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/*
* ad2s1200.c simple support for the ADI Resolver to Digital Converters:
* AD2S1200/1205
*
* Copyright (c) 2018-2018 David Veenstra <davidjulianveenstra@gmail.com>
* 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/bitops.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/types.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define DRV_NAME "ad2s1200"
/* input clock on serial interface */
#define AD2S1200_HZ 8192000
/* clock period in nano second */
#define AD2S1200_TSCLK (1000000000 / AD2S1200_HZ)
/**
* struct ad2s1200_state - driver instance specific data.
* @lock: protects both the GPIO pins and the rx buffer.
* @sdev: spi device.
* @sample: GPIO pin SAMPLE.
* @rdvel: GPIO pin RDVEL.
* @rx: buffer for spi transfers.
*/
struct ad2s1200_state {
struct mutex lock;
struct spi_device *sdev;
struct gpio_desc *sample;
struct gpio_desc *rdvel;
__be16 rx ____cacheline_aligned;
};
static int ad2s1200_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
struct ad2s1200_state *st = iio_priv(indio_dev);
int ret;
switch (m) {
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_ANGL:
/* 2 * Pi / (2^12 - 1) ~= 0.001534355 */
*val = 0;
*val2 = 1534355;
return IIO_VAL_INT_PLUS_NANO;
case IIO_ANGL_VEL:
/* 2 * Pi ~= 6.283185 */
*val = 6;
*val2 = 283185;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
break;
case IIO_CHAN_INFO_RAW:
mutex_lock(&st->lock);
gpiod_set_value(st->sample, 0);
/* delay (6 * AD2S1200_TSCLK + 20) nano seconds */
udelay(1);
gpiod_set_value(st->sample, 1);
gpiod_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 = be16_to_cpup(&st->rx) >> 4;
break;
case IIO_ANGL_VEL:
*val = sign_extend32(be16_to_cpup(&st->rx) >> 4, 11);
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;
default:
break;
}
return -EINVAL;
}
static const struct iio_chan_spec ad2s1200_channels[] = {
{
.type = IIO_ANGL,
.indexed = 1,
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
}, {
.type = IIO_ANGL_VEL,
.indexed = 1,
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
}
};
static const struct iio_info ad2s1200_info = {
.read_raw = ad2s1200_read_raw,
};
static int ad2s1200_probe(struct spi_device *spi)
{
struct ad2s1200_state *st;
struct iio_dev *indio_dev;
int 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 = devm_gpiod_get(&spi->dev, "adi,sample", GPIOD_OUT_LOW);
if (IS_ERR(st->sample)) {
dev_err(&spi->dev, "Failed to claim SAMPLE gpio: err=%ld\n",
PTR_ERR(st->sample));
return PTR_ERR(st->sample);
}
st->rdvel = devm_gpiod_get(&spi->dev, "adi,rdvel", GPIOD_OUT_LOW);
if (IS_ERR(st->rdvel)) {
dev_err(&spi->dev, "Failed to claim RDVEL gpio: err=%ld\n",
PTR_ERR(st->rdvel));
return PTR_ERR(st->rdvel);
}
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;
spi->max_speed_hz = AD2S1200_HZ;
spi->mode = SPI_MODE_3;
ret = spi_setup(spi);
if (ret < 0) {
dev_err(&spi->dev, "spi_setup failed!\n");
return ret;
}
return devm_iio_device_register(&spi->dev, indio_dev);
}
static const struct of_device_id ad2s1200_of_match[] = {
{ .compatible = "adi,ad2s1200", },
{ .compatible = "adi,ad2s1205", },
{ }
};
MODULE_DEVICE_TABLE(of, ad2s1200_of_match);
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,
.of_match_table = of_match_ptr(ad2s1200_of_match),
},
.probe = ad2s1200_probe,
.id_table = ad2s1200_id,
};
module_spi_driver(ad2s1200_driver);
MODULE_AUTHOR("David Veenstra <davidjulianveenstra@gmail.com>");
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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