Add support for GPIO line names via libgpiod

.gitignore

@@ -65,4 +65,7 @@ Makefile
 
 # Editor
 *.orig
-*.rej
+*.rej
+
+# build dirs
+build-*

CMakeLists.txt

@@ -5,14 +5,25 @@ project(libnfcnci
     DESCRIPTION "NFC NCI library adapted for use with EVerest"
     LANGUAGES C CXX)
 
+include(GNUInstallDirs)
+
 find_package(everest-cmake 0.1 REQUIRED
     PATHS ../everest-cmake
 )
 find_package(Threads REQUIRED)
-find_library(LIBRT rt)
+
 
 option(LIBNFCNCI_BUILD_EXAMPLES "enable building of examples" OFF)
 option(LIBNFCNCI_INSTALL "Install the library (shared data might be installed anyway)" ${EVC_MAIN_PROJECT})
+option(LIBNFCNCI_LIBGPIOD "Build with libgpiod support" OFF)
+
+if (LIBNFCNCI_LIBGPIOD)
+    # search for package PkgConfig
+    find_package(PkgConfig REQUIRED)
+
+    # search for libgpiod
+    pkg_search_module(LIBGPIOD REQUIRED libgpiodcxx)
+endif()
 
 if (NOT LIBNFCNCI_CONFIG_INSTALL_PATH)
     set (LIBNFCNCI_CONFIG_INSTALL_PATH "${CMAKE_INSTALL_SYSCONFDIR}/everest/libnfc_config/")
@@ -23,6 +34,14 @@ set (LIBNFCNCI_CONFIG_FILES
     conf/libnfc-nxp.conf
 )
 
+set(LIBNFCNCI_PUBLIC_HEADERS
+    src/include/linux_nfc_api.h
+    src/include/linux_nfc_api_compatibility.h
+    src/include/linux_nfc_factory_api.h
+)
+
+set(LIBNFCNCI_SOVERSION 1)
+
 set (LIBNFCNCI_SOURCES
     src/android/utility/base/file.cpp
     src/libnfc-utils/src/ConfigPathProvider.cc
@@ -227,10 +246,11 @@ set (COMPILE_DEFINITIONS
     -DSNEP_ENABLED
 )
 
+
 #
 # library target
 #
-add_library(libnfc_nci)
+add_library(libnfc_nci SHARED)
 add_library(libnfc_nci::libnfc_nci ALIAS libnfc_nci)
 
 target_sources(libnfc_nci
@@ -242,7 +262,9 @@ target_sources(libnfc_nci
 
 target_compile_definitions(libnfc_nci
     PRIVATE
-        ${COMPILE_DEFINITIONS})
+        ${COMPILE_DEFINITIONS}
+        $<$<BOOL:${LIBNFCNCI_LIBGPIOD}>:USE_LIBGPIOD>
+)
 
 # NOTE (aw): this is dangerous
 target_compile_options(libnfc_nci
@@ -261,9 +283,27 @@ target_include_directories(libnfc_nci
 target_link_libraries(libnfc_nci
     PRIVATE
         Threads::Threads
-        ${LIBRT}
 )
 
+set_target_properties(libnfc_nci
+    PROPERTIES
+        VERSION ${PROJECT_VERSION}
+        SOVERSION ${LIBNFCNCI_SOVERSION}
+        OUTPUT_NAME nfc_nci
+)
+
+if(LIBNFCNCI_LIBGPIOD)
+    target_include_directories(libnfc_nci
+        PRIVATE
+            ${LIBGPIOD_INCLUDE_DIRS}
+    )
+
+    target_link_libraries(libnfc_nci
+        PRIVATE
+            ${LIBGPIOD_LIBRARIES}
+    )
+endif()
+
 #
 # examples
 #
@@ -277,6 +317,10 @@ if(LIBNFCNCI_BUILD_EXAMPLES)
         PRIVATE
             libnfc_nci
     )
+    install(
+        TARGETS nfc_cb_example
+        RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+    )
 
     add_executable(nfc_demo)
     target_sources(nfc_demo
@@ -288,6 +332,10 @@ if(LIBNFCNCI_BUILD_EXAMPLES)
         PRIVATE
             libnfc_nci
     )
+    install(
+        TARGETS nfc_demo
+        RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+    )
 endif()
 
 #
@@ -297,10 +345,14 @@ if (LIBNFCNCI_INSTALL)
     install(
         TARGETS libnfc_nci
         EXPORT libnfc_nci-targets
+        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+        RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+        INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
     )
 
     install(
-        DIRECTORY src/include/
+        FILES ${LIBNFCNCI_PUBLIC_HEADERS}
         TYPE INCLUDE
     )
 
@@ -314,6 +366,10 @@ if (LIBNFCNCI_INSTALL)
         NAMESPACE libnfc_nci
         ADDITIONAL_CONTENT
             "find_dependency(Threads)"
+            "set(LIBNFCNCI_LIBGPIOD @LIBNFCNCI_LIBGPIOD@)"
+            "if(LIBNFCNCI_LIBGPIOD)"
+            "    find_dependency(PkgConfig)"
+            "    pkg_search_module(LIBGPIOD REQUIRED libgpiodcxx)"
+            "endif()"
     )
 endif()
-

