1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * ad2s1200.c simple support for the ADI Resolver to Digital Converters: |
4 | * AD2S1200/1205 |
5 | * |
6 | * Copyright (c) 2018-2018 David Veenstra <davidjulianveenstra@gmail.com> |
7 | * Copyright (c) 2010-2010 Analog Devices Inc. |
8 | */ |
9 | |
10 | #include <linux/bitops.h> |
11 | #include <linux/delay.h> |
12 | #include <linux/device.h> |
13 | #include <linux/gpio/consumer.h> |
14 | #include <linux/module.h> |
15 | #include <linux/mod_devicetable.h> |
16 | #include <linux/mutex.h> |
17 | #include <linux/spi/spi.h> |
18 | #include <linux/sysfs.h> |
19 | #include <linux/types.h> |
20 | |
21 | #include <linux/iio/iio.h> |
22 | #include <linux/iio/sysfs.h> |
23 | |
24 | #define DRV_NAME "ad2s1200" |
25 | |
26 | /* input clock on serial interface */ |
27 | #define AD2S1200_HZ 8192000 |
28 | /* clock period in nano second */ |
29 | #define AD2S1200_TSCLK (1000000000 / AD2S1200_HZ) |
30 | |
31 | /** |
32 | * struct ad2s1200_state - driver instance specific data. |
33 | * @lock: protects both the GPIO pins and the rx buffer. |
34 | * @sdev: spi device. |
35 | * @sample: GPIO pin SAMPLE. |
36 | * @rdvel: GPIO pin RDVEL. |
37 | * @rx: buffer for spi transfers. |
38 | */ |
39 | struct ad2s1200_state { |
40 | struct mutex lock; |
41 | struct spi_device *sdev; |
42 | struct gpio_desc *sample; |
43 | struct gpio_desc *rdvel; |
44 | __be16 rx __aligned(IIO_DMA_MINALIGN); |
45 | }; |
46 | |
47 | static int ad2s1200_read_raw(struct iio_dev *indio_dev, |
48 | struct iio_chan_spec const *chan, |
49 | int *val, |
50 | int *val2, |
51 | long m) |
52 | { |
53 | struct ad2s1200_state *st = iio_priv(indio_dev); |
54 | int ret; |
55 | |
56 | switch (m) { |
57 | case IIO_CHAN_INFO_SCALE: |
58 | switch (chan->type) { |
59 | case IIO_ANGL: |
60 | /* 2 * Pi / (2^12 - 1) ~= 0.001534355 */ |
61 | *val = 0; |
62 | *val2 = 1534355; |
63 | return IIO_VAL_INT_PLUS_NANO; |
64 | case IIO_ANGL_VEL: |
65 | /* 2 * Pi ~= 6.283185 */ |
66 | *val = 6; |
67 | *val2 = 283185; |
68 | return IIO_VAL_INT_PLUS_MICRO; |
69 | default: |
70 | return -EINVAL; |
71 | } |
72 | break; |
73 | case IIO_CHAN_INFO_RAW: |
74 | mutex_lock(&st->lock); |
75 | gpiod_set_value(desc: st->sample, value: 0); |
76 | |
77 | /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */ |
78 | udelay(1); |
79 | gpiod_set_value(desc: st->sample, value: 1); |
80 | gpiod_set_value(desc: st->rdvel, value: !!(chan->type == IIO_ANGL)); |
81 | |
82 | ret = spi_read(spi: st->sdev, buf: &st->rx, len: 2); |
83 | if (ret < 0) { |
84 | mutex_unlock(lock: &st->lock); |
85 | return ret; |
86 | } |
87 | |
88 | switch (chan->type) { |
89 | case IIO_ANGL: |
90 | *val = be16_to_cpup(p: &st->rx) >> 4; |
91 | break; |
92 | case IIO_ANGL_VEL: |
93 | *val = sign_extend32(be16_to_cpup(p: &st->rx) >> 4, index: 11); |
94 | break; |
95 | default: |
96 | mutex_unlock(lock: &st->lock); |
97 | return -EINVAL; |
98 | } |
99 | |
100 | /* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */ |
101 | udelay(1); |
102 | mutex_unlock(lock: &st->lock); |
103 | |
104 | return IIO_VAL_INT; |
105 | default: |
106 | break; |
107 | } |
108 | |
109 | return -EINVAL; |
110 | } |
111 | |
