Update rp2040 gpio driver error returns

Update error returns from the gpio driver to return {error, Reason} rather than
just an uninformative `error`.

This will complete rp2040 platform requiremments to satisfy the ongoing meta
issue #894.

Signed-off-by: Winford <[email protected]>

src/platforms/rp2040/src/lib/gpiodriver.c

@@ -30,6 +30,10 @@
 #include "rp2040_sys.h"
 #include "trace.h"
 
+#define INVALID_MODE_ATOM globalcontext_make_atom(ctx->global, ATOM_STR("\xC", "invalid_mode"))
+#define INVALID_LEVEL_ATOM globalcontext_make_atom(ctx->global, ATOM_STR("\xD", "invalid_level"))
+#define INVALID_PIN_ATOM globalcontext_make_atom(ctx->global, ATOM_STR("\xB", "invalid_pin"))
+
 static const struct Nif *gpio_nif_get_nif(const char *nifname);
 
 static const AtomStringIntPair pin_mode_table[] = {
@@ -105,7 +109,11 @@ static term nif_gpio_set_pin_mode(Context *ctx, int argc, term argv[])
     int gpio_num = term_to_int(argv[0]);
     int mode = interop_atom_term_select_int(pin_mode_table, argv[1], ctx->global);
     if (UNLIKELY(mode < 0)) {
-        return ERROR_ATOM;
+        BEGIN_WITH_STACK_HEAP(TUPLE_SIZE(2), heap);
+        term ret = term_alloc_tuple(2, &heap);
+        term_put_tuple_element(ret, 0, ERROR_ATOM);
+        term_put_tuple_element(ret, 1, INVALID_MODE_ATOM);
+        return ret;
     }
     gpio_set_dir(gpio_num, mode);
     return OK_ATOM;
@@ -133,12 +141,20 @@ static term nif_gpio_digital_write(Context *ctx, int argc, term argv[])
     if (term_is_integer(level_term)) {
         level = term_to_int32(level_term);
         if (UNLIKELY((level != 0) && (level != 1))) {
-            return ERROR_ATOM;
+            BEGIN_WITH_STACK_HEAP(TUPLE_SIZE(2), heap);
+            term ret = term_alloc_tuple(2, &heap);
+            term_put_tuple_element(ret, 0, ERROR_ATOM);
+            term_put_tuple_element(ret, 1, INVALID_LEVEL_ATOM);
+            return ret;
         }
     } else {
         level = interop_atom_term_select_int(pin_level_table, level_term, ctx->global);
         if (UNLIKELY(level < 0)) {
-            return ERROR_ATOM;
+            BEGIN_WITH_STACK_HEAP(TUPLE_SIZE(2), heap);
+            term ret = term_alloc_tuple(2, &heap);
+            term_put_tuple_element(ret, 0, ERROR_ATOM);
+            term_put_tuple_element(ret, 1, INVALID_LEVEL_ATOM);
+            return ret;
         }
     }
 
@@ -150,12 +166,20 @@ static term nif_gpio_digital_write(Context *ctx, int argc, term argv[])
     } else if (term_is_atom(gpio_pin)) {
         gpio_num = interop_atom_term_select_int(wl_pin_table, gpio_pin, ctx->global);
         if (UNLIKELY((gpio_num == -1) || (gpio_num > 1))) {
-            return ERROR_ATOM;
+            BEGIN_WITH_STACK_HEAP(TUPLE_SIZE(2), heap);
+            term ret = term_alloc_tuple(2, &heap);
+            term_put_tuple_element(ret, 0, ERROR_ATOM);
+            term_put_tuple_element(ret, 1, INVALID_PIN_ATOM);
+            return ret;
         }
         cyw43_arch_gpio_put(gpio_num, level);
 #endif
     } else {
-        return ERROR_ATOM;
+        BEGIN_WITH_STACK_HEAP(TUPLE_SIZE(2), heap);
+        term ret = term_alloc_tuple(2, &heap);
+        term_put_tuple_element(ret, 0, ERROR_ATOM)
+        term_put_tuple_element(ret, 1, INVALID_PIN_ATOM);
+        return ret;
     }
 
     return OK_ATOM;
@@ -176,12 +200,20 @@ static term nif_gpio_digital_read(Context *ctx, int argc, term argv[])
     } else if (term_is_atom(gpio_pin)) {
         gpio_num = interop_atom_term_select_int(wl_pin_table, gpio_pin, ctx->global);
         if (UNLIKELY((gpio_num != 2))) {
-            return ERROR_ATOM;
+            BEGIN_WITH_STACK_HEAP(TUPLE_SIZE(2), heap);
+            term ret = term_alloc_tuple(2, &heap);
+            term_put_tuple_element(ret, 0, ERROR_ATOM);
+            term_put_tuple_element(ret, 1, INVALID_PIN_ATOM);
+            return ret;
         }
         level = cyw43_arch_gpio_get(gpio_num);
 #endif
     } else {
-        return ERROR_ATOM;
+        BEGIN_WITH_STACK_HEAP(TUPLE_SIZE(2), heap);
+        term ret = term_alloc_tuple(2, &heap);
+        term_put_tuple_element(ret, 0, ERROR_ATOM)
+        term_put_tuple_element(ret, 1, INVALID_PIN_ATOM);
+        return ret;
     }
 
     return level ? globalcontext_make_atom(ctx->global, ATOM_STR("\x4", "high")) : globalcontext_make_atom(ctx->global, ATOM_STR("\x3", "low"));