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/*
* AD8366 SPI Dual-Digital Variable Gain Amplifier (VGA)
*
* Copyright 2012 Analog Devices Inc.
*
* Licensed under the GPL-2.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/bitrev.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
struct ad8366_state {
struct spi_device *spi;
struct regulator *reg;
unsigned char ch[2];
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
*/
unsigned char data[2] ____cacheline_aligned;
};
static int ad8366_write(struct iio_dev *indio_dev,
unsigned char ch_a, unsigned char ch_b)
{
struct ad8366_state *st = iio_priv(indio_dev);
int ret;
ch_a = bitrev8(ch_a & 0x3F);
ch_b = bitrev8(ch_b & 0x3F);
st->data[0] = ch_b >> 4;
st->data[1] = (ch_b << 4) | (ch_a >> 2);
ret = spi_write(st->spi, st->data, ARRAY_SIZE(st->data));
if (ret < 0)
dev_err(&indio_dev->dev, "write failed (%d)", ret);
return ret;
}
static int ad8366_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
struct ad8366_state *st = iio_priv(indio_dev);
int ret;
unsigned code;
mutex_lock(&indio_dev->mlock);
switch (m) {
case IIO_CHAN_INFO_HARDWAREGAIN:
code = st->ch[chan->channel];
/* Values in dB */
code = code * 253 + 4500;
*val = code / 1000;
*val2 = (code % 1000) * 1000;
ret = IIO_VAL_INT_PLUS_MICRO_DB;
break;
default:
ret = -EINVAL;
}
mutex_unlock(&indio_dev->mlock);
return ret;
};
static int ad8366_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val,
int val2,
long mask)
{
struct ad8366_state *st = iio_priv(indio_dev);
unsigned code;
int ret;
if (val < 0 || val2 < 0)
return -EINVAL;
/* Values in dB */
code = (((u8)val * 1000) + ((u32)val2 / 1000));
if (code > 20500 || code < 4500)
return -EINVAL;
code = (code - 4500) / 253;
mutex_lock(&indio_dev->mlock);
switch (mask) {
case IIO_CHAN_INFO_HARDWAREGAIN:
st->ch[chan->channel] = code;
ret = ad8366_write(indio_dev, st->ch[0], st->ch[1]);
break;
default:
ret = -EINVAL;
}
mutex_unlock(&indio_dev->mlock);
return ret;
}
static const struct iio_info ad8366_info = {
.read_raw = &ad8366_read_raw,
.write_raw = &ad8366_write_raw,
};
#define AD8366_CHAN(_channel) { \
.type = IIO_VOLTAGE, \
.output = 1, \
.indexed = 1, \
.channel = _channel, \
.info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),\
}
static const struct iio_chan_spec ad8366_channels[] = {
AD8366_CHAN(0),
AD8366_CHAN(1),
};
static int ad8366_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct ad8366_state *st;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (indio_dev == NULL)
return -ENOMEM;
st = iio_priv(indio_dev);
st->reg = devm_regulator_get(&spi->dev, "vcc");
if (!IS_ERR(st->reg)) {
ret = regulator_enable(st->reg);
if (ret)
return ret;
}
spi_set_drvdata(spi, indio_dev);
st->spi = spi;
indio_dev->dev.parent = &spi->dev;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->info = &ad8366_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ad8366_channels;
indio_dev->num_channels = ARRAY_SIZE(ad8366_channels);
ret = iio_device_register(indio_dev);
if (ret)
goto error_disable_reg;
ad8366_write(indio_dev, 0, 0);
return 0;
error_disable_reg:
if (!IS_ERR(st->reg))
regulator_disable(st->reg);
return ret;
}
static int ad8366_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct ad8366_state *st = iio_priv(indio_dev);
struct regulator *reg = st->reg;
iio_device_unregister(indio_dev);
if (!IS_ERR(reg))
regulator_disable(reg);
return 0;
}
static const struct spi_device_id ad8366_id[] = {
{"ad8366", 0},
{}
};
MODULE_DEVICE_TABLE(spi, ad8366_id);
static struct spi_driver ad8366_driver = {
.driver = {
.name = KBUILD_MODNAME,
},
.probe = ad8366_probe,
.remove = ad8366_remove,
.id_table = ad8366_id,
};
module_spi_driver(ad8366_driver);
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("Analog Devices AD8366 VGA");
MODULE_LICENSE("GPL v2");
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