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nrf53: Add APIs to change Low Frequency Clock source in the runtime #2993

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nrf53: Add APIs to change Low Frequency Clock source in the runtime #2993

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0ab3199
mcu/nrf5340_net: Add API to switch lpclk in the runtime
m-gorecki May 11, 2023
f9a2fbf
mcu/nrf5340_net: Use Low Frequency Clock source setting API in startup
m-gorecki May 11, 2023
942adc6
mcu/nrf5340: Add API to switch lpclk in the runtime
m-gorecki May 11, 2023
71d8fad
mcu/nrf5340: Use Low Frequency Clock source setting API in startup
m-gorecki May 11, 2023
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14 changes: 14 additions & 0 deletions hw/mcu/nordic/nrf5340/include/mcu/nrf5340_clock.h
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,20 @@ int nrf5340_clock_hfxo_request(void);
*/
int nrf5340_clock_hfxo_release(void);

/**
* Request low frequency clock source change.
*
* @param clksrc Value to determine requested clock source
* This parameter can be one of the following values:
* @arg CLOCK_LFCLKSTAT_SRC_LFRC - 32.768 kHz RC oscillator
* @arg CLOCK_LFCLKSTAT_SRC_LFXO - 32.768 kHz crystal oscillator
* @arg CLOCK_LFCLKSTAT_SRC_LFSYNT - 32.768 kHz synthesized from HFCLK
*
* @return int 0: clock source was already as requested. 1: clock source
* changed.
*/
int nrf5340_set_lf_clock_source(uint32_t clksrc);

/**
* Request HFCLK192M clock be turned on. Note that each request must have a
* corresponding release.
Expand Down
47 changes: 3 additions & 44 deletions hw/mcu/nordic/nrf5340/src/hal_system.c
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Original file line number Diff line number Diff line change
Expand Up @@ -84,12 +84,6 @@ void
hal_system_clock_start(void)
{
#if MYNEWT_VAL(MCU_LFCLK_SOURCE)
uint32_t regmsk;
uint32_t regval;
uint32_t clksrc;

regmsk = CLOCK_LFCLKSTAT_STATE_Msk | CLOCK_LFCLKSTAT_SRC_Msk;
regval = CLOCK_LFCLKSTAT_STATE_Running << CLOCK_LFCLKSTAT_STATE_Pos;

#if MYNEWT_VAL_CHOICE(MCU_LFCLK_SOURCE, LFXO)

Expand All @@ -107,50 +101,15 @@ hal_system_clock_start(void)
NRF_P0->PIN_CNF[0] = GPIO_PIN_CNF_MCUSEL_Peripheral << GPIO_PIN_CNF_MCUSEL_Pos;
NRF_P0->PIN_CNF[1] = GPIO_PIN_CNF_MCUSEL_Peripheral << GPIO_PIN_CNF_MCUSEL_Pos;
#endif
regval |= CLOCK_LFCLKSTAT_SRC_LFXO << CLOCK_LFCLKSTAT_SRC_Pos;
clksrc = CLOCK_LFCLKSTAT_SRC_LFXO;
nrf5340_set_lf_clock_source(CLOCK_LFCLKSTAT_SRC_LFXO);
#elif MYNEWT_VAL_CHOICE(MCU_LFCLK_SOURCE, LFSYNTH)
regval |= CLOCK_LFCLKSTAT_SRC_LFSYNT << CLOCK_LFCLKSTAT_SRC_Pos;
clksrc = CLOCK_LFCLKSTAT_SRC_LFSYNT;
nrf5340_set_lf_clock_source(CLOCK_LFCLKSTAT_SRC_LFSYNT);
#elif MYNEWT_VAL_CHOICE(MCU_LFCLK_SOURCE, LFRC)
regval |= CLOCK_LFCLKSTAT_SRC_LFRC << CLOCK_LFCLKSTAT_SRC_Pos;
clksrc = CLOCK_LFCLKSTAT_SRC_LFRC;
nrf5340_set_lf_clock_source(CLOCK_LFCLKSTAT_SRC_LFRC);
#else
#error Unknown LFCLK source selected
#endif

#if MYNEWT_VAL_CHOICE(MCU_LFCLK_SOURCE, LFSYNTH)
/* Must turn on HFLCK for synthesized 32768 crystal */
if ((NRF_CLOCK->HFCLKSTAT & CLOCK_HFCLKSTAT_STATE_Msk) !=
(CLOCK_HFCLKSTAT_STATE_Running << CLOCK_HFCLKSTAT_STATE_Pos)) {
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
nrf5340_clock_hfxo_request();
while (1) {
if ((NRF_CLOCK->EVENTS_HFCLKSTARTED) != 0) {
break;
}
}
} else {
nrf5340_clock_hfxo_request();
}
#endif

/* Check if this clock source is already running */
if ((NRF_CLOCK->LFCLKSTAT & regmsk) != regval) {
NRF_CLOCK->TASKS_LFCLKSTOP = 1;
NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
NRF_CLOCK->LFCLKSRC = clksrc;
NRF_CLOCK->TASKS_LFCLKSTART = 1;

