clock_gen_cs2200.c

#include "heivs/clock_gen_cs2200.h"
#include "stm32/stm32f4xx_gpio.h"
#include "stm32/stm32f4xx_rcc.h"
#include "stm32/stm32f4xx_i2c.h"
#include "stm32/stm32f4xx_misc.h"
#include "heivs/stm32_gpio.h"
#include "heivs/stm32_i2c.h"

#define EXTCLK_DIR_UP                   0
#define EXTCLK_DIR_DOWN                 1

#define CS_DEVICE_ID                    0x01
#define CS_DEVICE_CTRL                  0x02
#define CS_DEVICE_CFG1                  0x03
#define CS_GLOBAL_CFG                   0x05
#define CS_RATIO_3                      0x06 /* MSB byte of Ratio */
#define CS_RATIO_2                      0x07 /* MSB - 1 byte of Ratio */
#define CS_RATIO_1                      0x08 /* MSB - 2 byte of Ratio */
#define CS_RATIO_0                      0x09 /* LSB byte of Ratio */
#define CS_FUNCT_CFG1                   0x16
#define CS_FUNCT_CFG2                   0x17

static status_e clk_gen_WriteReg(struct clock_gen_t *dev, uint8_t reg, uint8_t Value)
{
    status_e status;
    const uint8_t cmd [] =
    {
        reg,
        Value,
    };

    status = bus_get(dev->bus);
    if (status != NO_ERROR)
    {
        return status;
    }

    status = bus_write(dev->bus, dev->i2c_address, cmd, ARRAY_SIZE(cmd));
    if (status != NO_ERROR)
    {
        return status;
    }

    status = bus_release(dev->bus);
    if (status != NO_ERROR)
    {
        return status;
    }

    return status;
}

static uint32_t ratio_compute(const struct _clk_gen_info_t *g)
{
    uint64_t ratio;
    ratio = g->f_out;
    ratio *= g->ppm;
    ratio /= 1000000;
    ratio += g->f_out;
    ratio *= (1 << 20);
    ratio /= g->f_in;

    return ratio;
}

status_e clock_gen_init(struct clock_gen_t *dev, uint32_t OutFreq, uint32_t InFreq)
{
    status_e status;
    uint32_t ratio;

    dev->info.f_in = InFreq;
    dev->info.f_out = OutFreq;
    dev->info.ppm = 0;

    status = bus_init(dev->bus);
    if (status != NO_ERROR)
    {
        return status;
    }

    /* Get the ratio to be programmed */
    ratio = ratio_compute(&dev->info);

    /* Freeze the configuration */
    status = clk_gen_WriteReg(dev, CS_GLOBAL_CFG, 0x08);
    if (status != NO_ERROR)
    {
        return status;
    }

    /* Auxilary output disabled */
    status = clk_gen_WriteReg(dev, CS_DEVICE_CTRL, 0x02);
    if (status != NO_ERROR)
    {
        return status;
    }

    /* No division on Ratio */
    status = clk_gen_WriteReg(dev, CS_DEVICE_CFG1, 0x00);
    if (status != NO_ERROR)
    {
        return status;
    }

    status = clk_gen_WriteReg(dev, CS_RATIO_3, (uint8_t) (((ratio & 0xFF000000) >> 24)));
    if (status != NO_ERROR)
    {
        return status;
    }

    status = clk_gen_WriteReg(dev, CS_RATIO_2, (uint8_t) (((ratio & 0xFF0000) >> 16)));
    if (status != NO_ERROR)
    {
        return status;
    }

    status = clk_gen_WriteReg(dev, CS_RATIO_1, (uint8_t) (((ratio & 0xFF00) >> 8)));
    if (status != NO_ERROR)
    {
        return status;
    }

    status = clk_gen_WriteReg(dev, CS_RATIO_0, (uint8_t) (ratio & 0xFF));
    if (status != NO_ERROR)
    {
        return status;
    }

    /* Reference clock input divider set to 2 (input = 24 MHz) */
    status = clk_gen_WriteReg(dev, CS_FUNCT_CFG1, 0x08);
    if (status != NO_ERROR)
    {
        return status;
    }

    /* Unfreeze: start clocking */
    status = clk_gen_WriteReg(dev, CS_GLOBAL_CFG, 0x01);
    if (status != NO_ERROR)
    {
        return status;
    }

    return NO_ERROR;
}

status_e clock_gen_adjust_ppm(struct clock_gen_t *dev, int32_t ppm)
{
    status_e status;
    uint32_t old_ratio;
    uint32_t ratio;

    old_ratio = ratio_compute(&dev->info);
    dev->info.ppm += ppm;
    ratio = ratio_compute(&dev->info);

    if (old_ratio == ratio)
    {
        /* Nothing to be done */
        return NO_ERROR;
    }

    /* freeze */
    status = clk_gen_WriteReg(dev, CS_GLOBAL_CFG, 0x09);
    if (status != NO_ERROR)
    {
        return status;
    }

    /* Write the Ratio bytes */
    status = clk_gen_WriteReg(dev, CS_RATIO_3, (uint8_t) (((ratio & 0xFF000000) >> 24)));
    if (status != NO_ERROR)
    {
        return status;
    }

    status = clk_gen_WriteReg(dev, CS_RATIO_2, (uint8_t) (((ratio & 0xFF0000) >> 16)));
    if (status != NO_ERROR)
    {
        return status;
    }

    status = clk_gen_WriteReg(dev, CS_RATIO_1, (uint8_t) (((ratio & 0xFF00) >> 8)));
    if (status != NO_ERROR)
    {
        return status;
    }

    status = clk_gen_WriteReg(dev, CS_RATIO_0, (uint8_t) (ratio & 0xFF));
    if (status != NO_ERROR)
    {
        return status;
    }

    /* unfreeze */
    status = clk_gen_WriteReg(dev, CS_GLOBAL_CFG, 0x01);
    if (status != NO_ERROR)
    {
        return status;
    }

    return status;
}