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/*
* Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com>
*
* Driver for Texas Instruments' ADC128S052 ADC chip.
* Datasheet can be found here:
* http://www.ti.com/lit/ds/symlink/adc128s052.pdf
*
* 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/err.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/regulator/consumer.h>
struct adc128 {
struct spi_device *spi;
struct regulator *reg;
struct mutex lock;
u8 buffer[2] ____cacheline_aligned;
};
static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
{
int ret;
mutex_lock(&adc->lock);
adc->buffer[0] = channel << 3;
adc->buffer[1] = 0;
ret = spi_write(adc->spi, &adc->buffer, 2);
if (ret < 0) {
mutex_unlock(&adc->lock);
return ret;
}
ret = spi_read(adc->spi, &adc->buffer, 2);
mutex_unlock(&adc->lock);
if (ret < 0)
return ret;
return ((adc->buffer[0] << 8 | adc->buffer[1]) & 0xFFF);
}
static int adc128_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
struct adc128 *adc = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = adc128_adc_conversion(adc, channel->channel);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(adc->reg);
if (ret < 0)
return ret;
*val = ret / 1000;
*val2 = 12;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
}
#define ADC128_VOLTAGE_CHANNEL(num) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (num), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
}
static const struct iio_chan_spec adc128_channels[] = {
ADC128_VOLTAGE_CHANNEL(0),
ADC128_VOLTAGE_CHANNEL(1),
ADC128_VOLTAGE_CHANNEL(2),
ADC128_VOLTAGE_CHANNEL(3),
ADC128_VOLTAGE_CHANNEL(4),
ADC128_VOLTAGE_CHANNEL(5),
ADC128_VOLTAGE_CHANNEL(6),
ADC128_VOLTAGE_CHANNEL(7),
};
static const struct iio_info adc128_info = {
.read_raw = adc128_read_raw,
.driver_module = THIS_MODULE,
};
static int adc128_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct adc128 *adc;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
if (!indio_dev)
return -ENOMEM;
adc = iio_priv(indio_dev);
adc->spi = spi;
spi_set_drvdata(spi, indio_dev);
indio_dev->dev.parent = &spi->dev;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &adc128_info;
indio_dev->channels = adc128_channels;
indio_dev->num_channels = ARRAY_SIZE(adc128_channels);
adc->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(adc->reg))
return PTR_ERR(adc->reg);
ret = regulator_enable(adc->reg);
if (ret < 0)
return ret;
mutex_init(&adc->lock);
ret = iio_device_register(indio_dev);
return ret;
}
static int adc128_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct adc128 *adc = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
regulator_disable(adc->reg);
return 0;
}
static const struct spi_device_id adc128_id[] = {
{ "adc128s052", 0},
{ }
};
MODULE_DEVICE_TABLE(spi, adc128_id);
static struct spi_driver adc128_driver = {
.driver = {
.name = "adc128s052",
.owner = THIS_MODULE,
},
.probe = adc128_probe,
.remove = adc128_remove,
.id_table = adc128_id,
};
module_spi_driver(adc128_driver);
MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
MODULE_DESCRIPTION("Texas Instruments ADC128S052");
MODULE_LICENSE("GPL v2");
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