145 lines
4 KiB
C
145 lines
4 KiB
C
/*
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* IIO driver for the Measurement Computing CIO-DAC
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* Copyright (C) 2016 William Breathitt Gray
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* This driver supports the following Measurement Computing devices: CIO-DAC16,
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* CIO-DAC06, and PC104-DAC06.
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*/
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#include <linux/bitops.h>
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/types.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/isa.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#define CIO_DAC_NUM_CHAN 16
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#define CIO_DAC_CHAN(chan) { \
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.type = IIO_VOLTAGE, \
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.channel = chan, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.indexed = 1, \
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.output = 1 \
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}
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#define CIO_DAC_EXTENT 32
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static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
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static unsigned int num_cio_dac;
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module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
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MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
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/**
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* struct cio_dac_iio - IIO device private data structure
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* @chan_out_states: channels' output states
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* @base: base port address of the IIO device
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*/
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struct cio_dac_iio {
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int chan_out_states[CIO_DAC_NUM_CHAN];
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unsigned int base;
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};
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static int cio_dac_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int *val, int *val2, long mask)
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{
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struct cio_dac_iio *const priv = iio_priv(indio_dev);
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if (mask != IIO_CHAN_INFO_RAW)
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return -EINVAL;
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*val = priv->chan_out_states[chan->channel];
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return IIO_VAL_INT;
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}
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static int cio_dac_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int val, int val2, long mask)
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{
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struct cio_dac_iio *const priv = iio_priv(indio_dev);
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const unsigned int chan_addr_offset = 2 * chan->channel;
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if (mask != IIO_CHAN_INFO_RAW)
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return -EINVAL;
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/* DAC can only accept up to a 16-bit value */
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if ((unsigned int)val > 65535)
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return -EINVAL;
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priv->chan_out_states[chan->channel] = val;
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outw(val, priv->base + chan_addr_offset);
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return 0;
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}
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static const struct iio_info cio_dac_info = {
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.read_raw = cio_dac_read_raw,
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.write_raw = cio_dac_write_raw
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};
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static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
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CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
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CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
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CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
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CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
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};
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static int cio_dac_probe(struct device *dev, unsigned int id)
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{
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struct iio_dev *indio_dev;
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struct cio_dac_iio *priv;
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unsigned int i;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
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if (!indio_dev)
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return -ENOMEM;
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if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
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dev_name(dev))) {
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dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
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base[id], base[id] + CIO_DAC_EXTENT);
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return -EBUSY;
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}
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indio_dev->info = &cio_dac_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = cio_dac_channels;
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indio_dev->num_channels = CIO_DAC_NUM_CHAN;
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indio_dev->name = dev_name(dev);
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indio_dev->dev.parent = dev;
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priv = iio_priv(indio_dev);
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priv->base = base[id];
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/* initialize DAC outputs to 0V */
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for (i = 0; i < 32; i += 2)
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outw(0, base[id] + i);
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return devm_iio_device_register(dev, indio_dev);
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}
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static struct isa_driver cio_dac_driver = {
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.probe = cio_dac_probe,
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.driver = {
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.name = "cio-dac"
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}
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};
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module_isa_driver(cio_dac_driver, num_cio_dac);
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MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
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MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
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MODULE_LICENSE("GPL v2");
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