iio/dac/cio-dac.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * IIO driver for the Measurement Computing CIO-DAC
0004  * Copyright (C) 2016 William Breathitt Gray
0005  *
0006  * This driver supports the following Measurement Computing devices: CIO-DAC16,
0007  * CIO-DAC06, and PC104-DAC06.
0008  */
0009 #include <linux/bitops.h>
0010 #include <linux/device.h>
0011 #include <linux/errno.h>
0012 #include <linux/iio/iio.h>
0013 #include <linux/iio/types.h>
0014 #include <linux/io.h>
0015 #include <linux/ioport.h>
0016 #include <linux/isa.h>
0017 #include <linux/module.h>
0018 #include <linux/moduleparam.h>
0019 #include <linux/types.h>
0020
0021 #define CIO_DAC_NUM_CHAN 16
0022
0023 #define CIO_DAC_CHAN(chan) {                \
0024     .type = IIO_VOLTAGE,                \
0025     .channel = chan,                \
0026     .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
0027     .indexed = 1,                   \
0028     .output = 1                 \
0029 }
0030
0031 #define CIO_DAC_EXTENT 32
0032
0033 static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
0034 static unsigned int num_cio_dac;
0035 module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
0036 MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
0037
0038 /**
0039  * struct cio_dac_iio - IIO device private data structure
0040  * @chan_out_states:    channels' output states
0041  * @base:       base memory address of the DAC device
0042  */
0043 struct cio_dac_iio {
0044     int chan_out_states[CIO_DAC_NUM_CHAN];
0045     u16 __iomem *base;
0046 };
0047
0048 static int cio_dac_read_raw(struct iio_dev *indio_dev,
0049     struct iio_chan_spec const *chan, int *val, int *val2, long mask)
0050 {
0051     struct cio_dac_iio *const priv = iio_priv(indio_dev);
0052
0053     if (mask != IIO_CHAN_INFO_RAW)
0054         return -EINVAL;
0055
0056     *val = priv->chan_out_states[chan->channel];
0057
0058     return IIO_VAL_INT;
0059 }
0060
0061 static int cio_dac_write_raw(struct iio_dev *indio_dev,
0062     struct iio_chan_spec const *chan, int val, int val2, long mask)
0063 {
0064     struct cio_dac_iio *const priv = iio_priv(indio_dev);
0065
0066     if (mask != IIO_CHAN_INFO_RAW)
0067         return -EINVAL;
0068
0069     /* DAC can only accept up to a 16-bit value */
0070     if ((unsigned int)val > 65535)
0071         return -EINVAL;
0072
0073     priv->chan_out_states[chan->channel] = val;
0074     iowrite16(val, priv->base + chan->channel);
0075
0076     return 0;
0077 }
0078
0079 static const struct iio_info cio_dac_info = {
0080     .read_raw = cio_dac_read_raw,
0081     .write_raw = cio_dac_write_raw
0082 };
0083
0084 static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
0085     CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
0086     CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
0087     CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
0088     CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
0089 };
0090
0091 static int cio_dac_probe(struct device *dev, unsigned int id)
0092 {
0093     struct iio_dev *indio_dev;
0094     struct cio_dac_iio *priv;
0095     unsigned int i;
0096
0097     indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
0098     if (!indio_dev)
0099         return -ENOMEM;
0100
0101     if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
0102         dev_name(dev))) {
0103         dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
0104             base[id], base[id] + CIO_DAC_EXTENT);
0105         return -EBUSY;
0106     }
0107
0108     priv = iio_priv(indio_dev);
0109     priv->base = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
0110     if (!priv->base)
0111         return -ENOMEM;
0112
0113     indio_dev->info = &cio_dac_info;
0114     indio_dev->modes = INDIO_DIRECT_MODE;
0115     indio_dev->channels = cio_dac_channels;
0116     indio_dev->num_channels = CIO_DAC_NUM_CHAN;
0117     indio_dev->name = dev_name(dev);
0118
0119     /* initialize DAC outputs to 0V */
0120     for (i = 0; i < CIO_DAC_NUM_CHAN; i++)
0121         iowrite16(0, priv->base + i);
0122
0123     return devm_iio_device_register(dev, indio_dev);
0124 }
0125
0126 static struct isa_driver cio_dac_driver = {
0127     .probe = cio_dac_probe,
0128     .driver = {
0129         .name = "cio-dac"
0130     }
0131 };
0132
0133 module_isa_driver(cio_dac_driver, num_cio_dac);
0134
0135 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
0136 MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
0137 MODULE_LICENSE("GPL v2");