[RFC PATCH v4 0/4] Create common DPLL/clock configuration API

[Kubalewski, Arkadiusz]

>From: Vadim Fedorenko <vfedorenko at novek.ru>
>Sent: Tuesday, November 29, 2022 10:37 PM
>
>Implement common API for clock/DPLL configuration and status reporting.
>The API utilises netlink interface as transport for commands and event
>notifications. This API aim to extend current pin configuration and make it
>flexible and easy to cover special configurations.
>
>v3 -> v4:
> * redesign framework to make pins dynamically allocated (Arkadiusz)
> * implement shared pins (Arkadiusz)
>v2 -> v3:
> * implement source select mode (Arkadiusz)
> * add documentation
> * implementation improvements (Jakub)
>v1 -> v2:
> * implement returning supported input/output types
> * ptp_ocp: follow suggestions from Jonathan
> * add linux-clk mailing list
>v0 -> v1:
> * fix code style and errors
> * add linux-arm mailing list
>
>
>Arkadiusz Kubalewski (1):
>  dpll: add dpll_attr/dpll_pin_attr helper classes
>
>Vadim Fedorenko (3):
>  dpll: Add DPLL framework base functions
>  dpll: documentation on DPLL subsystem interface
>  ptp_ocp: implement DPLL ops
>
> Documentation/networking/dpll.rst  | 271 ++++++++
> Documentation/networking/index.rst |   1 +
> MAINTAINERS                        |   8 +
> drivers/Kconfig                    |   2 +
> drivers/Makefile                   |   1 +
> drivers/dpll/Kconfig               |   7 +
> drivers/dpll/Makefile              |  11 +
> drivers/dpll/dpll_attr.c           | 278 +++++++++
> drivers/dpll/dpll_core.c           | 760 +++++++++++++++++++++++
> drivers/dpll/dpll_core.h           | 176 ++++++
> drivers/dpll/dpll_netlink.c        | 963 +++++++++++++++++++++++++++++
> drivers/dpll/dpll_netlink.h        |  24 +
> drivers/dpll/dpll_pin_attr.c       | 456 ++++++++++++++
> drivers/ptp/Kconfig                |   1 +
> drivers/ptp/ptp_ocp.c              | 123 ++--
> include/linux/dpll.h               | 261 ++++++++
> include/linux/dpll_attr.h          | 433 +++++++++++++
> include/uapi/linux/dpll.h          | 263 ++++++++
> 18 files changed, 4002 insertions(+), 37 deletions(-)  create mode 100644
>Documentation/networking/dpll.rst  create mode 100644 drivers/dpll/Kconfig
>create mode 100644 drivers/dpll/Makefile  create mode 100644
>drivers/dpll/dpll_attr.c  create mode 100644 drivers/dpll/dpll_core.c
>create mode 100644 drivers/dpll/dpll_core.h  create mode 100644
>drivers/dpll/dpll_netlink.c  create mode 100644 drivers/dpll/dpll_netlink.h
>create mode 100644 drivers/dpll/dpll_pin_attr.c  create mode 100644
>include/linux/dpll.h  create mode 100644 include/linux/dpll_attr.h  create
>mode 100644 include/uapi/linux/dpll.h
>
>--
>2.27.0

New thread with regard of our yesterday's call.

Is it possible to initialize a multiple output MUX?
Yes it is. Let's consider 4 input/2 output MUX and DPLL it connects with:
            +---+   
          --|   |   
  +---+     |   |   
--|   |   --| D |--
  |   |     | P |   
--| M |-----| L |--
  | U |     | L |   
--| X |-----|   |--
  |   |     |   |   
--|   |   --|   |   
  +---+     +---+  
 
Basically dpll pins are initialized and assigned ids, like:
5 inputs (0-4), 3 outputs (5-7).
   +---+   
0--|   |   
   |   |   
1--| D |--5
   | P |   
2--| L |--6
   | L |   
3--|   |--7
   |   |   
4--|   |   
   +---+

Then we would create and register muxed pins with existing dpll pins.
Each muxed pin is allocated and registered with each parent it can provide
signal with, like below (number in bracket is parent idx):
                           +---+   
                        0--|   |   
                +---+      |   |   
 8(2) /  9(3)---|   |   1--| D |--5
                |   |      | P |   
10(2) / 11(3)---| M |---2--| L |--6
                | U |      | L |   
12(2) / 13(3)---| X |---3--|   |--7
                |   |      |   |   
14(2) / 15(3)---|   |   4--|   |   
                +---+      +---+

Controlling the mux input/output:
In this case selecting pin #8 would provide its signal into DPLLs input#2 and
selecting #9 would provide its signal into DPLLs input#3.

BR,
Arkadiusz