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. >>> + 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
