks for your patch, which is now commit 1ddfecafabf71e0e ("ptp:
add FemtoClock3 Wireless as ptp hardware clock") in net-next/main.

> --- a/drivers/ptp/Kconfig
> +++ b/drivers/ptp/Kconfig
> @@ -155,6 +155,18 @@ config PTP_1588_CLOCK_IDTCM
>           To compile this driver as a module, choose M here: the module
>           will be called ptp_clockmatrix.
>
> +config PTP_1588_CLOCK_FC3W
> +       tristate "RENESAS FemtoClock3 Wireless as PTP clock"
> +       depends on PTP_1588_CLOCK && I2C

This driver does not seem to use any direct i2c functionality (it
does use regmap), so presumably it should depend on something else
(see below) instead?

> +       default n

"default n" is the default.

> +       help
> +         This driver adds support for using Renesas FemtoClock3 Wireless
> +         as a PTP clock. This clock is only useful if your time stamping
> +         MAC is connected to the RENESAS chip.
> +
> +         To compile this driver as a module, choose M here: the module
> +         will be called ptp_fc3.
> +
>  config PTP_1588_CLOCK_MOCK
>         tristate "Mock-up PTP clock"
>         depends on PTP_1588_CLOCK

> --- /dev/null
> +++ b/drivers/ptp/ptp_fc3.c

> +static struct platform_driver idtfc3_driver =3D {
> +       .driver =3D {
> +               .name =3D "rc38xxx-phc",
> +       },
> +       .probe =3D idtfc3_probe,
> +       .remove =3D idtfc3_remove,
> +};

Who is supposed to instantiate this platform device?
I couldn't find anything in-tree or on lore.kernel.org.
Presumably that driver should be a dependency for the
PTP_1588_CLOCK_FC3W config symbol.

Gr{oetje,eeting}s,

                        Geert

--=20
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds