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local base = _G
local io = require("io")
local string = require("string")
local cjson = require "cjson.safe"
local glob = require "posix.glob"
local time = require "posix.time"
local unistd = require "posix.unistd"
local _M = {}
local _internal_ = {}
_internal_.setup = {}
-- ############# i2c ###########
function _internal_.write_to_file(path, data)
-- base.print(string.format("writing '%s' to '%s'", data, path))
local f, err = io.open(path, "w")
if not f then return nil, err end
ret, err = f:write(data)
f:close()
return ret, err
end
function _internal_.read_from_file(path)
local f, err = io.open(path, "r")
if not f then return nil, err end
data, err = f:read("*a")
f:close()
return data, err
end
-- ############# i2c ###########
function _M.i2c_bus_path(bus)
return string.format("/sys/bus/i2c/devices/i2c-%d", bus)
end
function _M.i2c_device_name(bus, address)
return string.format("%d-%04X", bus, address)
end
function _M.i2c_device_path(bus, address)
return string.format("/sys/bus/i2c/devices/" .. _M.i2c_device_name(bus, address))
end
function _M.i2c_add_device(bus, address, name)
return _internal_.write_to_file(_M.i2c_bus_path(bus) .. "/new_device", string.format("%s 0x%02X", name, address))
end
function _M.i2c_delete_device(bus, address)
return _internal_.write_to_file(_M.i2c_bus_path(bus) .. "/delete_device", string.format("0x%02X", address))
end
function _M.i2c_get_mux_channels(parent, address)
local channel_paths, glob_result = glob.glob(_M.i2c_device_path(parent, address) .. "/channel-*", 0)
if not channel_paths then
if glob_result == glob.GLOB_NOMATCH then return {} end
if glob_result == glob.GLOB_ABORTED then return nil, "glob(): aborted" end
if glob_result == glob.GLOB_NOSPACE then return nil, "glob(): no space" end
return nil, "glob(): unknown error"
end
local channels = {}
for _, channel_path in base.pairs(channel_paths) do
local channel = string.match(channel_path, '/channel%-(%d+)$')
if not channel then return nil, "unable to parse channel number from path: " .. channel_path end
local bus_path, err = unistd.readlink(channel_path)
if not bus_path then return nil, err end
local bus = string.match(bus_path, '/i2c%-(%d+)$')
if not bus then return nil, "unable to parse bus number from path: " .. bus_path end
channels[tonumber(channel)] = tonumber(bus)
end
return channels
end
function _M.i2c_add_devices_recursive(bus, devices)
local num_devices = 0
local device
for _, device in base.ipairs(devices) do
-- base.print(string.format("i2c_add_device(%d, 0x%02X, %s)", bus, device.address, device.driver))
_M.i2c_add_device(bus, device.address, device.driver)
num_devices = num_devices + 1
local setup_function = _internal_.setup[device.driver]
if setup_function ~= nil then
time.nanosleep({tv_sec = 0, tv_nsec = 100000000})
setup_function(bus, device.address)
end
if device.channels then
time.nanosleep({tv_sec = 0, tv_nsec = 100000000})
local mux_channels, err = _M.i2c_get_mux_channels(bus, device.address)
if not mux_channels then return nil, error end
local channel
for _, channel in base.ipairs(device.channels) do
if not mux_channels[channel.number] then return nil, string.format("i2c-mux %s has no channel %d", _M.i2c_device_name(bus, device.address), channel.number) end
local tmp, err = _M.i2c_add_devices_recursive(mux_channels[channel.number], channel.devices)
if not tmp then return nil, err end
num_devices = num_devices + tmp
end
end
end
return num_devices
end
-- ############# II0 ###########
function _M.iio_device_path_from_i2c_device(bus, address)
local device_paths, glob_result = glob.glob(_M.i2c_device_path(bus, address) .. "/iio:device*", 0)
if not device_paths then
if glob_result == glob.GLOB_NOMATCH then return nil, "couldn't find IIO device handle for i2c device " .. _M.i2c_device_name(bus, address) end
if glob_result == glob.GLOB_ABORTED then return nil, "glob(): aborted" end
if glob_result == glob.GLOB_NOSPACE then return nil, "glob(): no space" end
return nil, "glob(): unknown error"
end
if #device_paths ~= 1 then return nil, "found more than one IIO device for i2c device " .. _M.i2c_device_name(bus, address) end
return device_paths[1]
end
function _M.iio_setup_bmp280(bus, address)
local iio_device, err = _M.iio_device_path_from_i2c_device(bus, address)
if not iio_device then return nil, err end
local ret, err = _internal_.write_to_file(iio_device .. '/in_pressure_oversampling_ratio', '1')
if not ret then return nil, err end
return _internal_.write_to_file(iio_device .. '/in_temp_oversampling_ratio', '1')
end
_internal_.setup['bmp280'] = _M.iio_setup_bmp280
function _M.iio_setup_bme280(bus, address)
local iio_device, err = _M.iio_device_path_from_i2c_device(bus, address)
if not iio_device then return nil, err end
local ret, err = _internal_.write_to_file(iio_device .. '/in_humidityrelative_oversampling_ratio', '1')
if not ret then return nil, err end
local ret, err = _internal_.write_to_file(iio_device .. '/in_pressure_oversampling_ratio', '1')
if not ret then return nil, err end
return _internal_.write_to_file(iio_device .. '/in_temp_oversampling_ratio', '1')
end
_internal_.setup['bme280'] = _M.iio_setup_bme280
-- ############# config ###########
function _M.read_config(path)
sensors_json, err = _internal_.read_from_file(path)
if not sensors_json then return nil, err end
return cjson.decode(sensors_json)
end
function _M.setup(config)
local num_devices = 0
if config.i2c then
local i2c_bus
for _, i2c_bus in ipairs(config.i2c) do
local tmp, err = _M.i2c_add_devices_recursive(i2c_bus.number, i2c_bus.devices)
if not tmp then return nil, err end
num_devices = num_devices + tmp
end
end
end
-- ################################
return _M
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