138 lines
3.0 KiB
C
138 lines
3.0 KiB
C
/*
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* ad2s90.c simple support for the ADI Resolver to Digital Converters: AD2S90
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*
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* Copyright (c) 2010-2010 Analog Devices Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/types.h>
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#include <linux/mutex.h>
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#include <linux/device.h>
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#include <linux/spi/spi.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/module.h>
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#include "../iio.h"
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#include "../sysfs.h"
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#define DRV_NAME "ad2s90"
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struct ad2s90_state {
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struct mutex lock;
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struct iio_dev *idev;
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struct spi_device *sdev;
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u8 rx[2] ____cacheline_aligned;
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};
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static ssize_t ad2s90_show_angular(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int ret;
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ssize_t len = 0;
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u16 val;
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struct ad2s90_state *st = iio_priv(dev_get_drvdata(dev));
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mutex_lock(&st->lock);
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ret = spi_read(st->sdev, st->rx, 2);
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if (ret)
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goto error_ret;
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val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
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len = sprintf(buf, "%d\n", val);
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error_ret:
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mutex_unlock(&st->lock);
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return ret ? ret : len;
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}
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#define IIO_DEV_ATTR_SIMPLE_RESOLVER(_show) \
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IIO_DEVICE_ATTR(angular, S_IRUGO, _show, NULL, 0)
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static IIO_DEV_ATTR_SIMPLE_RESOLVER(ad2s90_show_angular);
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static struct attribute *ad2s90_attributes[] = {
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&iio_dev_attr_angular.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ad2s90_attribute_group = {
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.attrs = ad2s90_attributes,
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};
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static const struct iio_info ad2s90_info = {
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.attrs = &ad2s90_attribute_group,
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.driver_module = THIS_MODULE,
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};
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static int __devinit ad2s90_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct ad2s90_state *st;
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int ret = 0;
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indio_dev = iio_allocate_device(sizeof(*st));
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if (indio_dev == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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st = iio_priv(indio_dev);
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spi_set_drvdata(spi, indio_dev);
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mutex_init(&st->lock);
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st->sdev = spi;
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indio_dev->dev.parent = &spi->dev;
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indio_dev->info = &ad2s90_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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ret = iio_device_register(st->idev);
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if (ret)
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goto error_free_dev;
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/* need 600ns between CS and the first falling edge of SCLK */
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spi->max_speed_hz = 830000;
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spi->mode = SPI_MODE_3;
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spi_setup(spi);
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return 0;
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error_free_dev:
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iio_free_device(st->idev);
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error_ret:
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return ret;
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}
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static int __devexit ad2s90_remove(struct spi_device *spi)
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{
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iio_device_unregister(spi_get_drvdata(spi));
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return 0;
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}
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static struct spi_driver ad2s90_driver = {
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.driver = {
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.name = DRV_NAME,
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.owner = THIS_MODULE,
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},
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.probe = ad2s90_probe,
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.remove = __devexit_p(ad2s90_remove),
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};
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static __init int ad2s90_spi_init(void)
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{
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return spi_register_driver(&ad2s90_driver);
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}
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module_init(ad2s90_spi_init);
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static __exit void ad2s90_spi_exit(void)
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{
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spi_unregister_driver(&ad2s90_driver);
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}
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module_exit(ad2s90_spi_exit);
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MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
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MODULE_DESCRIPTION("Analog Devices AD2S90 Resolver to Digital SPI driver");
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MODULE_LICENSE("GPL v2");
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