Release 4.14 drivers/iio/adc/max1118.c
/*
* MAX1117/MAX1118/MAX1119 8-bit, dual-channel ADCs driver
*
* Copyright (c) 2017 Akinobu Mita <akinobu.mita@gmail.com>
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1117-MAX1119.pdf
*
* SPI interface connections
*
* SPI MAXIM
* Master Direction MAX1117/8/9
* ------ --------- -----------
* nCS --> CNVST
* SCK --> SCLK
* MISO <-- DOUT
* ------ --------- -----------
*/
#include <linux/module.h>
#include <linux/spi/spi.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>
enum max1118_id {
max1117,
max1118,
max1119,
};
struct max1118 {
struct spi_device *spi;
struct mutex lock;
struct regulator *reg;
u8 data ____cacheline_aligned;
};
#define MAX1118_CHANNEL(ch) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (ch), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.scan_index = ch, \
.scan_type = { \
.sign = 'u', \
.realbits = 8, \
.storagebits = 8, \
}, \
}
static const struct iio_chan_spec max1118_channels[] = {
MAX1118_CHANNEL(0),
MAX1118_CHANNEL(1),
IIO_CHAN_SOFT_TIMESTAMP(2),
};
static int max1118_read(struct spi_device *spi, int channel)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct max1118 *adc = iio_priv(indio_dev);
struct spi_transfer xfers[] = {
/*
* To select CH1 for conversion, CNVST pin must be brought high
* and low for a second time.
*/
{
.len = 0,
.delay_usecs = 1, /* > CNVST Low Time 100 ns */
.cs_change = 1,
},
/*
* The acquisition interval begins with the falling edge of
* CNVST. The total acquisition and conversion process takes
* <7.5us.
*/
{
.len = 0,
.delay_usecs = 8,
},
{
.rx_buf = &adc->data,
.len = 1,
},
};
int ret;
if (channel == 0)
ret = spi_sync_transfer(spi, xfers + 1, 2);
else
ret = spi_sync_transfer(spi, xfers, 3);
if (ret)
return ret;
return adc->data;
}
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static int max1118_get_vref_mV(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct max1118 *adc = iio_priv(indio_dev);
const struct spi_device_id *id = spi_get_device_id(spi);
int vref_uV;
switch (id->driver_data) {
case max1117:
return 2048;
case max1119:
return 4096;
case max1118:
vref_uV = regulator_get_voltage(adc->reg);
if (vref_uV < 0)
return vref_uV;
return vref_uV / 1000;
}
return -ENODEV;
}
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static int max1118_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct max1118 *adc = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&adc->lock);
*val = max1118_read(adc->spi, chan->channel);
mutex_unlock(&adc->lock);
if (*val < 0)
return *val;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = max1118_get_vref_mV(adc->spi);
if (*val < 0)
return *val;
*val2 = 8;
return IIO_VAL_FRACTIONAL_LOG2;
}
return -EINVAL;
}
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static const struct iio_info max1118_info = {
.read_raw = max1118_read_raw,
.driver_module = THIS_MODULE,
};
static irqreturn_t max1118_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct max1118 *adc = iio_priv(indio_dev);
u8 data[16] = { }; /* 2x 8-bit ADC data + padding + 8 bytes timestamp */
int scan_index;
int i = 0;
mutex_lock(&adc->lock);
for_each_set_bit(scan_index, indio_dev->active_scan_mask,
indio_dev->masklength) {
const struct iio_chan_spec *scan_chan =
&indio_dev->channels[scan_index];
int ret = max1118_read(adc->spi, scan_chan->channel);
if (ret < 0) {
dev_warn(&adc->spi->dev,
"failed to get conversion data\n");
goto out;
}
data[i] = ret;
i++;
}
iio_push_to_buffers_with_timestamp(indio_dev, data,
iio_get_time_ns(indio_dev));
out:
mutex_unlock(&adc->lock);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
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static int max1118_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct max1118 *adc;
const struct spi_device_id *id = spi_get_device_id(spi);
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;
mutex_init(&adc->lock);
if (id->driver_data == max1118) {
adc->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(adc->reg)) {
dev_err(&spi->dev, "failed to get vref regulator\n");
return PTR_ERR(adc->reg);
}
ret = regulator_enable(adc->reg);
if (ret)
return ret;
}
spi_set_drvdata(spi, indio_dev);
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->dev.parent = &spi->dev;
indio_dev->info = &max1118_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = max1118_channels;
indio_dev->num_channels = ARRAY_SIZE(max1118_channels);
/*
* To reinitiate a conversion on CH0, it is necessary to allow for a
* conversion to be complete and all of the data to be read out. Once
* a conversion has been completed, the MAX1117/MAX1118/MAX1119 will go
* into AutoShutdown mode until the next conversion is initiated.
*/
max1118_read(spi, 0);
ret = iio_triggered_buffer_setup(indio_dev, NULL,
max1118_trigger_handler, NULL);
if (ret)
goto err_reg_disable;
ret = iio_device_register(indio_dev);
if (ret)
goto err_buffer_cleanup;
return 0;
err_buffer_cleanup:
iio_triggered_buffer_cleanup(indio_dev);
err_reg_disable:
if (id->driver_data == max1118)
regulator_disable(adc->reg);
return ret;
}
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static int max1118_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct max1118 *adc = iio_priv(indio_dev);
const struct spi_device_id *id = spi_get_device_id(spi);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
if (id->driver_data == max1118)
return regulator_disable(adc->reg);
return 0;
}
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static const struct spi_device_id max1118_id[] = {
{ "max1117", max1117 },
{ "max1118", max1118 },
{ "max1119", max1119 },
{}
};
MODULE_DEVICE_TABLE(spi, max1118_id);
#ifdef CONFIG_OF
static const struct of_device_id max1118_dt_ids[] = {
{ .compatible = "maxim,max1117" },
{ .compatible = "maxim,max1118" },
{ .compatible = "maxim,max1119" },
{},
};
MODULE_DEVICE_TABLE(of, max1118_dt_ids);
#endif
static struct spi_driver max1118_spi_driver = {
.driver = {
.name = "max1118",
.of_match_table = of_match_ptr(max1118_dt_ids),
},
.probe = max1118_probe,
.remove = max1118_remove,
.id_table = max1118_id,
};
module_spi_driver(max1118_spi_driver);
MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
MODULE_DESCRIPTION("MAXIM MAX1117/MAX1118/MAX1119 ADCs driver");
MODULE_LICENSE("GPL v2");
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