On Sun, May 29, 2016 at 12:00 PM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: > On 29/05/16 19:47, Matt Ranostay wrote: >> On Sun, May 29, 2016 at 11:44 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: >>> 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? >> >> Mainly that userspace will have to check the status bit itself to be >> sure a readings is valid. > That's ugly. hmm. Might be worth scrubbing the whole result in the buffer > to make that clear? Not filling the buffer at all will lead to issues so > not sure how best to handle this. > > Long ago we used to put -1 in timestamp fields when we had no way of knowing when > the sample occurred - perhaps something similar here... Works for me. will fix in v3 >> >>>>> + 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
