/*
* TI tlc4541 ADC Driver
*
* Copyright (C) 2017 Phil Reid
*
* Datasheets can be found here:
* http://www.ti.com/lit/gpn/tlc3541
* http://www.ti.com/lit/gpn/tlc4541
*
* 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.
*
* The tlc4541 requires 24 clock cycles to start a transfer.
* Conversion then takes 2.94us to complete before data is ready
* Data is returned MSB first.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
struct tlc4541_state {
struct spi_device *spi;
struct regulator *reg;
struct spi_transfer scan_single_xfer[3];
struct spi_message scan_single_msg;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
* 2 bytes data + 6 bytes padding + 8 bytes timestamp when
* call iio_push_to_buffers_with_timestamp.
*/
__be16 rx_buf[8] ____cacheline_aligned;
};
struct tlc4541_chip_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
};
enum tlc4541_id {
TLC3541,
TLC4541,
};
#define TLC4541_V_CHAN(bits, bitshift) { \
.type = IIO_VOLTAGE, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.scan_type = { \
.sign = 'u', \
.realbits = (bits), \
.storagebits = 16, \
.shift = (bitshift), \
.endianness = IIO_BE, \
}, \
}
#define DECLARE_TLC4541_CHANNELS(name, bits, bitshift) \
const struct iio_chan_spec name ## _channels[] = { \
TLC4541_V_CHAN(bits, bitshift), \
IIO_CHAN_SOFT_TIMESTAMP(1), \
}
static DECLARE_TLC4541_CHANNELS(tlc3541, 14, 2);
static DECLARE_TLC4541_CHANNELS(tlc4541, 16, 0);
static const struct tlc4541_chip_info tlc4541_chip_info[] = {
[TLC3541] = {
.channels = tlc3541_channels,
.num_channels = ARRAY_SIZE(tlc3541_channels),
},
[TLC4541] = {
.channels = tlc4541_channels,
.num_channels = ARRAY_SIZE(tlc4541_channels),
},
};
static irqreturn_t tlc4541_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct tlc4541_state *st = iio_priv(indio_dev);
int ret;
ret = spi_sync(st->spi, &st->scan_single_msg);
if (ret < 0)
goto done;
iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
iio_get_time_ns(indio_dev));
done:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int tlc4541_get_range(struct tlc4541_state *st)
{
int vref;
vref = regulator_get_voltage(st->reg);
if (vref < 0)
return vref;
vref /= 1000;
return vref;
}
static int tlc4541_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
int ret = 0;
struct tlc4541_state *st = iio_priv(indio_dev);
switch (m) {
case IIO_CHAN_INFO_RAW:
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
ret = spi_sync(st->spi, &st->scan_single_msg);
iio_device_release_direct_mode(indio_dev);
if (ret < 0)
return ret;
*val = be16_to_cpu(st->rx_buf[0]);
*val = *val >> chan->scan_type.shift;
*val &= GENMASK(chan->scan_type.realbits - 1, 0);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = tlc4541_get_range(st);
if (ret < 0)
return ret;
*val = ret;
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
}
return -EINVAL;
}
static const struct iio_info tlc4541_info = {
.read_raw = &tlc4541_read_raw,
};
static int tlc4541_probe(struct spi_device *spi)
{
struct tlc4541_state *st;
struct iio_dev *indio_dev;
const struct tlc4541_chip_info *info;
int ret;
int8_t device_init = 0;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (indio_dev == NULL)
return -ENOMEM;
st = iio_priv(indio_dev);
spi_set_drvdata(spi, indio_dev);
st->spi = spi;
info = &tlc4541_chip_info[spi_get_device_id(spi)->driver_data];
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->dev.parent = &spi->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = info->channels;
indio_dev->num_channels = info->num_channels;
indio_dev->info = &tlc4541_info;
/* perform reset */
spi_write(spi, &device_init, 1);
/* Setup default message */
st->scan_single_xfer[0].rx_buf = &st->rx_buf[0];
st->scan_single_xfer[0].len = 3;
st->scan_single_xfer[1].delay_usecs = 3;
st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
st->scan_single_xfer[2].len = 2;
spi_message_init_with_transfers(&st->scan_single_msg,
st->scan_single_xfer, 3);
st->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(st->reg))
return PTR_ERR(st->reg);
ret = regulator_enable(st->reg);
if (ret)
return ret;
ret = iio_triggered_buffer_setup(indio_dev, NULL,
&tlc4541_trigger_handler, NULL);
if (ret)
goto error_disable_reg;
ret = iio_device_register(indio_dev);
if (ret)
goto error_cleanup_buffer;
return 0;
error_cleanup_buffer:
iio_triggered_buffer_cleanup(indio_dev);
error_disable_reg:
regulator_disable(st->reg);
return ret;
}
static int tlc4541_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct tlc4541_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
regulator_disable(st->reg);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id tlc4541_dt_ids[] = {
{ .compatible = "ti,tlc3541", },
{ .compatible = "ti,tlc4541", },
{}
};
MODULE_DEVICE_TABLE(of, tlc4541_dt_ids);
#endif
static const struct spi_device_id tlc4541_id[] = {
{"tlc3541", TLC3541},
{"tlc4541", TLC4541},
{}
};
MODULE_DEVICE_TABLE(spi, tlc4541_id);
static struct spi_driver tlc4541_driver = {
.driver = {
.name = "tlc4541",
.of_match_table = of_match_ptr(tlc4541_dt_ids),
},
.probe = tlc4541_probe,
.remove = tlc4541_remove,
.id_table = tlc4541_id,
};
module_spi_driver(tlc4541_driver);
MODULE_AUTHOR("Phil Reid <preid@electromag.com.au>");
MODULE_DESCRIPTION("Texas Instruments TLC4541 ADC");
MODULE_LICENSE("GPL v2");
