Switch to raw sysfs

Author: BenChung

deploy/Manifest.toml

@@ -2,7 +2,7 @@
 
 julia_version = "1.12.4"
 manifest_format = "2.0"
-project_hash = "1f4210cd068465307a9c95f53a8d8f3e44b6baa9"
+project_hash = "87738c60e6c51224ddbda83104ac0e922de89472"
 
 [[deps.ArgTools]]
 uuid = "0dad84c5-d112-42e6-8d28-ef12dabb789f"
@@ -35,12 +35,6 @@ version = "1.7.0"
 uuid = "7b1f6079-737a-58dc-b8bc-7a2ca5c1b5ee"
 version = "1.11.0"
 
-[[deps.JLLWrappers]]
-deps = ["Artifacts", "Preferences"]
-git-tree-sha1 = "0533e564aae234aff59ab625543145446d8b6ec2"
-uuid = "692b3bcd-3c85-4b1f-b108-f13ce0eb3210"
-version = "1.7.1"
-
 [[deps.JuliaSyntaxHighlighting]]
 deps = ["StyledStrings"]
 uuid = "ac6e5ff7-fb65-4e79-a425-ec3bc9c03011"
@@ -198,18 +192,6 @@ version = "1.11.0"
 uuid = "4ec0a83e-493e-50e2-b9ac-8f72acf5a8f5"
 version = "1.11.0"
 
-[[deps.WiringPi]]
-deps = ["WiringPi_jll"]
-git-tree-sha1 = "9c9733c7f8ca73698ce601fc2df625be5270f334"
-uuid = "56b06491-0088-44d9-858f-9bc194f2c904"
-version = "0.2.2"
-
-[[deps.WiringPi_jll]]
-deps = ["Artifacts", "JLLWrappers", "Libdl"]
-git-tree-sha1 = "99a7679f9e8618aca73b022548c032eecdac42e1"
-uuid = "39e6258f-44e5-5edf-b49b-51a5e5bce6ab"
-version = "3.16.0+0"
-
 [[deps.Zlib_jll]]
 deps = ["Libdl"]
 uuid = "83775a58-1f1d-513f-b197-d71354ab007a"

deploy/Project.toml

@@ -2,4 +2,3 @@
 Printf = "de0858da-6303-5e67-8744-51eddeeeb8d7"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Timers = "21f18d07-b854-4dab-86f0-c15a3821819a"
-WiringPi = "56b06491-0088-44d9-858f-9bc194f2c904"

deploy/src/encoder.jl

@@ -1,25 +1,29 @@
-using WiringPi
+include(joinpath(@__DIR__, "gpio.jl"))
+using .GPIO
 
 #=============================================================================
   Encoder Struct and Basic Operations
 =============================================================================#
 
 mutable struct Encoder
-    pin::Int
+    line::GPIO.GPIOLine
     count::Int
     state::Bool
 end
 
-function Encoder(pin::Int)
-    return Encoder(pin, 0, digitalRead(pin) == HIGH)
+function Encoder(chip::GPIO.GPIOChip, pin::Int)
+    line = GPIO.get_line(chip, pin)
+    GPIO.request_input(line, "encoder")
+    initial_state = GPIO.get_value(line) == 1
+    return Encoder(line, 0, initial_state)
 end
 
 function step!(e::Encoder)
-    new_state = digitalRead(e.pin)
-    if e.state && new_state == LOW
+    new_state = GPIO.get_value(e.line)
+    if e.state && new_state == 0
         e.count += 1
         e.state = false
-    elseif !e.state && new_state == HIGH
+    elseif !e.state && new_state == 1
         e.state = true
     end
 end
@@ -28,6 +32,10 @@ function reset!(e::Encoder)
     e.count = 0
 end
 
+function close!(e::Encoder)
+    GPIO.release_line(e.line)
+end
+
 #=============================================================================
   Threaded Encoder Wrapper
 =============================================================================#
@@ -42,7 +50,8 @@ Send commands via the command channel, receive count via the response channel.
 
