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1 | /* |
2 | * DAC driver for the Apex Embedded Systems STX104 | |
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 | #include <linux/bitops.h> | |
15 | #include <linux/device.h> | |
16 | #include <linux/errno.h> | |
17 | #include <linux/iio/iio.h> | |
18 | #include <linux/iio/types.h> | |
19 | #include <linux/io.h> | |
20 | #include <linux/ioport.h> | |
21 | #include <linux/isa.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/moduleparam.h> | |
24 | ||
25 | #define STX104_NUM_CHAN 2 | |
26 | ||
27 | #define STX104_CHAN(chan) { \ | |
28 | .type = IIO_VOLTAGE, \ | |
29 | .channel = chan, \ | |
30 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
31 | .indexed = 1, \ | |
32 | .output = 1 \ | |
33 | } | |
34 | ||
35 | #define STX104_EXTENT 16 | |
97a445da | 36 | |
9c2cfc19 WBG |
37 | static unsigned int base[max_num_isa_dev(STX104_EXTENT)]; |
38 | static unsigned int num_stx104; | |
97a445da WBG |
39 | module_param_array(base, uint, &num_stx104, 0); |
40 | MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses"); | |
41 | ||
42 | /** | |
43 | * struct stx104_iio - IIO device private data structure | |
44 | * @chan_out_states: channels' output states | |
45 | * @base: base port address of the IIO device | |
46 | */ | |
47 | struct stx104_iio { | |
48 | unsigned chan_out_states[STX104_NUM_CHAN]; | |
49 | unsigned base; | |
50 | }; | |
51 | ||
52 | static int stx104_read_raw(struct iio_dev *indio_dev, | |
53 | struct iio_chan_spec const *chan, int *val, int *val2, long mask) | |
54 | { | |
55 | struct stx104_iio *const priv = iio_priv(indio_dev); | |
56 | ||
57 | if (mask != IIO_CHAN_INFO_RAW) | |
58 | return -EINVAL; | |
59 | ||
60 | *val = priv->chan_out_states[chan->channel]; | |
61 | ||
62 | return IIO_VAL_INT; | |
63 | } | |
64 | ||
65 | static int stx104_write_raw(struct iio_dev *indio_dev, | |
66 | struct iio_chan_spec const *chan, int val, int val2, long mask) | |
67 | { | |
68 | struct stx104_iio *const priv = iio_priv(indio_dev); | |
69 | const unsigned chan_addr_offset = 2 * chan->channel; | |
70 | ||
71 | if (mask != IIO_CHAN_INFO_RAW) | |
72 | return -EINVAL; | |
73 | ||
74 | priv->chan_out_states[chan->channel] = val; | |
75 | outw(val, priv->base + 4 + chan_addr_offset); | |
76 | ||
77 | return 0; | |
78 | } | |
79 | ||
80 | static const struct iio_info stx104_info = { | |
81 | .driver_module = THIS_MODULE, | |
82 | .read_raw = stx104_read_raw, | |
83 | .write_raw = stx104_write_raw | |
84 | }; | |
85 | ||
86 | static const struct iio_chan_spec stx104_channels[STX104_NUM_CHAN] = { | |
87 | STX104_CHAN(0), | |
88 | STX104_CHAN(1) | |
89 | }; | |
90 | ||
91 | static int stx104_probe(struct device *dev, unsigned int id) | |
92 | { | |
93 | struct iio_dev *indio_dev; | |
94 | struct stx104_iio *priv; | |
95 | ||
96 | indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); | |
97 | if (!indio_dev) | |
98 | return -ENOMEM; | |
99 | ||
100 | if (!devm_request_region(dev, base[id], STX104_EXTENT, | |
101 | dev_name(dev))) { | |
102 | dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", | |
103 | base[id], base[id] + STX104_EXTENT); | |
104 | return -EBUSY; | |
105 | } | |
106 | ||
107 | indio_dev->info = &stx104_info; | |
108 | indio_dev->modes = INDIO_DIRECT_MODE; | |
109 | indio_dev->channels = stx104_channels; | |
110 | indio_dev->num_channels = STX104_NUM_CHAN; | |
111 | indio_dev->name = dev_name(dev); | |
112 | ||
113 | priv = iio_priv(indio_dev); | |
114 | priv->base = base[id]; | |
115 | ||
116 | /* initialize DAC output to 0V */ | |
117 | outw(0, base[id] + 4); | |
118 | outw(0, base[id] + 6); | |
119 | ||
120 | return devm_iio_device_register(dev, indio_dev); | |
121 | } | |
122 | ||
123 | static struct isa_driver stx104_driver = { | |
124 | .probe = stx104_probe, | |
125 | .driver = { | |
126 | .name = "stx104" | |
127 | } | |
128 | }; | |
129 | ||
9c2cfc19 | 130 | module_isa_driver(stx104_driver, num_stx104); |
97a445da WBG |
131 | |
132 | MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); | |
133 | MODULE_DESCRIPTION("Apex Embedded Systems STX104 DAC driver"); | |
134 | MODULE_LICENSE("GPL v2"); |