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authorJonathan Herman <hermanjl@cs.unc.edu>2013-01-22 10:38:37 -0500
committerJonathan Herman <hermanjl@cs.unc.edu>2013-01-22 10:38:37 -0500
commitfcc9d2e5a6c89d22b8b773a64fb4ad21ac318446 (patch)
treea57612d1888735a2ec7972891b68c1ac5ec8faea /drivers/staging/iio/resolver
parent8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff)
Added missing tegra files.HEADmaster
Diffstat (limited to 'drivers/staging/iio/resolver')
-rw-r--r--drivers/staging/iio/resolver/ad2s120x.c177
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
33struct 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
41static 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');
74error_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
82static IIO_DEVICE_ATTR(pos, S_IRUGO, ad2s120x_show_val, NULL, 1);
83static IIO_DEVICE_ATTR(vel, S_IRUGO, ad2s120x_show_val, NULL, 0);
84
85static struct attribute *ad2s120x_attributes[] = {
86 &iio_dev_attr_pos.dev_attr.attr,
87 &iio_dev_attr_vel.dev_attr.attr,
88 NULL,
89};
90
91static const struct attribute_group ad2s120x_attribute_group = {
92 .attrs = ad2s120x_attributes,
93};
94
95static const struct iio_info ad2s120x_info = {
96 .attrs = &ad2s120x_attribute_group,
97 .driver_module = THIS_MODULE,
98};
99
100static 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
139error_free_dev:
140 iio_free_device(indio_dev);
141error_ret:
142 for (--pn; pn >= 0; pn--)
143 gpio_free(pins[pn]);
144 return ret;
145}
146
147static int __devexit ad2s120x_remove(struct spi_device *spi)
148{
149 iio_device_unregister(spi_get_drvdata(spi));
150
151 return 0;
152}
153
154static 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
163static __init int ad2s120x_spi_init(void)
164{
165 return spi_register_driver(&ad2s120x_driver);
166}
167module_init(ad2s120x_spi_init);
168
169static __exit void ad2s120x_spi_exit(void)
170{
171 spi_unregister_driver(&ad2s120x_driver);
172}
173module_exit(ad2s120x_spi_exit);
174
175MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
176MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver");
177MODULE_LICENSE("GPL v2");