Allow using Pico-W WL_GPIO pins with gpio nifs

Modifies the Pico gpio dirver to accept atoms for the special wl_gpio pins
present in the Pico-W.
- Adds support for `wl0` and `wl1` as output pins in `gpio:digital_write/2`.
- Adds support for `wl2` as an input pin in `gpio:digital_read/1`.

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

libs/eavmlib/src/gpio.erl

@@ -49,7 +49,7 @@
 ]).
 
 -type gpio() :: pid().
--type pin() :: non_neg_integer() | {atom(), non_neg_integer()}.
+-type pin() :: non_neg_integer() | {atom(), non_neg_integer()} | atom().
 -type direction() :: input | output | output_od.
 -type pull() :: up | down | up_down | floating.
 -type low_level() :: low | 0.

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

@@ -66,6 +66,15 @@ static const AtomStringIntPair pin_level_table[] = {
     SELECT_INT_DEFAULT(AtomVMRP2040GPIOInvalid)
 };
 
+#ifdef LIB_PICO_CYW43_ARCH
+static const AtomStringIntPair wl_pin_table[] = {
+    { ATOM_STR("\x3", "wl0"), 0 },
+    { ATOM_STR("\x3", "wl1"), 1 },
+    { ATOM_STR("\x3", "wl2"), 2 },
+    SELECT_INT_DEFAULT(-1)
+};
+#endif
+
 static term nif_gpio_init(Context *ctx, int argc, term argv[])
 {
     UNUSED(ctx);
@@ -117,8 +126,7 @@ static term nif_gpio_digital_write(Context *ctx, int argc, term argv[])
 {
     UNUSED(argc);
 
-    VALIDATE_VALUE(argv[0], term_is_integer);
-    int gpio_num = term_to_int(argv[0]);
+    term gpio_pin = argv[0];
     term level_term = argv[1];
 
     int level;
@@ -133,7 +141,22 @@ static term nif_gpio_digital_write(Context *ctx, int argc, term argv[])
             return ERROR_ATOM;
         }
     }
-    gpio_put(gpio_num, level);
+
+    int gpio_num;
+    if (term_is_integer(gpio_pin)) {
+        gpio_num = gpio_pin;
+        gpio_put(gpio_num, level);
+#ifdef LIB_PICO_CYW43_ARCH
+    } 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;
+        }
+        cyw43_arch_gpio_put(gpio_num, level);
+#endif
+    } else {
+        return ERROR_ATOM;
+    }
 
     return OK_ATOM;
 }
@@ -142,9 +165,24 @@ static term nif_gpio_digital_read(Context *ctx, int argc, term argv[])
 {
     UNUSED(argc);
 
-    VALIDATE_VALUE(argv[0], term_is_integer);
-    int gpio_num = term_to_int(argv[0]);
-    bool level = gpio_get(gpio_num);
+    term gpio_pin = argv[0];
+    int gpio_num;
+    bool level;
+
+    if (term_is_integer(gpio_pin)) {
+        gpio_num = gpio_pin;
+        level = gpio_get(gpio_num);
+#ifdef LIB_PICO_CYW43_ARCH
+    } 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;
+        }
+        level = cyw43_arch_gpio_get(gpio_num);
+#endif
+    } else {
+        return ERROR_ATOM;
+    }
 
     return level ? globalcontext_make_atom(ctx->global, ATOM_STR("\x4", "high")) : globalcontext_make_atom(ctx->global, ATOM_STR("\x3", "low"));
 }