On 03/06/16 13:33, Jonathan Cameron wrote: > 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. Hmm. Deadly silence. Daniel, Lars, Peter - this is a fairly fundamental abi question. What do we do to signify an 'invalid reading' in the buffer. Here the part is driven by a software trigger - and if we skip a reading we are obviously out of sync. Old and nasty trick we used in some (possibly only one) early driver was to set an invalid state for these cases. Anyone have a better idea? Jonathan > >> --- >> >> 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 > -- 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