/* Wait here till started! */
while (1) {
if (NRF_CLOCK->EVENTS_LFCLKSTARTED) {
if ((NRF_CLOCK->LFCLKSTAT & regmsk) == regval) {
break;
}
}
}
}
#endif
if (MYNEWT_VAL(MCU_HFCLCK192_DIV) == 1) {
NRF_CLOCK->HFCLK192MCTRL = 0;
Expand Down
49 changes: 49 additions & 0 deletions hw/mcu/nordic/nrf5340/src/nrf5340_clock.c
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Original file line number Diff line number Diff line change
Expand Up @@ -100,3 +100,52 @@ nrf5340_clock_hfclk192m_release(void)

return stopped;
}

int
nrf5340_set_lf_clock_source(uint32_t clksrc)
{
uint32_t regmsk;
uint32_t regval;

regmsk = CLOCK_LFCLKSTAT_STATE_Msk | CLOCK_LFCLKSTAT_SRC_Msk;
regval = CLOCK_LFCLKSTAT_STATE_Running << CLOCK_LFCLKSTAT_STATE_Pos;

regval |= clksrc << CLOCK_LFCLKSTAT_SRC_Pos;

/* Check if this clock source isn't already running */
if ((NRF_CLOCK->LFCLKSTAT & regmsk) == regval) {
return 0;
}

/*
* Request HFXO if LFSYNTH is going to be set as source. If LFSYNTH is going to be
* replaced with other source, release HFXO.
*/
if (clksrc == CLOCK_LFCLKSTAT_SRC_LFSYNT) {
if ((NRF_CLOCK->HFCLKSTAT & CLOCK_HFCLKSTAT_STATE_Msk) !=
(CLOCK_HFCLKSTAT_STATE_Running << CLOCK_HFCLKSTAT_STATE_Pos)) {
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
nrf5340_clock_hfxo_request();
while (!NRF_CLOCK->EVENTS_HFCLKSTARTED) {
}
} else {
nrf5340_clock_hfxo_request();
}
} else if (NRF_CLOCK->LFCLKSRC == CLOCK_LFCLKSTAT_SRC_LFSYNT) {
nrf5340_clock_hfxo_release();
}

NRF_CLOCK->LFCLKSRC = clksrc;
NRF_CLOCK->TASKS_LFCLKSTART = 1;

/* Wait here till started! */
while (1) {
if (NRF_CLOCK->EVENTS_LFCLKSTARTED) {
if ((NRF_CLOCK->LFCLKSTAT & regmsk) == regval) {
break;
}
}
}

return 1;
}
14 changes: 14 additions & 0 deletions hw/mcu/nordic/nrf5340_net/include/mcu/nrf5340_net_clock.h
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,20 @@ int nrf5340_net_clock_hfxo_request(void);
*/
int nrf5340_net_clock_hfxo_release(void);

/**
* Request low frequency clock source change.
*
* @param clksrc Value to determine requested clock source
* This parameter can be one of the following values:
* @arg CLOCK_LFCLKSTAT_SRC_LFRC - 32.768 kHz RC oscillator
* @arg CLOCK_LFCLKSTAT_SRC_LFXO - 32.768 kHz crystal oscillator
* @arg CLOCK_LFCLKSTAT_SRC_LFSYNT - 32.768 kHz synthesized from HFCLK
*
* @return int 0: clock source was already as requested. 1: clock source
* changed.
*/
int nrf5340_net_set_lf_clock_source(uint32_t clksrc);

#ifdef __cplusplus
}
#endif
Expand Down
47 changes: 3 additions & 44 deletions hw/mcu/nordic/nrf5340_net/src/hal_system.c
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Original file line number Diff line number Diff line change
Expand Up @@ -70,57 +70,16 @@ void
hal_system_clock_start(void)
{
#if MYNEWT_VAL(MCU_LFCLK_SOURCE)
uint32_t regmsk;
uint32_t regval;
uint32_t clksrc;

regmsk = CLOCK_LFCLKSTAT_STATE_Msk | CLOCK_LFCLKSTAT_SRC_Msk;
regval = CLOCK_LFCLKSTAT_STATE_Running << CLOCK_LFCLKSTAT_STATE_Pos;

