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c3701185ee
The CIO-DAC series of devices only supports DAC values up to 12-bit
rather than 16-bit. Trying to write a 16-bit value results in only the
lower 12 bits affecting the DAC output which is not what the user
expects. Instead, adjust the DAC write value check to reject values
larger than 12-bit so that they fail explicitly as invalid for the user.
Fixes: 3b8df5fd52 ("iio: Add IIO support for the Measurement Computing CIO-DAC family")
Cc: stable@vger.kernel.org
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/20230311002248.8548-1-william.gray@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
138 lines
3.6 KiB
C
138 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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 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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#include <linux/types.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 memory address of the DAC 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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u16 __iomem *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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if (mask != IIO_CHAN_INFO_RAW)
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return -EINVAL;
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/* DAC can only accept up to a 12-bit value */
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if ((unsigned int)val > 4095)
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return -EINVAL;
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priv->chan_out_states[chan->channel] = val;
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iowrite16(val, priv->base + chan->channel);
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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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priv = iio_priv(indio_dev);
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priv->base = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
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if (!priv->base)
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return -ENOMEM;
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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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/* initialize DAC outputs to 0V */
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for (i = 0; i < CIO_DAC_NUM_CHAN; i++)
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iowrite16(0, priv->base + 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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