/**
* Copyright (C) 2017 Axis Communications AB
*
* Driver for Texas Instruments' ADC084S021 ADC chip.
* Datasheets can be found here:
* http://www.ti.com/lit/ds/symlink/adc084s021.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/interrupt.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/regulator/consumer.h>
#define ADC084S021_DRIVER_NAME "adc084s021"
struct adc084s021 {
struct spi_device *spi;
struct spi_message message;
struct spi_transfer spi_trans;
struct regulator *reg;
struct mutex lock;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache line.
*/
u16 tx_buf[4] ____cacheline_aligned;
__be16 rx_buf[5]; /* First 16-bits are trash */
};
#define ADC084S021_VOLTAGE_CHANNEL(num) \
{ \
.type = IIO_VOLTAGE, \
.channel = (num), \
.indexed = 1, \
.scan_index = (num), \
.scan_type = { \
.sign = 'u', \
.realbits = 8, \
.storagebits = 16, \
.shift = 4, \
.endianness = IIO_BE, \
}, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
}
static const struct iio_chan_spec adc084s021_channels[] = {
ADC084S021_VOLTAGE_CHANNEL(0),
ADC084S021_VOLTAGE_CHANNEL(1),
ADC084S021_VOLTAGE_CHANNEL(2),
ADC084S021_VOLTAGE_CHANNEL(3),
IIO_CHAN_SOFT_TIMESTAMP(4),
};
/**
* Read an ADC channel and return its value.
*
* @adc: The ADC SPI data.
* @data: Buffer for converted data.
*/
static int adc084s021_adc_conversion(struct adc084s021 *adc, void *data)
{
int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */
int ret, i = 0;
u16 *p = data;
/* Do the transfer */
ret = spi_sync(adc->spi, &adc->message);
if (ret < 0)
return ret;
for (; i < n_words; i++)
*(p + i) = adc->rx_buf[i + 1];
return ret;
}
static int adc084s021_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
struct adc084s021 *adc = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = iio_device_claim_direct_mode(indio_dev);
if (ret < 0)
return ret;
ret = regulator_enable(adc->reg);
if (ret) {
iio_device_release_direct_mode(indio_dev);
return ret;
}
adc->tx_buf[0] = channel->channel << 3;
ret = adc084s021_adc_conversion(adc, val);
iio_device_release_direct_mode(indio_dev);
regulator_disable(adc->reg);
if (ret < 0)
return ret;
*val = be16_to_cpu(*val);
*val = (*val >> channel->scan_type.shift) & 0xff;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = regulator_enable(adc->reg);
if (ret)
return ret;
ret = regulator_get_voltage(adc->reg);
regulator_disable(adc->reg);
if (ret < 0)
return ret;
*val = ret / 1000;
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
/**
* Read enabled ADC channels and push data to the buffer.
*
* @irq: The interrupt number (not used).
* @pollfunc: Pointer to the poll func.
*/
static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)
{
struct iio_poll_func *pf = pollfunc;
struct iio_dev *indio_dev = pf->indio_dev;
struct adc084s021 *adc = iio_priv(indio_dev);
__be16 data[8] = {0}; /* 4 * 16-bit words of data + 8 bytes timestamp */
mutex_lock(&adc->lock);
if (adc084s021_adc_conversion(adc, &data) < 0)
dev_err(&adc->spi->dev, "Failed to read data\n");
iio_push_to_buffers_with_timestamp(indio_dev, data,
iio_get_time_ns(indio_dev));
mutex_unlock(&adc->lock);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)
{
struct adc084s021 *adc = iio_priv(indio_dev);
int scan_index;
int i = 0;
for_each_set_bit(scan_index, indio_dev->active_scan_mask,
indio_dev->masklength) {
const struct iio_chan_spec *channel =
&indio_dev->channels[scan_index];
adc->tx_buf[i++] = channel->channel << 3;
}
adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */
return regulator_enable(adc->reg);
}
static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)
{
struct adc084s021 *adc = iio_priv(indio_dev);
adc->spi_trans.len = 4; /* Trash + single channel */
return regulator_disable(adc->reg);
}
static const struct iio_info adc084s021_info = {
.read_raw = adc084s021_read_raw,
};
static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {
.preenable = adc084s021_buffer_preenable,
.postenable = iio_triggered_buffer_postenable,
.predisable = iio_triggered_buffer_predisable,
.postdisable = adc084s021_buffer_postdisable,
};
static int adc084s021_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct adc084s021 *adc;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
if (!indio_dev) {
dev_err(&spi->dev, "Failed to allocate IIO device\n");
return -ENOMEM;
}
adc = iio_priv(indio_dev);
adc->spi = spi;
/* Connect the SPI device and the iio dev */
spi_set_drvdata(spi, indio_dev);
/* Initiate the Industrial I/O device */
indio_dev->dev.parent = &spi->dev;
indio_dev->dev.of_node = spi->dev.of_node;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &adc084s021_info;
indio_dev->channels = adc084s021_channels;
indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);
/* Create SPI transfer for channel reads */
adc->spi_trans.tx_buf = adc->tx_buf;
adc->spi_trans.rx_buf = adc->rx_buf;
adc->spi_trans.len = 4; /* Trash + single channel */
spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);
adc->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(adc->reg))
return PTR_ERR(adc->reg);
mutex_init(&adc->lock);
/* Setup triggered buffer with pollfunction */
ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
adc084s021_buffer_trigger_handler,
&adc084s021_buffer_setup_ops);
if (ret) {
dev_err(&spi->dev, "Failed to setup triggered buffer\n");
return ret;
}
return devm_iio_device_register(&spi->dev, indio_dev);
}
static const struct of_device_id adc084s021_of_match[] = {
{ .compatible = "ti,adc084s021", },
{},
};
MODULE_DEVICE_TABLE(of, adc084s021_of_match);
static const struct spi_device_id adc084s021_id[] = {
{ ADC084S021_DRIVER_NAME, 0},
{}
};
MODULE_DEVICE_TABLE(spi, adc084s021_id);
static struct spi_driver adc084s021_driver = {
.driver = {
.name = ADC084S021_DRIVER_NAME,
.of_match_table = of_match_ptr(adc084s021_of_match),
},
.probe = adc084s021_probe,
.id_table = adc084s021_id,
};
module_spi_driver(adc084s021_driver);
MODULE_AUTHOR("Mårten Lindahl <martenli@axis.com>");
MODULE_DESCRIPTION("Texas Instruments ADC084S021");
MODULE_LICENSE("GPL v2");
MODULE_VERSION("1.0");
