Broadcom port: Add 'fake' RTC support

The Broadcom chips apparently don't have an RTC, so this PR uses the
timer to add dummy RTC responses and allow resonable results
from time.localtime() as well as setting the time and date while
the board is powered.

ports/broadcom/common-hal/rtc/RTC.c

@@ -0,0 +1,66 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Nick Moore for Adafruit Industries
+ * Copyright (c) 2019 Artur Pacholec
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+
+#include "py/obj.h"
+#include "py/runtime.h"
+#include "shared/timeutils/timeutils.h"
+#include "shared-bindings/rtc/__init__.h"
+#include "shared-bindings/rtc/RTC.h"
+#include "common-hal/rtc/RTC.h"
+#include "supervisor/port.h"
+#include "supervisor/shared/translate/translate.h"
+
+void rtc_init(void) {
+}
+
+// This is the time in seconds since 2000 that the RTC was started.
+// TODO: Change the offset to ticks so that it can be a subsecond adjustment.
+static uint32_t rtc_offset = 0;
+
+void common_hal_rtc_get_time(timeutils_struct_time_t *tm) {
+    uint64_t ticks_s = port_get_raw_ticks(NULL) / 1024;
+    timeutils_seconds_since_2000_to_struct_time(rtc_offset + ticks_s, tm);
+}
+
+void common_hal_rtc_set_time(timeutils_struct_time_t *tm) {
+    uint64_t ticks_s = port_get_raw_ticks(NULL) / 1024;
+    uint32_t epoch_s = timeutils_seconds_since_2000(
+        tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec
+        );
+    rtc_offset = epoch_s - ticks_s;
+}
+
+int common_hal_rtc_get_calibration(void) {
+    return 0;
+}
+
+void common_hal_rtc_set_calibration(int calibration) {
+    // SNVS has HPCALB_VAL bits for calibration.
+    mp_raise_NotImplementedError_varg(translate("%q"), MP_QSTR_calibration);
+}

ports/broadcom/common-hal/rtc/RTC.h

@@ -0,0 +1,34 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Noralf Trønnes
+ * Copyright (c) 2019 Artur Pacholec
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_MIMXRT10XX_COMMON_HAL_RTC_RTC_H
+#define MICROPY_INCLUDED_MIMXRT10XX_COMMON_HAL_RTC_RTC_H
+
+extern void rtc_init(void);
+extern void rtc_reset(void);
+
+#endif  // MICROPY_INCLUDED_MIMXRT10XX_COMMON_HAL_RTC_RTC_H

ports/broadcom/mpconfigport.mk

@@ -15,7 +15,7 @@ CIRCUITPY_PARALLELDISPLAY = 0
 CIRCUITPY_PULSEIO = 0
 CIRCUITPY_PWMIO = 0
 CIRCUITPY_ROTARYIO = 0
-CIRCUITPY_RTC = 0
+CIRCUITPY_RTC = 1
 
 CIRCUITPY_SDIOIO = 1
 CIRCUITPY_VIDEOCORE = 1

ports/broadcom/supervisor/port.c

@@ -32,7 +32,7 @@
 
 #include "genhdr/mpversion.h"
 
-// #include "common-hal/rtc/RTC.h"
+#include "common-hal/rtc/RTC.h"
 #include "common-hal/busio/I2C.h"
 #include "common-hal/busio/SPI.h"
 #include "common-hal/busio/UART.h"