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Merge pull request #15556 from benpicco/cpu/samd51-spurious_tamper

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cpu/samd5x: RTC: add timeout to spurious tamper event
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benpicco 2021-01-12 18:22:49 +01:00 committed by GitHub
commit 20f2ab44ac
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1 changed files with 25 additions and 15 deletions
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40
cpu/sam0_common/periph/rtc_rtt.c
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@ -25,7 +25,6 @@
*/
#include <stdint.h>
#include "mutex.h"
#include "periph/rtc.h"
#include "periph/rtt.h"
#include "periph_conf.h"
@ -337,14 +336,9 @@ int rtc_tamper_register(gpio_t pin, gpio_flank_t flank)
return 0;
}
static void _unlock(void *m)
{
mutex_unlock(m);
}
void rtc_tamper_enable(void)
{
mutex_t m = MUTEX_INIT;
DEBUG("enable tamper\n");
/* clear tamper id */
RTC->MODE0.TAMPID.reg = 0xF;
@ -352,16 +346,32 @@ void rtc_tamper_enable(void)
/* work around errata 2.17.4:
* ignore the first tamper event on the rising edge */
if (RTC->MODE0.TAMPCTRL.reg & RTC_TAMPCTRL_TAMLVL_Msk) {
mutex_lock(&m);
tamper_cb.cb = _unlock;
tamper_cb.arg = &m;
/* If an RTC alarm happened before, the spurious tamper
* event is sometimes not generated.
* Tamper event must happen within one RTC clock period. */
unsigned timeout = CLOCK_CORECLOCK / 32768;
/* prevent RTC interrupt from triggering */
NVIC_DisableIRQ(RTC_IRQn);
/* enable tamper detect as wake-up source */
RTC->MODE0.INTENSET.bit.TAMPER = 1;
/* wait for first tamper event */
while (!RTC->MODE0.INTFLAG.bit.TAMPER && --timeout) {}
/* clear tamper flag flag */
RTC->MODE0.INTFLAG.reg = RTC_MODE0_INTFLAG_TAMPER;
/* restore RTC IRQ */
NVIC_EnableIRQ(RTC_IRQn);
} else {
/* no spurious event on falling edge */
RTC->MODE0.INTENSET.bit.TAMPER = 1;
}
/* enable tamper detect as wake-up source */
RTC->MODE0.INTENSET.bit.TAMPER = 1;
/* wait for first tamper event */
mutex_lock(&m);
DEBUG("tamper enabled\n");
}
#endif /* RTC_NUM_OF_TAMPERS */