README.md

@@ -12,6 +12,7 @@ The [original upstream source code](https://github.com/NXPNFCLinux/linux_libnfc-
 - Added CMakeLists.txt
 - Allow for runtime configuration of interface properties for alternative I²C/SPI interface
 - Allow configuration files to be in a custom path
+- Added support for using GPIO line names via libgpiod
 
 ## Building
 
@@ -51,6 +52,13 @@ cmake --install .
 ```
 This will also install the configuration files into the expected folder.
 
+### libgpiod
+
+Building against `libgpiod` can be enabled by passing the property `LIBNFCNCI_LIBGPIOD` set to `ON` to cmake.
+By default, this is disabled.
+Using libgpiod and GPIO line names should be the preferred way to access GPIO lines from user-space since
+the older Linux' sysfs interface is deprecated since ages.
+
 ## Runtime Configuration
 
 Runtime configuration (debug output levels, detailled NFC behaviour, interface specification) happens via the above-mentioned files.
@@ -65,7 +73,6 @@ Relevant settings are:
 
 ```
 NXP_TRANSPORT=0x02
-NXP_NFC_DEV_NODE="/dev/nxpnfc"
 PIN_INT=535
 PIN_ENABLE=536
 PIN_FWDNLD=537
@@ -74,6 +81,20 @@ I2C_BUS="/dev/i2c-1"
 SPI_BUS="/dev/spidev0.0"
 ```
 
+When compiled with libgpiod support, then instead of using integers for Linux' legacy sysfs interface,
+it is possible to use GPIO line names. These are usually defined via Device Tree for your board.
+Such line names must be enclosed in quotation marks to indicate that the configuration value is a string.
+And it cannot be mixed: all pin configuration values needs to be GPIO line names.
+
+```
+NXP_TRANSPORT=0x02
+PIN_INT="RFID_IRQ"
+PIN_ENABLE="nRESET_RFID"
+PIN_FWDNLD="RFID_DWL_REQ"
+I2C_ADDRESS=0x28
+I2C_BUS="/dev/i2c-1"
+```
+
 
 ---
 

conf/libnfc-nxp.conf

@@ -29,19 +29,34 @@ NXPLOG_FWDNLD_LOGLEVEL=0x00
 NXPLOG_TML_LOGLEVEL=0x00
 ###############################################################################
 # TRANSPORT Type
-# 0x00 - I2C /SPI for noraml nxpnfc driver
+# 0x00 - I2C / SPI for normal nxpnfc driver
 # 0x01 - Not Used, kept to align with Android code
-# 0x02 - ALT_I2C
-# 0x03 - ALT_SPI
+# 0x02 - ALT_I2C: standard I2C Linux interface
+# 0x03 - ALT_SPI: standard SPIDEV Linux interface
 NXP_TRANSPORT=0x02
 
 ###############################################################################
-# Nfc Device Node name
+# Nfc Device Node name (only used for NXP_TRANSPORT=0x00)
 NXP_NFC_DEV_NODE="/dev/nxpnfc"
 
 ###############################################################################
 # ALT_I2C/SPI Interface Configuration
 # [PINs defined as GPIO23/24/25 on RPi4 (choose 594, 595, 596 for RPi5)]
+#
+# Integer numbers are used for Linux' deprecated sysfs GPIO interface. When
+# the library is built against libgpiod, then use GPIO line names. Prefixing
+# a line name with '!' signals to libgpiod that the line should be handled with
+# ACTIVE_LOW semantic. In the following example, however, the 'reset pin'
+# has inverted logic and gives thus 'enable' functionality without the need
+# to mark it as active-low.
+# Note: Mixing plain integers and GPIO line names is not supported and results
+# in undefined behavior.
+#
+# Example for GPIO line names usage:
+# PIN_INT="RFID_IRQ"
+# PIN_ENABLE="nRESET_RFID"
+# PIN_FWDNLD="RFID_DWL_REQ"
+#
 PIN_INT=535
 PIN_ENABLE=536
 PIN_FWDNLD=537

demoapp/nfc_cb_example.cpp

@@ -40,7 +40,7 @@ NfcHandler::NfcHandler() {
         throw std::runtime_error("Only one global nfc handler instance allowed");
     }
 
-    setConfigPath("../../build/dist/etc/everest/libnfc_config")
+    setConfigPath("../../build/dist/etc/everest/libnfc_config");
 
     InitializeLogLevel();
 

src/nfcandroid_nfc_hidlimpl/halimpl/tml/transport/NfccAltI2cTransport.cc

@@ -275,26 +275,3 @@ int NfccAltI2cTransport::Write(void* pDevHandle, uint8_t* pBuffer,
   NXPLOG_TML_D("%s exit", __func__);
   return numWrote;
 }
-
-/*******************************************************************************
-**
-** Function         Close
-**
-** Description      Closes NFCC device
-**
-** Parameters       pDevHandle - device handle
-**
-** Returns          None
-**
-*******************************************************************************/
-void NfccAltI2cTransport::Close(void* pDevHandle) {
-  NXPLOG_TML_D("%s Enter", __func__);
-  if (NULL != pDevHandle) {
-    close((intptr_t)pDevHandle);
-  }
-  if (iEnableFd) close(iEnableFd);
-  if (iInterruptFd) close(iInterruptFd);
