rp2/machine_pin: Fix simulated open drain with more than 32 GPIOs.

Changes are:
- Refactor the open-drain macros, add GPIO_ENABLE/DISABLE_OPEN_DRAIN, and
  move them to `mphalport.h`.
- Only use `uint64_t` for the open-drain mask if there are more than 32
  GPIOs (saves code size).
- Ensure we're shifting a `uint64_t` by using 1ULL constants.

Signed-off-by: Phil Howard <github@gadgetoid.com>

Author: Gadgetoid

ports/rp2/machine_pin.c

@@ -46,9 +46,6 @@
 
 #define GPIO_IRQ_ALL (0xf)
 
-// Open drain behaviour is simulated.
-#define GPIO_IS_OPEN_DRAIN(id) (machine_pin_open_drain_mask & (1 << (id)))
-
 #ifndef MICROPY_HW_PIN_RESERVED
 #define MICROPY_HW_PIN_RESERVED(i) (0)
 #endif
@@ -83,7 +80,11 @@ static const mp_irq_methods_t machine_pin_irq_methods;
 static const int num_intr_regs = sizeof(iobank0_hw->intr) / sizeof(iobank0_hw->intr[0]);
 
 // Mask with "1" indicating that the corresponding pin is in simulated open-drain mode.
+#if NUM_BANK0_GPIOS > 32
 uint64_t machine_pin_open_drain_mask;
+#else
+uint32_t machine_pin_open_drain_mask;
+#endif
 
 #if MICROPY_HW_PIN_EXT_COUNT
 static inline bool is_ext_pin(__unused const machine_pin_obj_t *self) {
@@ -292,7 +293,7 @@ static mp_obj_t machine_pin_obj_init_helper(const machine_pin_obj_t *self, size_
                 mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("invalid pin af: %d"), af);
             }
             gpio_set_function(self->id, af);
-            machine_pin_open_drain_mask &= ~(1ULL << self->id);
+            GPIO_DISABLE_OPEN_DRAIN(self->id);
         }
     }
 

ports/rp2/mphalport.h

@@ -123,7 +123,18 @@ static inline mp_uint_t mp_hal_get_cpu_freq(void) {
 #define MP_HAL_PIN_PULL_UP              (1)
 #define MP_HAL_PIN_PULL_DOWN            (2)
 
+// Open drain behaviour is simulated.
+#if NUM_BANK0_GPIOS > 32
 extern uint64_t machine_pin_open_drain_mask;
+#define GPIO_IS_OPEN_DRAIN(id)          (machine_pin_open_drain_mask & (1ULL << id))
+#define GPIO_ENABLE_OPEN_DRAIN(id)      (machine_pin_open_drain_mask |= (1ULL << id))
+#define GPIO_DISABLE_OPEN_DRAIN(id)     (machine_pin_open_drain_mask &= ~(1ULL << id))
+#else
+extern uint32_t machine_pin_open_drain_mask;
+#define GPIO_IS_OPEN_DRAIN(id)          (machine_pin_open_drain_mask & (1U << id))
+#define GPIO_ENABLE_OPEN_DRAIN(id)      (machine_pin_open_drain_mask |= (1U << id))
+#define GPIO_DISABLE_OPEN_DRAIN(id)     (machine_pin_open_drain_mask &= ~(1U << id))
+#endif
 
 mp_hal_pin_obj_t mp_hal_get_pin_obj(mp_obj_t pin_in);
 
@@ -133,13 +144,13 @@ static inline unsigned int mp_hal_pin_name(mp_hal_pin_obj_t pin) {
 
 static inline void mp_hal_pin_input(mp_hal_pin_obj_t pin) {
     gpio_set_dir(pin, GPIO_IN);
-    machine_pin_open_drain_mask &= ~(1 << pin);
+    GPIO_DISABLE_OPEN_DRAIN(pin);
     gpio_set_function(pin, GPIO_FUNC_SIO);
 }
 
 static inline void mp_hal_pin_output(mp_hal_pin_obj_t pin) {
     gpio_set_dir(pin, GPIO_OUT);
-    machine_pin_open_drain_mask &= ~(1 << pin);
+    GPIO_DISABLE_OPEN_DRAIN(pin);
     gpio_set_function(pin, GPIO_FUNC_SIO);
 }
 
@@ -151,7 +162,7 @@ static inline void mp_hal_pin_open_drain_with_value(mp_hal_pin_obj_t pin, int v)
         gpio_put(pin, 0);
         gpio_set_dir(pin, GPIO_OUT);
     }
-    machine_pin_open_drain_mask |= 1 << pin;
+    GPIO_ENABLE_OPEN_DRAIN(pin);
     gpio_set_function(pin, GPIO_FUNC_SIO);
 }