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/*
* ad2s1200.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 <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define DRV_NAME "ad2s1200"
/* input pin sample and rdvel is controlled by driver */
#define AD2S1200_PN 2
/* input clock on serial interface */
#define AD2S1200_HZ 8192000
/* clock period in nano second */
#define AD2S1200_TSCLK (1000000000/AD2S1200_HZ)
struct ad2s1200_state {
struct mutex lock;
struct spi_device *sdev;
int sample;
int rdvel;
u8 rx[2] ____cacheline_aligned;
};
static int ad2s1200_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
int ret = 0;
s16 vel;
struct ad2s1200_state *st = iio_priv(indio_dev);
mutex_lock(&st->lock);
gpio_set_value(st->sample, 0);
/* delay (6 * AD2S1200_TSCLK + 20) nano seconds */
udelay(1);
gpio_set_value(st->sample, 1);
gpio_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
ret = spi_read(st->sdev, st->rx, 2);
if (ret < 0) {
mutex_unlock(&st->lock);
return ret;
}
switch (chan->type) {
case IIO_ANGL:
*val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
break;
case IIO_ANGL_VEL:
vel = (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
vel = (vel << 4) >> 4;
*val = vel;
break;
default:
mutex_unlock(&st->lock);
return -EINVAL;
}
/* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */
udelay(1);
mutex_unlock(&st->lock);
return IIO_VAL_INT;
}
static const struct iio_chan_spec ad2s1200_channels[] = {
{
.type = IIO_ANGL,
.indexed = 1,
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
}, {
.type = IIO_ANGL_VEL,
.indexed = 1,
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
}
};
static const struct iio_info ad2s1200_info = {
.read_raw = &ad2s1200_read_raw,
.driver_module = THIS_MODULE,
};
static int ad2s1200_probe(struct spi_device *spi)
{
struct ad2s1200_state *st;
struct iio_dev *indio_dev;
int pn, ret = 0;
unsigned short *pins = spi->dev.platform_data;
for (pn = 0; pn < AD2S1200_PN; pn++)
ret = devm_gpio_request_one(&spi->dev, pins[pn], GPIOF_DIR_OUT,
DRV_NAME);
if (ret) {
dev_err(&spi->dev, "request gpio pin %d failed\n",
pins[pn]);
return ret;
}
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
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 = &ad2s1200_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ad2s1200_channels;
indio_dev->num_channels = ARRAY_SIZE(ad2s1200_channels);
indio_dev->name = spi_get_device_id(spi)->name;
ret = devm_iio_device_register(&spi->dev, indio_dev);
if (ret)
return ret;
spi->max_speed_hz = AD2S1200_HZ;
spi->mode = SPI_MODE_3;
spi_setup(spi);
return 0;
}
static const struct spi_device_id ad2s1200_id[] = {
{ "ad2s1200" },
{ "ad2s1205" },
{}
};
MODULE_DEVICE_TABLE(spi, ad2s1200_id);
static struct spi_driver ad2s1200_driver = {
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
},
.probe = ad2s1200_probe,
.id_table = ad2s1200_id,
};
module_spi_driver(ad2s1200_driver);
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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