LuPPC/src/lua/core/gpio.lua

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local gpio = {}
local fopen = native.fs_open
local fread = native.fs_read
local fwrite = native.fs_write
local fclose = native.fs_close
local fexists = native.fs_exists
local function _read(file)
local fd = fopen(file, "r")
if not fd then
return nil, "Can't open " .. file .. " for reading"
end
local v = fread(fd, 1024)
fclose(fd)
return v
end
local function _write(file, value)
local fd = fopen(file, "w")
if not fd then
return false, "Can't open " .. file .. " for writing"
end
fwrite(fd, value)
fclose(fd)
return true
end
gpio.register = function ()
if not fexists("/sys/class/gpio") then
return
end
local component = {}
function component.pinMode(pin, mode) --TODO: return current mode if no new is specified
checkArg(1, pin, "number")
checkArg(2, mode, "string")
pin = tostring(math.floor(pin))
if mode ~= "in" and mode ~= "out" then
return false, "Invalid mode string"
end
if not fexists("/sys/class/gpio/gpio" .. pin) then
_write("/sys/class/gpio/export", pin)
end
if not _write("/sys/class/gpio/gpio" .. pin .. "/direction", mode) then
return false, "Couldn't set pin mode"
end
return mode
end
function component.write(pin, value)
checkArg(1, pin, "number")
checkArg(2, pin, "boolean", "number", "nil")
pin = tostring(math.floor(pin))
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value = (value == true or (type(value) == "number" and value & 1 == 1) ) and "1" or "0"
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if not fexists("/sys/class/gpio/gpio" .. pin) then
return false, "Set pin mode first"
end
if not _write("/sys/class/gpio/gpio" .. pin .. "/value", value) then
return false, "Couldn't set pin value"
end
end
function component.read(pin)
checkArg(1, pin, "number")
pin = tostring(math.floor(pin))
if not fexists("/sys/class/gpio/gpio" .. pin) then
return false, "Set pin mode first"
end
return _read("/sys/class/gpio/gpio" .. pin .. "/value")
end
return modules.component.api.register(uuid, "gpio", component)
end
return gpio