From e876094f54aa3d4fc57b0ee3455ba5653facce67 Mon Sep 17 00:00:00 2001
From: Paul Oliver <contact@pauloliver.dev>
Date: Mon, 27 Jan 2025 21:43:49 +0000
Subject: Adds C bindings to interface with libgpiod
---
hsm-gpio/Hsm/GPIO/Lib.hsc | 116 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 116 insertions(+)
create mode 100644 hsm-gpio/Hsm/GPIO/Lib.hsc
(limited to 'hsm-gpio/Hsm/GPIO/Lib.hsc')
diff --git a/hsm-gpio/Hsm/GPIO/Lib.hsc b/hsm-gpio/Hsm/GPIO/Lib.hsc
new file mode 100644
index 0000000..6716f3a
--- /dev/null
+++ b/hsm-gpio/Hsm/GPIO/Lib.hsc
@@ -0,0 +1,116 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE ForeignFunctionInterface #-}
+
+-- This module provides C bindings to the `gpiod` library for direct GPIO pin
+-- control. It includes bindings only for the C functions that are currently
+-- used. In the future, creating a complete set of bindings for the entire
+-- `gpiod` library as an external package would be a valuable contribution to
+-- Hackage.
+
+module Hsm.GPIO.Lib
+ ( chipOpen
+ , chipClose
+ , input
+ , output
+ , LineValue
+ , active
+ , inactive
+ , lineSettingsNew
+ , lineSettingsFree
+ , lineSettingsSetDirection
+ , lineSettingsSetOutputValue
+ , lineConfigNew
+ , lineConfigFree
+ , lineConfigAddLineSettings
+ , requestConfigNew
+ , requestConfigFree
+ , requestConfigSetConsumer
+ , requestLines
+ , LineRequest
+ , lineRequestRelease
+ , lineRequestSetValue
+ , lineRequestSetValues
+ ) where
+
+#include <gpiod.h>
+
+import Foreign.C.String (CString)
+import Foreign.C.Types (CInt(CInt), CSize(CSize), CUInt(CUInt))
+import Foreign.Ptr (Ptr)
+import Foreign.Storable (Storable)
+
+data Chip
+
+foreign import ccall unsafe "gpiod.h gpiod_chip_open"
+ chipOpen :: CString -> IO (Ptr Chip)
+
+foreign import ccall unsafe "gpiod.h gpiod_chip_close"
+ chipClose :: Ptr Chip -> IO ()
+
+data LineSettings
+
+newtype LineDirection =
+ LineDirection CInt
+ deriving (Show)
+
+#{enum LineDirection, LineDirection
+ , input = GPIOD_LINE_DIRECTION_INPUT
+ , output = GPIOD_LINE_DIRECTION_OUTPUT
+}
+
+newtype LineValue =
+ LineValue CInt
+ deriving (Show, Storable)
+
+#{enum LineValue, LineValue
+ , active = GPIOD_LINE_VALUE_ACTIVE
+ , inactive = GPIOD_LINE_VALUE_INACTIVE
+}
+
+foreign import ccall unsafe "gpiod.h gpiod_line_settings_new"
+ lineSettingsNew :: IO (Ptr LineSettings)
+
+foreign import ccall unsafe "gpiod.h gpiod_line_settings_free"
+ lineSettingsFree :: Ptr LineSettings -> IO ()
+
+foreign import ccall unsafe "gpiod.h gpiod_line_settings_set_direction"
+ lineSettingsSetDirection :: Ptr LineSettings -> LineDirection -> IO CInt
+
+foreign import ccall unsafe "gpiod.h gpiod_line_settings_set_output_value"
+ lineSettingsSetOutputValue :: Ptr LineSettings -> LineValue -> IO CInt
+
+data LineConfig
+
+foreign import ccall unsafe "gpiod.h gpiod_line_config_new"
+ lineConfigNew :: IO (Ptr LineConfig)
+
+foreign import ccall unsafe "gpiod.h gpiod_line_config_free"
+ lineConfigFree :: Ptr LineConfig -> IO ()
+
+foreign import ccall unsafe "gpiod.d gpiod_line_config_add_line_settings"
+ lineConfigAddLineSettings :: Ptr LineConfig -> Ptr CUInt -> CSize -> Ptr LineSettings -> IO CInt
+
+data RequestConfig
+
+foreign import ccall unsafe "gpiod.h gpiod_request_config_new"
+ requestConfigNew :: IO (Ptr RequestConfig)
+
+foreign import ccall unsafe "gpiod.h gpiod_request_config_free"
+ requestConfigFree :: Ptr RequestConfig -> IO ()
+
+foreign import ccall unsafe "gpiod.h gpiod_request_config_set_consumer"
+ requestConfigSetConsumer :: Ptr RequestConfig -> CString -> IO ()
+
+data LineRequest
+
+foreign import ccall unsafe "gpiod.h gpiod_chip_request_lines"
+ requestLines :: Ptr Chip -> Ptr RequestConfig -> Ptr LineConfig -> IO (Ptr LineRequest)
+
+foreign import ccall unsafe "gpiod.h gpiod_line_request_release"
+ lineRequestRelease :: Ptr LineRequest -> IO ()
+
+foreign import ccall unsafe "gpiod.h gpiod_line_request_set_value"
+ lineRequestSetValue :: Ptr LineRequest -> CUInt -> LineValue -> IO CInt
+
+foreign import ccall unsafe "gpiod.h gpiod_line_request_set_values"
+ lineRequestSetValues :: Ptr LineRequest -> Ptr LineValue -> IO CInt
--
cgit v1.2.1