From c2228ee0f9386978ada1ce0148bce64eebf55ef2 Mon Sep 17 00:00:00 2001
From: Bill Sideris <bill88t@feline.gr>
Date: Wed, 3 Jan 2024 17:48:16 +0200
Subject: [PATCH] Settable analogio vref for espressif

---
 ports/espressif/common-hal/analogio/AnalogIn.c | 17 +++++++++++++++--
 ports/espressif/common-hal/analogio/AnalogIn.h |  1 +
 shared-bindings/analogio/AnalogIn.c            | 16 ++++++++++++++--
 shared-bindings/analogio/AnalogIn.h            |  1 +
 4 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/ports/espressif/common-hal/analogio/AnalogIn.c b/ports/espressif/common-hal/analogio/AnalogIn.c
index 51ee5a9cb27bc..ffd829a555f93 100644
--- a/ports/espressif/common-hal/analogio/AnalogIn.c
+++ b/ports/espressif/common-hal/analogio/AnalogIn.c
@@ -71,6 +71,7 @@ void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self,
     // Turn off the pull-up as soon as we know the pin will be used for analog reads,
     // since it may take a while for the voltage to stabilize if the input is high-impedance.
     gpio_pullup_dis(pin->number);
+    self->vref = 3300;
 }
 
 bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
@@ -86,6 +87,10 @@ void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
 }
 
 uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
+    if (!self->vref) {
+        // Do not divide by zero.
+        return 65535;
+    }
     adc_oneshot_unit_handle_t adc_handle;
     adc_oneshot_unit_init_cfg_t adc_config = {
         .unit_id = self->pin->adc_index,
@@ -166,9 +171,17 @@ uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
     }
     #endif
     adc_oneshot_del_unit(adc_handle);
-    return voltage * ((1 << 16) - 1) / 3300;
+    return voltage * ((1 << 16) - 1) / self->vref;
 }
 
 float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self) {
-    return 3.3f;
+    return (float)self->vref * 0.001f;
+}
+
+void common_hal_analogio_analogin_set_reference_voltage(analogio_analogin_obj_t *self, mp_float_t value) {
+    if (value <= 0.0f) {
+        self->vref = 0;
+    } else {
+        self->vref = (int)(value * 1000);
+    }
 }
diff --git a/ports/espressif/common-hal/analogio/AnalogIn.h b/ports/espressif/common-hal/analogio/AnalogIn.h
index 5ac9c63f4dbe1..f2550c3c9ca53 100644
--- a/ports/espressif/common-hal/analogio/AnalogIn.h
+++ b/ports/espressif/common-hal/analogio/AnalogIn.h
@@ -37,6 +37,7 @@
 typedef struct {
     mp_obj_base_t base;
     const mcu_pin_obj_t *pin;
+    mp_int_t vref;
 } analogio_analogin_obj_t;
 
 #endif // MICROPY_INCLUDED_ESPRESSIF_COMMON_HAL_ANALOGIO_ANALOGIN_H
diff --git a/shared-bindings/analogio/AnalogIn.c b/shared-bindings/analogio/AnalogIn.c
index cff9e10b89533..494b74038b706 100644
--- a/shared-bindings/analogio/AnalogIn.c
+++ b/shared-bindings/analogio/AnalogIn.c
@@ -136,8 +136,20 @@ STATIC mp_obj_t analogio_analogin_obj_get_reference_voltage(mp_obj_t self_in) {
 MP_DEFINE_CONST_FUN_OBJ_1(analogio_analogin_get_reference_voltage_obj,
     analogio_analogin_obj_get_reference_voltage);
 
-MP_PROPERTY_GETTER(analogio_analogin_reference_voltage_obj,
-    (mp_obj_t)&analogio_analogin_get_reference_voltage_obj);
+STATIC mp_obj_t analogio_analogin_obj_set_reference_voltage(mp_obj_t self_in, mp_obj_t value) {
+    analogio_analogin_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    check_for_deinit(self);
+
+    common_hal_analogio_analogin_set_reference_voltage(self, mp_obj_get_float(value));
+    return mp_const_none;
+}
+
+MP_DEFINE_CONST_FUN_OBJ_2(analogio_analogin_set_reference_voltage_obj,
+    analogio_analogin_obj_set_reference_voltage);
+
+MP_PROPERTY_GETSET(analogio_analogin_reference_voltage_obj,
+    (mp_obj_t)&analogio_analogin_get_reference_voltage_obj,
+    (mp_obj_t)&analogio_analogin_set_reference_voltage_obj);
 
 STATIC const mp_rom_map_elem_t analogio_analogin_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_deinit),             MP_ROM_PTR(&analogio_analogin_deinit_obj) },
diff --git a/shared-bindings/analogio/AnalogIn.h b/shared-bindings/analogio/AnalogIn.h
index 7d667ed3f4683..d2446ad68ad24 100644
--- a/shared-bindings/analogio/AnalogIn.h
+++ b/shared-bindings/analogio/AnalogIn.h
@@ -38,5 +38,6 @@ void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self);
 bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self);
 uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self);
 float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self);
+void common_hal_analogio_analogin_set_reference_voltage(analogio_analogin_obj_t *self, mp_float_t value);
 
 #endif  // __MICROPY_INCLUDED_SHARED_BINDINGS_ANALOGIO_ANALOGIN_H__