#include <linux/init.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/spi/spi.h>
#include <linux/types.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#define MAXIM_THERMOCOUPLE_DRV_NAME "maxim_thermocouple"
enum {
MAX6675,
MAX31855,
MAX31855K,
MAX31855J,
MAX31855N,
MAX31855S,
MAX31855T,
MAX31855E,
MAX31855R,
};
static const char maxim_tc_types[] = {
'K', '?', 'K', 'J', 'N', 'S', 'T', 'E', 'R'
};
static const struct iio_chan_spec max6675_channels[] = {
{
.type = IIO_TEMP,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE),
.scan_index = 0,
.scan_type = {
.sign = 's',
.realbits = 13,
.storagebits = 16,
.shift = 3,
.endianness = IIO_BE,
},
},
IIO_CHAN_SOFT_TIMESTAMP(1),
};
static const struct iio_chan_spec max31855_channels[] = {
{
.type = IIO_TEMP,
.address = 2,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE),
.scan_index = 0,
.scan_type = {
.sign = 's',
.realbits = 14,
.storagebits = 16,
.shift = 2,
.endianness = IIO_BE,
},
},
{
.type = IIO_TEMP,
.address = 0,
.channel2 = IIO_MOD_TEMP_AMBIENT,
.modified = 1,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 1,
.scan_type = {
.sign = 's',
.realbits = 12,
.storagebits = 16,
.shift = 4,
.endianness = IIO_BE,
},
},
IIO_CHAN_SOFT_TIMESTAMP(2),
};
static const unsigned long max31855_scan_masks[] = {0x3, 0};
struct maxim_thermocouple_chip {
const struct iio_chan_spec *channels;
const unsigned long *scan_masks;
u8 num_channels;
u8 read_size;
u32 status_bit;
};
static const struct maxim_thermocouple_chip maxim_thermocouple_chips[] = {
[MAX6675] = {
.channels = max6675_channels,
.num_channels = ARRAY_SIZE(max6675_channels),
.read_size = 2,
.status_bit = BIT(2),
},
[MAX31855] = {
.channels = max31855_channels,
.num_channels = ARRAY_SIZE(max31855_channels),
.read_size = 4,
.scan_masks = max31855_scan_masks,
.status_bit = BIT(16),
},
};
struct maxim_thermocouple_data {
struct spi_device *spi;
const struct maxim_thermocouple_chip *chip;
char tc_type;
struct {
union {
__be16 raw16;
__be32 raw32;
__be16 raw[2];
};
aligned_s64 timestamp;
} buffer __aligned(IIO_DMA_MINALIGN);
};
static int maxim_thermocouple_read(struct maxim_thermocouple_data *data,
struct iio_chan_spec const *chan, int *val)
{
unsigned int storage_bytes = data->chip->read_size;
unsigned int shift = chan->scan_type.shift + (chan->address * 8);
int ret;
switch (storage_bytes) {
case 2:
ret = spi_read(data->spi, &data->buffer.raw16, storage_bytes);
*val = be16_to_cpu(data->buffer.raw16);
break;
case 4:
ret = spi_read(data->spi, &data->buffer.raw32, storage_bytes);
*val = be32_to_cpu(data->buffer.raw32);
break;
default:
ret = -EINVAL;
}
if (ret)
return ret;
if (*val & data->chip->status_bit)
return -EINVAL;
*val = sign_extend32(*val >> shift, chan->scan_type.realbits - 1);
return 0;
}
static irqreturn_t maxim_thermocouple_trigger_handler(int irq, void *private)
{
struct iio_poll_func *pf = private;
struct iio_dev *indio_dev = pf->indio_dev;
struct maxim_thermocouple_data *data = iio_priv(indio_dev);
int ret;
ret = spi_read(data->spi, data->buffer.raw, data->chip->read_size);
if (!ret) {
iio_push_to_buffers_with_ts(indio_dev, &data->buffer,
sizeof(data->buffer),
iio_get_time_ns(indio_dev));
}
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int maxim_thermocouple_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct maxim_thermocouple_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (!iio_device_claim_direct(indio_dev))
return -EBUSY;
ret = maxim_thermocouple_read(data, chan, val);
iio_device_release_direct(indio_dev);
if (ret)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
switch (chan->channel2) {
case IIO_MOD_TEMP_AMBIENT:
*val = 62;
*val2 = 500000;
return IIO_VAL_INT_PLUS_MICRO;
default:
*val = 250;
return IIO_VAL_INT;
}
case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
*val = data->tc_type;
return IIO_VAL_CHAR;
default:
return -EINVAL;
}
}
static const struct iio_info maxim_thermocouple_info = {
.read_raw = maxim_thermocouple_read_raw,
};
static int maxim_thermocouple_probe(struct spi_device *spi)
{
const struct spi_device_id *id = spi_get_device_id(spi);
struct iio_dev *indio_dev;
struct maxim_thermocouple_data *data;
const int chip_type = (id->driver_data == MAX6675) ? MAX6675 : MAX31855;
const struct maxim_thermocouple_chip *chip =
&maxim_thermocouple_chips[chip_type];
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
indio_dev->info = &maxim_thermocouple_info;
indio_dev->name = MAXIM_THERMOCOUPLE_DRV_NAME;
indio_dev->channels = chip->channels;
indio_dev->available_scan_masks = chip->scan_masks;
indio_dev->num_channels = chip->num_channels;
indio_dev->modes = INDIO_DIRECT_MODE;
data = iio_priv(indio_dev);
data->spi = spi;
data->chip = chip;
data->tc_type = maxim_tc_types[id->driver_data];
ret = devm_iio_triggered_buffer_setup(&spi->dev,
indio_dev, NULL,
maxim_thermocouple_trigger_handler, NULL);
if (ret)
return ret;
if (id->driver_data == MAX31855)
dev_warn(&spi->dev, "generic max31855 ID is deprecated\nplease use more specific part type");
return devm_iio_device_register(&spi->dev, indio_dev);
}
static const struct spi_device_id maxim_thermocouple_id[] = {
{"max6675", MAX6675},
{"max31855", MAX31855},
{"max31855k", MAX31855K},
{"max31855j", MAX31855J},
{"max31855n", MAX31855N},
{"max31855s", MAX31855S},
{"max31855t", MAX31855T},
{"max31855e", MAX31855E},
{"max31855r", MAX31855R},
{ }
};
MODULE_DEVICE_TABLE(spi, maxim_thermocouple_id);
static const struct of_device_id maxim_thermocouple_of_match[] = {
{ .compatible = "maxim,max6675" },
{ .compatible = "maxim,max31855" },
{ .compatible = "maxim,max31855k" },
{ .compatible = "maxim,max31855j" },
{ .compatible = "maxim,max31855n" },
{ .compatible = "maxim,max31855s" },
{ .compatible = "maxim,max31855t" },
{ .compatible = "maxim,max31855e" },
{ .compatible = "maxim,max31855r" },
{ },
};
MODULE_DEVICE_TABLE(of, maxim_thermocouple_of_match);
static struct spi_driver maxim_thermocouple_driver = {
.driver = {
.name = MAXIM_THERMOCOUPLE_DRV_NAME,
.of_match_table = maxim_thermocouple_of_match,
},
.probe = maxim_thermocouple_probe,
.id_table = maxim_thermocouple_id,
};
module_spi_driver(maxim_thermocouple_driver);
MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
MODULE_DESCRIPTION("Maxim thermocouple sensors");
MODULE_LICENSE("GPL");
