[LEDE-DEV] telephony: adding telephony functionality

[Giuseppe Lippolis]

>Dear All,
>after some investigation on my DWR-512 board I discovered the hw
architecture of the telephone voice channel embedded in the router.
>The board embeds one 3g modem plugged on the mini pcie slot and one proslic
device (si3210 - subscriber line interface circuit).
>The hw architecture is shown below.
>
>        T                   V
>        |                   |
>      +-------+           +-------+
>IRQ   |       |  PCM bus  |       | events
>  +---|  si   |<=========>|   3g  |---------+
>  |   | 3210  |           | modem |         |
>  |   +-------+           +-------+         |
>  |     ^                     ^             |
>  |     |                     |             |
>  |     | spidev1.0           |             |
>  |     |                     | ttyUSB0/1   |
>  |   +-------+               |             |
>  |   |       |---------------+             |
>  +-->|  uP   |                             |
>gpio1 |       |<----------------------------+
>      +-------+     ttyUSB1
>	  

>My next plan is to develop a driver for the si3210 and then one userspace
daemon to enable the telephone voice (and sms) channel functions.

>Have someone some comments about this plan?

I found an interesting tentative to add a telephony class in linux, it was
the phonedev.c class by Alan Cox.
Nevertheless this piece of code has been removed since kernel 3.6
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7
326446c728f633a0d6b3318cf491f71f044dce0
Make sense revert it back?

Bye.