Support adjustable backlight brightness

2 files changed, 74 insertions, 3 deletions

diff --git a/shared-bindings/displayio/Display.c b/shared-bindings/displayio/Display.c
index 398bca166..e59905258 100644
--- a/shared-bindings/displayio/Display.c
+++ b/shared-bindings/displayio/Display.c
@@ -84,9 +84,10 @@
 //|   :param int set_column_command: Command used to set the start and end columns to update
 //|   :param int set_row_command: Command used so set the start and end rows to update
 //|   :param int write_ram_command: Command used to write pixels values into the update region
+//|   :param microcontroller.Pin backlight_pin: Pin connected to the display's backlight
 //|
 STATIC mp_obj_t displayio_display_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_display_bus, ARG_init_sequence, ARG_width, ARG_height, ARG_colstart, ARG_rowstart, ARG_color_depth, ARG_set_column_command, ARG_set_row_command, ARG_write_ram_command };
+    enum { ARG_display_bus, ARG_init_sequence, ARG_width, ARG_height, ARG_colstart, ARG_rowstart, ARG_color_depth, ARG_set_column_command, ARG_set_row_command, ARG_write_ram_command, ARG_backlight_pin };
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_display_bus, MP_ARG_REQUIRED | MP_ARG_OBJ },
         { MP_QSTR_init_sequence, MP_ARG_REQUIRED | MP_ARG_OBJ },
@@ -98,6 +99,7 @@ STATIC mp_obj_t displayio_display_make_new(const mp_obj_type_t *type, size_t n_a
         { MP_QSTR_set_column_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x2a} },
         { MP_QSTR_set_row_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x2b} },
         { MP_QSTR_write_ram_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x2c} },
+        { MP_QSTR_backlight_pin, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = mp_const_none} },
     };
     mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
     mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
@@ -107,6 +109,9 @@ STATIC mp_obj_t displayio_display_make_new(const mp_obj_type_t *type, size_t n_a
     mp_buffer_info_t bufinfo;
     mp_get_buffer_raise(args[ARG_init_sequence].u_obj, &bufinfo, MP_BUFFER_READ);
 
+    mp_obj_t backlight_pin = args[ARG_backlight_pin].u_obj;
+    assert_pin_free(backlight_pin);
+
     displayio_display_obj_t *self = NULL;
     for (uint8_t i = 0; i < CIRCUITPY_DISPLAY_LIMIT; i++) {
         if (displays[i].display.base.type == NULL ||
@@ -119,11 +124,10 @@ STATIC mp_obj_t displayio_display_make_new(const mp_obj_type_t *type, size_t n_a
         mp_raise_RuntimeError(translate("Too many displays"));
     }
     self->base.type = &displayio_display_type;
-    // TODO(tannewt): Support backlight pin.
     common_hal_displayio_display_construct(self,
             display_bus, args[ARG_width].u_int, args[ARG_height].u_int, args[ARG_colstart].u_int, args[ARG_rowstart].u_int,
             args[ARG_color_depth].u_int, args[ARG_set_column_command].u_int, args[ARG_set_row_command].u_int,
-            args[ARG_write_ram_command].u_int, bufinfo.buf, bufinfo.len, NULL);
+            args[ARG_write_ram_command].u_int, bufinfo.buf, bufinfo.len, backlight_pin);
 
     return self;
 }
@@ -170,11 +174,72 @@ STATIC mp_obj_t displayio_display_obj_wait_for_frame(mp_obj_t self_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(displayio_display_wait_for_frame_obj, displayio_display_obj_wait_for_frame);
 
