flm01/mote/v2/openwrt/package/flukso/luasrc/spid.lua

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#! /usr/bin/env lua
--[[
spid.lua - Lua part of the Flukso daemon
Copyright (C) 2011 Bart Van Der Meerssche <bart.vandermeerssche@flukso.net>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
]]--
local dbg = require 'dbg'
local spi = require 'flukso.spi'
local nixio = require 'nixio'
nixio.fs = require 'nixio.fs'
local arg = arg or {} -- needed when this code is not loaded via the interpreter
local DEBUG = (arg[1] == '-d')
local SPI_DEV = '/dev/spidev0.0'
local SPI_MAX_CLK_SPEED_HZ = 1e6
local SPI_MIN_BYTE_DELAY_US = 250
local SPI_TX_RX_DELAY_NS = 2e7
local SPI_CT_DELAY_NS = 5e8
local POLL_TIMEOUT_MS = 100
local TIMERFD_ENABLE = 1
local TIMERFD_SEC = 1
local TIMERFD_NS = 0
local GET_DELTA = 'gd'
local DAEMON = os.getenv('DAEMON') or 'spid'
local DAEMON_PATH = os.getenv('DAEMON_PATH') or '/var/run/' .. DAEMON
local O_RDWR_NONBLOCK = nixio.open_flags('rdwr', 'nonblock')
local POLLIN = nixio.poll_flags('in')
function mkfifos(input)
local path = string.format('%s/%s/', DAEMON_PATH, input)
nixio.fs.mkdirr(path)
-- nixio.fs.unlink(path .. 'in') -- clean up mess from previous run
-- nixio.fs.unlink(path .. 'out') -- idem
nixio.fs.mkfifo(path .. 'in', '644')
nixio.fs.mkfifo(path .. 'out', '644')
local fdin = nixio.open(path .. 'in', O_RDWR_NONBLOCK)
local fdout = nixio.open(path .. 'out', O_RDWR_NONBLOCK)
return { fd = fdin, -- need this entry for nixio.poll
fdin = fdin,
fdout = fdout,
events = POLLIN,
revents = 0,
line = fdin:linesource() }
end
local uart = mkfifos('uart')
local ctrl = mkfifos('ctrl')
local delta = mkfifos('delta')
if TIMERFD_ENABLE == 1 then
delta.fd = nixio.timerfd(TIMERFD_SEC, TIMERFD_NS, TIMERFD_SEC, TIMERFD_NS)
end
local fds = { uart, ctrl, delta }
local spidev = nixio.open(SPI_DEV, O_RDWR_NONBLOCK)
nixio.spi.setspeed(spidev, SPI_MAX_CLK_SPEED_HZ, SPI_MIN_BYTE_DELAY_US)
spidev:lock('lock') -- blocks until it can place a write lock on the spidev device
while true do
local msg
local poll = nixio.poll(fds, POLL_TIMEOUT_MS)
if poll == 0 then -- poll timed out, so time to 'poll' the spi bus
msg = spi.new_msg('', '')
elseif poll > 0 then
if ctrl.revents == POLLIN then
msg = spi.new_msg('ctrl', ctrl.line())
msg:parse()
elseif delta.revents == POLLIN then
if TIMERFD_ENABLE == 1 then
delta.fd:numexp() -- reset the numexp counter
else
delta.line()
end
msg = spi.new_msg('delta', GET_DELTA)
msg:parse()
elseif uart.revents == POLLIN then
msg = spi.new_msg('uart', uart.line())
end
msg:encode()
msg:tx(spidev)
msg:wait(SPI_TX_RX_DELAY_NS, SPI_CT_DELAY_NS)
end
if poll >= 0 then
msg:rx(spidev)
local dispatch = msg:decode()
if DEBUG then dbg.vardump(msg) end
if dispatch.ctrl then
ctrl.fdout:write(dispatch.ctrl .. '\n')
end
if dispatch.delta then
delta.fdout:write(dispatch.delta .. '\n')
end
if dispatch.uart then
uart.fdout:write(dispatch.uart .. '\n')
end
end
end