1 /*
2 * IIO driver for the Measurement Computing CIO-DAC
3 * Copyright (C) 2016 William Breathitt Gray
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2, as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * This driver supports the following Measurement Computing devices: CIO-DAC16,
15 * CIO-DAC06, and PC104-DAC06.
16 */
17 #include <linux/bitops.h>
18 #include <linux/device.h>
19 #include <linux/errno.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/types.h>
22 #include <linux/io.h>
23 #include <linux/ioport.h>
24 #include <linux/isa.h>
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27
28 #define CIO_DAC_NUM_CHAN 16
29
30 #define CIO_DAC_CHAN(chan) { \
31 .type = IIO_VOLTAGE, \
32 .channel = chan, \
33 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
34 .indexed = 1, \
35 .output = 1 \
36 }
37
38 #define CIO_DAC_EXTENT 32
39
40 static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
41 static unsigned int num_cio_dac;
42 module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
43 MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
44
45 /**
46 * struct cio_dac_iio - IIO device private data structure
47 * @chan_out_states: channels' output states
48 * @base: base port address of the IIO device
49 */
50 struct cio_dac_iio {
51 int chan_out_states[CIO_DAC_NUM_CHAN];
52 unsigned int base;
53 };
54
cio_dac_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)55 static int cio_dac_read_raw(struct iio_dev *indio_dev,
56 struct iio_chan_spec const *chan, int *val, int *val2, long mask)
57 {
58 struct cio_dac_iio *const priv = iio_priv(indio_dev);
59
60 if (mask != IIO_CHAN_INFO_RAW)
61 return -EINVAL;
62
63 *val = priv->chan_out_states[chan->channel];
64
65 return IIO_VAL_INT;
66 }
67
cio_dac_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)68 static int cio_dac_write_raw(struct iio_dev *indio_dev,
69 struct iio_chan_spec const *chan, int val, int val2, long mask)
70 {
71 struct cio_dac_iio *const priv = iio_priv(indio_dev);
72 const unsigned int chan_addr_offset = 2 * chan->channel;
73
74 if (mask != IIO_CHAN_INFO_RAW)
75 return -EINVAL;
76
77 /* DAC can only accept up to a 16-bit value */
78 if ((unsigned int)val > 65535)
79 return -EINVAL;
80
81 priv->chan_out_states[chan->channel] = val;
82 outw(val, priv->base + chan_addr_offset);
83
84 return 0;
85 }
86
87 static const struct iio_info cio_dac_info = {
88 .read_raw = cio_dac_read_raw,
89 .write_raw = cio_dac_write_raw
90 };
91
92 static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
93 CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
94 CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
95 CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
96 CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
97 };
98
cio_dac_probe(struct device * dev,unsigned int id)99 static int cio_dac_probe(struct device *dev, unsigned int id)
100 {
101 struct iio_dev *indio_dev;
102 struct cio_dac_iio *priv;
103 unsigned int i;
104
105 indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
106 if (!indio_dev)
107 return -ENOMEM;
108
109 if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
110 dev_name(dev))) {
111 dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
112 base[id], base[id] + CIO_DAC_EXTENT);
113 return -EBUSY;
114 }
115
116 indio_dev->info = &cio_dac_info;
117 indio_dev->modes = INDIO_DIRECT_MODE;
118 indio_dev->channels = cio_dac_channels;
119 indio_dev->num_channels = CIO_DAC_NUM_CHAN;
120 indio_dev->name = dev_name(dev);
121 indio_dev->dev.parent = dev;
122
123 priv = iio_priv(indio_dev);
124 priv->base = base[id];
125
126 /* initialize DAC outputs to 0V */
127 for (i = 0; i < 32; i += 2)
128 outw(0, base[id] + i);
129
130 return devm_iio_device_register(dev, indio_dev);
131 }
132
133 static struct isa_driver cio_dac_driver = {
134 .probe = cio_dac_probe,
135 .driver = {
136 .name = "cio-dac"
137 }
138 };
139
140 module_isa_driver(cio_dac_driver, num_cio_dac);
141
142 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
143 MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
144 MODULE_LICENSE("GPL v2");
145
