firmware/app/zedmon/ina.c

#include <app/zedmon/ina.h>

#include <app/zedmon/usb.h>
#include <assert.h>
#include <lk/err.h>
#include <dev/i2c.h>
#include <kernel/timer.h>
#include <lib/cbuf.h>
#include <lib/console.h>
#include <platform.h>
#include <stdint.h>
#include <stdio.h>
#include <target/gpioconfig.h>

#include "ina231.h"
#include "ina233.h"

typedef struct __attribute__((packed)) {
    lk_bigtime_t time;
    uint8_t type:2;
    uint8_t channel:6;
} ina_alert_event_t;


enum event_type {
    EVENT_TYPE_SAMPLE = 0x0,
    EVENT_TYPE_HEARTBEAT = 0x1,
};

static cbuf_t ina_alert_events;
static timer_t ina_heartbeat_timer;

static bool (*ina_sample)(uint16_t *v_shunt, uint16_t *v_bus);
static bool ina_initialized = false;

static uint32_t ina_errors;
static uint32_t ina_samples;
static uint16_t ina_v_shunt;
static uint16_t ina_v_bus;
static uint16_t ina_samples_since_heartbeat;

// This exepects to be called from irq context.
bool send_irq_event(ina_alert_event_t *event) {
    // This won't race because we're in irq context.
    if (cbuf_space_avail(&ina_alert_events) >= sizeof(*event)) {
        cbuf_write(&ina_alert_events, event, sizeof(*event), false);
        return true;
    }
    return false;
}

bool ina_alert_irq(int index, uint64_t timestamp) {
    // We only handle a single channel right now.
    assert(index == 0);

    if (!ina_initialized) {
        return false;
    }

    ina_alert_event_t event = {
        .type = EVENT_TYPE_SAMPLE,
        .channel = 0,
        .time = timestamp,
    };

    return send_irq_event(&event);
}

enum handler_return ina_heartbeat_handler(struct timer *timer, lk_time_t now, void *arg){
    ina_alert_event_t event = {
        .type = EVENT_TYPE_HEARTBEAT,
        .channel = 0,
        .time = 0,
    };

    return send_irq_event(&event);
}

void ina_init(void) {
    cbuf_initialize(&ina_alert_events, 32);

    if (ina233_init()) {
        printf("ina233 found\n");
        ina_sample = ina233_sample;
    } else if (ina231_init()) {
        printf("ina231 found\n");
        ina_sample = ina231_sample;
    }

    timer_initialize(&ina_heartbeat_timer);
    ina_initialized = true;

    // call sample once to unstick the conversion ready flag.
    uint16_t v_shunt;
    uint16_t v_bus;
    ina_sample(&v_shunt, &v_bus);

    timer_set_periodic(&ina_heartbeat_timer, 1000, ina_heartbeat_handler, NULL);
}


void ina_loop(void) {
    while (true) {
        ina_alert_event_t event;
        cbuf_read(&ina_alert_events, &event, sizeof(event), true);

        if (ina_sample == NULL) {
            continue;
        }

        uint16_t v_shunt;
        uint16_t v_bus;

        // If we miss an alert signal edge, we'll stop sampling.  To protect
        // against this, we do an extra sample if we've gotten no samples
        // between two heartbeats.
        if (event.type == EVENT_TYPE_HEARTBEAT) {
            uint16_t samples = ina_samples_since_heartbeat;
            ina_samples_since_heartbeat = 0;
            if (samples > 0) {
                continue;
            }
            // Kick off a read below to restart the pipeline.
        }


        if (!ina_sample(&v_shunt, &v_bus)) {
            ina_errors++;
            continue;
        }

        // Don't report heartbeat samples.
        if (event.type == EVENT_TYPE_SAMPLE) {
            ina_v_shunt = v_shunt;
            ina_v_bus = v_bus;
            ina_samples++;
            ina_samples_since_heartbeat++;
            zedmon_usb_add_sample(event.time, v_shunt, v_bus);
        }
    }
}

static int cmd_ina_status(int argc, const cmd_args *argv) {
    float v_shunt = ina_v_shunt * 0.0025;
    float v_bus = ina_v_bus * 0.00125;

    printf("samples: %u\n", ina_samples);
    printf("errors: %u\n", ina_errors);
    printf("v_bus: %f V \n", v_bus);
    printf("v_shunt: %f mV\n", v_shunt);
    return 0;
}

STATIC_COMMAND_START
STATIC_COMMAND("ina_status", "ina status", &cmd_ina_status)
STATIC_COMMAND_END(ina);