338 lines
8.3 KiB
C
338 lines
8.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* TI ADC108S102 SPI ADC driver
|
|
*
|
|
* Copyright (c) 2013-2015 Intel Corporation.
|
|
* Copyright (c) 2017 Siemens AG
|
|
*
|
|
* This IIO device driver is designed to work with the following
|
|
* analog to digital converters from Texas Instruments:
|
|
* ADC108S102
|
|
* ADC128S102
|
|
* The communication with ADC chip is via the SPI bus (mode 3).
|
|
*/
|
|
|
|
#include <linux/acpi.h>
|
|
#include <linux/iio/iio.h>
|
|
#include <linux/iio/buffer.h>
|
|
#include <linux/iio/types.h>
|
|
#include <linux/iio/triggered_buffer.h>
|
|
#include <linux/iio/trigger_consumer.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mod_devicetable.h>
|
|
#include <linux/property.h>
|
|
#include <linux/regulator/consumer.h>
|
|
#include <linux/spi/spi.h>
|
|
|
|
/*
|
|
* In case of ACPI, we use the hard-wired 5000 mV of the Galileo and IOT2000
|
|
* boards as default for the reference pin VA. Device tree users encode that
|
|
* via the vref-supply regulator.
|
|
*/
|
|
#define ADC108S102_VA_MV_ACPI_DEFAULT 5000
|
|
|
|
/*
|
|
* Defining the ADC resolution being 12 bits, we can use the same driver for
|
|
* both ADC108S102 (10 bits resolution) and ADC128S102 (12 bits resolution)
|
|
* chips. The ADC108S102 effectively returns a 12-bit result with the 2
|
|
* least-significant bits unset.
|
|
*/
|
|
#define ADC108S102_BITS 12
|
|
#define ADC108S102_MAX_CHANNELS 8
|
|
|
|
/*
|
|
* 16-bit SPI command format:
|
|
* [15:14] Ignored
|
|
* [13:11] 3-bit channel address
|
|
* [10:0] Ignored
|
|
*/
|
|
#define ADC108S102_CMD(ch) ((u16)(ch) << 11)
|
|
|
|
/*
|
|
* 16-bit SPI response format:
|
|
* [15:12] Zeros
|
|
* [11:0] 12-bit ADC sample (for ADC108S102, [1:0] will always be 0).
|
|
*/
|
|
#define ADC108S102_RES_DATA(res) ((u16)res & GENMASK(11, 0))
|
|
|
|
struct adc108s102_state {
|
|
struct spi_device *spi;
|
|
struct regulator *reg;
|
|
u32 va_millivolt;
|
|
/* SPI transfer used by triggered buffer handler*/
|
|
struct spi_transfer ring_xfer;
|
|
/* SPI transfer used by direct scan */
|
|
struct spi_transfer scan_single_xfer;
|
|
/* SPI message used by ring_xfer SPI transfer */
|
|
struct spi_message ring_msg;
|
|
/* SPI message used by scan_single_xfer SPI transfer */
|
|
struct spi_message scan_single_msg;
|
|
|
|
/*
|
|
* SPI message buffers:
|
|
* tx_buf: |C0|C1|C2|C3|C4|C5|C6|C7|XX|
|
|
* rx_buf: |XX|R0|R1|R2|R3|R4|R5|R6|R7|tt|tt|tt|tt|
|
|
*
|
|
* tx_buf: 8 channel read commands, plus 1 dummy command
|
|
* rx_buf: 1 dummy response, 8 channel responses, plus 64-bit timestamp
|
|
*/
|
|
__be16 rx_buf[13] ____cacheline_aligned;
|
|
__be16 tx_buf[9] ____cacheline_aligned;
|
|
};
|
|
|
|
#define ADC108S102_V_CHAN(index) \
|
|
{ \
|
|
.type = IIO_VOLTAGE, \
|
|
.indexed = 1, \
|
|
.channel = index, \
|
|
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
|
|
BIT(IIO_CHAN_INFO_SCALE), \
|
|
.address = index, \
|
|
.scan_index = index, \
|
|
.scan_type = { \
|
|
.sign = 'u', \
|
|
.realbits = ADC108S102_BITS, \
|
|
.storagebits = 16, \
|
|
.endianness = IIO_BE, \
|
|
}, \
|
|
}
|
|
|
|
static const struct iio_chan_spec adc108s102_channels[] = {
|
|
ADC108S102_V_CHAN(0),
|
|
ADC108S102_V_CHAN(1),
|
|
ADC108S102_V_CHAN(2),
|
|
ADC108S102_V_CHAN(3),
|
|
ADC108S102_V_CHAN(4),
|
|
ADC108S102_V_CHAN(5),
|
|
ADC108S102_V_CHAN(6),
|
|
ADC108S102_V_CHAN(7),
|
|
IIO_CHAN_SOFT_TIMESTAMP(8),
|
|
};
|
|
|
|
static int adc108s102_update_scan_mode(struct iio_dev *indio_dev,
|
|
unsigned long const *active_scan_mask)
|
|
{
|
|
struct adc108s102_state *st = iio_priv(indio_dev);
|
|
unsigned int bit, cmds;
|
|
|
|
/*
|
|
* Fill in the first x shorts of tx_buf with the number of channels
|
|
* enabled for sampling by the triggered buffer.
