Re: [PATCH net-next v4 0/8] Add Microchip ZL3073x support (part 1)

[Ivan Vecera]

On 24. 04. 25 5:51 odp., Lee Jones wrote:
> On Thu, 24 Apr 2025, Ivan Vecera wrote:
>
> > Add support for Microchip Azurite DPLL/PTP/SyncE chip family that
> > provides DPLL and PTP functionality. This series bring first part
> > that adds the common MFD driver that provides an access to the bus
> > that can be either I2C or SPI.
> >
> > The next part of the series is bringing the DPLL driver that will
> > covers DPLL functionality. Another series will bring PTP driver and
> > flashing capability via devlink in the MFD driver will follow soon.
> >
> > Testing was done by myself and by Prathosh Satish on Microchip EDS2
> > development board with ZL30732 DPLL chip connected over I2C bus.
> >
> > Patch breakdown
> > ===============
> > Patch 1 - Common DT schema for DPLL device and pin
> > Patch 2 - DT bindings for microchip,zl3073* devices
> > Patch 3 - Basic support for I2C, SPI and regmap configuration
> > Patch 4 - Devlink device registration and info
> > Patch 5 - Helpers for reading and writing register mailboxes
>
> Whoops!  I just this second replied to v3.
>
> This needs moving out to somewhere more appropriate.
>
> Use MFD to allocate and split the resources, then the sub-devices can do
> the technical and heavy API stuff.

They cannot because the bus is shared and MFD parent device acts as bus
arbitrator. It has to ensure that sub-devices access the registers
safely.

Mailbox could be confusing for somebody but it does not have anything
common with HW mailboxes. In this context the mailbox is just a sequence
of register reads and writes in certain order and this sequence has
to be done atomically (I tried to describe this in my previous replies).

I have followed Andrew's recommendation to hide these special sequences
and provide sub-devices some simple API to use them without special
locking needs.

Thanks,
Ivan