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// Commands for counting edges on GPIO input pins
//
// Copyright (C) 2021 Adrian Keet <arkeet@gmail.com>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include "basecmd.h" // oid_alloc
#include "board/gpio.h" // struct gpio_in
#include "board/irq.h" // irq_disable
#include "board/misc.h" // timer_read_time
#include "command.h" // DECL_COMMAND
#include "sched.h" // DECL_TASK
struct counter {
struct timer timer;
uint32_t poll_ticks;
uint32_t sample_ticks, next_sample_time;
uint32_t count, last_count_time;
uint8_t flags;
struct gpio_in pin;
};
enum {
CF_PENDING = 1,
};
static struct task_wake counter_wake;
static uint_fast8_t
counter_event(struct timer *timer)
{
struct counter *c = container_of(timer, struct counter, timer);
uint32_t time = c->timer.waketime;
uint8_t last_value = c->count & 1;
uint8_t value = gpio_in_read(c->pin);
if (last_value != value) {
c->count++;
c->last_count_time = time;
}
// useful invariant: c->count & 1 == value
if (timer_is_before(c->next_sample_time, time)) {
c->flags |= CF_PENDING;
c->next_sample_time = time + c->sample_ticks;
sched_wake_task(&counter_wake);
}
c->timer.waketime += c->poll_ticks;
return SF_RESCHEDULE;
}
void
command_config_counter(uint32_t *args)
{
struct counter *c = oid_alloc(
args[0], command_config_counter, sizeof(*c));
c->pin = gpio_in_setup(args[1], args[2]);
c->timer.func = counter_event;
}
DECL_COMMAND(command_config_counter,
"config_counter oid=%c pin=%u pull_up=%c");
void
command_query_counter(uint32_t *args)
{
struct counter *c = oid_lookup(args[0], command_config_counter);
sched_del_timer(&c->timer);
c->timer.waketime = args[1];
c->poll_ticks = args[2];
c->sample_ticks = args[3];
c->next_sample_time = c->timer.waketime; // sample immediately
sched_add_timer(&c->timer);
}
DECL_COMMAND(command_query_counter,
"query_counter oid=%c clock=%u poll_ticks=%u sample_ticks=%u");
void
counter_task(void)
{
if (!sched_check_wake(&counter_wake))
return;
uint8_t oid;
struct counter *c;
foreach_oid(oid, c, command_config_counter) {
if (!(c->flags & CF_PENDING))
continue;
irq_disable();
uint32_t waketime = c->timer.waketime;
uint32_t count = c->count;
uint32_t count_time = c->last_count_time;
c->flags &= ~CF_PENDING;
irq_enable();
sendf("counter_state oid=%c next_clock=%u count=%u count_clock=%u",
oid, waketime, count, count_time);
}
}
DECL_TASK(counter_task);
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