piolib: Make piolib a first class library

Reorganise the management of PIO chips so that piolib can be built as a
library, adding the necessary install rules for the library and header
files.

Signed-off-by: Phil Elwell <[email protected]>

Author: pelwell

piolib/CMakeLists.txt

@@ -7,12 +7,30 @@ add_subdirectory(examples)
 #set project name
 project(piolib)
 
+add_compile_definitions(LIBRARY_BUILD=1)
+
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Werror")
 
 if (CMAKE_COMPILER_IS_GNUCC)
    add_definitions (-ffunction-sections)
 endif ()
 
-add_library (pio OBJECT piolib.c pio_rp1.c)
-target_include_directories(pio PRIVATE include)
-target_link_libraries(pio)
+add_library (pio STATIC piolib.c library_piochips.c pio_rp1.c)
+target_include_directories(pio PUBLIC include)
+
+set(INCLUDE_FILES
+    "piolib.h"
+    "pio_platform.h"
+    "hardware/clocks.h"
+    "hardware/gpio.h"
+    "hardware/pio.h"
+    "hardware/pio_instructions.h"
+    "hardware/timer.h"
+    "pico/stdlib.h"
+)
+
+install(TARGETS pio ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
+foreach ( file ${INCLUDE_FILES} )
+    get_filename_component( dir ${file} DIRECTORY )
+    install( FILES "include/${file}" DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/piolib/${dir}" )
+endforeach()

piolib/include/piolib_priv.h

@@ -9,8 +9,22 @@
 
 #include "pio_platform.h"
 
+#define PIO_CHIP(name) name ## _pio_chip
+
+#if LIBRARY_BUILD
+#define DECLARE_PIO_CHIP(chip) \
+    const PIO_CHIP_T chip ## _pio_chip =
+
+extern const PIO_CHIP_T *const library_piochips[];
+extern const int library_piochips_count;
+#else
 #define DECLARE_PIO_CHIP(chip) \
-    const PIO_CHIP_T *__ptr_ ## chip __attribute__ ((section ("piochips"))) __attribute__ ((used)) = \
-    &chip
+    const PIO_CHIP_T PIO_CHIP(chip); \
+    const PIO_CHIP_T *__ptr_ ## chip __attribute__ ((section ("piochips"))) __attribute__ ((used)) = &PIO_CHIP(chip); \
+    const PIO_CHIP_T PIO_CHIP(chip) =
+
+extern const PIO_CHIP_T *__start_piochips;
+extern const PIO_CHIP_T *__stop_piochips;
+#endif
 
 #endif

piolib/library_piochips.c

@@ -0,0 +1,15 @@
+#include "piolib.h"
+#include "piolib_priv.h"
+
+#define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0]))
+
+#define EXTERN_PIO_CHIP(name) extern const PIO_CHIP_T PIO_CHIP(name)
+
+EXTERN_PIO_CHIP(rp1);
+
+const PIO_CHIP_T *const library_piochips[] =
+{
+    &PIO_CHIP(rp1),
+};
+
+const int library_piochips_count = ARRAY_SIZE(library_piochips);

piolib/pio_rp1.c

@@ -822,7 +822,7 @@ static void rp1_pio_gpio_init(PIO pio, uint pin)
     rp1_gpio_set_function(pio, pin, RP1_GPIO_FUNC_PIO);
 }
 
-PIO rp1_create_instance(PIO_CHIP_T *chip, uint index)
+static PIO rp1_create_instance(PIO_CHIP_T *chip, uint index)
 {
     char pathbuf[20];
     RP1_PIO pio = NULL;
@@ -845,7 +845,7 @@ PIO rp1_create_instance(PIO_CHIP_T *chip, uint index)
     return &pio->base;
 }
 
-int rp1_open_instance(PIO pio)
+static int rp1_open_instance(PIO pio)
 {
     RP1_PIO rp = (RP1_PIO)pio;
     int fd;
@@ -857,13 +857,13 @@ int rp1_open_instance(PIO pio)
     return 0;
 }
 
-void rp1_close_instance(PIO pio)
+static void rp1_close_instance(PIO pio)
 {
     RP1_PIO rp = (RP1_PIO)pio;
     close(rp->fd);
 }
 
-static const PIO_CHIP_T rp1_pio_chip = {
+DECLARE_PIO_CHIP(rp1) {
     .name = "rp1",
     .compatible = "raspberrypi,rp1-pio",
     .instr_count = RP1_PIO_INSTRUCTION_COUNT,
@@ -970,5 +970,3 @@ static const PIO_CHIP_T rp1_pio_chip = {
     .gpio_set_input_enabled = rp1_gpio_set_input_enabled,
     .gpio_set_drive_strength = rp1_gpio_set_drive_strength,
 };
-
-DECLARE_PIO_CHIP(rp1_pio_chip);

piolib/piolib.c

@@ -19,9 +19,6 @@
 
 #define PIO_MAX_INSTANCES 4
 
-extern PIO_CHIP_T *__start_piochips;
-extern PIO_CHIP_T *__stop_piochips;
-
 static __thread PIO __pio;
 
 static PIO pio_instances[PIO_MAX_INSTANCES];
@@ -53,6 +50,13 @@ int pio_get_index(PIO pio)
 
 int pio_init(void)
 {
+#if LIBRARY_BUILD
+    const PIO_CHIP_T *const *start = &library_piochips[0];
+    const PIO_CHIP_T *const *end = &library_piochips[0] + library_piochips_count;
+#else
+    const PIO_CHIP_T *const *start = &__start_piochips;
+    const PIO_CHIP_T *const *end = &__stop_piochips;
+#endif
     static bool initialised;
     const PIO_CHIP_T * const *p;
     uint i = 0;
@@ -61,8 +65,9 @@ int pio_init(void)
     if (initialised)
         return 0;
     num_instances = 0;
-    p = &__start_piochips;
-    while (p < &__stop_piochips && num_instances < PIO_MAX_INSTANCES)
+
+    p = start;
+    while (p < end)
     {
         PIO_CHIP_T *chip = *p;
         PIO pio = chip->create_instance(chip, i);