mimxrt/machine_rtc: Add RTC alarm/wakeup functionality.

Following the documented Python machine.RTC API.

Signed-off-by: "Kwabena W. Agyeman" <kwagyeman@live.com>

3 files changed, 225 insertions, 1 deletions

diff --git a/ports/mimxrt/machine_rtc.c b/ports/mimxrt/machine_rtc.c
index 54a19dacb..2a2800530 100644
--- a/ports/mimxrt/machine_rtc.c
+++ b/ports/mimxrt/machine_rtc.c
@@ -25,16 +25,117 @@
  * THE SOFTWARE.
  */
 
+#include "py/mperrno.h"
 #include "py/runtime.h"
+#include "shared/runtime/mpirq.h"
 #include "shared/timeutils/timeutils.h"
 #include "modmachine.h"
 #include "ticks.h"
 #include "fsl_snvs_lp.h"
 #include "fsl_snvs_hp.h"
 
+STATIC mp_int_t timeout = 0;
+
+void machine_rtc_alarm_clear_en(void) {
+    SNVS_LP_SRTC_DisableInterrupts(SNVS, SNVS_LPCR_LPTA_EN_MASK);
+    while (SNVS->LPCR & SNVS_LPCR_LPTA_EN_MASK) {
+    }
+}
+
+void machine_rtc_alarm_set_en() {
+    SNVS_LP_SRTC_EnableInterrupts(SNVS, SNVS_LPCR_LPTA_EN_MASK);
+    while (!(SNVS->LPCR & SNVS_LPCR_LPTA_EN_MASK)) {
+    }
+}
+
+void machine_rtc_alarm_off(bool clear) {
+    machine_rtc_alarm_clear_en();
+    DisableIRQ(SNVS_HP_WRAPPER_IRQn);
+
+    if (clear) {
+        SNVS->LPTAR = 0;
+        timeout = 0;
+        SNVS->LPSR = SNVS_LPSR_LPTA_MASK;
+    }
+}
+
+void machine_rtc_alarm_on() {
+    EnableIRQ(SNVS_HP_WRAPPER_IRQn);
+    machine_rtc_alarm_set_en();
+}
+
+uint32_t machine_rtc_get_seconds() {
+    uint32_t seconds = 0;
+    uint32_t tmp = 0;
+
+    // Do consecutive reads until value is correct
+    do {
+        seconds = tmp;
+        tmp = (SNVS->LPSRTCMR << 17U);
+        tmp |= (SNVS->LPSRTCLR >> 15U);
+    } while (tmp != seconds);
+
+    return seconds;
+}
+
+void machine_rtc_alarm_helper(int seconds, bool repeat) {
+    machine_rtc_alarm_off(true);
+
+    SNVS->LPTAR = machine_rtc_get_seconds() + seconds;
+
+    if (repeat) {
+        timeout = seconds;
+    }
+
+    machine_rtc_alarm_on();
+}
+
+typedef struct _machine_rtc_irq_obj_t {
+    mp_irq_obj_t base;
+} machine_rtc_irq_obj_t;
+
+STATIC mp_uint_t machine_rtc_irq_trigger(mp_obj_t self_in, mp_uint_t new_trigger) {
+    new_trigger /= 1000;
+    if (!new_trigger) {
+        machine_rtc_alarm_off(true);
+    } else {
+        machine_rtc_alarm_helper(new_trigger, true);
+    }
+    return 0;
+}
+
+STATIC mp_uint_t machine_rtc_irq_info(mp_obj_t self_in, mp_uint_t info_type) {
+    return 0;
+}
+
+STATIC const mp_irq_methods_t machine_rtc_irq_methods = {
+    .trigger = machine_rtc_irq_trigger,
+    .info = machine_rtc_irq_info,
+};
+
+void SNVS_HP_WRAPPER_IRQHandler(void) {
+    if (SNVS->LPSR & SNVS_LPSR_LPTA_MASK) {
+        SNVS->LPSR = SNVS_LPSR_LPTA_MASK;
+        machine_rtc_irq_obj_t *irq = MP_STATE_PORT(machine_rtc_irq_object);
+        if (irq != NULL) {
+            mp_irq_handler(&irq->base);
+        }
+        if (timeout > 0) {
+            machine_rtc_alarm_clear_en();
+            SNVS->LPTAR += timeout;
+            machine_rtc_alarm_set_en();
+        }
+    }
+}
+
+// Deinit rtc IRQ handler.
+void machine_rtc_irq_deinit(void) {
+    machine_rtc_alarm_off(true);
+    MP_STATE_PORT(machine_rtc_irq_object) = NULL;
+}
+
 typedef struct _machine_rtc_obj_t {
     mp_obj_base_t base;
-    mp_obj_t callback;
 } machine_rtc_obj_t;
 
