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-DAC08, and PC104-DAC06.
8 */
9 #include <linux/bits.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/iio/iio.h>
13 #include <linux/iio/types.h>
14 #include <linux/isa.h>
15 #include <linux/module.h>
16 #include <linux/moduleparam.h>
17 #include <linux/regmap.h>
18 #include <linux/types.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 #define CIO_DAC_BASE 0x00
38 #define CIO_DAC_CHANNEL_STRIDE 2
39
cio_dac_precious_reg(struct device * dev,unsigned int reg)40 static bool cio_dac_precious_reg(struct device *dev, unsigned int reg)
41 {
42 /*
43 * All registers are considered precious; if the XFER jumper is set on
44 * the device, then no update occurs until a DAC register is read.
45 */
46 return true;
47 }
48
49 static const struct regmap_config cio_dac_regmap_config = {
50 .reg_bits = 16,
51 .reg_stride = 2,
52 .val_bits = 16,
53 .io_port = true,
54 .max_register = 0x1F,
55 .precious_reg = cio_dac_precious_reg,
56 };
57
58 /**
59 * struct cio_dac_iio - IIO device private data structure
60 * @map: Regmap for the device
61 */
62 struct cio_dac_iio {
63 struct regmap *map;
64 };
65
cio_dac_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)66 static int cio_dac_read_raw(struct iio_dev *indio_dev,
67 struct iio_chan_spec const *chan, int *val, int *val2, long mask)
68 {
69 struct cio_dac_iio *const priv = iio_priv(indio_dev);
70 const unsigned int offset = chan->channel * CIO_DAC_CHANNEL_STRIDE;
71 int err;
72 unsigned int dac_val;
73
74 if (mask != IIO_CHAN_INFO_RAW)
75 return -EINVAL;
76
77 err = regmap_read(priv->map, CIO_DAC_BASE + offset, &dac_val);
78 if (err)
79 return err;
80
81 *val = dac_val;
82
83 return IIO_VAL_INT;
84 }
85
cio_dac_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)86 static int cio_dac_write_raw(struct iio_dev *indio_dev,
87 struct iio_chan_spec const *chan, int val, int val2, long mask)
88 {
89 struct cio_dac_iio *const priv = iio_priv(indio_dev);
90 const unsigned int offset = chan->channel * CIO_DAC_CHANNEL_STRIDE;
91
92 if (mask != IIO_CHAN_INFO_RAW)
93 return -EINVAL;
94
95 /* DAC can only accept up to a 12-bit value */
96 if ((unsigned int)val > 4095)
97 return -EINVAL;
98
99 return regmap_write(priv->map, CIO_DAC_BASE + offset, val);
100 }
101
102 static const struct iio_info cio_dac_info = {
103 .read_raw = cio_dac_read_raw,
104 .write_raw = cio_dac_write_raw
105 };
106
107 static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
108 CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
109 CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
110 CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
111 CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
112 };
113
cio_dac_probe(struct device * dev,unsigned int id)114 static int cio_dac_probe(struct device *dev, unsigned int id)
115 {
116 struct iio_dev *indio_dev;
117 struct cio_dac_iio *priv;
118 void __iomem *regs;
119
120 indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
121 if (!indio_dev)
122 return -ENOMEM;
123
124 if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
125 dev_name(dev))) {
126 dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
127 base[id], base[id] + CIO_DAC_EXTENT);
128 return -EBUSY;
129 }
130
131 regs = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
132 if (!regs)
133 return -ENOMEM;
134
135 priv = iio_priv(indio_dev);
136 priv->map = devm_regmap_init_mmio(dev, regs, &cio_dac_regmap_config);
137 if (IS_ERR(priv->map))
138 return dev_err_probe(dev, PTR_ERR(priv->map),
139 "Unable to initialize register map\n");
140
141 indio_dev->info = &cio_dac_info;
142 indio_dev->modes = INDIO_DIRECT_MODE;
143 indio_dev->channels = cio_dac_channels;
144 indio_dev->num_channels = CIO_DAC_NUM_CHAN;
145 indio_dev->name = dev_name(dev);
146
147 return devm_iio_device_register(dev, indio_dev);
148 }
149
150 static struct isa_driver cio_dac_driver = {
151 .probe = cio_dac_probe,
152 .driver = {
153 .name = "cio-dac"
154 }
155 };
156
157 module_isa_driver(cio_dac_driver, num_cio_dac);
158
159 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
160 MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
161 MODULE_LICENSE("GPL v2");
162
