On Thu, 20 Apr 2023 13:39:46 +0100
Lee Jones <lee@xxxxxxxxxx> wrote:
> On Mon, 17 Apr 2023, Herve Codina wrote:
>
> > The Lantiq PEF2256 is a framer and line interface component designed to
> > fulfill all required interfacing between an analog E1/T1/J1 line and the
> > digital PCM system highway/H.100 bus.
> >
> > Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx>
> > ---
> > drivers/mfd/Kconfig | 16 +
> > drivers/mfd/Makefile | 1 +
> > drivers/mfd/pef2256-regs.h | 250 ++++++++++
> > drivers/mfd/pef2256.c | 950 ++++++++++++++++++++++++++++++++++++
>
> 95% of this driver needs to be moved somewhere else.
>
> What is a Framer? Perhaps sound/ is a good candidate?
The pef2256 framer is a device that transfers data to/from a TDM (time-slots
data) from/to quite old telecommunication lines (E1 in my case).
Several subsystem can set/get data to/from the TDM. Each device using their
own time-slots set.
On my use-case, I have some audio consumer and a not yet upstreamed HDLC
consumer. Both of them uses the framer to know the E1 link state.
The framer needs to be initialized 'globally' and not by a specific consumer
as several consumers can use the framer.
>
> > include/linux/mfd/pef2256.h | 52 ++
> > 5 files changed, 1269 insertions(+)
> > create mode 100644 drivers/mfd/pef2256-regs.h
> > create mode 100644 drivers/mfd/pef2256.c
> > create mode 100644 include/linux/mfd/pef2256.h
>
> [...]
>
> > +static int pef2256_add_audio_devices(struct pef2256 *pef2256)
> > +{
> > + const char *compatible = "lantiq,pef2256-codec";
> > + struct mfd_cell *audio_devs;
> > + struct device_node *np;
> > + unsigned int count = 0;
> > + unsigned int i;
> > + int ret;
> > +
> > + for_each_available_child_of_node(pef2256->dev->of_node, np) {
> > + if (of_device_is_compatible(np, compatible))
> > + count++;
> > + }
>
> Converting Device Tree nodes into MFD cells to register with the
> Platform Device API is not a reasonable use-case of MFD.
>
> Have the CODEC driver match on "lantiq,pef2256-codec" and let it
> instantiate itself.
As the framer is going to used by several subsystem, I cannot instantiate
it in the specific ASoC subsystem.
>
> Your first version using of_platform_populate() was closer to the mark.
The issue was that I need MFD cells for the pinctrl part.
>
> > + if (!count)
> > + return 0;
> > +
> > + audio_devs = kcalloc(count, sizeof(*audio_devs), GFP_KERNEL);
> > + if (!audio_devs)
> > + return -ENOMEM;
> > +
> > + for (i = 0; i < count; i++) {
> > + (audio_devs + i)->name = "lantiq-pef2256-codec";
> > + (audio_devs + i)->of_compatible = compatible;
> > + (audio_devs + i)->id = i;
> > + }
> > +
> > + ret = mfd_add_devices(pef2256->dev, 0, audio_devs, count, NULL, 0, NULL);
> > + kfree(audio_devs);
> > + return ret;
> > +}
>
Best regards,
Hervé
--
Hervé Codina, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
