alif/modmachine: Implement timeout_ms argument to deepsleep.

This allows `machine.deepsleep(N)` to wake the device after the timout N
seconds.

Could probably also do the same thing for lightsleep.

Note that this uses the LPTIMER0 resource, which would not work if
`MICROPY_HW_SYSTEM_TICK_USE_LPTIMER` was ever enabled (it's currently never
enabled, so OK for now).

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

ports/alif/boards/ALIF_ENSEMBLE/board.c

@@ -81,8 +81,8 @@ void board_early_init(void) {
         .vtor_address = SCB->VTOR,
         .vtor_address_ns = SCB->VTOR,
         // Configure wake-up sources.
-        .ewic_cfg = EWIC_VBAT_GPIO | EWIC_RTC_A,
-        .wakeup_events = WE_LPGPIO7 | WE_LPGPIO6 | WE_LPGPIO5 | WE_LPGPIO4 | WE_LPRTC,
+        .ewic_cfg = EWIC_VBAT_GPIO | EWIC_VBAT_TIMER | EWIC_RTC_A,
+        .wakeup_events = WE_LPGPIO7 | WE_LPGPIO6 | WE_LPGPIO5 | WE_LPGPIO4 | WE_LPTIMER0 | WE_LPRTC,
     };
 
     if (se_services_set_off_profile(&off_profile)) {

ports/alif/boards/OPENMV_AE3/board.c

@@ -154,8 +154,8 @@ void board_early_init(void) {
         .vtor_address = SCB->VTOR,
         .vtor_address_ns = SCB->VTOR,
         // Configure wake-up sources.
-        .ewic_cfg = EWIC_VBAT_GPIO | EWIC_RTC_A,
-        .wakeup_events = WE_LPGPIO7 | WE_LPGPIO6 | WE_LPGPIO5 | WE_LPGPIO4 | WE_LPRTC,
+        .ewic_cfg = EWIC_VBAT_GPIO | EWIC_VBAT_TIMER | EWIC_RTC_A,
+        .wakeup_events = WE_LPGPIO7 | WE_LPGPIO6 | WE_LPGPIO5 | WE_LPGPIO4 | WE_LPTIMER0 | WE_LPRTC,
     };
 
     if (se_services_set_off_profile(&off_profile)) {

ports/alif/modmachine.c

@@ -27,6 +27,7 @@
 // This file is never compiled standalone, it's included directly from
 // extmod/modmachine.c via MICROPY_PY_MACHINE_INCLUDEFILE.
 
+#include "modmachine.h"
 #include "se_services.h"
 #include "tusb.h"
 
@@ -116,7 +117,37 @@ static void mp_machine_lightsleep(size_t n_args, const mp_obj_t *args) {
     #endif
 }
 
+#include "lptimer.h"
+#include "sys_ctrl_lptimer.h"
+
+#define LPTIMER ((LPTIMER_Type *)LPTIMER_BASE)
+#define LPTIMER_CH_A (0)
+
+static void lptimer_set_wakeup(uint64_t timeout_us) {
+    lptimer_disable_counter(LPTIMER, LPTIMER_CH_A);
+
+    ANA_REG->MISC_CTRL |= 1 << 0; // SEL_32K, select LXFO
+
+    select_lptimer_clk(LPTIMER_CLK_SOURCE_32K, LPTIMER_CH_A);
+
+    // Maximum 131 second timeout, to not overflow 32-bit ticks when
+    // LPTIMER is clocked at 32768Hz.
+    uint32_t timeout_ticks = (uint64_t)MIN(timeout_us, 131000000) * 32768 / 1000000;
+
+    // Set up the LPTIMER interrupt to fire after the given timeout.
+    lptimer_set_mode_userdefined(LPTIMER, LPTIMER_CH_A);
+    lptimer_load_count(LPTIMER, LPTIMER_CH_A, &timeout_ticks);
+    lptimer_clear_interrupt(LPTIMER, LPTIMER_CH_A);
+    lptimer_unmask_interrupt(LPTIMER, LPTIMER_CH_A);
+    lptimer_enable_counter(LPTIMER, LPTIMER_CH_A);
+}
+
 MP_NORETURN static void mp_machine_deepsleep(size_t n_args, const mp_obj_t *args) {
+    mp_int_t sleep_ms = -1;
+    if (n_args != 0) {
+        sleep_ms = mp_obj_get_int(args[0]);
+    }
+
     #if MICROPY_HW_ENABLE_USBDEV
     mp_machine_enable_usb(false);
     #endif
@@ -127,6 +158,14 @@ MP_NORETURN static void mp_machine_deepsleep(size_t n_args, const mp_obj_t *args
 
     __disable_irq();
 
+    if (sleep_ms >= 0) {
+        if (sleep_ms < 10000) {
+            lptimer_set_wakeup(sleep_ms * 1000);
+        } else {
+            machine_rtc_set_wakeup(sleep_ms / 1000);
+        }
+    }
+
     // If power is removed from the subsystem, the function does
     // not return, and the CPU will reboot when/if the subsystem
     // is next powered up.