From 3b966cc260b464e09f7fd99d58d332525c271997 Mon Sep 17 00:00:00 2001
From: Hoernchen20 <felix@horn-witten.de>
Date: Sun, 29 Dec 2019 17:56:45 +0100
Subject: [PATCH] cpu/stm32f1: improve rtc irq

---
 cpu/stm32f1/periph/rtc.c | 59 ++++++++++++++++++++++------------------
 1 file changed, 32 insertions(+), 27 deletions(-)
 mode change 100644 => 100755 cpu/stm32f1/periph/rtc.c

diff --git a/cpu/stm32f1/periph/rtc.c b/cpu/stm32f1/periph/rtc.c
old mode 100644
new mode 100755
index 0ef9ceb093..41ca26a259
--- a/cpu/stm32f1/periph/rtc.c
+++ b/cpu/stm32f1/periph/rtc.c
@@ -23,6 +23,11 @@
 #define ENABLE_DEBUG        (0)
 #include "debug.h"
 
+#define EXTI_IMR_BIT        (EXTI_IMR_MR17)
+#define EXTI_FTSR_BIT       (EXTI_FTSR_TR17)
+#define EXTI_RTSR_BIT       (EXTI_RTSR_TR17)
+#define EXTI_PR_BIT         (EXTI_PR_PR17)
+
 static struct {
     rtc_alarm_cb_t cb;          /**< callback called from RTC interrupt */
     void *arg;                  /**< argument passed to the callback */
@@ -99,6 +104,15 @@ static void _rtc_config(void)
 
     /* disable backup domain write protection */
     PWR->CR &= ~PWR_CR_DBP;
+
+    /* configure the EXTI channel, as RTC interrupts are routed through it.
+     * Needs to be configured to trigger on rising edges. */
+    EXTI->FTSR &= ~(EXTI_FTSR_BIT);
+    EXTI->RTSR |= EXTI_RTSR_BIT;
+    EXTI->IMR  |= EXTI_IMR_BIT;
+    EXTI->PR   |= EXTI_PR_BIT;
+    /* enable global RTC interrupt */
+    NVIC_EnableIRQ(RTC_Alarm_IRQn);
 }
 
 static time_t _rtc_get_time(void)
@@ -170,7 +184,7 @@ static void _rtc_enable_alarm(void)
 static void _rtc_disable_alarm(void)
 {
     _rtc_enter_config_mode();
-    RTC->CRH &= ~(RTC_CRH_ALRIE | RTC_CRH_SECIE);
+    RTC->CRH &= ~RTC_CRH_ALRIE;
     _rtc_exit_config_mode();
 }
 
@@ -189,24 +203,20 @@ static void _rtc_set_alarm_time(time_t alarm_time)
 
 int rtc_set_alarm(struct tm *time, rtc_alarm_cb_t cb, void *arg)
 {
-    /* enable global RTC interrupt */
-    if (cb && !NVIC_GetEnableIRQ(RTC_IRQn)) {
-        NVIC_EnableIRQ(RTC_IRQn);
-        DEBUG("%s enable RTC IRQ\n", __func__);
-    }
-
-    /* save callback and argument */
-    isr_ctx.cb = cb;
-    isr_ctx.arg = arg;
-
-    /* set wakeup time */
     time_t timestamp = mktime(time);
 
     if (timestamp == -1) {
         return -2;
     }
 
-    _rtc_disable_alarm();
+    /* disable existing alarm (if enabled) */
+    rtc_clear_alarm();
+
+    /* save callback and argument */
+    isr_ctx.cb = cb;
+    isr_ctx.arg = arg;
+
+    /* set wakeup time */
     _rtc_set_alarm_time(timestamp);
 
     /* enable Alarm */
@@ -227,18 +237,12 @@ int rtc_get_alarm(struct tm *time)
     return 0;
 }
 
-static void _rtc_clear_isr_ctx(void)
-{
-    isr_ctx.cb = NULL;
-    isr_ctx.arg = NULL;
-}
-
 void rtc_clear_alarm(void)
 {
     _rtc_disable_alarm();
-    _rtc_set_alarm_time(0);
 
-    _rtc_clear_isr_ctx();
+    isr_ctx.cb = NULL;
+    isr_ctx.arg = NULL;
 }
 
 void rtc_poweron(void)
@@ -253,13 +257,14 @@ void rtc_poweroff(void)
     return;
 }
 
-void isr_rtc(void)
+void isr_rtc_alarm(void)
 {
-    _rtc_disable_alarm();
-
-    if (isr_ctx.cb != NULL) {
-        isr_ctx.cb(isr_ctx.arg);
+    if (RTC->CRL & RTC_CRL_ALRF) {
+        if (isr_ctx.cb != NULL) {
+            isr_ctx.cb(isr_ctx.arg);
+        }
+        RTC->CRL &= ~RTC_CRL_ALRF;
     }
-
+    EXTI->PR |= EXTI_PR_BIT;
     cortexm_isr_end();
 }