|
|
*/
|
|
cmds = 0;
|
|
for_each_set_bit(bit, active_scan_mask, ADC108S102_MAX_CHANNELS)
|
|
st->tx_buf[cmds++] = cpu_to_be16(ADC108S102_CMD(bit));
|
|
|
|
/* One dummy command added, to clock in the last response */
|
|
st->tx_buf[cmds++] = 0x00;
|
|
|
|
/* build SPI ring message */
|
|
st->ring_xfer.tx_buf = &st->tx_buf[0];
|
|
st->ring_xfer.rx_buf = &st->rx_buf[0];
|
|
st->ring_xfer.len = cmds * sizeof(st->tx_buf[0]);
|
|
|
|
spi_message_init_with_transfers(&st->ring_msg, &st->ring_xfer, 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static irqreturn_t adc108s102_trigger_handler(int irq, void *p)
|
|
{
|
|
struct iio_poll_func *pf = p;
|
|
struct iio_dev *indio_dev = pf->indio_dev;
|
|
struct adc108s102_state *st = iio_priv(indio_dev);
|
|
int ret;
|
|
|
|
ret = spi_sync(st->spi, &st->ring_msg);
|
|
if (ret < 0)
|
|
goto out_notify;
|
|
|
|
/* Skip the dummy response in the first slot */
|
|
iio_push_to_buffers_with_timestamp(indio_dev,
|
|
(u8 *)&st->rx_buf[1],
|
|
iio_get_time_ns(indio_dev));
|
|
|
|
out_notify:
|
|
iio_trigger_notify_done(indio_dev->trig);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static int adc108s102_scan_direct(struct adc108s102_state *st, unsigned int ch)
|
|
{
|
|
int ret;
|
|
|
|
st->tx_buf[0] = cpu_to_be16(ADC108S102_CMD(ch));
|
|
ret = spi_sync(st->spi, &st->scan_single_msg);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* Skip the dummy response in the first slot */
|
|
return be16_to_cpu(st->rx_buf[1]);
|
|
}
|
|
|
|
static int adc108s102_read_raw(struct iio_dev *indio_dev,
|
|
struct iio_chan_spec const *chan,
|
|
int *val, int *val2, long m)
|
|
{
|
|
struct adc108s102_state *st = iio_priv(indio_dev);
|
|
int ret;
|
|
|
|
switch (m) {
|
|
case IIO_CHAN_INFO_RAW:
|
|
ret = iio_device_claim_direct_mode(indio_dev);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = adc108s102_scan_direct(st, chan->address);
|
|
|
|
iio_device_release_direct_mode(indio_dev);
|
|
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
*val = ADC108S102_RES_DATA(ret);
|
|
|
|
return IIO_VAL_INT;
|
|
case IIO_CHAN_INFO_SCALE:
|
|
if (chan->type != IIO_VOLTAGE)
|
|
break;
|
|
|
|
*val = st->va_millivolt;
|
|
*val2 = chan->scan_type.realbits;
|
|
|
|
return IIO_VAL_FRACTIONAL_LOG2;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static const struct iio_info adc108s102_info = {
|
|
.read_raw = &adc108s102_read_raw,
|
|
.update_scan_mode = &adc108s102_update_scan_mode,
|
|
};
|
|
|
|
static int adc108s102_probe(struct spi_device *spi)
|
|
{
|
|
struct adc108s102_state *st;
|
|
struct iio_dev *indio_dev;
|
|
int ret;
|
|
|
|
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
|
|
if (!indio_dev)
|
|
return -ENOMEM;
|
|
|
|
st = iio_priv(indio_dev);
|
|
|
|
if (ACPI_COMPANION(&spi->dev)) {
|
|
st->va_millivolt = ADC108S102_VA_MV_ACPI_DEFAULT;