112 | static const struct iio_chan_spec ad2s1200_channels[] = { |
113 | { |
114 | .type = IIO_ANGL, |
115 | .indexed = 1, |
116 | .channel = 0, |
117 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), |
118 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), |
119 | }, { |
120 | .type = IIO_ANGL_VEL, |
121 | .indexed = 1, |
122 | .channel = 0, |
123 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), |
124 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), |
125 | } |
126 | }; |
127 | |
128 | static const struct iio_info ad2s1200_info = { |
129 | .read_raw = ad2s1200_read_raw, |
130 | }; |
131 | |
132 | static int ad2s1200_probe(struct spi_device *spi) |
133 | { |
134 | struct ad2s1200_state *st; |
135 | struct iio_dev *indio_dev; |
136 | int ret; |
137 | |
138 | indio_dev = devm_iio_device_alloc(parent: &spi->dev, sizeof_priv: sizeof(*st)); |
139 | if (!indio_dev) |
140 | return -ENOMEM; |
141 | |
142 | spi_set_drvdata(spi, data: indio_dev); |
143 | st = iio_priv(indio_dev); |
144 | mutex_init(&st->lock); |
145 | st->sdev = spi; |
146 | |
147 | st->sample = devm_gpiod_get(dev: &spi->dev, con_id: "adi,sample" , flags: GPIOD_OUT_LOW); |
148 | if (IS_ERR(ptr: st->sample)) { |
149 | dev_err(&spi->dev, "Failed to claim SAMPLE gpio: err=%ld\n" , |
150 | PTR_ERR(st->sample)); |
151 | return PTR_ERR(ptr: st->sample); |
152 | } |
153 | |
154 | st->rdvel = devm_gpiod_get(dev: &spi->dev, con_id: "adi,rdvel" , flags: GPIOD_OUT_LOW); |
155 | if (IS_ERR(ptr: st->rdvel)) { |
156 | dev_err(&spi->dev, "Failed to claim RDVEL gpio: err=%ld\n" , |
157 | PTR_ERR(st->rdvel)); |
158 | return PTR_ERR(ptr: st->rdvel); |
159 | } |
160 | |
161 | indio_dev->info = &ad2s1200_info; |
162 | indio_dev->modes = INDIO_DIRECT_MODE; |
163 | indio_dev->channels = ad2s1200_channels; |
164 | indio_dev->num_channels = ARRAY_SIZE(ad2s1200_channels); |
165 | indio_dev->name = spi_get_device_id(sdev: spi)->name; |
166 | |
167 | spi->max_speed_hz = AD2S1200_HZ; |
168 | spi->mode = SPI_MODE_3; |
169 | ret = spi_setup(spi); |
170 | |
171 | if (ret < 0) { |
172 | dev_err(&spi->dev, "spi_setup failed!\n" ); |
173 | return ret; |
174 | } |
175 | |
176 | return devm_iio_device_register(&spi->dev, indio_dev); |
177 | } |
178 | |
179 | static const struct of_device_id ad2s1200_of_match[] = { |
180 | { .compatible = "adi,ad2s1200" , }, |
181 | { .compatible = "adi,ad2s1205" , }, |
182 | { } |
183 | }; |
184 | MODULE_DEVICE_TABLE(of, ad2s1200_of_match); |
185 | |
186 | static const struct spi_device_id ad2s1200_id[] = { |
187 | { "ad2s1200" }, |
188 | { "ad2s1205" }, |
189 | {} |
190 | }; |
191 | MODULE_DEVICE_TABLE(spi, ad2s1200_id); |
192 | |
193 | static struct spi_driver ad2s1200_driver = { |
194 | .driver = { |
195 | .name = DRV_NAME, |
196 | .of_match_table = ad2s1200_of_match, |
197 | }, |
198 | .probe = ad2s1200_probe, |
199 | .id_table = ad2s1200_id, |
200 | }; |
201 | module_spi_driver(ad2s1200_driver); |
202 | |
203 | MODULE_AUTHOR("David Veenstra <davidjulianveenstra@gmail.com>" ); |
204 | MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>" ); |
205 | MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver" ); |
206 | MODULE_LICENSE("GPL v2" ); |
207 | |