 // Singleton RTC object.
@@ -163,11 +264,130 @@ STATIC mp_obj_t machine_rtc_calibration(mp_obj_t self_in, mp_obj_t cal_in) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_2(machine_rtc_calibration_obj, machine_rtc_calibration);
 
+STATIC mp_obj_t machine_rtc_alarm(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    STATIC const mp_arg_t allowed_args[] = {
+        { MP_QSTR_id,                            MP_ARG_INT,  {.u_int = 0} },
+        { MP_QSTR_time,                          MP_ARG_OBJ,  {.u_obj = mp_const_none} },
+        { MP_QSTR_repeat,     MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
+    };
+
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(args), allowed_args, args);
+
+    // check the alarm id
+    if (args[0].u_int != 0) {
+        mp_raise_OSError(MP_ENODEV);
+    }
+
+    mp_int_t seconds = 0;
+    snvs_lp_srtc_datetime_t srtc_date;
+    bool repeat = args[2].u_bool;
+    if (mp_obj_is_type(args[1].u_obj, &mp_type_tuple)) { // datetime tuple given
+        // repeat cannot be used with a datetime tuple
+        if (repeat) {
+            mp_raise_ValueError(MP_ERROR_TEXT("invalid argument(s) value"));
+        }
+        // Set date and time.
+        mp_obj_t *items;
+        mp_int_t year;
+        mp_obj_get_array_fixed_n(args[1].u_obj, 8, &items);
+
+        year = mp_obj_get_int(items[0]);
+        srtc_date.year = year >= 100 ? year : year + 2000; // allow 21 for 2021
+        srtc_date.month = mp_obj_get_int(items[1]);
+        srtc_date.day = mp_obj_get_int(items[2]);
+        // Ignore weekday at items[3]
+        srtc_date.hour = mp_obj_get_int(items[4]);
+        srtc_date.minute = mp_obj_get_int(items[5]);
+        srtc_date.second = mp_obj_get_int(items[6]);
+        machine_rtc_alarm_off(true);
+        if (SNVS_LP_SRTC_SetAlarm(SNVS, &srtc_date) != kStatus_Success) {
+            mp_raise_ValueError(NULL);
+        }
+        machine_rtc_alarm_on();
+    } else { // then it must be an integer
+        seconds = (args[1].u_obj == mp_const_none) ? 0 : (mp_obj_get_int(args[1].u_obj) / 1000);
+        machine_rtc_alarm_helper(seconds, repeat);
+    }
+
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(machine_rtc_alarm_obj, 1, machine_rtc_alarm);
+
+STATIC mp_obj_t machine_rtc_alarm_left(size_t n_args, const mp_obj_t *args) {
+    // only alarm id 0 is available
+    if (n_args > 1 && mp_obj_get_int(args[1]) != 0) {
+        mp_raise_OSError(MP_ENODEV);
+    }
+    uint32_t seconds = machine_rtc_get_seconds();
+    uint32_t alarmSeconds = SNVS->LPTAR;
+    return mp_obj_new_int((alarmSeconds >= seconds) ? ((alarmSeconds - seconds) * 1000) : 0);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_rtc_alarm_left_obj, 1, 2, machine_rtc_alarm_left);
+
+STATIC mp_obj_t machine_rtc_alarm_cancel(size_t n_args, const mp_obj_t *args) {
+    // only alarm id 0 is available
+    if (n_args > 1 && mp_obj_get_int(args[1]) != 0) {
+        mp_raise_OSError(MP_ENODEV);
+    }
+    machine_rtc_alarm_off(true);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_rtc_alarm_cancel_obj, 1, 2, machine_rtc_alarm_cancel);
+
+STATIC mp_obj_t machine_rtc_irq(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_trigger, ARG_handler, ARG_wake, ARG_hard };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_trigger, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_handler, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
+        { MP_QSTR_wake, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_hard, MP_ARG_BOOL, {.u_bool = false} },
+    };
+
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    // check we want alarm0
+    if (args[ARG_trigger].u_int != 0) {
+        mp_raise_OSError(MP_ENODEV);
+    }
+
+    machine_rtc_irq_obj_t *irq = MP_STATE_PORT(machine_rtc_irq_object);
+
+    // Allocate the IRQ object if it doesn't already exist.
+    if (irq == NULL) {
+        irq = m_new_obj(machine_rtc_irq_obj_t);
+        irq->base.base.type = &mp_irq_type;
+        irq->base.methods = (mp_irq_methods_t *)&machine_rtc_irq_methods;
+        irq->base.parent = MP_OBJ_FROM_PTR(pos_args[0]);
+        irq->base.handler = mp_const_none;
+        irq->base.ishard = args[ARG_hard].u_bool;
+        MP_STATE_PORT(machine_rtc_irq_object) = irq;
+    }
+
+    machine_rtc_alarm_off(false);
+
+    irq->base.handler = args[ARG_handler].u_obj;
+
+    if (SNVS->LPTAR) {
+        machine_rtc_alarm_on();
+    }
+
+    return MP_OBJ_FROM_PTR(irq);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(machine_rtc_irq_obj, 1, machine_rtc_irq);
+
 STATIC const mp_rom_map_elem_t machine_rtc_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_rtc_init_obj) },
     { MP_ROM_QSTR(MP_QSTR_datetime), MP_ROM_PTR(&machine_rtc_datetime_obj) },
     { MP_ROM_QSTR(MP_QSTR_now), MP_ROM_PTR(&machine_rtc_now_obj) },
     { MP_ROM_QSTR(MP_QSTR_calibration), MP_ROM_PTR(&machine_rtc_calibration_obj) },
+    { MP_ROM_QSTR(MP_QSTR_alarm), MP_ROM_PTR(&machine_rtc_alarm_obj) },
+    { MP_ROM_QSTR(MP_QSTR_alarm_left), MP_ROM_PTR(&machine_rtc_alarm_left_obj) },
+    { MP_ROM_QSTR(MP_QSTR_alarm_cancel), MP_ROM_PTR(&machine_rtc_alarm_cancel_obj) },
+    { MP_ROM_QSTR(MP_QSTR_cancel), MP_ROM_PTR(&machine_rtc_alarm_cancel_obj) },
+    { MP_ROM_QSTR(MP_QSTR_irq), MP_ROM_PTR(&machine_rtc_irq_obj) },
+    { MP_ROM_QSTR(MP_QSTR_ALARM0), MP_ROM_INT(0) },
 };
 STATIC MP_DEFINE_CONST_DICT(machine_rtc_locals_dict, machine_rtc_locals_dict_table);
 
