LXR linux/drivers/iio/dac/cio-dac.c

   1/*
   2 * IIO driver for the Measurement Computing CIO-DAC
   3 * Copyright (C) 2016 William Breathitt Gray
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License, version 2, as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it will be useful, but
  10 * WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 * General Public License for more details.
  13 *
  14 * This driver supports the following Measurement Computing devices: CIO-DAC16,
  15 * CIO-DAC06, and PC104-DAC06.
  16 */
  17#include <linux/bitops.h>
  18#include <linux/device.h>
  19#include <linux/errno.h>
  20#include <linux/iio/iio.h>
  21#include <linux/iio/types.h>
  22#include <linux/io.h>
  23#include <linux/ioport.h>
  24#include <linux/isa.h>
  25#include <linux/module.h>
  26#include <linux/moduleparam.h>
  27
  28#define CIO_DAC_NUM_CHAN 16
  29
  30#define CIO_DAC_CHAN(chan) {                            \
  31        .type = IIO_VOLTAGE,                            \
  32        .channel = chan,                                \
  33        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
  34        .indexed = 1,                                   \
  35        .output = 1                                     \
  36}
  37
  38#define CIO_DAC_EXTENT 32
  39
  40static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
  41static unsigned int num_cio_dac;
  42module_param_array(base, uint, &num_cio_dac, 0);
  43MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
  44
  45/**
  46 * struct cio_dac_iio - IIO device private data structure
  47 * @chan_out_states:    channels' output states
  48 * @base:               base port address of the IIO device
  49 */
  50struct cio_dac_iio {
  51        int chan_out_states[CIO_DAC_NUM_CHAN];
  52        unsigned int base;
  53};
  54
  55static int cio_dac_read_raw(struct iio_dev *indio_dev,
  56        struct iio_chan_spec const *chan, int *val, int *val2, long mask)
  57{
  58        struct cio_dac_iio *const priv = iio_priv(indio_dev);
  59
  60        if (mask != IIO_CHAN_INFO_RAW)
  61                return -EINVAL;
  62
  63        *val = priv->chan_out_states[chan->channel];
  64
  65        return IIO_VAL_INT;
  66}
  67
  68static int cio_dac_write_raw(struct iio_dev *indio_dev,
  69        struct iio_chan_spec const *chan, int val, int val2, long mask)
  70{
  71        struct cio_dac_iio *const priv = iio_priv(indio_dev);
  72        const unsigned int chan_addr_offset = 2 * chan->channel;
  73
  74        if (mask != IIO_CHAN_INFO_RAW)
  75                return -EINVAL;
  76
  77        /* DAC can only accept up to a 16-bit value */
  78        if ((unsigned int)val > 65535)
  79                return -EINVAL;
  80
  81        priv->chan_out_states[chan->channel] = val;
  82        outw(val, priv->base + chan_addr_offset);
  83
  84        return 0;
  85}
  86
  87static const struct iio_info cio_dac_info = {
  88        .driver_module = THIS_MODULE,
  89        .read_raw = cio_dac_read_raw,
  90        .write_raw = cio_dac_write_raw
  91};
  92
  93static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
  94        CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
  95        CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
  96        CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
  97        CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
  98};
  99
 100static int cio_dac_probe(struct device *dev, unsigned int id)
 101{
 102        struct iio_dev *indio_dev;
 103        struct cio_dac_iio *priv;
 104        unsigned int i;
 105
 106        indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
 107        if (!indio_dev)
 108                return -ENOMEM;
 109
 110        if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
 111                dev_name(dev))) {
 112                dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
 113                        base[id], base[id] + CIO_DAC_EXTENT);
 114                return -EBUSY;
 115        }
 116
 117        indio_dev->info = &cio_dac_info;
 118        indio_dev->modes = INDIO_DIRECT_MODE;
 119        indio_dev->channels = cio_dac_channels;
 120        indio_dev->num_channels = CIO_DAC_NUM_CHAN;
 121        indio_dev->name = dev_name(dev);
 122
 123        priv = iio_priv(indio_dev);
 124        priv->base = base[id];
 125
 126        /* initialize DAC outputs to 0V */
 127        for (i = 0; i < 32; i += 2)
 128                outw(0, base[id] + i);
 129
 130        return devm_iio_device_register(dev, indio_dev);
 131}
 132
 133static struct isa_driver cio_dac_driver = {
 134        .probe = cio_dac_probe,
 135        .driver = {
 136                .name = "cio-dac"
 137        }
 138};
 139
 140module_isa_driver(cio_dac_driver, num_cio_dac);
 141
 142MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 143MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
 144MODULE_LICENSE("GPL v2");
 145