Add ow naming+snmp

[sittner]

Added support for name mapping of onewire rom addresses to meaningful names. Mappings are stored in EEPROM.
Values and names are queryable by snmp.
Option for reading out values via "1w list"

[mguentner]

I would store the sensor name inside the ow_sensor_t (*ow_sensors) to avoid data duplication of ow_rom_code.

[sittner]

The intention behind the usage of ow_names_table where three points:

• independent usage of ONEWIRE_POLLING_SUPPORT and ONEWIRE_NAMING_SUPPORT
• edit name table in RAM and make it persistent by ecmd command
• fixed index table for SNMP support

But you are right, the n x 64 bit rom codes waste a lot of ram. My sugesstion is to use ow_sensors in every case ONEWIRE_POLLING_SUPPORT/ONEWIRE_NAMING_SUPPORT is involved and to define the members as needed. ow_discover_sensor will update records with matching rom codes and append new sensors. The rom codes of named sensors are not touched by ow_discover_sensor if the sensor is not present.

[mguentner]

Sounds good to me.
While you're at it, can you have a look at my commit which slightly reduces the size of ow_sensor_t ? I haven't tested the code so far. If it works for you, feel free to include the commit in your PR.
mguentner@c057d04

[sittner]

I've tried to fix the issues. Your commit is included.

[mguentner]

That was fast :). Looks good!

Have you tested the code in combination with ONEWIRE_BUSCOUNT > 1 ?
I assume it will work but you cannot be sure without testing. Maybe @sauttefk can test whether the code works with more than one bus.

[sittner]

I can test it on weekend. I've planed to split my bus anyway :-)

[sittner]

OK. I did the tests even with two buses and I hope I've tested all cominations. I've done the following changes (nothing related to ONEWIRE_BUSCOUNT):

• trigger discovery on add/remove a name
• simplified output generation for emcd to save flash memory
• fix the loop in ow_periodic. Please take a look to the comment in onewire.c on the last commit.

[mguentner]

Please document your changes in the wiki aswell. http://ethersex.de/index.php/Onewire

[sauttefk]

On 10.04.2012 19:32, Maximilian Güntner wrote:

Please document your changes in the wiki aswell.
http://ethersex.de/index.php/Onewire
von mir stammt die multibus geschichte und ein paar verbesserungen am
onewire timining (weniger interrupt blockierung).

die konfiguration der busse ist ja bereits im o.g. link beschrieben, der
rest sind internas, die den normalen nutzer nicht interessieren.

grüße
frank