1
0
mirror of https://github.com/RIOT-OS/RIOT.git synced 2024-12-29 04:50:03 +01:00
RIOT/sys/ztimer/convert_frac.c
2023-03-15 15:13:48 +01:00

127 lines
4.1 KiB
C

/*
* Copyright (C) 2020 Kaspar Schleiser <kaspar@schleiser.de>
* 2020 Freie Universität Berlin
* 2020 Inria
* 2018 Joakim Nohlgård <joakim.nohlgard@eistec.se>
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for more
* details.
*/
/**
* @ingroup sys_ztimer_convert_frac
*
* @{
*
* @file
* @brief ztimer conversion using frac implementation
*
* @author Joakim Nohlgård <joakim.nohlgard@eistec.se>
* @author Kaspar Schleiser <kaspar@schleiser.de>
* @}
*/
#include <stdint.h>
#include <inttypes.h>
#include "frac.h"
#include "assert.h"
#include "irq.h"
#include "ztimer/convert.h"
#include "ztimer/convert_frac.h"
#define ENABLE_DEBUG 0
#include "debug.h"
/**
* @brief Compute the scaling parameters for the given two frequencies
*
* @param[in] self pointer to instance to operate on
* @param[in] freq_self desired frequency of this clock
* @param[in] freq_lower frequency of the underlying clock
*/
static void ztimer_convert_frac_compute_scale(ztimer_convert_frac_t *self,
uint32_t freq_self,
uint32_t freq_lower);
static void ztimer_convert_frac_op_set(ztimer_clock_t *z, uint32_t val)
{
ztimer_convert_frac_t *self = (ztimer_convert_frac_t *)z;
uint32_t target_lower = frac_scale(&self->scale_set, val + self->round);
DEBUG("ztimer_convert_frac_op_set(%" PRIu32 ")=%" PRIu32 "\n", val,
target_lower);
ztimer_set(self->super.lower, &self->super.lower_entry, target_lower);
}
static uint32_t ztimer_convert_frac_op_now(ztimer_clock_t *z)
{
ztimer_convert_frac_t *self = (ztimer_convert_frac_t *)z;
uint32_t lower_now = ztimer_now(self->super.lower);
if (lower_now == 0) {
return 0;
}
uint32_t scaled = frac_scale(&self->scale_now, lower_now);
DEBUG("ztimer_convert_frac_op_now() %" PRIu32 "->%" PRIu32 "\n", lower_now,
scaled);
return scaled;
}
static const ztimer_ops_t ztimer_convert_frac_ops = {
.set = ztimer_convert_frac_op_set,
.now = ztimer_convert_frac_op_now,
.cancel = ztimer_convert_cancel,
#if MODULE_ZTIMER_ONDEMAND
.start = ztimer_convert_start,
.stop = ztimer_convert_stop,
#endif
};
static void ztimer_convert_frac_compute_scale(ztimer_convert_frac_t *self,
uint32_t freq_self,
uint32_t freq_lower)
{
assert(freq_self);
assert(freq_lower);
frac_init(&self->scale_now, freq_self, freq_lower);
frac_init(&self->scale_set, freq_lower, freq_self);
}
void ztimer_convert_frac_init(ztimer_convert_frac_t *self,
ztimer_clock_t *lower, uint32_t freq_self,
uint32_t freq_lower)
{
DEBUG("ztimer_convert_frac_init: %p->%p fs=%" PRIu32 " fl=%" PRIu32 "\n",
(void *)self, (void *)lower, freq_self, freq_lower);
*self = (ztimer_convert_frac_t) {
.super.super = { .ops = &ztimer_convert_frac_ops, },
.super.lower = lower,
.super.lower_entry =
{ .callback = (void (*)(void *)) ztimer_handler, .arg = &self->super, },
};
ztimer_convert_frac_compute_scale(self, freq_self, freq_lower);
if (freq_self < freq_lower) {
self->super.super.max_value = frac_scale(&self->scale_now, UINT32_MAX);
#if !MODULE_ZTIMER_ONDEMAND
/* extend lower clock only if the ondemand driver isn't selected
* otherwise, the clock extension will be called with the first
* ztimer_acquire() call */
ztimer_init_extend(&self->super.super);
#endif
}
else {
DEBUG("ztimer_convert_frac_init: rounding up val:%" PRIu32 "\n",
(uint32_t)(freq_self / freq_lower));
self->round = freq_self / freq_lower;
self->super.super.max_value = UINT32_MAX;
}
#if MODULE_PM_LAYERED && !MODULE_ZTIMER_ONDEMAND
self->super.super.block_pm_mode = ZTIMER_CLOCK_NO_REQUIRED_PM_MODE;
#endif
}