@@ -178,3 +398,5 @@ MP_DEFINE_CONST_OBJ_TYPE(
     make_new, machine_rtc_make_new,
     locals_dict, &machine_rtc_locals_dict
     );
+
+MP_REGISTER_ROOT_POINTER(void *machine_rtc_irq_object);
diff --git a/ports/mimxrt/main.c b/ports/mimxrt/main.c
index f5d57d530..376d72f19 100644
--- a/ports/mimxrt/main.c
+++ b/ports/mimxrt/main.c
@@ -141,6 +141,7 @@ int main(void) {
     soft_reset_exit:
         mp_printf(MP_PYTHON_PRINTER, "MPY: soft reboot\n");
         machine_pin_irq_deinit();
+        machine_rtc_irq_deinit();
         #if MICROPY_PY_MACHINE_I2S
         machine_i2s_deinit_all();
         #endif
diff --git a/ports/mimxrt/modmachine.h b/ports/mimxrt/modmachine.h
index 904419df2..d00d2031c 100644
--- a/ports/mimxrt/modmachine.h
+++ b/ports/mimxrt/modmachine.h
@@ -42,6 +42,7 @@ extern const mp_obj_type_t machine_wdt_type;
 
 void machine_adc_init(void);
 void machine_pin_irq_deinit(void);
+void machine_rtc_irq_deinit(void);
 void machine_pwm_deinit_all(void);
 void machine_uart_deinit_all(void);
 void machine_timer_init_PIT(void);