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12#include <linux/types.h>
13#include <linux/mutex.h>
14#include <linux/device.h>
15#include <linux/spi/spi.h>
16#include <linux/slab.h>
17#include <linux/sysfs.h>
18#include <linux/delay.h>
19#include <linux/gpio.h>
20#include <linux/module.h>
21
22#include <linux/iio/iio.h>
23#include <linux/iio/sysfs.h>
24
25#define DRV_NAME "ad2s1200"
26
27
28#define AD2S1200_PN 2
29
30
31#define AD2S1200_HZ 8192000
32
33#define AD2S1200_TSCLK (1000000000/AD2S1200_HZ)
34
35struct ad2s1200_state {
36 struct mutex lock;
37 struct spi_device *sdev;
38 int sample;
39 int rdvel;
40 u8 rx[2] ____cacheline_aligned;
41};
42
43static int ad2s1200_read_raw(struct iio_dev *indio_dev,
44 struct iio_chan_spec const *chan,
45 int *val,
46 int *val2,
47 long m)
48{
49 int ret = 0;
50 s16 vel;
51 struct ad2s1200_state *st = iio_priv(indio_dev);
52
53 mutex_lock(&st->lock);
54 gpio_set_value(st->sample, 0);
55
56 udelay(1);
57 gpio_set_value(st->sample, 1);
58 gpio_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
59 ret = spi_read(st->sdev, st->rx, 2);
60 if (ret < 0) {
61 mutex_unlock(&st->lock);
62 return ret;
63 }
64
65 switch (chan->type) {
66 case IIO_ANGL:
67 *val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
68 break;
69 case IIO_ANGL_VEL:
70 vel = (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
71 vel = (vel << 4) >> 4;
72 *val = vel;
73 default:
74 mutex_unlock(&st->lock);
75 return -EINVAL;
76 }
77
78 udelay(1);
79 mutex_unlock(&st->lock);
80 return IIO_VAL_INT;
81}
82
83static const struct iio_chan_spec ad2s1200_channels[] = {
84 {
85 .type = IIO_ANGL,
86 .indexed = 1,
87 .channel = 0,
88 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
89 }, {
90 .type = IIO_ANGL_VEL,
91 .indexed = 1,
92 .channel = 0,
93 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
94 }
95};
96
97static const struct iio_info ad2s1200_info = {
98 .read_raw = &ad2s1200_read_raw,
99 .driver_module = THIS_MODULE,
100};
101
102static int ad2s1200_probe(struct spi_device *spi)
103{
104 struct ad2s1200_state *st;
105 struct iio_dev *indio_dev;
106 int pn, ret = 0;
107 unsigned short *pins = spi->dev.platform_data;
108
109 for (pn = 0; pn < AD2S1200_PN; pn++)
110 if (gpio_request_one(pins[pn], GPIOF_DIR_OUT, DRV_NAME)) {
111 pr_err("%s: request gpio pin %d failed\n",
112 DRV_NAME, pins[pn]);
113 goto error_ret;
114 }
115 indio_dev = iio_device_alloc(sizeof(*st));
116 if (indio_dev == NULL) {
117 ret = -ENOMEM;
118 goto error_ret;
119 }
120 spi_set_drvdata(spi, indio_dev);
121 st = iio_priv(indio_dev);
122 mutex_init(&st->lock);
123 st->sdev = spi;
124 st->sample = pins[0];
125 st->rdvel = pins[1];
126
127 indio_dev->dev.parent = &spi->dev;
128 indio_dev->info = &ad2s1200_info;
129 indio_dev->modes = INDIO_DIRECT_MODE;
130 indio_dev->channels = ad2s1200_channels;
131 indio_dev->num_channels = ARRAY_SIZE(ad2s1200_channels);
132 indio_dev->name = spi_get_device_id(spi)->name;
133
134 ret = iio_device_register(indio_dev);
135 if (ret)
136 goto error_free_dev;
137
138 spi->max_speed_hz = AD2S1200_HZ;
139 spi->mode = SPI_MODE_3;
140 spi_setup(spi);
141
142 return 0;
143
144error_free_dev:
145 iio_device_free(indio_dev);
146error_ret:
147 for (--pn; pn >= 0; pn--)
148 gpio_free(pins[pn]);
149 return ret;
150}
151
152static int ad2s1200_remove(struct spi_device *spi)
153{
154 iio_device_unregister(spi_get_drvdata(spi));
155 iio_device_free(spi_get_drvdata(spi));
156
157 return 0;
158}
159
160static const struct spi_device_id ad2s1200_id[] = {
161 { "ad2s1200" },
162 { "ad2s1205" },
163 {}
164};
165MODULE_DEVICE_TABLE(spi, ad2s1200_id);
166
167static struct spi_driver ad2s1200_driver = {
168 .driver = {
169 .name = DRV_NAME,
170 .owner = THIS_MODULE,
171 },
172 .probe = ad2s1200_probe,
173 .remove = ad2s1200_remove,
174 .id_table = ad2s1200_id,
175};
176module_spi_driver(ad2s1200_driver);
177
178MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
179MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver");
180MODULE_LICENSE("GPL v2");
181
