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>
19 #include <linux/iio/iio.h>
20 #include <linux/iio/sysfs.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
= {
58 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
),
61 static int ad2s90_probe(struct spi_device
*spi
)
63 struct iio_dev
*indio_dev
;
64 struct ad2s90_state
*st
;
67 indio_dev
= iio_device_alloc(sizeof(*st
));
68 if (indio_dev
== NULL
) {
72 st
= iio_priv(indio_dev
);
73 spi_set_drvdata(spi
, indio_dev
);
75 mutex_init(&st
->lock
);
77 indio_dev
->dev
.parent
= &spi
->dev
;
78 indio_dev
->info
= &ad2s90_info
;
79 indio_dev
->modes
= INDIO_DIRECT_MODE
;
80 indio_dev
->channels
= &ad2s90_chan
;
81 indio_dev
->num_channels
= 1;
82 indio_dev
->name
= spi_get_device_id(spi
)->name
;
84 ret
= iio_device_register(indio_dev
);
88 /* need 600ns between CS and the first falling edge of SCLK */
89 spi
->max_speed_hz
= 830000;
90 spi
->mode
= SPI_MODE_3
;
96 iio_device_free(indio_dev
);
101 static int ad2s90_remove(struct spi_device
*spi
)
103 iio_device_unregister(spi_get_drvdata(spi
));
104 iio_device_free(spi_get_drvdata(spi
));
109 static const struct spi_device_id ad2s90_id
[] = {
113 MODULE_DEVICE_TABLE(spi
, ad2s90_id
);
115 static struct spi_driver ad2s90_driver
= {
118 .owner
= THIS_MODULE
,
120 .probe
= ad2s90_probe
,
121 .remove
= ad2s90_remove
,
122 .id_table
= ad2s90_id
,
124 module_spi_driver(ad2s90_driver
);
126 MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
127 MODULE_DESCRIPTION("Analog Devices AD2S90 Resolver to Digital SPI driver");
128 MODULE_LICENSE("GPL v2");