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// Support for gathering acceleration data from ADXL345 chip
//
// Copyright (C) 2020 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include <string.h> // memcpy
#include "board/irq.h" // irq_disable
#include "board/misc.h" // timer_read_time
#include "basecmd.h" // oid_alloc
#include "command.h" // DECL_COMMAND
#include "sched.h" // DECL_TASK
#include "spicmds.h" // spidev_transfer
struct adxl345 {
struct timer timer;
uint32_t rest_ticks;
struct spidev_s *spi;
uint16_t sequence, limit_count;
uint8_t flags, data_count;
uint8_t data[48];
};
enum {
AX_HAVE_START = 1<<0, AX_RUNNING = 1<<1, AX_PENDING = 1<<2,
};
static struct task_wake adxl345_wake;
static uint_fast8_t
adxl345_event(struct timer *timer)
{
struct adxl345 *ax = container_of(timer, struct adxl345, timer);
ax->flags |= AX_PENDING;
sched_wake_task(&adxl345_wake);
return SF_DONE;
}
void
command_config_adxl345(uint32_t *args)
{
struct adxl345 *ax = oid_alloc(args[0], command_config_adxl345
, sizeof(*ax));
ax->timer.func = adxl345_event;
ax->spi = spidev_oid_lookup(args[1]);
}
DECL_COMMAND(command_config_adxl345, "config_adxl345 oid=%c spi_oid=%c");
// Report local measurement buffer
static void
adxl_report(struct adxl345 *ax, uint8_t oid)
{
sendf("adxl345_data oid=%c sequence=%hu data=%*s"
, oid, ax->sequence, ax->data_count, ax->data);
ax->data_count = 0;
ax->sequence++;
}
// Chip registers
#define AR_POWER_CTL 0x2D
#define AR_DATAX0 0x32
#define AR_FIFO_STATUS 0x39
#define AM_READ 0x80
#define AM_MULTI 0x40
// Query accelerometer data
static void
adxl_query(struct adxl345 *ax, uint8_t oid)
{
uint8_t msg[9] = { AR_DATAX0 | AM_READ | AM_MULTI, 0, 0, 0, 0, 0, 0, 0, 0 };
spidev_transfer(ax->spi, 1, sizeof(msg), msg);
memcpy(&ax->data[ax->data_count], &msg[1], 6);
ax->data_count += 6;
if (ax->data_count + 6 > ARRAY_SIZE(ax->data))
adxl_report(ax, oid);
uint_fast8_t fifo_status = msg[8] & ~0x80; // Ignore trigger bit
if (fifo_status >= 31 && ax->limit_count != 0xffff)
ax->limit_count++;
if (fifo_status > 1 && fifo_status <= 32) {
// More data in fifo - wake this task again
sched_wake_task(&adxl345_wake);
} else if (ax->flags & AX_RUNNING) {
// Sleep until next check time
sched_del_timer(&ax->timer);
ax->flags &= ~AX_PENDING;
irq_disable();
ax->timer.waketime = timer_read_time() + ax->rest_ticks;
sched_add_timer(&ax->timer);
irq_enable();
}
}
// Startup measurements
static void
adxl_start(struct adxl345 *ax, uint8_t oid)
{
sched_del_timer(&ax->timer);
ax->flags = AX_RUNNING;
uint8_t msg[2] = { AR_POWER_CTL, 0x08 };
uint32_t start1_time = timer_read_time();
spidev_transfer(ax->spi, 0, sizeof(msg), msg);
irq_disable();
uint32_t start2_time = timer_read_time();
ax->timer.waketime = start2_time + ax->rest_ticks;
sched_add_timer(&ax->timer);
irq_enable();
sendf("adxl345_start oid=%c start1_clock=%u start2_clock=%u"
, oid, start1_time, start2_time);
}
// End measurements
static void
adxl_stop(struct adxl345 *ax, uint8_t oid)
{
// Disable measurements
sched_del_timer(&ax->timer);
ax->flags = 0;
uint8_t msg[2] = { AR_POWER_CTL, 0x00 };
uint32_t end1_time = timer_read_time();
spidev_transfer(ax->spi, 0, sizeof(msg), msg);
uint32_t end2_time = timer_read_time();
// Drain any measurements still in fifo
uint_fast8_t i;
for (i=0; i<33; i++) {
msg[0] = AR_FIFO_STATUS | AM_READ;
msg[1] = 0;
spidev_transfer(ax->spi, 1, sizeof(msg), msg);
if (!(msg[1] & 0x3f))
break;
adxl_query(ax, oid);
}
// Report final data
if (ax->data_count)
adxl_report(ax, oid);
sendf("adxl345_end oid=%c end1_clock=%u end2_clock=%u"
" limit_count=%hu sequence=%hu"
, oid, end1_time, end2_time, ax->limit_count, ax->sequence);
}
void
command_query_adxl345(uint32_t *args)
{
struct adxl345 *ax = oid_lookup(args[0], command_config_adxl345);
if (!args[2]) {
// End measurements
adxl_stop(ax, args[0]);
return;
}
// Start new measurements query
sched_del_timer(&ax->timer);
ax->timer.waketime = args[1];
ax->rest_ticks = args[2];
ax->flags = AX_HAVE_START;
ax->sequence = ax->limit_count = 0;
ax->data_count = 0;
sched_add_timer(&ax->timer);
}
DECL_COMMAND(command_query_adxl345,
"query_adxl345 oid=%c clock=%u rest_ticks=%u");
void
adxl345_task(void)
{
if (!sched_check_wake(&adxl345_wake))
return;
uint8_t oid;
struct adxl345 *ax;
foreach_oid(oid, ax, command_config_adxl345) {
uint_fast8_t flags = ax->flags;
if (!(flags & AX_PENDING))
continue;
if (flags & AX_HAVE_START)
adxl_start(ax, oid);
else
adxl_query(ax, oid);
}
}
DECL_TASK(adxl345_task);
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