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/*
* ad2s120x.c simple support for the ADI Resolver to Digital Converters: AD2S1200/1205
*
* Copyright (c) 2010-2010 Analog Devices Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/module.h>
#include "../iio.h"
#include "../sysfs.h"
#define DRV_NAME "ad2s120x"
/* input pin sample and rdvel is controlled by driver */
#define AD2S120X_PN 2
/* input clock on serial interface */
#define AD2S120X_HZ 8192000
/* clock period in nano second */
#define AD2S120X_TSCLK (1000000000/AD2S120X_HZ)
struct ad2s120x_state {
struct mutex lock;
struct spi_device *sdev;
int sample;
int rdvel;
u8 rx[2] ____cacheline_aligned;
};
static ssize_t ad2s120x_show_val(struct device *dev,
struct device_attribute *attr, char *buf)
{
int ret = 0;
ssize_t len = 0;
u16 pos;
s16 vel;
u8 status;
struct ad2s120x_state *st = iio_priv(dev_get_drvdata(dev));
struct iio_dev_attr *iattr = to_iio_dev_attr(attr);
mutex_lock(&st->lock);
gpio_set_value(st->sample, 0);
/* delay (6 * AD2S120X_TSCLK + 20) nano seconds */
udelay(1);
gpio_set_value(st->sample, 1);
gpio_set_value(st->rdvel, iattr->address);
ret = spi_read(st->sdev, st->rx, 2);
if (ret < 0)
goto error_ret;
status = st->rx[1];
if (iattr->address)
pos = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
else {
vel = (st->rx[0] & 0x80) ? 0xf000 : 0;
vel |= (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
}
len = sprintf(buf, "%d %c%c%c%c ", iattr->address ? pos : vel,
(status & 0x8) ? 'P' : 'V',
(status & 0x4) ? 'd' : '_',
(status & 0x2) ? 'l' : '_',
(status & 0x1) ? '1' : '0');
error_ret:
/* delay (2 * AD2S120X_TSCLK + 20) ns for sample pulse */
udelay(1);
mutex_unlock(&st->lock);
return ret ? ret : len;
}
static IIO_DEVICE_ATTR(pos, S_IRUGO, ad2s120x_show_val, NULL, 1);
static IIO_DEVICE_ATTR(vel, S_IRUGO, ad2s120x_show_val, NULL, 0);
static struct attribute *ad2s120x_attributes[] = {
&iio_dev_attr_pos.dev_attr.attr,
&iio_dev_attr_vel.dev_attr.attr,
NULL,
};
static const struct attribute_group ad2s120x_attribute_group = {
.attrs = ad2s120x_attributes,
};
static const struct iio_info ad2s120x_info = {
.attrs = &ad2s120x_attribute_group,
.driver_module = THIS_MODULE,
};
static int __devinit ad2s120x_probe(struct spi_device *spi)
{
struct ad2s120x_state *st;
struct iio_dev *indio_dev;
int pn, ret = 0;
unsigned short *pins = spi->dev.platform_data;
for (pn = 0; pn < AD2S120X_PN; pn++)
if (gpio_request_one(pins[pn], GPIOF_DIR_OUT, DRV_NAME)) {
pr_err("%s: request gpio pin %d failed\n",
DRV_NAME, pins[pn]);
goto error_ret;
}
indio_dev = iio_allocate_device(sizeof(*st));
if (indio_dev == NULL) {
ret = -ENOMEM;
goto error_ret;
}
spi_set_drvdata(spi, indio_dev);
st = iio_priv(indio_dev);
mutex_init(&st->lock);
st->sdev = spi;
st->sample = pins[0];
st->rdvel = pins[1];
indio_dev->dev.parent = &spi->dev;
indio_dev->info = &ad2s120x_info;
indio_dev->modes = INDIO_DIRECT_MODE;
ret = iio_device_register(indio_dev);
if (ret)
goto error_free_dev;
spi->max_speed_hz = AD2S120X_HZ;
spi->mode = SPI_MODE_3;
spi_setup(spi);
return 0;
error_free_dev:
iio_free_device(indio_dev);
error_ret:
for (--pn; pn >= 0; pn--)
gpio_free(pins[pn]);
return ret;
}
static int __devexit ad2s120x_remove(struct spi_device *spi)
{
iio_device_unregister(spi_get_drvdata(spi));
return 0;
}
static struct spi_driver ad2s120x_driver = {
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
},
.probe = ad2s120x_probe,
.remove = __devexit_p(ad2s120x_remove),
};
static __init int ad2s120x_spi_init(void)
{
return spi_register_driver(&ad2s120x_driver);
}
module_init(ad2s120x_spi_init);
static __exit void ad2s120x_spi_exit(void)
{
spi_unregister_driver(&ad2s120x_driver);
}
module_exit(ad2s120x_spi_exit);
MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver");
MODULE_LICENSE("GPL v2");
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