linux/drivers/iio/dac/cio-dac.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * IIO driver for the Measurement Computing CIO-DAC
   4 * Copyright (C) 2016 William Breathitt Gray
   5 *
   6 * This driver supports the following Measurement Computing devices: CIO-DAC16,
   7 * CIO-DAC06, and PC104-DAC06.
   8 */
   9#include <linux/bitops.h>
  10#include <linux/device.h>
  11#include <linux/errno.h>
  12#include <linux/iio/iio.h>
  13#include <linux/iio/types.h>
  14#include <linux/io.h>
  15#include <linux/ioport.h>
  16#include <linux/isa.h>
  17#include <linux/module.h>
  18#include <linux/moduleparam.h>
  19
  20#define CIO_DAC_NUM_CHAN 16
  21
  22#define CIO_DAC_CHAN(chan) {                            \
  23        .type = IIO_VOLTAGE,                            \
  24        .channel = chan,                                \
  25        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
  26        .indexed = 1,                                   \
  27        .output = 1                                     \
  28}
  29
  30#define CIO_DAC_EXTENT 32
  31
  32static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
  33static unsigned int num_cio_dac;
  34module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
  35MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
  36
  37/**
  38 * struct cio_dac_iio - IIO device private data structure
  39 * @chan_out_states:    channels' output states
  40 * @base:               base port address of the IIO device
  41 */
  42struct cio_dac_iio {
  43        int chan_out_states[CIO_DAC_NUM_CHAN];
  44        unsigned int base;
  45};
  46
  47static int cio_dac_read_raw(struct iio_dev *indio_dev,
  48        struct iio_chan_spec const *chan, int *val, int *val2, long mask)
  49{
  50        struct cio_dac_iio *const priv = iio_priv(indio_dev);
  51
  52        if (mask != IIO_CHAN_INFO_RAW)
  53                return -EINVAL;
  54
  55        *val = priv->chan_out_states[chan->channel];
  56
  57        return IIO_VAL_INT;
  58}
  59
  60static int cio_dac_write_raw(struct iio_dev *indio_dev,
  61        struct iio_chan_spec const *chan, int val, int val2, long mask)
  62{
  63        struct cio_dac_iio *const priv = iio_priv(indio_dev);
  64        const unsigned int chan_addr_offset = 2 * chan->channel;
  65
  66        if (mask != IIO_CHAN_INFO_RAW)
  67                return -EINVAL;
  68
  69        /* DAC can only accept up to a 16-bit value */
  70        if ((unsigned int)val > 65535)
  71                return -EINVAL;
  72
  73        priv->chan_out_states[chan->channel] = val;
  74        outw(val, priv->base + chan_addr_offset);
  75
  76        return 0;
  77}
  78
  79static const struct iio_info cio_dac_info = {
  80        .read_raw = cio_dac_read_raw,
  81        .write_raw = cio_dac_write_raw
  82};
  83
  84static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
  85        CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
  86        CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
  87        CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
  88        CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
  89};
  90
  91static int cio_dac_probe(struct device *dev, unsigned int id)
  92{
  93        struct iio_dev *indio_dev;
  94        struct cio_dac_iio *priv;
  95        unsigned int i;
  96
  97        indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
  98        if (!indio_dev)
  99                return -ENOMEM;
 100
 101        if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
 102                dev_name(dev))) {
 103                dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
 104                        base[id], base[id] + CIO_DAC_EXTENT);
 105                return -EBUSY;
 106        }
 107
 108        indio_dev->info = &cio_dac_info;
 109        indio_dev->modes = INDIO_DIRECT_MODE;
 110        indio_dev->channels = cio_dac_channels;
 111        indio_dev->num_channels = CIO_DAC_NUM_CHAN;
 112        indio_dev->name = dev_name(dev);
 113
 114        priv = iio_priv(indio_dev);
 115        priv->base = base[id];
 116
 117        /* initialize DAC outputs to 0V */
 118        for (i = 0; i < 32; i += 2)
 119                outw(0, base[id] + i);
 120
 121        return devm_iio_device_register(dev, indio_dev);
 122}
 123
 124static struct isa_driver cio_dac_driver = {
 125        .probe = cio_dac_probe,
 126        .driver = {
 127                .name = "cio-dac"
 128        }
 129};
 130
 131module_isa_driver(cio_dac_driver, num_cio_dac);
 132
 133MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 134MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
 135MODULE_LICENSE("GPL v2");
 136
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