Rudamentary backlight support

9 files changed, 122 insertions, 18 deletions

diff --git a/ports/atmel-samd/boards/pyportal/board.c b/ports/atmel-samd/boards/pyportal/board.c
index 6e5b37dd2..980a28e9b 100644
--- a/ports/atmel-samd/boards/pyportal/board.c
+++ b/ports/atmel-samd/boards/pyportal/board.c
@@ -87,7 +87,8 @@ void board_init(void) {
         MIPI_COMMAND_SET_PAGE_ADDRESS, // Set row command
         MIPI_COMMAND_WRITE_MEMORY_START, // Write memory command
         display_init_sequence,
-        sizeof(display_init_sequence));
+        sizeof(display_init_sequence),
+        &pin_PB31);
 }
 
 bool board_requests_safe_mode(void) {
diff --git a/ports/atmel-samd/common-hal/pulseio/PWMOut.c b/ports/atmel-samd/common-hal/pulseio/PWMOut.c
index 825bdd181..2740a9e55 100644
--- a/ports/atmel-samd/common-hal/pulseio/PWMOut.c
+++ b/ports/atmel-samd/common-hal/pulseio/PWMOut.c
@@ -58,6 +58,26 @@ uint8_t tcc_channels[3];   // Set by pwmout_reset() to {0xf0, 0xfc, 0xfc} initia
 uint8_t tcc_channels[5];   // Set by pwmout_reset() to {0xc0, 0xf0, 0xf8, 0xfc, 0xfc} initially.
 #endif
 
+static uint8_t never_reset_tc_or_tcc[TC_INST_NUM + TCC_INST_NUM];
+
+void common_hal_pulseio_pwmout_never_reset(pulseio_pwmout_obj_t *self) {
+    if (self->timer->is_tc) {
+        never_reset_tc_or_tcc[self->timer->index] += 1;
+    } else {
+        never_reset_tc_or_tcc[TC_INST_NUM + self->timer->index] += 1;
+    }
+
+    never_reset_pin_number(self->pin->number);
+}
+
+void common_hal_pulseio_pwmout_reset_ok(pulseio_pwmout_obj_t *self) {
+    if (self->timer->is_tc) {
+        never_reset_tc_or_tcc[self->timer->index] -= 1;
+    } else {
+        never_reset_tc_or_tcc[TC_INST_NUM + self->timer->index] -= 1;
+    }
+}
+
 void pwmout_reset(void) {
     // Reset all timers
     for (int i = 0; i < TCC_INST_NUM; i++) {
@@ -66,6 +86,9 @@ void pwmout_reset(void) {
     }
     Tcc *tccs[TCC_INST_NUM] = TCC_INSTS;
     for (int i = 0; i < TCC_INST_NUM; i++) {
+        if (never_reset_tc_or_tcc[TC_INST_NUM + i] > 0) {
+            continue;
+        }
         // Disable the module before resetting it.
         if (tccs[i]->CTRLA.bit.ENABLE == 1) {
             tccs[i]->CTRLA.bit.ENABLE = 0;
@@ -81,6 +104,9 @@ void pwmout_reset(void) {
     }
     Tc *tcs[TC_INST_NUM] = TC_INSTS;
     for (int i = 0; i < TC_INST_NUM; i++) {
+        if (never_reset_tc_or_tcc[i] > 0) {
+            continue;
+        }
         tcs[i]->COUNT16.CTRLA.bit.SWRST = 1;
         while (tcs[i]->COUNT16.CTRLA.bit.SWRST == 1) {
         }
@@ -99,11 +125,11 @@ bool channel_ok(const pin_timer_t* t) {
             t->is_tc;
 }
 
-void common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
-                                          const mcu_pin_obj_t* pin,
-                                          uint16_t duty,
-                                          uint32_t frequency,
-                                          bool variable_frequency) {
+pwmout_result_t common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
+                                                    const mcu_pin_obj_t* pin,
+                                                    uint16_t duty,
+                                                    uint32_t frequency,
+                                                    bool variable_frequency) {
     self->pin = pin;
     self->variable_frequency = variable_frequency;
 
