8863b3e785
When the kernel is running in secure boot mode, we lock down the kernel to prevent userspace from modifying the running kernel image. Whilst this includes prohibiting access to things like /dev/mem, it must also prevent access by means of configuring driver modules in such a way as to cause a device to access or modify the kernel image. To this end, annotate module_param* statements that refer to hardware configuration and indicate for future reference what type of parameter they specify. The parameter parser in the core sees this information and can skip such parameters with an error message if the kernel is locked down. The module initialisation then runs as normal, but just sees whatever the default values for those parameters is. Note that we do still need to do the module initialisation because some drivers have viable defaults set in case parameters aren't specified and some drivers support automatic configuration (e.g. PNP or PCI) in addition to manually coded parameters. This patch annotates drivers in drivers/iio/. Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> Acked-by: Jonathan Cameron <jic23@kernel.org> cc: linux-iio@vger.kernel.org
145 lines
4.0 KiB
C
145 lines
4.0 KiB
C
/*
|
|
* 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);
|
|
|
|
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");
|