linux-imx

/*

 * IIO driver for the Measurement Computing CIO-DAC

 * Copyright (C) 2016 William Breathitt Gray

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License, version 2, as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 *

 * This driver supports the following Measurement Computing devices: CIO-DAC16,

 * CIO-DAC06, and PC104-DAC06.

 */

#include <linux/bitops.h>

#include <linux/device.h>

#include <linux/errno.h>

#include <linux/iio/iio.h>

#include <linux/iio/types.h>

#include <linux/io.h>

#include <linux/ioport.h>

#include <linux/isa.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

​

#define CIO_DAC_NUM_CHAN 16

​

#define CIO_DAC_CHAN(chan) {                \

    .type = IIO_VOLTAGE,                \

    .channel = chan,                \

    .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \

    .indexed = 1,                   \

    .output = 1                 \

}

​

#define CIO_DAC_EXTENT 32

​

static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];

static unsigned int num_cio_dac;

module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);

MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");

​

/**

 * struct cio_dac_iio - IIO device private data structure

 * @chan_out_states:    channels' output states

 * @base:       base port address of the IIO device

 */

struct cio_dac_iio {

    int chan_out_states[CIO_DAC_NUM_CHAN];

    unsigned int base;

};

​

static int cio_dac_read_raw(struct iio_dev *indio_dev,

    struct iio_chan_spec const *chan, int *val, int *val2, long mask)

{

    struct cio_dac_iio *const priv = iio_priv(indio_dev);

​

    if (mask != IIO_CHAN_INFO_RAW)

        return -EINVAL;

​

    *val = priv->chan_out_states[chan->channel];