From eaddd774bd64a3fa4eda7658e59f459ce8c5fcf7 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@spreadspace.org>
Date: Thu, 14 Oct 2021 00:43:17 +0200
Subject: sensornodes: add support for gpio

---
 files/common/openwrt/sensors.module_lua | 69 ++++++++++++++++++++++++++++++++-
 1 file changed, 68 insertions(+), 1 deletion(-)

(limited to 'files/common/openwrt/sensors.module_lua')

diff --git a/files/common/openwrt/sensors.module_lua b/files/common/openwrt/sensors.module_lua
index 087ed7d5..499886b0 100644
--- a/files/common/openwrt/sensors.module_lua
+++ b/files/common/openwrt/sensors.module_lua
@@ -11,6 +11,8 @@ local _internal_ = {}
 _internal_.setup = {}
 _internal_.read = {}
 
+
+
 -- ############# utils ###########
 
 function _internal_.write_to_file(path, data)
@@ -32,6 +34,8 @@ function _internal_.read_from_file(path)
     return data, err
 end
 
+
+
 -- ############# i2c ###########
 
 function _M.i2c_bus_path(bus)
@@ -83,7 +87,8 @@ function _M.i2c_add_devices_recursive(bus, devices)
     local num_devices = 0
     local device
     for _, device in base.ipairs(devices) do
-        _M.i2c_add_device(bus, device.address, device.type)
+        local ret, err = _M.i2c_add_device(bus, device.address, device.type)
+        if not ret then return nil, err end
         num_devices = num_devices + 1
 
         local setup_function = _internal_.setup[device.type]
@@ -154,6 +159,7 @@ function _M.w1_device_family_and_serial(address)
     return family, serial
 end
 
+
 function _M.w1_read_sensors(devices)
     local readings = {}
     local device
@@ -176,6 +182,56 @@ function _M.w1_read_sensors(devices)
 end
 
 
+
+-- ############# gpio ###########
+
+function _M.gpio_pin_path(number)
+    return string.format("/sys/class/gpio/gpio%d", number)
+end
+
+function _M.gpio_export_pin(number)
+    return _internal_.write_to_file("/sys/class/gpio/export", string.format("%d", number))
+end
+
+function _M.gpio_unexport_pin(number)
+    return _internal_.write_to_file("/sys/class/gpio/unexport", string.format("%d", number))
+end
+
+function _M.gpio_read_pin(number)
+    local value, err = _internal_.read_from_file(_M.gpio_pin_path(number) .. "/value")
+    if not value then return nil, err end
+    return value:match( "^%s*(.-)%s*$" )
+end
+
+
+function _M.gpio_setup_pins(pins)
+    local num_pins = 0
+    local pin
+    for _, pin in base.ipairs(pins) do
+        local ret, err = _M.gpio_export_pin(pin.number)
+        if not ret then return nil, err end
+        num_pins = num_pins + 1
+    end
+
+    return num_pins
+end
+
+function _M.gpio_read_pins(pins)
+    local readings = {}
+    local pin
+    for _, pin in base.ipairs(pins) do
+        local name = pin.name ~= nil and pin.name or string.format("gpio-%d", pin.number)
+        local value, err = _M.gpio_read_pin(pin.number)
+        if value ~= nil then
+            readings[name] = { gpio = value, _kind_ = 'gpio' }
+        end
+    end
+
+    return readings
+end
+
+
+
 -- ############# iio ###########
 
 function _M.iio_device_path_from_i2c_device(bus, address)
@@ -297,6 +353,7 @@ function _M.hwmon_device_path_from_w1_device(address)
     return device_paths[1]
 end
 
+
 function _M.hwmon_read_w1_therm(address)
     local hwmon_device, err = _M.hwmon_device_path_from_w1_device(address)
     if not hwmon_device then return end
@@ -339,6 +396,11 @@ function _M.setup(config)
     end
     -- for now the only supported 1-wire master device is i2c based and will be initialized above
     -- also sensors on 1-wire busses are discvored automatically and for now no supported sensor needs any setup
+    if config.gpio then
+        local tmp, err = _M.gpio_setup_pins(config.gpio)
+        if not tmp then return nil, err end
+        num_devices = num_devices + tmp
+    end
 end
 
 function _M.read(config)
@@ -354,11 +416,16 @@ function _M.read(config)
         local tmp, err = _M.w1_read_sensors(config.w1)
         if tmp ~= nil then for k,v in base.pairs(tmp) do readings[k] = v end end
     end
+    if config.gpio then
+        local tmp, err = _M.gpio_read_pins(config.gpio)
+        if tmp ~= nil then for k,v in base.pairs(tmp) do readings[k] = v end end
+    end
 
     return readings
 end
 
 
+
 -- ################################
 
 return _M
-- 
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