#if MYNEWT_VAL_CHOICE(MCU_LFCLK_SOURCE, LFXO)
regval |= CLOCK_LFCLKSTAT_SRC_LFXO << CLOCK_LFCLKSTAT_SRC_Pos;
clksrc = CLOCK_LFCLKSTAT_SRC_LFXO;
nrf5340_net_set_lf_clock_source(CLOCK_LFCLKSTAT_SRC_LFXO);
#elif MYNEWT_VAL_CHOICE(MCU_LFCLK_SOURCE, LFSYNTH)
regval |= CLOCK_LFCLKSTAT_SRC_LFSYNT << CLOCK_LFCLKSTAT_SRC_Pos;
clksrc = CLOCK_LFCLKSTAT_SRC_LFSYNT;
nrf5340_net_set_lf_clock_source(CLOCK_LFCLKSTAT_SRC_LFSYNT);
#elif MYNEWT_VAL_CHOICE(MCU_LFCLK_SOURCE, LFRC)
regval |= CLOCK_LFCLKSTAT_SRC_LFRC << CLOCK_LFCLKSTAT_SRC_Pos;
clksrc = CLOCK_LFCLKSTAT_SRC_LFRC;
nrf5340_net_set_lf_clock_source(CLOCK_LFCLKSTAT_SRC_LFRC);
#else
#error Unknown LFCLK source selected
#endif

#if MYNEWT_VAL_CHOICE(MCU_LFCLK_SOURCE, LFSYNTH)
/* Must turn on HFLCK for synthesized 32768 crystal */
if ((NRF_CLOCK_NS->HFCLKSTAT & CLOCK_HFCLKSTAT_STATE_Msk) !=
(CLOCK_HFCLKSTAT_STATE_Running << CLOCK_HFCLKSTAT_STATE_Pos)) {
NRF_CLOCK_NS->EVENTS_HFCLKSTARTED = 0;
nrf5340_net_clock_hfxo_request();
while (1) {
if ((NRF_CLOCK_NS->EVENTS_HFCLKSTARTED) != 0) {
break;
}
}
} else {
nrf5340_net_clock_hfxo_request();
}
#endif

/* Check if this clock source is already running */
if ((NRF_CLOCK_NS->LFCLKSTAT & regmsk) != regval) {
NRF_CLOCK_NS->TASKS_LFCLKSTOP = 1;
NRF_CLOCK_NS->EVENTS_LFCLKSTARTED = 0;
NRF_CLOCK_NS->LFCLKSRC = clksrc;
NRF_CLOCK_NS->TASKS_LFCLKSTART = 1;

/* Wait here till started! */
while (1) {
if (NRF_CLOCK_NS->EVENTS_LFCLKSTARTED) {
if ((NRF_CLOCK_NS->LFCLKSTAT & regmsk) == regval) {
break;
}
}
}
}
#endif
}
55 changes: 55 additions & 0 deletions hw/mcu/nordic/nrf5340_net/src/nrf5340_net_clock.c
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Original file line number Diff line number Diff line change
Expand Up @@ -75,3 +75,58 @@ nrf5340_net_clock_hfxo_release(void)

return stopped;
}

/**
* Request low frequency clock source change.
*
* @return int 0: clock source was already as requested. 1: clock source
* changed.
*/
int
nrf5340_net_set_lf_clock_source(uint32_t clksrc)
{
uint32_t regmsk;
uint32_t regval;

regmsk = CLOCK_LFCLKSTAT_STATE_Msk | CLOCK_LFCLKSTAT_SRC_Msk;
regval = CLOCK_LFCLKSTAT_STATE_Running << CLOCK_LFCLKSTAT_STATE_Pos;

regval |= clksrc << CLOCK_LFCLKSTAT_SRC_Pos;

/* Check if this clock source isn't already running */
if ((NRF_CLOCK_NS->LFCLKSTAT & regmsk) == regval) {
return 0;
}

/*
* Request HFXO if LFSYNTH is going to be set as source. If LFSYNTH is going to be
* replaced with other source, release HFXO.
*/
if (clksrc == CLOCK_LFCLKSTAT_SRC_LFSYNT) {
if ((NRF_CLOCK_NS->HFCLKSTAT & CLOCK_HFCLKSTAT_STATE_Msk) !=
(CLOCK_HFCLKSTAT_STATE_Running << CLOCK_HFCLKSTAT_STATE_Pos)) {
NRF_CLOCK_NS->EVENTS_HFCLKSTARTED = 0;
nrf5340_net_clock_hfxo_request();
while (!NRF_CLOCK_NS->EVENTS_HFCLKSTARTED) {
}
} else {
nrf5340_net_clock_hfxo_request();
}
} else if (NRF_CLOCK_NS->LFCLKSRC == CLOCK_LFCLKSTAT_SRC_LFSYNT) {
nrf5340_net_clock_hfxo_release();
}

NRF_CLOCK_NS->LFCLKSRC = clksrc;
NRF_CLOCK_NS->TASKS_LFCLKSTART = 1;
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lfclk source can be changes without restarting lfclk:
The LFCLK source can be configured at any time (for instance, when the LFCLK has already been started). The content of the LFCLKSRC register only takes effect when the LFCLKSTART task is triggered.

so we can only start lfclk once on system startup, then this API can change source at any time only taking care of hfxo when switching to/from lfsynth


/* Wait here till started! */
while (1) {
if (NRF_CLOCK_NS->EVENTS_LFCLKSTARTED) {
if ((NRF_CLOCK_NS->LFCLKSTAT & regmsk) == regval) {
break;
}
}
}

return 1;
}