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drivers: timer: stm32 adjust lptimer with slow LPTIM clock

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Commit to adjust the next_arr with slow LPTIM clock
The next_arr must not be < 0.

Signed-off-by: Francois Ramu <francois.ramu@st.com>
This commit is contained in:
Francois Ramu 2022-05-11 17:29:32 +02:00 committed by Marti Bolivar
parent 39fab29c10
commit 403279cc76
1 changed files with 6 additions and 4 deletions
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10
drivers/timer/stm32_lptim_timer.c
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@ -61,10 +61,10 @@ static const struct device *const clk_ctrl = DEVICE_DT_GET(STM32_CLOCK_CONTROL_N
* 0xFFFF / (LSE freq (32768Hz) / 128) * 0xFFFF / (LSE freq (32768Hz) / 128)
*/ */
static uint32_t lptim_clock_freq = 32000; static uint32_t lptim_clock_freq = KHZ(32);
static int32_t lptim_time_base; static int32_t lptim_time_base;
/* The prescaler given by the DTS and to apply to the lptim clock */ /* The prescaler given by the DTS and to apply to the lptim_clock_freq */
#define LPTIM_CLOCK_RATIO DT_PROP(DT_DRV_INST(0), st_prescaler) #define LPTIM_CLOCK_RATIO DT_PROP(DT_DRV_INST(0), st_prescaler)
/* Minimum nb of clock cycles to have to set autoreload register correctly */ /* Minimum nb of clock cycles to have to set autoreload register correctly */
@ -225,9 +225,9 @@ void sys_clock_set_timeout(int32_t ticks, bool idle)
next_arr = (((lp_time * CONFIG_SYS_CLOCK_TICKS_PER_SEC) next_arr = (((lp_time * CONFIG_SYS_CLOCK_TICKS_PER_SEC)
/ lptim_clock_freq) + 1) * lptim_clock_freq / lptim_clock_freq) + 1) * lptim_clock_freq
/ (CONFIG_SYS_CLOCK_TICKS_PER_SEC); / (CONFIG_SYS_CLOCK_TICKS_PER_SEC);
/* add count unit from the expected nb of Ticks */
next_arr = next_arr + ((uint32_t)(ticks) * lptim_clock_freq) next_arr = next_arr + ((uint32_t)(ticks) * lptim_clock_freq)
/ CONFIG_SYS_CLOCK_TICKS_PER_SEC - 1; / CONFIG_SYS_CLOCK_TICKS_PER_SEC;
/* if the lptim_clock_freq < one ticks/sec, then next_arr must be > 0 */
/* maximise to TIMEBASE */ /* maximise to TIMEBASE */
if (next_arr > lptim_time_base) { if (next_arr > lptim_time_base) {
@ -240,6 +240,8 @@ void sys_clock_set_timeout(int32_t ticks, bool idle)
else if (next_arr < (lp_time + LPTIM_GUARD_VALUE)) { else if (next_arr < (lp_time + LPTIM_GUARD_VALUE)) {
next_arr = lp_time + LPTIM_GUARD_VALUE; next_arr = lp_time + LPTIM_GUARD_VALUE;
} }
/* with slow lptim_clock_freq, LPTIM_GUARD_VALUE of 1 is enough */
next_arr = next_arr - 1;
/* Update autoreload register */ /* Update autoreload register */
lptim_set_autoreload(next_arr); lptim_set_autoreload(next_arr);