On 30/05/16 02:37, Matt Ranostay wrote: > Add initial driver support for MAX6675, and MAX31885 thermocouple chips. > > Cc: Marek Vasut <marex@xxxxxxx> > Cc: Matt Porter <mporter@xxxxxxxxxxxx> > Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx> I'm going to let this sit for a sort while as I'd like some discussion of the invalidate buffer bit. Cc'd a few more people for views. > --- > > Changes from v1: > * switch to iio_device_*_direct_mode wrappers > * add const to structs > * removed useless cast > > Changes from v2: > * mark buffer data invalid on disconnected thermocouple > * add .address = 0 to be consistent > * add missing scan_mask for the max31855 part > > .../iio/temperature/maxim_thermocouple.txt | 21 ++ > drivers/iio/temperature/Kconfig | 14 + > drivers/iio/temperature/Makefile | 1 + > drivers/iio/temperature/maxim_thermocouple.c | 300 +++++++++++++++++++++ > 4 files changed, 336 insertions(+) > create mode 100644 Documentation/devicetree/bindings/iio/temperature/maxim_thermocouple.txt > create mode 100644 drivers/iio/temperature/maxim_thermocouple.c > > diff --git a/Documentation/devicetree/bindings/iio/temperature/maxim_thermocouple.txt b/Documentation/devicetree/bindings/iio/temperature/maxim_thermocouple.txt > new file mode 100644 > index 0000000..44fb029 > --- /dev/null > +++ b/Documentation/devicetree/bindings/iio/temperature/maxim_thermocouple.txt > @@ -0,0 +1,21 @@ > +Maxim thermocouple support > + > +* https://datasheets.maximintegrated.com/en/ds/MAX6675.pdf > +* https://datasheets.maximintegrated.com/en/ds/MAX31855.pdf > + > +Required properties: > + > + - compatible: must be "maxim,max31885" or "maxim,max6675" > + - reg: SPI chip select number for the device > + - spi-max-frequency: must be 4300000 > + - spi-cpha: must be defined for max6675 to enable SPI mode 1 > + > + Refer to spi/spi-bus.txt for generic SPI slave bindings. > + > +Example: > + > + max31885@0 { > + compatible = "maxim,max31885"; > + reg = <0>; > + spi-max-frequency = <4300000>; > + }; > diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig > index c4664e5..c9f5342 100644 > --- a/drivers/iio/temperature/Kconfig > +++ b/drivers/iio/temperature/Kconfig > @@ -3,6 +3,20 @@ > # > menu "Temperature sensors" > > +config MAXIM_THERMOCOUPLE > + tristate "Maxim thermocouple sensors" > + depends on SPI > + help > + If you say yes here you get support for the Maxim series of > + thermocouple sensors connected via SPI. > + > + Supported sensors: > + * MAX6675 > + * MAX31885 > + > + This driver can also be built as a module. If so, the module will > + be called maxim_thermocouple. > + > config MLX90614 > tristate "MLX90614 contact-less infrared sensor" > depends on I2C > diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile > index 02bc79d..78c3de0 100644 > --- a/drivers/iio/temperature/Makefile > +++ b/drivers/iio/temperature/Makefile > @@ -2,6 +2,7 @@ > # Makefile for industrial I/O temperature drivers > # > > +obj-$(CONFIG_MAXIM_THERMOCOUPLE) += maxim_thermocouple.o > obj-$(CONFIG_MLX90614) += mlx90614.o > obj-$(CONFIG_TMP006) += tmp006.o > obj-$(CONFIG_TSYS01) += tsys01.o > diff --git a/drivers/iio/temperature/maxim_thermocouple.c b/drivers/iio/temperature/maxim_thermocouple.c > new file mode 100644 > index 0000000..59ef7fd > --- /dev/null > +++ b/drivers/iio/temperature/maxim_thermocouple.c > @@ -0,0 +1,300 @@ > +/* > + * maxim_thermocouple.c - Support for Maxim thermocouple chips > + * > + * Copyright (C) 2016 Matt Ranostay <mranostay@xxxxxxxxx> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that 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. > + */ > + > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/mutex.h> > +#include <linux/err.h> > +#include <linux/spi/spi.h> > +#include <linux/iio/iio.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, > + MAX31885, > +}; > + > +const struct iio_chan_spec max6675_channels[] = { > + { /* thermocouple temperature */ > + .type = IIO_TEMP, > + .info_mask_separate = > + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), > + .scan_index = 0, > + .scan_type = { > + .sign = 's', > + .realbits = 13, > + .storagebits = 16, > + .shift = 3, > + .endianness = IIO_BE, > + }, > + }, > + IIO_CHAN_SOFT_TIMESTAMP(1), > +}; > + > +const struct iio_chan_spec max31885_channels[] = { > + { /* thermocouple temperature */ > + .type = IIO_TEMP, > + .address = 2, > + .info_mask_separate = > + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), > + .scan_index = 0, > + .scan_type = { > + .sign = 's', > + .realbits = 14, > + .storagebits = 16, > + .shift = 2, > + .endianness = IIO_BE, > + }, > + }, > + { /* cold junction temperature */ > + .