307 lines
6.9 KiB
C
307 lines
6.9 KiB
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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
static const struct iio_info max1118_info = {
|
|
.read_raw = max1118_read_raw,
|
|
};
|
|
|
|
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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
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");
|