2 * ad2s90.c simple support for the ADI Resolver to Digital Converters: AD2S90
4 * Copyright (c) 2010-2010 Analog Devices Inc.
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.
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/module.h>
24 struct spi_device *sdev;
25 u8 rx[2] ____cacheline_aligned;
28 static int ad2s90_read_raw(struct iio_dev *indio_dev,
29 struct iio_chan_spec const *chan,
35 struct ad2s90_state *st = iio_priv(indio_dev);
37 mutex_lock(&st->lock);
38 ret = spi_read(st->sdev, st->rx, 2);
41 *val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
44 mutex_unlock(&st->lock);
49 static const struct iio_info ad2s90_info = {
50 .read_raw = &ad2s90_read_raw,
51 .driver_module = THIS_MODULE,
54 static const struct iio_chan_spec ad2s90_chan = {
60 static int __devinit ad2s90_probe(struct spi_device *spi)
62 struct iio_dev *indio_dev;
63 struct ad2s90_state *st;
66 indio_dev = iio_allocate_device(sizeof(*st));
67 if (indio_dev == NULL) {
71 st = iio_priv(indio_dev);
72 spi_set_drvdata(spi, indio_dev);
74 mutex_init(&st->lock);
76 indio_dev->dev.parent = &spi->dev;
77 indio_dev->info = &ad2s90_info;
78 indio_dev->modes = INDIO_DIRECT_MODE;
79 indio_dev->channels = &ad2s90_chan;
80 indio_dev->num_channels = 1;
81 indio_dev->name = spi_get_device_id(spi)->name;
83 ret = iio_device_register(indio_dev);
87 /* need 600ns between CS and the first falling edge of SCLK */
88 spi->max_speed_hz = 830000;
89 spi->mode = SPI_MODE_3;
95 iio_free_device(indio_dev);
100 static int __devexit ad2s90_remove(struct spi_device *spi)
102 iio_device_unregister(spi_get_drvdata(spi));
103 iio_free_device(spi_get_drvdata(spi));
108 static const struct spi_device_id ad2s90_id[] = {
112 MODULE_DEVICE_TABLE(spi, ad2s90_id);
114 static struct spi_driver ad2s90_driver = {
117 .owner = THIS_MODULE,
119 .probe = ad2s90_probe,
120 .remove = __devexit_p(ad2s90_remove),
121 .id_table = ad2s90_id,
124 static __init int ad2s90_spi_init(void)
126 return spi_register_driver(&ad2s90_driver);
128 module_init(ad2s90_spi_init);
130 static __exit void ad2s90_spi_exit(void)
132 spi_unregister_driver(&ad2s90_driver);
134 module_exit(ad2s90_spi_exit);
136 MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
137 MODULE_DESCRIPTION("Analog Devices AD2S90 Resolver to Digital SPI driver");
138 MODULE_LICENSE("GPL v2");