@@ -113,11 +139,11 @@ void common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
         && pin->timer[2].index >= TCC_INST_NUM
 #endif
         ) {
-        mp_raise_ValueError(translate("Invalid pin"));
+        return PWMOUT_INVALID_PIN;
     }
 
     if (frequency == 0 || frequency > 6000000) {
-        mp_raise_ValueError(translate("Invalid PWM frequency"));
+        return PWMOUT_INVALID_FREQUENCY;
     }
 
     // Figure out which timer we are using.
@@ -184,11 +210,9 @@ void common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
 
         if (timer == NULL) {
             if (found) {
-                mp_raise_ValueError(translate("All timers for this pin are in use"));
-            } else {
-                mp_raise_RuntimeError(translate("All timers in use"));
+                return PWMOUT_ALL_TIMERS_ON_PIN_IN_USE;
             }
-            return;
+            return PWMOUT_ALL_TIMERS_IN_USE;
         }
 
         uint8_t resolution = 0;
@@ -259,6 +283,7 @@ void common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
     gpio_set_pin_function(pin->number, GPIO_PIN_FUNCTION_E + mux_position);
 
     common_hal_pulseio_pwmout_set_duty_cycle(self, duty);
+    return PWMOUT_OK;
 }
 
 bool common_hal_pulseio_pwmout_deinited(pulseio_pwmout_obj_t* self) {
diff --git a/shared-bindings/displayio/Display.c b/shared-bindings/displayio/Display.c
index 1838228af..398bca166 100644
--- a/shared-bindings/displayio/Display.c
+++ b/shared-bindings/displayio/Display.c
@@ -119,10 +119,11 @@ 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);
+            args[ARG_write_ram_command].u_int, bufinfo.buf, bufinfo.len, NULL);
 
     return self;
 }
diff --git a/shared-bindings/displayio/Display.h b/shared-bindings/displayio/Display.h
index 4cec66058..181afc941 100644
--- a/shared-bindings/displayio/Display.h
+++ b/shared-bindings/displayio/Display.h
@@ -40,7 +40,7 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
     mp_obj_t bus, uint16_t width, uint16_t height,
     int16_t colstart, int16_t rowstart, uint16_t color_depth,
     uint8_t set_column_command, uint8_t set_row_command, uint8_t write_ram_command,
-    uint8_t* init_sequence, uint16_t init_sequence_len);
+    uint8_t* init_sequence, uint16_t init_sequence_len, const mcu_pin_obj_t* backlight_pin);
 
 int32_t common_hal_displayio_display_wait_for_frame(displayio_display_obj_t* self);
 
diff --git a/shared-bindings/pulseio/PWMOut.c b/shared-bindings/pulseio/PWMOut.c
index ed3acd804..bba5fe883 100644
--- a/shared-bindings/pulseio/PWMOut.c
+++ b/shared-bindings/pulseio/PWMOut.c
@@ -108,7 +108,16 @@ STATIC mp_obj_t pulseio_pwmout_make_new(const mp_obj_type_t *type, size_t n_args
     // create PWM object from the given pin
     pulseio_pwmout_obj_t *self = m_new_obj(pulseio_pwmout_obj_t);
     self->base.type = &pulseio_pwmout_type;
-    common_hal_pulseio_pwmout_construct(self, pin, duty_cycle, frequency, variable_frequency);
+    pwmout_result_t result = common_hal_pulseio_pwmout_construct(self, pin, duty_cycle, frequency, variable_frequency);
+    if (result == PWMOUT_INVALID_PIN) {
+        mp_raise_ValueError(translate("Invalid pin"));
+    } else if (result == PWMOUT_INVALID_FREQUENCY) {
+        mp_raise_ValueError(translate("Invalid PWM frequency"));
+    } else if (result == PWMOUT_ALL_TIMERS_ON_PIN_IN_USE) {
+        mp_raise_ValueError(translate("All timers for this pin are in use"));
+    } else if (result == PWMOUT_ALL_TIMERS_IN_USE) {
+        mp_raise_RuntimeError(translate("All timers in use"));
+    }
 
     return MP_OBJ_FROM_PTR(self);
 }
diff --git a/shared-bindings/pulseio/PWMOut.h b/shared-bindings/pulseio/PWMOut.h
index 0b630816b..c01e0c926 100644
--- a/shared-bindings/pulseio/PWMOut.h
+++ b/shared-bindings/pulseio/PWMOut.h
@@ -32,7 +32,15 @@
 
 extern const mp_obj_type_t pulseio_pwmout_type;
 
