diff options
author | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
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committer | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
commit | fcc9d2e5a6c89d22b8b773a64fb4ad21ac318446 (patch) | |
tree | a57612d1888735a2ec7972891b68c1ac5ec8faea /drivers/staging/iio/resolver | |
parent | 8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff) |
Diffstat (limited to 'drivers/staging/iio/resolver')
-rw-r--r-- | drivers/staging/iio/resolver/ad2s120x.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/drivers/staging/iio/resolver/ad2s120x.c b/drivers/staging/iio/resolver/ad2s120x.c new file mode 100644 index 00000000000..bed4c725f2d --- /dev/null +++ b/drivers/staging/iio/resolver/ad2s120x.c | |||
@@ -0,0 +1,177 @@ | |||
1 | /* | ||
2 | * ad2s120x.c simple support for the ADI Resolver to Digital Converters: AD2S1200/1205 | ||
3 | * | ||
4 | * Copyright (c) 2010-2010 Analog Devices Inc. | ||
5 | * | ||
6 | * This program is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU General Public License version 2 as | ||
8 | * published by the Free Software Foundation. | ||
9 | * | ||
10 | */ | ||
11 | #include <linux/types.h> | ||
12 | #include <linux/mutex.h> | ||
13 | #include <linux/device.h> | ||
14 | #include <linux/spi/spi.h> | ||
15 | #include <linux/slab.h> | ||
16 | #include <linux/sysfs.h> | ||
17 | #include <linux/delay.h> | ||
18 | #include <linux/gpio.h> | ||
19 | |||
20 | #include "../iio.h" | ||
21 | #include "../sysfs.h" | ||
22 | |||
23 | #define DRV_NAME "ad2s120x" | ||
24 | |||
25 | /* input pin sample and rdvel is controlled by driver */ | ||
26 | #define AD2S120X_PN 2 | ||
27 | |||
28 | /* input clock on serial interface */ | ||
29 | #define AD2S120X_HZ 8192000 | ||
30 | /* clock period in nano second */ | ||
31 | #define AD2S120X_TSCLK (1000000000/AD2S120X_HZ) | ||
32 | |||
33 | struct ad2s120x_state { | ||
34 | struct mutex lock; | ||
35 | struct spi_device *sdev; | ||
36 | int sample; | ||
37 | int rdvel; | ||
38 | u8 rx[2] ____cacheline_aligned; | ||
39 | }; | ||
40 | |||
41 | static ssize_t ad2s120x_show_val(struct device *dev, | ||
42 | struct device_attribute *attr, char *buf) | ||
43 | { | ||
44 | int ret = 0; | ||
45 | ssize_t len = 0; | ||
46 | u16 pos; | ||
47 | s16 vel; | ||
48 | u8 status; | ||
49 | struct ad2s120x_state *st = iio_priv(dev_get_drvdata(dev)); | ||
50 | struct iio_dev_attr *iattr = to_iio_dev_attr(attr); | ||
51 | |||
52 | mutex_lock(&st->lock); | ||
53 | |||
54 | gpio_set_value(st->sample, 0); | ||
55 | /* delay (6 * AD2S120X_TSCLK + 20) nano seconds */ | ||
56 | udelay(1); | ||
57 | gpio_set_value(st->sample, 1); | ||
58 | gpio_set_value(st->rdvel, iattr->address); | ||
59 | ret = spi_read(st->sdev, st->rx, 2); | ||
60 | if (ret < 0) | ||
61 | goto error_ret; | ||
62 | status = st->rx[1]; | ||
63 | if (iattr->address) | ||
64 | pos = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4); | ||
65 | else { | ||
66 | vel = (st->rx[0] & 0x80) ? 0xf000 : 0; | ||
67 | vel |= (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4); | ||
68 | } | ||
69 | len = sprintf(buf, "%d %c%c%c%c ", iattr->address ? pos : vel, | ||
70 | (status & 0x8) ? 'P' : 'V', | ||
71 | (status & 0x4) ? 'd' : '_', | ||
72 | (status & 0x2) ? 'l' : '_', | ||
73 | (status & 0x1) ? '1' : '0'); | ||
74 | error_ret: | ||
