On 29/05/16 09:16, Peter Meerwald-Stadler wrote: > >> Add initial driver support for MAX6675, and MAX31885 thermocouple chips. > > comments below Not much to add other than a question inline... Jonathan > >> Cc: Marek Vasut <marex@xxxxxxx> >> Cc: Matt Porter <mporter@xxxxxxxxxxxx> >> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx> >> --- >> Changes from v1: >> * switch to iio_device_*_direct_mode wrappers >> * add const to structs >> * removed useless cast >> >> .../iio/temperature/maxim_thermocouple.txt | 21 ++ >> drivers/iio/temperature/Kconfig | 14 ++ >> drivers/iio/temperature/Makefile | 1 + >> drivers/iio/temperature/maxim_thermocouple.c | 273 +++++++++++++++++++++ >> 4 files changed, 309 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..dffe3c2 >> --- /dev/null >> +++ b/drivers/iio/temperature/maxim_thermocouple.c >> @@ -0,0 +1,273 @@ >> +/* >> + * 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, > > .address seems to be used; maybe make it explicit by setting it 0 > >> + .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, >> + .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), >> +}; >> + >> +struct maxim_thermocouple_chip { >> + const struct iio_chan_spec *channels; >> + 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, >> + .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 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; >> + >> + /* userspace HAL must do validation of data pushed to buffers */ Silly question, but what do you mean by this comment? >> + ret = spi_read(data->spi, &data->buffer, data->chip->read_size); > > read_size can be 4 (bytes) but storagebits can be 16?! > >> + if (!ret) >> + 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->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