 # Example
 ```julia
-enc = Encoder(pin)
+chip = GPIO.open_chip()
+enc = Encoder(chip, pin)
 tenc = ThreadedEncoder(enc, 1_000_000)  # 1ms poll interval
 
 # Read current count

deploy/src/gpio.jl

@@ -0,0 +1,228 @@
+#=============================================================================
+  GPIO Wrapper using sysfs
+
+  Provides Julia interface for GPIO control via /sys/class/gpio/
+  No external library dependencies - pure file I/O.
+=============================================================================#
+
+module GPIO
+
+export GPIOPin, INPUT, OUTPUT
+export export_pin, unexport_pin, set_direction, set_value, get_value
+
+const GPIO_SYSFS_PATH = "/sys/class/gpio"
+
+# Line direction
+@enum LineDirection begin
+    INPUT
+    OUTPUT
+end
+
+#=============================================================================
+  GPIO Pin Handle
+=============================================================================#
+
+mutable struct GPIOPin
+    pin::Int
+    path::String
+    exported::Bool
+    direction::LineDirection
+end
+
+#=============================================================================
+  Low-level sysfs Operations
+=============================================================================#
+
+"""
+    sysfs_write(path::String, value::String)
+
+Write a value to a sysfs file.
+"""
+function sysfs_write(path::String, value::String)
+    f = open(path, "w")
+    try
+        write(f, value)
+    finally
+        close(f)
+    end
+end
+
+"""
+    sysfs_read(path::String) -> String
+
+Read a value from a sysfs file.
+"""
+function sysfs_read(path::String)
+    f = open(path, "r")
+    try
+        return strip(read(f, String))
+    finally
+        close(f)
+    end
+end
+
+#=============================================================================
+  Pin Export/Unexport
+=============================================================================#
+
+"""
+    export_pin(pin::Int) -> GPIOPin
+
+Export a GPIO pin for userspace control.
+"""
+function export_pin(pin::Int)
+    pin_path = joinpath(GPIO_SYSFS_PATH, "gpio$pin")
+
+    # Export if not already exported
+    if !isdir(pin_path)
+        export_file = joinpath(GPIO_SYSFS_PATH, "export")
+        sysfs_write(export_file, string(pin))
+        # Wait for sysfs to create the directory
+        sleep(0.05)
+    end
+
+    if !isdir(pin_path)
+        error("Failed to export GPIO pin $pin")
+    end
+
+    return GPIOPin(pin, pin_path, true, INPUT)
+end
+
+"""
+    unexport_pin(gpio::GPIOPin)
+
+Unexport a GPIO pin.
+"""
+function unexport_pin(gpio::GPIOPin)
+    if gpio.exported
+        unexport_file = joinpath(GPIO_SYSFS_PATH, "unexport")
+        sysfs_write(unexport_file, string(gpio.pin))
+        gpio.exported = false
+    end
+end
+
+#=============================================================================
+  Direction Control
+=============================================================================#
+
+"""
+    set_direction(gpio::GPIOPin, direction::LineDirection)
+
+Set the GPIO pin direction (INPUT or OUTPUT).
+"""
+function set_direction(gpio::GPIOPin, direction::LineDirection)
+    direction_file = joinpath(gpio.path, "direction")
+    dir_str = direction == OUTPUT ? "out" : "in"
+    sysfs_write(direction_file, dir_str)
+    gpio.direction = direction
+end
+
+#=============================================================================
+  Value Read/Write
+=============================================================================#
+
+"""
+    set_value(gpio::GPIOPin, value::Int)
+
+Set the value of an output pin (0 or 1).
+"""
+function set_value(gpio::GPIOPin, value::Int)
+    value_file = joinpath(gpio.path, "value")
+    sysfs_write(value_file, value == 0 ? "0" : "1")
+end
+
+"""
+    get_value(gpio::GPIOPin) -> Int
+
+Get the value of a pin (0 or 1).
+"""
+function get_value(gpio::GPIOPin)
+    value_file = joinpath(gpio.path, "value")
+    val_str = sysfs_read(value_file)
+    return parse(Int, val_str)
+end
+
+#=============================================================================
+  Convenience Functions (compatible with previous API)
+=============================================================================#
+
+# Compatibility types
+const GPIOChip = Nothing
+const GPIOLine = GPIOPin
+
+"""
+    open_chip(path::String="/dev/gpiochip0") -> Nothing
+
+Dummy function for API compatibility. sysfs doesn't use chip handles.
+"""
+function open_chip(path::String="/dev/gpiochip0")
+    return nothing
+end
+
+"""
+    close_chip(chip::Nothing)
+
+Dummy function for API compatibility.
+"""
+function close_chip(chip::Nothing)
+    return nothing
+end
+
+"""
+    get_line(chip::Nothing, pin::Int) -> GPIOPin
+
+Export and return a GPIO pin. Chip argument ignored (sysfs doesn't use it).
+"""
+function get_line(chip::Nothing, pin::Int)
+    return export_pin(pin)
+end
+
+"""
+    request_output(gpio::GPIOPin, consumer::String, default_value::Int=0)
+
+Configure pin as output with initial value.
+"""
+function request_output(gpio::GPIOPin, consumer::String, default_value::Int=0)
+    set_direction(gpio, OUTPUT)
+    set_value(gpio, default_value)
+    return 0
+end
+
+"""
+    request_input(gpio::GPIOPin, consumer::String)
+
+Configure pin as input.
+"""
+function request_input(gpio::GPIOPin, consumer::String)
+    set_direction(gpio, INPUT)
+    return 0
+end
+
+"""
+    release_line(gpio::GPIOPin)
+
+Unexport the GPIO pin.
+"""
+function release_line(gpio::GPIOPin)
+    unexport_pin(gpio)
+end
+
+"""
+    digitalWrite(gpio::GPIOPin, value::Bool)
+
+Set a GPIO output pin high (true) or low (false).
+"""
+function digitalWrite(gpio::GPIOPin, value::Bool)
+    set_value(gpio, value ? 1 : 0)
+end
+
+"""
+    digitalRead(gpio::GPIOPin) -> Bool
+
+Read a GPIO input pin state.
+"""
+function digitalRead(gpio::GPIOPin)
+    return get_value(gpio) == 1
+end
+
+end # module GPIO