|
|
} else {
|
|
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 < 0) {
|
|
dev_err(&spi->dev, "Cannot enable vref regulator\n");
|
|
return ret;
|
|
}
|
|
|
|
ret = regulator_get_voltage(st->reg);
|
|
if (ret < 0) {
|
|
dev_err(&spi->dev, "vref get voltage failed\n");
|
|
return ret;
|
|
}
|
|
|
|
st->va_millivolt = ret / 1000;
|
|
}
|
|
|
|
spi_set_drvdata(spi, indio_dev);
|
|
st->spi = spi;
|
|
|
|
indio_dev->name = spi->modalias;
|
|
indio_dev->modes = INDIO_DIRECT_MODE;
|
|
indio_dev->channels = adc108s102_channels;
|
|
indio_dev->num_channels = ARRAY_SIZE(adc108s102_channels);
|
|
indio_dev->info = &adc108s102_info;
|
|
|
|
/* Setup default message */
|
|
st->scan_single_xfer.tx_buf = st->tx_buf;
|
|
st->scan_single_xfer.rx_buf = st->rx_buf;
|
|
st->scan_single_xfer.len = 2 * sizeof(st->tx_buf[0]);
|
|
|
|
spi_message_init_with_transfers(&st->scan_single_msg,
|
|
&st->scan_single_xfer, 1);
|
|
|
|
ret = iio_triggered_buffer_setup(indio_dev, NULL,
|
|
&adc108s102_trigger_handler, NULL);
|
|
if (ret)
|
|
goto error_disable_reg;
|
|
|
|
ret = iio_device_register(indio_dev);
|
|
if (ret) {
|
|
dev_err(&spi->dev, "Failed to register IIO device\n");
|
|
goto error_cleanup_triggered_buffer;
|
|
}
|
|
return 0;
|
|
|
|
error_cleanup_triggered_buffer:
|
|
iio_triggered_buffer_cleanup(indio_dev);
|
|
|
|
error_disable_reg:
|
|
regulator_disable(st->reg);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int adc108s102_remove(struct spi_device *spi)
|
|
{
|
|
struct iio_dev *indio_dev = spi_get_drvdata(spi);
|
|
struct adc108s102_state *st = iio_priv(indio_dev);
|
|
|
|
iio_device_unregister(indio_dev);
|
|
iio_triggered_buffer_cleanup(indio_dev);
|
|
|
|
regulator_disable(st->reg);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct of_device_id adc108s102_of_match[] = {
|
|
{ .compatible = "ti,adc108s102" },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, adc108s102_of_match);
|
|
|
|
#ifdef CONFIG_ACPI
|
|
static const struct acpi_device_id adc108s102_acpi_ids[] = {
|
|
{ "INT3495", 0 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(acpi, adc108s102_acpi_ids);
|
|
#endif
|
|
|
|
static const struct spi_device_id adc108s102_id[] = {
|
|
{ "adc108s102", 0 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(spi, adc108s102_id);
|
|
|
|
static struct spi_driver adc108s102_driver = {
|
|
.driver = {
|
|
.name = "adc108s102",
|
|
.of_match_table = adc108s102_of_match,
|
|
.acpi_match_table = ACPI_PTR(adc108s102_acpi_ids),
|
|
},
|
|
.probe = adc108s102_probe,
|
|
.remove = adc108s102_remove,
|
|
.id_table = adc108s102_id,
|
|
};
|
|
module_spi_driver(adc108s102_driver);
|
|
|
|
MODULE_AUTHOR("Bogdan Pricop <bogdan.pricop@emutex.com>");
|
|
MODULE_DESCRIPTION("Texas Instruments ADC108S102 and ADC128S102 driver");
|
|
MODULE_LICENSE("GPL v2");
|