-  if (iFwDnldFd) close(iFwDnldFd);
-  NXPLOG_TML_D("%s exit", __func__);
-  return;
-}

src/nfcandroid_nfc_hidlimpl/halimpl/tml/transport/NfccAltI2cTransport.h

@@ -21,7 +21,7 @@
 #include <NfccTransport.h>
 
 class NfccAltI2cTransport : public NfccAltTransport {
- public:
+public:
   /*****************************************************************************
    **
    ** Function         OpenAndConfigure
@@ -36,7 +36,7 @@ class NfccAltI2cTransport : public NfccAltTransport {
    **                  NFCSTATUS_INVALID_DEVICE - device open operation failure
    **
    ****************************************************************************/
-  NFCSTATUS OpenAndConfigure(pphTmlNfc_Config_t pConfig, void** pLinkHandle);
+  virtual NFCSTATUS OpenAndConfigure(pphTmlNfc_Config_t pConfig, void** pLinkHandle) override;
 
   /*****************************************************************************
    **
@@ -54,7 +54,7 @@ class NfccAltI2cTransport : public NfccAltTransport {
    **                  -1        - read operation failure
    **
    ****************************************************************************/
-  int Read(void* pDevHandle, uint8_t* pBuffer, int nNbBytesToRead);
+  virtual int Read(void* pDevHandle, uint8_t* pBuffer, int nNbBytesToRead) override;
 
   /*****************************************************************************
   **
@@ -71,6 +71,5 @@ class NfccAltI2cTransport : public NfccAltTransport {
   **                  -1         - write operation failure
   **
   *****************************************************************************/
-  int Write(void* pDevHandle, uint8_t* pBuffer, int nNbBytesToWrite);
-  void Close(void* pDevHandle);
+  virtual int Write(void* pDevHandle, uint8_t* pBuffer, int nNbBytesToWrite) override;
 };

src/nfcandroid_nfc_hidlimpl/halimpl/tml/transport/NfccAltSpiTransport.cc

@@ -390,26 +390,3 @@ int NfccAltSpiTransport::Write(void* pDevHandle, uint8_t* pBuffer,
   NXPLOG_TML_D("%s exit", __func__);
   return numWrote - PREFIX_LENGTH;
 }
-
-/*******************************************************************************
-**
-** Function         Close
-**
-** Description      Closes NFCC device
-**
-** Parameters       pDevHandle - device handle
-**
-** Returns          None
-**
-*******************************************************************************/
-void NfccAltSpiTransport::Close(void* pDevHandle) {
-  NXPLOG_TML_D("%s Enter", __func__);
-  if (NULL != pDevHandle) {
-    close((intptr_t)pDevHandle);
-  }
-  if (iEnableFd) close(iEnableFd);
-  if (iInterruptFd) close(iInterruptFd);
-  if (iFwDnldFd) close(iFwDnldFd);
-  NXPLOG_TML_D("%s exit", __func__);
-  return;
-}

src/nfcandroid_nfc_hidlimpl/halimpl/tml/transport/NfccAltSpiTransport.h

@@ -21,7 +21,7 @@
 #include <NfccTransport.h>
 
 class NfccAltSpiTransport : public NfccAltTransport {
- public:
+public:
   /*****************************************************************************
    **
    ** Function         OpenAndConfigure
@@ -36,7 +36,7 @@ class NfccAltSpiTransport : public NfccAltTransport {
    **                  NFCSTATUS_INVALID_DEVICE - device open operation failure
    **
    ****************************************************************************/
-  NFCSTATUS OpenAndConfigure(pphTmlNfc_Config_t pConfig, void** pLinkHandle);
+  virtual NFCSTATUS OpenAndConfigure(pphTmlNfc_Config_t pConfig, void** pLinkHandle) override;
 
   /*****************************************************************************
    **
@@ -54,7 +54,7 @@ class NfccAltSpiTransport : public NfccAltTransport {
    **                  -1        - read operation failure
    **
    ****************************************************************************/
-  int Read(void* pDevHandle, uint8_t* pBuffer, int nNbBytesToRead);
+  virtual int Read(void* pDevHandle, uint8_t* pBuffer, int nNbBytesToRead) override;
 
   /*****************************************************************************
   **
@@ -71,6 +71,5 @@ class NfccAltSpiTransport : public NfccAltTransport {
   **                  -1         - write operation failure
   **
   *****************************************************************************/
-  int Write(void* pDevHandle, uint8_t* pBuffer, int nNbBytesToWrite);
-  void Close(void* pDevHandle);
+  virtual int Write(void* pDevHandle, uint8_t* pBuffer, int nNbBytesToWrite) override;
 };