linux-imx

/*

 * AD5592R Digital <-> Analog converters driver

 *

 * Copyright 2015-2016 Analog Devices Inc.

 * Author: Paul Cercueil <paul.cercueil@analog.com>

 *

 * Licensed under the GPL-2.

 */

​

#include "ad5592r-base.h"

​

#include <linux/bitops.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/spi/spi.h>

#include <linux/acpi.h>

​

#define AD5592R_GPIO_READBACK_EN    BIT(10)

#define AD5592R_LDAC_READBACK_EN    BIT(6)

​

static int ad5592r_spi_wnop_r16(struct ad5592r_state *st, __be16 *buf)

{

    struct spi_device *spi = container_of(st->dev, struct spi_device, dev);

    struct spi_transfer t = {

            .tx_buf = &st->spi_msg_nop,

            .rx_buf = buf,

            .len = 2

        };

​

    st->spi_msg_nop = 0; /* NOP */

​

    return spi_sync_transfer(spi, &t, 1);

}

​

static int ad5592r_write_dac(struct ad5592r_state *st, unsigned chan, u16 value)

{

    struct spi_device *spi = container_of(st->dev, struct spi_device, dev);

​

    st->spi_msg = cpu_to_be16(BIT(15) | (chan << 12) | value);

​

    return spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));

}

​

static int ad5592r_read_adc(struct ad5592r_state *st, unsigned chan, u16 *value)

{

    struct spi_device *spi = container_of(st->dev, struct spi_device, dev);

    int ret;

​

    st->spi_msg = cpu_to_be16((AD5592R_REG_ADC_SEQ << 11) | BIT(chan));

​

    ret = spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));

    if (ret)

        return ret;

​

    /*

     * Invalid data:

     * See Figure 40. Single-Channel ADC Conversion Sequence

     */

    ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);

    if (ret)

        return ret;

​

    ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);