+//|   .. attribute:: brightness
+//|
+//|     The brightness of the display as a float. 0.0 is off and 1.0 is full brightness. When
+//|     `auto_brightness` is True this value will change automatically and setting it will have no
+//|     effect. To control the brightness, auto_brightness must be false.
+//|
+STATIC mp_obj_t displayio_display_obj_get_brightness(mp_obj_t self_in) {
+    displayio_display_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_float_t brightness = common_hal_displayio_display_get_brightness(self);
+    if (brightness < 0) {
+        mp_raise_RuntimeError(translate("Brightness not adjustable"));
+    }
+    return mp_obj_new_float(brightness);
+}
+MP_DEFINE_CONST_FUN_OBJ_1(displayio_display_get_brightness_obj, displayio_display_obj_get_brightness);
+
+STATIC mp_obj_t displayio_display_obj_set_brightness(mp_obj_t self_in, mp_obj_t brightness) {
+    displayio_display_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    bool ok = common_hal_displayio_display_set_brightness(self, mp_obj_get_float(brightness));
+    if (!ok) {
+        mp_raise_RuntimeError(translate("Brightness not adjustable"));
+    }
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(displayio_display_set_brightness_obj, displayio_display_obj_set_brightness);
+
+const mp_obj_property_t displayio_display_brightness_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&displayio_display_get_brightness_obj,
+              (mp_obj_t)&displayio_display_set_brightness_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
+
+//|   .. attribute:: auto_brightness
+//|
+//|     True when the display brightness is auto adjusted.
+//|
+STATIC mp_obj_t displayio_display_obj_get_auto_brightness(mp_obj_t self_in) {
+    displayio_display_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    return mp_obj_new_bool(common_hal_displayio_display_get_auto_brightness(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(displayio_display_get_auto_brightness_obj, displayio_display_obj_get_auto_brightness);
+
+STATIC mp_obj_t displayio_display_obj_set_auto_brightness(mp_obj_t self_in, mp_obj_t auto_brightness) {
+    displayio_display_obj_t *self = MP_OBJ_TO_PTR(self_in);
+
+    common_hal_displayio_display_set_auto_brightness(self, mp_obj_is_true(auto_brightness));
+
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(displayio_display_set_auto_brightness_obj, displayio_display_obj_set_auto_brightness);
+
+const mp_obj_property_t displayio_display_auto_brightness_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&displayio_display_get_auto_brightness_obj,
+              (mp_obj_t)&displayio_display_set_auto_brightness_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
 
 STATIC const mp_rom_map_elem_t displayio_display_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_show), MP_ROM_PTR(&displayio_display_show_obj) },
     { MP_ROM_QSTR(MP_QSTR_refresh_soon), MP_ROM_PTR(&displayio_display_refresh_soon_obj) },
     { MP_ROM_QSTR(MP_QSTR_wait_for_frame), MP_ROM_PTR(&displayio_display_wait_for_frame_obj) },
+
+    { MP_ROM_QSTR(MP_QSTR_brightness), MP_ROM_PTR(&displayio_display_brightness_obj) },
+    { MP_ROM_QSTR(MP_QSTR_auto_brightness), MP_ROM_PTR(&displayio_display_auto_brightness_obj) },
 };
 STATIC MP_DEFINE_CONST_DICT(displayio_display_locals_dict, displayio_display_locals_dict_table);
 
diff --git a/shared-bindings/displayio/Display.h b/shared-bindings/displayio/Display.h
index 181afc941..906c3620d 100644
--- a/shared-bindings/displayio/Display.h
+++ b/shared-bindings/displayio/Display.h
@@ -56,4 +56,10 @@ bool displayio_display_refresh_queued(displayio_display_obj_t* self);
 void displayio_display_finish_refresh(displayio_display_obj_t* self);
 bool displayio_display_send_pixels(displayio_display_obj_t* self, uint32_t* pixels, uint32_t length);
 
+bool common_hal_displayio_display_get_auto_brightness(displayio_display_obj_t* self);
+void common_hal_displayio_display_set_auto_brightness(displayio_display_obj_t* self, bool auto_brightness);
+
+mp_float_t common_hal_displayio_display_get_brightness(displayio_display_obj_t* self);
+bool common_hal_displayio_display_set_brightness(displayio_display_obj_t* self, mp_float_t brightness);
+
 #endif // MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYBUSIO_DISPLAY_H