75 | /* delay (2 * AD2S120X_TSCLK + 20) ns for sample pulse */ | ||
76 | udelay(1); | ||
77 | mutex_unlock(&st->lock); | ||
78 | |||
79 | return ret ? ret : len; | ||
80 | } | ||
81 | |||
82 | static IIO_DEVICE_ATTR(pos, S_IRUGO, ad2s120x_show_val, NULL, 1); | ||
83 | static IIO_DEVICE_ATTR(vel, S_IRUGO, ad2s120x_show_val, NULL, 0); | ||
84 | |||
85 | static struct attribute *ad2s120x_attributes[] = { | ||
86 | &iio_dev_attr_pos.dev_attr.attr, | ||
87 | &iio_dev_attr_vel.dev_attr.attr, | ||
88 | NULL, | ||
89 | }; | ||
90 | |||
91 | static const struct attribute_group ad2s120x_attribute_group = { | ||
92 | .attrs = ad2s120x_attributes, | ||
93 | }; | ||
94 | |||
95 | static const struct iio_info ad2s120x_info = { | ||
96 | .attrs = &ad2s120x_attribute_group, | ||
97 | .driver_module = THIS_MODULE, | ||
98 | }; | ||
99 | |||
100 | static int __devinit ad2s120x_probe(struct spi_device *spi) | ||
101 | { | ||
102 | struct ad2s120x_state *st; | ||
103 | struct iio_dev *indio_dev; | ||
104 | int pn, ret = 0; | ||
105 | unsigned short *pins = spi->dev.platform_data; | ||
106 | |||
107 | for (pn = 0; pn < AD2S120X_PN; pn++) | ||
108 | if (gpio_request_one(pins[pn], GPIOF_DIR_OUT, DRV_NAME)) { | ||
109 | pr_err("%s: request gpio pin %d failed\n", | ||
110 | DRV_NAME, pins[pn]); | ||
111 | goto error_ret; | ||
112 | } | ||
113 | indio_dev = iio_allocate_device(sizeof(*st)); | ||
114 | if (indio_dev == NULL) { | ||
115 | ret = -ENOMEM; | ||
116 | goto error_ret; | ||
117 | } | ||
118 | spi_set_drvdata(spi, indio_dev); | ||
119 | st = iio_priv(indio_dev); | ||
120 | mutex_init(&st->lock); | ||
121 | st->sdev = spi; | ||
122 | st->sample = pins[0]; | ||
123 | st->rdvel = pins[1]; | ||
124 | |||
125 | indio_dev->dev.parent = &spi->dev; | ||
126 | indio_dev->info = &ad2s120x_info; | ||
127 | indio_dev->modes = INDIO_DIRECT_MODE; | ||
128 | |||
129 | ret = iio_device_register(indio_dev); | ||
130 | if (ret) | ||
131 | goto error_free_dev; | ||
132 | |||
133 | spi->max_speed_hz = AD2S120X_HZ; | ||
134 | spi->mode = SPI_MODE_3; | ||
135 | spi_setup(spi); | ||
136 | |||
137 | return 0; | ||
138 | |||
139 | error_free_dev: | ||
140 | iio_free_device(indio_dev); | ||
141 | error_ret: | ||
142 | for (--pn; pn >= 0; pn--) | ||
143 | gpio_free(pins[pn]); | ||
144 | return ret; | ||
145 | } | ||
146 | |||
147 | static int __devexit ad2s120x_remove(struct spi_device *spi) | ||
148 | { | ||
149 | iio_device_unregister(spi_get_drvdata(spi)); | ||
150 | |||
151 | return 0; | ||
152 | } | ||
153 | |||
154 | static struct spi_driver ad2s120x_driver = { | ||
155 | .driver = { | ||
156 | .name = DRV_NAME, | ||
157 | .owner = THIS_MODULE, | ||
158 | }, | ||
159 | .probe = ad2s120x_probe, | ||
160 | .remove = __devexit_p(ad2s120x_remove), | ||
161 | }; | ||
162 | |||
163 | static __init int ad2s120x_spi_init(void) | ||
164 | { | ||
165 | return spi_register_driver(&ad2s120x_driver); | ||
166 | } | ||
167 | module_init(ad2s120x_spi_init); | ||
168 | |||
169 | static __exit void ad2s120x_spi_exit(void) | ||
170 | { | ||
171 | spi_unregister_driver(&ad2s120x_driver); | ||
172 | } | ||
173 | module_exit(ad2s120x_spi_exit); | ||
174 | |||
175 | MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>"); | ||
176 | MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver"); | ||
177 | MODULE_LICENSE("GPL v2"); | ||