forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
130 lines
3.0 KiB
130 lines
3.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* ad2s90.c simple support for the ADI Resolver to Digital Converters: AD2S90 |
|
* |
|
* Copyright (c) 2010-2010 Analog Devices Inc. |
|
*/ |
|
#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/module.h> |
|
|
|
#include <linux/iio/iio.h> |
|
#include <linux/iio/sysfs.h> |
|
|
|
/* |
|
* Although chip's max frequency is 2Mhz, it needs 600ns between CS and the |
|
* first falling edge of SCLK, so frequency should be at most 1 / (2 * 6e-7) |
|
*/ |
|
#define AD2S90_MAX_SPI_FREQ_HZ 830000 |
|
|
|
struct ad2s90_state { |
|
struct mutex lock; /* lock to protect rx buffer */ |
|
struct spi_device *sdev; |
|
u8 rx[2] ____cacheline_aligned; |
|
}; |
|
|
|
static int ad2s90_read_raw(struct iio_dev *indio_dev, |
|
struct iio_chan_spec const *chan, |
|
int *val, |
|
int *val2, |
|
long m) |
|
{ |
|
int ret; |
|
struct ad2s90_state *st = iio_priv(indio_dev); |
|
|
|
if (chan->type != IIO_ANGL) |
|
return -EINVAL; |
|
|
|
switch (m) { |
|
case IIO_CHAN_INFO_SCALE: |
|
/* 2 * Pi / 2^12 */ |
|
*val = 6283; /* mV */ |
|
*val2 = 12; |
|
return IIO_VAL_FRACTIONAL_LOG2; |
|
case IIO_CHAN_INFO_RAW: |
|
mutex_lock(&st->lock); |
|
ret = spi_read(st->sdev, st->rx, 2); |
|
if (ret < 0) { |
|
mutex_unlock(&st->lock); |
|
return ret; |
|
} |
|
*val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4); |
|
|
|
mutex_unlock(&st->lock); |
|
|
|
return IIO_VAL_INT; |
|
default: |
|
break; |
|
} |
|
|
|
return -EINVAL; |
|
} |
|
|
|
static const struct iio_info ad2s90_info = { |
|
.read_raw = ad2s90_read_raw, |
|
}; |
|
|
|
static const struct iio_chan_spec ad2s90_chan = { |
|
.type = IIO_ANGL, |
|
.indexed = 1, |
|
.channel = 0, |
|
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), |
|
}; |
|
|
|
static int ad2s90_probe(struct spi_device *spi) |
|
{ |
|
struct iio_dev *indio_dev; |
|
struct ad2s90_state *st; |
|
|
|
if (spi->max_speed_hz > AD2S90_MAX_SPI_FREQ_HZ) { |
|
dev_err(&spi->dev, "SPI CLK, %d Hz exceeds %d Hz\n", |
|
spi->max_speed_hz, AD2S90_MAX_SPI_FREQ_HZ); |
|
return -EINVAL; |
|
} |
|
|
|
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); |
|
if (!indio_dev) |
|
return -ENOMEM; |
|
st = iio_priv(indio_dev); |
|
spi_set_drvdata(spi, indio_dev); |
|
|
|
mutex_init(&st->lock); |
|
st->sdev = spi; |
|
indio_dev->info = &ad2s90_info; |
|
indio_dev->modes = INDIO_DIRECT_MODE; |
|
indio_dev->channels = &ad2s90_chan; |
|
indio_dev->num_channels = 1; |
|
indio_dev->name = spi_get_device_id(spi)->name; |
|
|
|
return devm_iio_device_register(indio_dev->dev.parent, indio_dev); |
|
} |
|
|
|
static const struct of_device_id ad2s90_of_match[] = { |
|
{ .compatible = "adi,ad2s90", }, |
|
{} |
|
}; |
|
MODULE_DEVICE_TABLE(of, ad2s90_of_match); |
|
|
|
static const struct spi_device_id ad2s90_id[] = { |
|
{ "ad2s90" }, |
|
{} |
|
}; |
|
MODULE_DEVICE_TABLE(spi, ad2s90_id); |
|
|
|
static struct spi_driver ad2s90_driver = { |
|
.driver = { |
|
.name = "ad2s90", |
|
.of_match_table = ad2s90_of_match, |
|
}, |
|
.probe = ad2s90_probe, |
|
.id_table = ad2s90_id, |
|
}; |
|
module_spi_driver(ad2s90_driver); |
|
|
|
MODULE_AUTHOR("Graff Yang <[email protected]>"); |
|
MODULE_DESCRIPTION("Analog Devices AD2S90 Resolver to Digital SPI driver"); |
|
MODULE_LICENSE("GPL v2");
|
|
|