1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * IIO driver for the Measurement Computing CIO-DAC
4 * Copyright (C) 2016 William Breathitt Gray
5 *
6 * This driver supports the following Measurement Computing devices: CIO-DAC16,
7 * CIO-DAC06, and PC104-DAC06.
8 */
9 #include <linux/bitops.h>
10 #include <linux/device.h>
11 #include <linux/errno.h>
12 #include <linux/iio/iio.h>
13 #include <linux/iio/types.h>
14 #include <linux/io.h>
15 #include <linux/ioport.h>
16 #include <linux/isa.h>
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19
20 #define CIO_DAC_NUM_CHAN 16
21
22 #define CIO_DAC_CHAN(chan) { \
23 .type = IIO_VOLTAGE, \
24 .channel = chan, \
25 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
26 .indexed = 1, \
27 .output = 1 \
28 }
29
30 #define CIO_DAC_EXTENT 32
31
32 static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
33 static unsigned int num_cio_dac;
34 module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
35 MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
36
37 /**
38 * struct cio_dac_iio - IIO device private data structure
39 * @chan_out_states: channels' output states
40 * @base: base port address of the IIO device
41 */
42 struct cio_dac_iio {
43 int chan_out_states[CIO_DAC_NUM_CHAN];
44 unsigned int base;
45 };
46
cio_dac_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)47 static int cio_dac_read_raw(struct iio_dev *indio_dev,
48 struct iio_chan_spec const *chan, int *val, int *val2, long mask)
49 {
50 struct cio_dac_iio *const priv = iio_priv(indio_dev);
51
52 if (mask != IIO_CHAN_INFO_RAW)
53 return -EINVAL;
54
55 *val = priv->chan_out_states[chan->channel];
56
57 return IIO_VAL_INT;
58 }
59
cio_dac_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)60 static int cio_dac_write_raw(struct iio_dev *indio_dev,
61 struct iio_chan_spec const *chan, int val, int val2, long mask)
62 {
63 struct cio_dac_iio *const priv = iio_priv(indio_dev);
64 const unsigned int chan_addr_offset = 2 * chan->channel;
65
66 if (mask != IIO_CHAN_INFO_RAW)
67 return -EINVAL;
68
69 /* DAC can only accept up to a 16-bit value */
70 if ((unsigned int)val > 65535)
71 return -EINVAL;
72
73 priv->chan_out_states[chan->channel] = val;
74 outw(val, priv->base + chan_addr_offset);
75
76 return 0;
77 }
78
79 static const struct iio_info cio_dac_info = {
80 .read_raw = cio_dac_read_raw,
81 .write_raw = cio_dac_write_raw
82 };
83
84 static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
85 CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
86 CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
87 CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
88 CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
89 };
90
cio_dac_probe(struct device * dev,unsigned int id)91 static int cio_dac_probe(struct device *dev, unsigned int id)
92 {
93 struct iio_dev *indio_dev;
94 struct cio_dac_iio *priv;
95 unsigned int i;
96
97 indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
98 if (!indio_dev)
99 return -ENOMEM;
100
101 if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
102 dev_name(dev))) {
103 dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
104 base[id], base[id] + CIO_DAC_EXTENT);
105 return -EBUSY;
106 }
107
108 indio_dev->info = &cio_dac_info;
109 indio_dev->modes = INDIO_DIRECT_MODE;
110 indio_dev->channels = cio_dac_channels;
111 indio_dev->num_channels = CIO_DAC_NUM_CHAN;
112 indio_dev->name = dev_name(dev);
113
114 priv = iio_priv(indio_dev);
115 priv->base = base[id];
116
117 /* initialize DAC outputs to 0V */
118 for (i = 0; i < 32; i += 2)
119 outw(0, base[id] + i);
120
121 return devm_iio_device_register(dev, indio_dev);
122 }
123
124 static struct isa_driver cio_dac_driver = {
125 .probe = cio_dac_probe,
126 .driver = {
127 .name = "cio-dac"
128 }
129 };
130
131 module_isa_driver(cio_dac_driver, num_cio_dac);
132
133 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
134 MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
135 MODULE_LICENSE("GPL v2");
136