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drivers: stm32: pwm: Fix PWM set period
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Fix PWM set period function as reinitialization of timer with new extra params as local variable demolishing other properties such as trigger, polarity etc.

Signed-off-by: Naga Himanshu Indraganti <[email protected]>
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@NagaHimanshu @buha
NagaHimanshu authored and buha committed Feb 20, 2025
1 parent ccac941 commit e735b97
Showing 1 changed file with 50 additions and 51 deletions.
101 changes: 50 additions & 51 deletions drivers/platform/stm32/stm32_pwm.c
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/***************************************************************************//**
* @file stm32/stm32_pwm.h
* @file stm32/stm32_pwm.c
* @brief Implementation of stm32 pwm driver.
********************************************************************************
* Copyright 2023(c) Analog Devices, Inc.
Expand Down Expand Up @@ -52,31 +52,43 @@
/******************************************************************************/
/**
* @brief Calculate the period in ticks.
* @param desc - STM32 PWM descriptor.
* @param timer_clk_hz - timer clock frequency.
* @param get_timer_clock - timer source clock function.
* @param clock_divider - timer clock divider.
* @param prescaler - timer prescaler.
* @param period_ns - timer period.
* @return return period value in ticks.
*/
static uint32_t _compute_period_ticks(struct stm32_pwm_desc *desc,
uint32_t timer_clk_hz, uint32_t period_ns)
static uint32_t _compute_period_ticks(uint32_t (*get_timer_clock)(void),
uint32_t clock_divider,
uint32_t prescaler,
uint32_t period_ns)
{
float pwm_frequency;
uint32_t timer_frequency_hz;
uint32_t period;

/* Formula for timer period count calculation:
* timer frequency = timer clock / (prescaler + 1)
* pwm frequency = 1 / pwm period (sec)
* timer period count = (timer frequency / pwm frequency) - 1
* Example:
* Timer clock = 216Mhz, pwm period = 1000ns, prescaler = 1
* timer frequency = 216 / (0+1) = 216Mhz
* pwm frequency = 1 / 1000ns = 1Mhz
* timer period count = (216 / 1) - 1 = 215
**/
/* Timer period is determined based on the timer peripheral frequency */
pwm_frequency = (1.0 / period_ns);
period = (uint32_t)(timer_clk_hz / (pwm_frequency *
FREQUENCY_HZ_TO_TIME_NS_FACTOR)) - 1;
if (get_timer_clock) {
timer_frequency_hz = get_timer_clock();
timer_frequency_hz *= clock_divider;
timer_frequency_hz /= (prescaler + 1);

/* Formula for timer period count calculation:
* timer frequency = timer clock / (prescaler + 1)
* pwm frequency = 1 / pwm period (sec)
* timer period count = (timer frequency / pwm frequency) - 1
* Example:
* Timer clock = 216Mhz, pwm period = 1000ns, prescaler = 1
* timer frequency = 216 / (0+1) = 216Mhz
* pwm frequency = 1 / 1000ns = 1Mhz
* timer period count = (216 / 1) - 1 = 215
**/
/* Timer period is determined based on the timer peripheral frequency */
pwm_frequency = (1.0 / period_ns);
period = (uint32_t)(timer_frequency_hz / (pwm_frequency *
FREQUENCY_HZ_TO_TIME_NS_FACTOR)) - 1;
} else {
period = PWM_DEFAULT_PERIOD - 1;
}

return period;
}
Expand All @@ -95,20 +107,14 @@ static int32_t stm32_init_timer(struct stm32_pwm_desc *desc,
int32_t ret;
uint32_t period;
TIM_TypeDef *base = NULL;
uint32_t timer_frequency_hz;
struct stm32_pwm_init_param *sparam = param->extra;
TIM_ClockConfigTypeDef sClockSourceConfig = {0};
TIM_MasterConfigTypeDef sMasterConfig = {0};
TIM_SlaveConfigTypeDef sSlaveConfig = {0};

if (sparam->get_timer_clock) {
timer_frequency_hz = sparam->get_timer_clock();
timer_frequency_hz *= sparam->clock_divider;
timer_frequency_hz /= (sparam->prescaler + 1);
period = _compute_period_ticks(desc, timer_frequency_hz, param->period_ns);
} else {
period = PWM_DEFAULT_PERIOD - 1;
}
/* Compute period ticks */
period = _compute_period_ticks(sparam->get_timer_clock, sparam->clock_divider,
sparam->prescaler, param->period_ns);

switch (param->id) {
#if defined(TIM1)
Expand Down Expand Up @@ -599,32 +605,25 @@ int32_t stm32_pwm_disable(struct no_os_pwm_desc *desc)
int32_t stm32_pwm_set_period(struct no_os_pwm_desc *desc,
uint32_t period_ns)
{
int32_t ret;
struct no_os_pwm_init_param param;
struct stm32_pwm_init_param sparam = {0};

param.id = desc->id;
param.duty_cycle_ns = desc->duty_cycle_ns;
param.period_ns = period_ns;
param.phase_ns = desc->phase_ns;
param.pwm_callback = desc->pwm_callback;
param.irq_id = desc->irq_id;
sparam.clock_divider = ((struct stm32_pwm_desc *)desc->extra)->clock_divider;
sparam.prescaler = ((struct stm32_pwm_desc *)desc->extra)->prescaler;
sparam.timer_autoreload = ((struct stm32_pwm_desc *)
desc->extra)->timer_autoreload;
sparam.get_timer_clock = ((struct stm32_pwm_desc *)
desc->extra)->get_timer_clock;
sparam.timer_chn = ((struct stm32_pwm_desc *)desc->extra)->timer_chn;
sparam.timer_callback = ((struct stm32_pwm_desc*)desc->extra)->timer_callback;
param.extra = &sparam;
struct stm32_pwm_desc *sdesc = desc->extra;
uint32_t period;

if (!desc || !desc->extra)
if (!sdesc)
return -EINVAL;

ret = stm32_init_timer(desc->extra, &param);
if (ret != HAL_OK)
return -EIO;
/* Compute period ticks */
period = _compute_period_ticks(sdesc->get_timer_clock, sdesc->clock_divider,
sdesc->prescaler, period_ns);

sdesc->htimer.Init.AutoReloadPreload = sdesc->timer_autoreload ?
TIM_AUTORELOAD_PRELOAD_ENABLE : TIM_MASTERSLAVEMODE_DISABLE;
sdesc->htimer.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
sdesc->htimer.Init.CounterMode = TIM_COUNTERMODE_UP;
sdesc->htimer.Init.Prescaler = sdesc->prescaler;
sdesc->htimer.Init.Period = period;
sdesc->htimer.Init.RepetitionCounter = sdesc->repetitions;

TIM_Base_SetConfig(sdesc->htimer.Instance, &sdesc->htimer.Init);

desc->period_ns = period_ns;

Expand Down

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