esp8266: Move mp_hal_pin_open_drain from esp_mphal.c to machine_pin.c.

It belongs with the other pin config functions in machine_pin.c.  Also,
esp_mphal.c is put in iRAM so this change saves about 300 bytes of iRAM
(and mp_hal_pin_open_drain is not a time critical function so doesn't
need to be in iRAM).

1 files changed, 22 insertions, 0 deletions

diff --git a/esp8266/machine_pin.c b/esp8266/machine_pin.c
index 385551578..febbc1587 100644
--- a/esp8266/machine_pin.c
+++ b/esp8266/machine_pin.c
@@ -163,6 +163,28 @@ void mp_hal_pin_output(mp_hal_pin_obj_t pin_id) {
     }
 }
 
+void mp_hal_pin_open_drain(mp_hal_pin_obj_t pin_id) {
+    const pyb_pin_obj_t *pin = &pyb_pin_obj[pin_id];
+
+    if (pin->phys_port == 16) {
+        // configure GPIO16 as input with output register holding 0
+        WRITE_PERI_REG(PAD_XPD_DCDC_CONF, (READ_PERI_REG(PAD_XPD_DCDC_CONF) & 0xffffffbc) | 1);
+        WRITE_PERI_REG(RTC_GPIO_CONF, READ_PERI_REG(RTC_GPIO_CONF) & ~1);
+        WRITE_PERI_REG(RTC_GPIO_ENABLE, (READ_PERI_REG(RTC_GPIO_ENABLE) & ~1)); // input
+        WRITE_PERI_REG(RTC_GPIO_OUT, (READ_PERI_REG(RTC_GPIO_OUT) & ~1)); // out=0
+        return;
+    }
+
+    ETS_GPIO_INTR_DISABLE();
+    PIN_FUNC_SELECT(pin->periph, pin->func);
+    GPIO_REG_WRITE(GPIO_PIN_ADDR(GPIO_ID_PIN(pin->phys_port)),
+        GPIO_REG_READ(GPIO_PIN_ADDR(GPIO_ID_PIN(pin->phys_port)))
+        | GPIO_PIN_PAD_DRIVER_SET(GPIO_PAD_DRIVER_ENABLE)); // open drain
+    GPIO_REG_WRITE(GPIO_ENABLE_ADDRESS,
+        GPIO_REG_READ(GPIO_ENABLE_ADDRESS) | (1 << pin->phys_port));
+    ETS_GPIO_INTR_ENABLE();
+}
+
 int pin_get(uint pin) {
     if (pin == 16) {
         return READ_PERI_REG(RTC_GPIO_IN_DATA) & 1;