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9#include <linux/device.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/sysfs.h>
13#include <linux/spi/spi.h>
14#include <linux/regulator/consumer.h>
15#include <linux/err.h>
16#include <linux/module.h>
17#include <linux/bitrev.h>
18
19#include <linux/iio/iio.h>
20#include <linux/iio/sysfs.h>
21
22struct ad8366_state {
23 struct spi_device *spi;
24 struct regulator *reg;
25 unsigned char ch[2];
26
27
28
29
30 unsigned char data[2] ____cacheline_aligned;
31};
32
33static int ad8366_write(struct iio_dev *indio_dev,
34 unsigned char ch_a, unsigned char ch_b)
35{
36 struct ad8366_state *st = iio_priv(indio_dev);
37 int ret;
38
39 ch_a = bitrev8(ch_a & 0x3F);
40 ch_b = bitrev8(ch_b & 0x3F);
41
42 st->data[0] = ch_b >> 4;
43 st->data[1] = (ch_b << 4) | (ch_a >> 2);
44
45 ret = spi_write(st->spi, st->data, ARRAY_SIZE(st->data));
46 if (ret < 0)
47 dev_err(&indio_dev->dev, "write failed (%d)", ret);
48
49 return ret;
50}
51
52static int ad8366_read_raw(struct iio_dev *indio_dev,
53 struct iio_chan_spec const *chan,
54 int *val,
55 int *val2,
56 long m)
57{
58 struct ad8366_state *st = iio_priv(indio_dev);
59 int ret;
60 unsigned code;
61
62 mutex_lock(&indio_dev->mlock);
63 switch (m) {
64 case IIO_CHAN_INFO_HARDWAREGAIN:
65 code = st->ch[chan->channel];
66
67
68 code = code * 253 + 4500;
69 *val = code / 1000;
70 *val2 = (code % 1000) * 1000;
71
72 ret = IIO_VAL_INT_PLUS_MICRO_DB;
73 break;
74 default:
75 ret = -EINVAL;
76 }
77 mutex_unlock(&indio_dev->mlock);
78
79 return ret;
80};
81
82static int ad8366_write_raw(struct iio_dev *indio_dev,
83 struct iio_chan_spec const *chan,
84 int val,
85 int val2,
86 long mask)
87{
88 struct ad8366_state *st = iio_priv(indio_dev);
89 unsigned code;
90 int ret;
91
92 if (val < 0 || val2 < 0)
93 return -EINVAL;
94
95
96 code = (((u8)val * 1000) + ((u32)val2 / 1000));
97
98 if (code > 20500 || code < 4500)
99 return -EINVAL;
100
101 code = (code - 4500) / 253;
102
103 mutex_lock(&indio_dev->mlock);
104 switch (mask) {
105 case IIO_CHAN_INFO_HARDWAREGAIN:
106 st->ch[chan->channel] = code;
107 ret = ad8366_write(indio_dev, st->ch[0], st->ch[1]);
108 break;
109 default:
110 ret = -EINVAL;
111 }
112 mutex_unlock(&indio_dev->mlock);
113
114 return ret;
115}
116
117static const struct iio_info ad8366_info = {
118 .read_raw = &ad8366_read_raw,
119 .write_raw = &ad8366_write_raw,
120 .driver_module = THIS_MODULE,
121};
122
123#define AD8366_CHAN(_channel) { \
124 .type = IIO_VOLTAGE, \
125 .output = 1, \
126 .indexed = 1, \
127 .channel = _channel, \
128 .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),\
129}
130
131static const struct iio_chan_spec ad8366_channels[] = {
132 AD8366_CHAN(0),
133 AD8366_CHAN(1),
134};
135
136static int ad8366_probe(struct spi_device *spi)
137{
138 struct iio_dev *indio_dev;
139 struct ad8366_state *st;
140 int ret;
141
142 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
143 if (indio_dev == NULL)
144 return -ENOMEM;
145
146 st = iio_priv(indio_dev);
147
148 st->reg = devm_regulator_get(&spi->dev, "vcc");
149 if (!IS_ERR(st->reg)) {
150 ret = regulator_enable(st->reg);
151 if (ret)
152 return ret;
153 }
154
155 spi_set_drvdata(spi, indio_dev);
156 st->spi = spi;
157
158 indio_dev->dev.parent = &spi->dev;
159 indio_dev->name = spi_get_device_id(spi)->name;
160 indio_dev->info = &ad8366_info;
161 indio_dev->modes = INDIO_DIRECT_MODE;
162 indio_dev->channels = ad8366_channels;
163 indio_dev->num_channels = ARRAY_SIZE(ad8366_channels);
164
165 ret = iio_device_register(indio_dev);
166 if (ret)
167 goto error_disable_reg;
168
169 ad8366_write(indio_dev, 0, 0);
170
171 return 0;
172
173error_disable_reg:
174 if (!IS_ERR(st->reg))
175 regulator_disable(st->reg);
176
177 return ret;
178}
179
180static int ad8366_remove(struct spi_device *spi)
181{
182 struct iio_dev *indio_dev = spi_get_drvdata(spi);
183 struct ad8366_state *st = iio_priv(indio_dev);
184 struct regulator *reg = st->reg;
185
186 iio_device_unregister(indio_dev);
187
188 if (!IS_ERR(reg))
189 regulator_disable(reg);
190
191 return 0;
192}
193
194static const struct spi_device_id ad8366_id[] = {
195 {"ad8366", 0},
196 {}
197};
198MODULE_DEVICE_TABLE(spi, ad8366_id);
199
200static struct spi_driver ad8366_driver = {
201 .driver = {
202 .name = KBUILD_MODNAME,
203 },
204 .probe = ad8366_probe,
205 .remove = ad8366_remove,
206 .id_table = ad8366_id,
207};
208
209module_spi_driver(ad8366_driver);
210
211MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
212MODULE_DESCRIPTION("Analog Devices AD8366 VGA");
213MODULE_LICENSE("GPL v2");
214
