Release 4.14 drivers/iio/adc/ti-adc108s102.c
/*
* TI ADC108S102 SPI ADC driver
*
* Copyright (c) 2013-2015 Intel Corporation.
* Copyright (c) 2017 Siemens AG
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* 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/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;
}
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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;
}
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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]);
}
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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;
}
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static const struct iio_info adc108s102_info = {
.read_raw = &adc108s102_read_raw,
.update_scan_mode = &adc108s102_update_scan_mode,
.driver_module = THIS_MODULE,
};
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->dev.parent = &spi->dev;
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;
}
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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;
}
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#ifdef CONFIG_OF
static const struct of_device_id adc108s102_of_match[] = {
{ .compatible = "ti,adc108s102" },
{ }
};
MODULE_DEVICE_TABLE(of, adc108s102_of_match);
#endif
#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 = of_match_ptr(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");
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