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 max31885_scan_masks[] = {0x3, 0}; > + > +struct maxim_thermocouple_chip { > + const struct iio_chan_spec *channels; > + const unsigned long *scan_masks; > + int num_channels; > + int read_size; > + > + /* bit-check for valid input */ > + int status_bit; > +}; > + > +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), > + }, > + [MAX31885] = { > + .channels = max31885_channels, > + .num_channels = ARRAY_SIZE(max31885_channels), > + .read_size = 4, > + .scan_masks = max31885_scan_masks, > + .status_bit = BIT(16), > + }, > +}; > + > +struct maxim_thermocouple_data { > + struct spi_device *spi; > + const struct maxim_thermocouple_chip *chip; > + > + u8 buffer[16]; /* 4 byte data + 4 byte padding + 8 byte timestamp */ > +}; > + > +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); > + unsigned int buf; > + int ret; > + > + ret = spi_read(data->spi, (void *) &buf, storage_bytes); > + if (ret) > + return ret; > + > + switch (storage_bytes) { > + case 2: > + *val = be16_to_cpu(buf); > + break; > + case 4: > + *val = be32_to_cpu(buf); > + break; > + } > + > + /* check to be sure this is a valid reading */ > + if (*val & data->chip->status_bit) > + return -EINVAL; > + > + *val = sign_extend32(*val >> shift, chan->scan_type.realbits - 1); > + > + return 0; > +} > + > +static void maxim_thermocouple_validate_buffer(struct maxim_thermocouple_data *data) > +{ > + unsigned int storage_bytes = data->chip->read_size; > + unsigned int *buf = (unsigned int *) data->buffer; > + int tmp = 0; > + > + switch (storage_bytes) { > + case 2: > + tmp = be16_to_cpu(*buf); > + break; > + case 4: > + tmp = be32_to_cpu(*buf); > + break; > + } > + > + /* check to be sure this is a valid reading, mark result -1 if not */ > + if (tmp & data->chip->status_bit) > + memset(data->buffer, 0xff, storage_bytes); > +} > + > +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, data->chip->read_size); > + if (!ret) { > + maxim_thermocouple_validate_buffer(data); > + iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, > + iio_get_time_ns()); > + } > + > + 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 = -EINVAL; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + if (iio_device_claim_direct_mode(indio_dev)) > + return -EBUSY; > + > + ret = maxim_thermocouple_read(data, chan, val); > + if (!ret) > + ret = IIO_VAL_INT; > + > + iio_device_release_direct_mode(indio_dev); > + break; > + case IIO_CHAN_INFO_SCALE: > + switch (chan->channel2) { > + case IIO_MOD_TEMP_AMBIENT: > + *val = 62; > + *val2 = 500000; /* 1000 * 0.0625 */ > + ret = IIO_VAL_INT_PLUS_MICRO; > + break; > + default: > + *val = 250; /* 1000 * 0.25 */ > + ret = IIO_VAL_INT; > + }; > + break; > + } > + > + return ret; > +} > + > +static const struct iio_info maxim_thermocouple_info = { > + .driver_module = THIS_MODULE, > + .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 struct maxim_thermocouple_chip *chip = > + &maxim_thermocouple_chips[id->driver_data]; > + 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; > + > + ret = iio_triggered_buffer_setup(indio_dev, NULL, > + maxim_thermocouple_trigger_handler, NULL); > + if (ret) > + return ret; > + > + ret = iio_device_register(indio_dev); > + if (ret) > + goto error_unreg_buffer; > + > + return 0; > + > +error_unreg_buffer: > + iio_triggered_buffer_cleanup(indio_dev); > + > + return ret; > +} > + > +static int maxim_thermocouple_remove(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev = spi_get_drvdata(spi); > + > + iio_device_unregister(indio_dev); > + iio_triggered_buffer_cleanup(indio_dev); > + > + return 0; > +} > + > +static const struct spi_device_id maxim_thermocouple_id[] = { > + {"max6675", MAX6675}, > + {"max31885", MAX31885}, > + {}, > +}; > +MODULE_DEVICE_TABLE(spi, maxim_thermocouple_id); > + > +static struct spi_driver maxim_thermocouple_driver = { > + .driver = { > + .name = MAXIM_THERMOCOUPLE_DRV_NAME, > + }, > + .probe = maxim_thermocouple_probe, > + .remove = maxim_thermocouple_remove, > + .id_table = maxim_thermocouple_id, > +}; > +module_spi_driver(maxim_thermocouple_driver); > + > +MODULE_AUTHOR("Matt Ranostay <mranostay@xxxxxxxxx>"); > +MODULE_DESCRIPTION("Maxim thermocouple sensors"); > +MODULE_LICENSE("GPL"); > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
