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// SPDX-License-Identifier: GPL-2.0-only
/*
* IIO driver for the Measurement Computing CIO-DAC
* Copyright (C) 2016 William Breathitt Gray
*
* This driver supports the following Measurement Computing devices: CIO-DAC16,
* CIO-DAC08, and PC104-DAC06.
*/
#include <linux/bits.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/iio/iio.h>
#include <linux/iio/types.h>
#include <linux/isa.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/regmap.h>
#include <linux/types.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");
#define CIO_DAC_BASE 0x00
#define CIO_DAC_CHANNEL_STRIDE 2
static bool cio_dac_precious_reg(struct device *dev, unsigned int reg)
{
/*
* All registers are considered precious; if the XFER jumper is set on
* the device, then no update occurs until a DAC register is read.
*/
return true;
}
static const struct regmap_config cio_dac_regmap_config = {
.reg_bits = 16,
.reg_stride = 2,
.val_bits = 16,
.io_port = true,
.max_register = 0x1F,
.precious_reg = cio_dac_precious_reg,
};
/**
* struct cio_dac_iio - IIO device private data structure
* @map: Regmap for the device
*/
struct cio_dac_iio {
struct regmap *map;
};
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);
const unsigned int offset = chan->channel * CIO_DAC_CHANNEL_STRIDE;
int err;
unsigned int dac_val;
if (mask != IIO_CHAN_INFO_RAW)
return -EINVAL;
err = regmap_read(priv->map, CIO_DAC_BASE + offset, &dac_val);
if (err)
return err;
*val = dac_val;
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 offset = chan->channel * CIO_DAC_CHANNEL_STRIDE;
if (mask != IIO_CHAN_INFO_RAW)
return -EINVAL;
/* DAC can only accept up to a 12-bit value */
if ((unsigned int)val > 4095)
return -EINVAL;
return regmap_write(priv->map, CIO_DAC_BASE + offset, val);
}
static const struct iio_info cio_dac_info = {
.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;
void __iomem *regs;
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;
}
regs = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
if (!regs)
return -ENOMEM;
priv = iio_priv(indio_dev);
priv->map = devm_regmap_init_mmio(dev, regs, &cio_dac_regmap_config);
if (IS_ERR(priv->map))
return dev_err_probe(dev, PTR_ERR(priv->map),
"Unable to initialize register map\n");
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);
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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