linux-imx

/*

 * AD5421 Digital to analog converters  driver

 *

 * Copyright 2011 Analog Devices Inc.

 *

 * Licensed under the GPL-2.

 */

​

#include <linux/device.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/module.h>

#include <linux/interrupt.h>

#include <linux/kernel.h>

#include <linux/spi/spi.h>

#include <linux/slab.h>

#include <linux/sysfs.h>

​

#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>

#include <linux/iio/events.h>

#include <linux/iio/dac/ad5421.h>

​

​

#define AD5421_REG_DAC_DATA     0x1

#define AD5421_REG_CTRL         0x2

#define AD5421_REG_OFFSET       0x3

#define AD5421_REG_GAIN         0x4

/* load dac and fault shared the same register number. Writing to it will cause

 * a dac load command, reading from it will return the fault status register */

#define AD5421_REG_LOAD_DAC     0x5

#define AD5421_REG_FAULT        0x5

#define AD5421_REG_FORCE_ALARM_CURRENT  0x6

#define AD5421_REG_RESET        0x7

#define AD5421_REG_START_CONVERSION 0x8

#define AD5421_REG_NOOP         0x9

​

#define AD5421_CTRL_WATCHDOG_DISABLE    BIT(12)

#define AD5421_CTRL_AUTO_FAULT_READBACK BIT(11)

#define AD5421_CTRL_MIN_CURRENT     BIT(9)

#define AD5421_CTRL_ADC_SOURCE_TEMP BIT(8)

#define AD5421_CTRL_ADC_ENABLE      BIT(7)

#define AD5421_CTRL_PWR_DOWN_INT_VREF   BIT(6)

​

#define AD5421_FAULT_SPI            BIT(15)

#define AD5421_FAULT_PEC            BIT(14)

#define AD5421_FAULT_OVER_CURRENT       BIT(13)

#define AD5421_FAULT_UNDER_CURRENT      BIT(12)

#define AD5421_FAULT_TEMP_OVER_140      BIT(11)

#define AD5421_FAULT_TEMP_OVER_100      BIT(10)

#define AD5421_FAULT_UNDER_VOLTAGE_6V       BIT(9)

#define AD5421_FAULT_UNDER_VOLTAGE_12V      BIT(8)

​

/* These bits will cause the fault pin to go high */

#define AD5421_FAULT_TRIGGER_IRQ \

    (AD5421_FAULT_SPI | AD5421_FAULT_PEC | AD5421_FAULT_OVER_CURRENT | \

    AD5421_FAULT_UNDER_CURRENT | AD5421_FAULT_TEMP_OVER_140)

​

/**

 * struct ad5421_state - driver instance specific data

 * @spi:        spi_device

 * @ctrl:       control register cache

 * @current_range:  current range which the device is configured for

 * @data:       spi transfer buffers

 * @fault_mask:     software masking of events

 */

struct ad5421_state {

    struct spi_device       *spi;

    unsigned int            ctrl;

    enum ad5421_current_range   current_range;

    unsigned int            fault_mask;

​

    /*

     * DMA (thus cache coherency maintenance) requires the

     * transfer buffers to live in their own cache lines.

     */

    union {

        __be32 d32;

        u8 d8[4];

    } data[2] ____cacheline_aligned;

};

​

static const struct iio_event_spec ad5421_current_event[] = {

    {

        .type = IIO_EV_TYPE_THRESH,

        .dir = IIO_EV_DIR_RISING,

        .mask_separate = BIT(IIO_EV_INFO_VALUE) |

            BIT(IIO_EV_INFO_ENABLE),

    }, {

        .type = IIO_EV_TYPE_THRESH,

        .dir = IIO_EV_DIR_FALLING,

        .mask_separate = BIT(IIO_EV_INFO_VALUE) |