-extern void common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
+typedef enum {
+    PWMOUT_OK,
+    PWMOUT_INVALID_PIN,
+    PWMOUT_INVALID_FREQUENCY,
+    PWMOUT_ALL_TIMERS_ON_PIN_IN_USE,
+    PWMOUT_ALL_TIMERS_IN_USE
+} pwmout_result_t;
+
+extern pwmout_result_t common_hal_pulseio_pwmout_construct(pulseio_pwmout_obj_t* self,
     const mcu_pin_obj_t* pin, uint16_t duty, uint32_t frequency,
     bool variable_frequency);
 extern void common_hal_pulseio_pwmout_deinit(pulseio_pwmout_obj_t* self);
@@ -43,4 +51,8 @@ extern void common_hal_pulseio_pwmout_set_frequency(pulseio_pwmout_obj_t* self,
 extern uint32_t common_hal_pulseio_pwmout_get_frequency(pulseio_pwmout_obj_t* self);
 extern bool common_hal_pulseio_pwmout_get_variable_frequency(pulseio_pwmout_obj_t* self);
 
+// This is used by the supervisor to claim PWMOut devices indefinitely.
+extern void common_hal_pulseio_pwmout_never_reset(pulseio_pwmout_obj_t *self);
+extern void common_hal_pulseio_pwmout_reset_ok(pulseio_pwmout_obj_t *self);
+
 #endif // MICROPY_INCLUDED_SHARED_BINDINGS_PULSEIO_PWMOUT_H
diff --git a/shared-module/displayio/Display.c b/shared-module/displayio/Display.c
index fd082c19d..504f130c7 100644
--- a/shared-module/displayio/Display.c
+++ b/shared-module/displayio/Display.c
@@ -29,6 +29,7 @@
 #include "py/runtime.h"
 #include "shared-bindings/displayio/FourWire.h"
 #include "shared-bindings/displayio/ParallelBus.h"
+#include "shared-bindings/microcontroller/Pin.h"
 #include "shared-bindings/time/__init__.h"
 #include "shared-module/displayio/__init__.h"
 #include "supervisor/shared/display.h"
@@ -42,7 +43,8 @@
 void common_hal_displayio_display_construct(displayio_display_obj_t* self,
         mp_obj_t bus, uint16_t width, uint16_t height, int16_t colstart, int16_t rowstart,
         uint16_t color_depth, uint8_t set_column_command, uint8_t set_row_command,
-        uint8_t write_ram_command, uint8_t* init_sequence, uint16_t init_sequence_len) {
+        uint8_t write_ram_command, uint8_t* init_sequence, uint16_t init_sequence_len,
+        const mcu_pin_obj_t* backlight_pin) {
     self->width = width;
     self->height = height;
     self->color_depth = color_depth;
@@ -96,6 +98,19 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
     // initialization.
     self->refresh = true;
     self->current_group = &circuitpython_splash;
+
+    if (backlight_pin != NULL && common_hal_mcu_pin_is_free(backlight_pin)) {
+        pwmout_result_t result = common_hal_pulseio_pwmout_construct(&self->backlight_pwm, backlight_pin, 0, 5000, false);
+        if (result != PWMOUT_OK) {
+            self->backlight_inout.base.type = &digitalio_digitalinout_type;
+            common_hal_digitalio_digitalinout_construct(&self->backlight_inout, backlight_pin);
+            never_reset_pin_number(backlight_pin->number);
+        } else {
+            self->backlight_pwm.base.type = &pulseio_pwmout_type;
+            common_hal_pulseio_pwmout_never_reset(&self->backlight_pwm);
+        }
+    }
+    self->auto_brightness = true;
 }
 
