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/*
* 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];
return IIO_VAL_INT;
}
static int cio_dac_write_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);
const unsigned int chan_addr_offset = 2 * chan->channel;
if (mask != IIO_CHAN_INFO_RAW)
return -EINVAL;
/* DAC can only accept up to a 16-bit value */
if ((unsigned int)val > 65535)
return -EINVAL;
priv->chan_out_states[chan->channel] = val;
outw(val, priv->base + chan_addr_offset);
return 0;
}
static const struct iio_info cio_dac_info = {
.driver_module = THIS_MODULE,
.read_raw = cio_dac_read_raw,
.write_raw = cio_dac_write_raw
};
static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
};
static int cio_dac_probe(struct device *dev, unsigned int id)
{
struct iio_dev *indio_dev;
struct cio_dac_iio *priv;
unsigned int i;
indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
if (!indio_dev)
return -ENOMEM;
if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
dev_name(dev))) {
dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
base[id], base[id] + CIO_DAC_EXTENT);
return -EBUSY;
}
indio_dev->info = &cio_dac_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = cio_dac_channels;
indio_dev->num_channels = CIO_DAC_NUM_CHAN;
indio_dev->name = dev_name(dev);
indio_dev->dev.parent = dev;
priv = iio_priv(indio_dev);
priv->base = base[id];
/* initialize DAC outputs to 0V */
for (i = 0; i < 32; i += 2)
outw(0, base[id] + i);
return devm_iio_device_register(dev, indio_dev);
}
static struct isa_driver cio_dac_driver = {
.probe = cio_dac_probe,
.driver = {
.name = "cio-dac"
}
};
module_isa_driver(cio_dac_driver, num_cio_dac);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
MODULE_LICENSE("GPL v2");
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