 void common_hal_displayio_display_show(displayio_display_obj_t* self, displayio_group_t* root_group) {
@@ -158,3 +173,29 @@ bool displayio_display_send_pixels(displayio_display_obj_t* self, uint32_t* pixe
     self->send(self->bus, false, (uint8_t*) pixels, length * 4);
     return true;
 }
+
+void displayio_display_update_backlight(displayio_display_obj_t* self) {
+    if (!self->auto_brightness || self->updating_backlight) {
+        return;
+    }
+    if (ticks_ms - self->last_backlight_refresh < 100) {
+        return;
+    }
+    self->updating_backlight = true;
+    if (self->backlight_pwm.base.type == &pulseio_pwmout_type) {
+        common_hal_pulseio_pwmout_set_duty_cycle(&self->backlight_pwm, 0xffff);
+    } else if (self->backlight_inout.base.type == &digitalio_digitalinout_type) {
+        common_hal_digitalio_digitalinout_set_value(&self->backlight_inout, true);
+    }
+    self->updating_backlight = false;
+    self->last_backlight_refresh = ticks_ms;
+}
+
+void release_display(displayio_display_obj_t* self) {
+    if (self->backlight_pwm.base.type == &pulseio_pwmout_type) {
+        common_hal_pulseio_pwmout_reset_ok(&self->backlight_pwm);
+        common_hal_pulseio_pwmout_deinit(&self->backlight_pwm);
+    } else if (self->backlight_inout.base.type == &digitalio_digitalinout_type) {
+        common_hal_digitalio_digitalinout_deinit(&self->backlight_inout);
+    }
+}
diff --git a/shared-module/displayio/Display.h b/shared-module/displayio/Display.h
index 1f1355d31..0d7393aff 100644
--- a/shared-module/displayio/Display.h
+++ b/shared-module/displayio/Display.h
@@ -27,7 +27,9 @@
 #ifndef MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_DISPLAY_H
 #define MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_DISPLAY_H
 
-#include "shared-module/displayio/Group.h"
+#include "shared-bindings/digitalio/DigitalInOut.h"
+#include "shared-bindings/displayio/Group.h"
+#include "shared-bindings/pulseio/PWMOut.h"
 
 typedef bool (*display_bus_begin_transaction)(mp_obj_t bus);
 typedef void (*display_bus_send)(mp_obj_t bus, bool command, uint8_t *data, uint32_t data_length);
@@ -50,6 +52,16 @@ typedef struct {
     display_bus_begin_transaction begin_transaction;
     display_bus_send send;
     display_bus_end_transaction end_transaction;
+    union {
+        digitalio_digitalinout_obj_t backlight_inout;
+        pulseio_pwmout_obj_t backlight_pwm;
+    };
+    uint64_t last_backlight_refresh;
+    bool auto_brightness:1;
+    bool updating_backlight:1;
 } displayio_display_obj_t;
 
+void displayio_display_update_backlight(displayio_display_obj_t* self);
+void release_display(displayio_display_obj_t* self);
+
 #endif // MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_DISPLAY_H
diff --git a/shared-module/displayio/__init__.c b/shared-module/displayio/__init__.c
index dbfeacc3d..8e4904954 100644
--- a/shared-module/displayio/__init__.c
+++ b/shared-module/displayio/__init__.c
@@ -20,6 +20,7 @@ void displayio_refresh_displays(void) {
             continue;
         }
         displayio_display_obj_t* display = &displays[i].display;
+        displayio_display_update_backlight(display);
 
         if (!displayio_display_frame_queued(display)) {
             return;
@@ -82,6 +83,7 @@ void common_hal_displayio_release_displays(void) {
         displays[i].fourwire_bus.base.type = &mp_type_NoneType;
     }
     for (uint8_t i = 0; i < CIRCUITPY_DISPLAY_LIMIT; i++) {
+        release_display(&displays[i].display);
         displays[i].display.base.type = &mp_type_NoneType;
     }
 
@@ -117,6 +119,7 @@ void reset_displays(void) {
             continue;
         }
         displayio_display_obj_t* display = &displays[i].display;
+        display->auto_brightness = true;
         common_hal_displayio_display_show(display, &circuitpython_splash);
     }
 }