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Message-ID: <20150803231302.GK15004@beef>
Date: Mon, 3 Aug 2015 19:13:02 -0400
From: Matt Porter <mporter@...sulko.com>
To: Peter Meerwald <pmeerw@...erw.net>
Cc: Linux IIO List <linux-iio@...r.kernel.org>,
Jonathan Cameron <jic23@...nel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/3] iio: temperature: add max6675 thermocouple converter
driver
On Mon, Aug 03, 2015 at 11:26:12PM +0200, Peter Meerwald wrote:
> On Mon, 3 Aug 2015, Matt Porter wrote:
>
> > Add a driver for the MAX6675 thermocouple converter. This
> > device interfaces with K-type thermocouples and provides
> > cold-junction compensated temperature readings via a
> > SPI interface.
>
> comments below
Thanks for the fast turnaround on the review! Will incorporate
the comments into v2 as noted below.
> > Signed-off-by: Matt Porter <mporter@...sulko.com>
> > ---
> > drivers/iio/temperature/Kconfig | 11 +++
> > drivers/iio/temperature/Makefile | 1 +
> > drivers/iio/temperature/max6675.c | 155 ++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 167 insertions(+)
> > create mode 100644 drivers/iio/temperature/max6675.c
> >
> > diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
> > index 21feaa4..b73fbf4 100644
> > --- a/drivers/iio/temperature/Kconfig
> > +++ b/drivers/iio/temperature/Kconfig
> > @@ -3,6 +3,17 @@
> > #
> > menu "Temperature sensors"
> >
> > +config MAX6675
> > + tristate "MAX6675 thermocouple converter"
> > + depends on SPI
> > + help
> > + If you say yes here you get support for the Maxim
> > + MAX6675 thermocouple converter connected with SPI.
> > +
> > + This driver can also be built as a module. If so, the module will
> > + be called max6675.
> > +
>
> extra newline
Ok
>
> > +
> > config MLX90614
> > tristate "MLX90614 contact-less infrared sensor"
> > depends on I2C
> > diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
> > index 40710a8..d67ef40 100644
> > --- a/drivers/iio/temperature/Makefile
> > +++ b/drivers/iio/temperature/Makefile
> > @@ -2,5 +2,6 @@
> > # Makefile for industrial I/O temperature drivers
> > #
> >
> > +obj-$(CONFIG_MAX6675) += max6675.o
> > obj-$(CONFIG_MLX90614) += mlx90614.o
> > obj-$(CONFIG_TMP006) += tmp006.o
> > diff --git a/drivers/iio/temperature/max6675.c b/drivers/iio/temperature/max6675.c
> > new file mode 100644
> > index 0000000..2d1fda2
> > --- /dev/null
> > +++ b/drivers/iio/temperature/max6675.c
> > @@ -0,0 +1,155 @@
> > +/*
> > + * max6675.c - MAX6675 thermocouple converter driver
> > + *
> > + * Copyright (C) 2015 Konsulko Group, Matt Porter <mporter@...sulko.com>
> > + *
> > + * 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/acpi.h>
> > +#include <linux/init.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/spi/spi.h>
> > +
> > +struct max6675_state {
> > + struct spi_device *spi;
> > +};
> > +
> > +static const struct iio_chan_spec max6675_channels[] = {
> > + {
> > + .type = IIO_TEMP,
> > + .info_mask_separate =
> > + BIT(IIO_CHAN_INFO_RAW) |
> > + BIT(IIO_CHAN_INFO_SCALE),
> > + },
> > +};
> > +
> > +static int max6675_read(struct max6675_state *st, int *val)
> > +{
> > + int ret;
> > +
> > + ret = spi_read(st->spi, val, 2);
> > + if (ret < 0)
> > + return ret;
> > +
> > + /* Temperature is bits 14..3 */
> > + *val = (*val >> 3) & 0xfff;
>
> what about endianness conversion?
> use be16_to_cpu()
Ok, will fix.
> > +
> > + return ret;
> > +}
> > +
> > +static int max6675_read_raw(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + int *val,
> > + int *val2,
> > + long m)
> > +{
> > + struct max6675_state *st = iio_priv(indio_dev);
> > + int ret;
> > +
> > + if (m == IIO_CHAN_INFO_RAW) {
> > + *val2 = 0;
>
> no need to set *val2 to 0 when returning VAL_INT
Ok
>
> > + ret = max6675_read(st, val);
> > + if (ret)
> > + return ret;
> > + } else if (m == IIO_CHAN_INFO_SCALE) {
> > + *val = 250;
> > + *val2 = 0;
> > + } else
> > + return -EINVAL;
> > +
> > + return IIO_VAL_INT;
> > +}
> > +
> > +static const struct iio_info max6675_info = {
> > + .driver_module = THIS_MODULE,
> > + .read_raw = &max6675_read_raw,
> > +};
> > +
> > +static int max6675_probe(struct spi_device *spi)
> > +{
> > + struct iio_dev *indio_dev;
> > + struct max6675_state *st;
> > + int ret = 0;
>
> no need to initialize ret
Ok
>
> > +
> > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> > + if (!indio_dev)
> > + return -ENOMEM;
> > +
> > + st = iio_priv(indio_dev);
> > + st->spi = spi;
> > +
> > + spi->mode = SPI_MODE_1;
> > + spi->bits_per_word = 16;
> > +
> > + spi_set_drvdata(spi, indio_dev);
> > +
> > + indio_dev->dev.parent = &spi->dev;
> > + indio_dev->name = spi_get_device_id(spi)->name;
> > + indio_dev->channels = max6675_channels;
> > + indio_dev->num_channels = ARRAY_SIZE(max6675_channels);
> > + indio_dev->modes = INDIO_DIRECT_MODE;
> > + indio_dev->info = &max6675_info;
> > +
> > + ret = iio_device_register(indio_dev);
>
> devm_ and drop _remove()
Ok
>
> > + if (ret < 0)
> > + dev_err(&spi->dev, "unable to register device\n");
> > +
> > + return ret;
> > +}
> > +
> > +static int max6675_remove(struct spi_device *spi)
> > +{
> > + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> > +
> > + iio_device_unregister(indio_dev);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct acpi_device_id max6675_acpi_ids[] = {
> > + { "MXIM6675", 0 },
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(acpi, max6675_acpi_ids);
> > +
> > +static const struct of_device_id max6675_dt_ids[] = {
> > + { .compatible = "maxim,max6675" },
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(of, max6675_dt_ids);
> > +
> > +static const struct spi_device_id max6675_spi_ids[] = {
> > + {"max6675", 0},
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(spi, max6675_spi_ids);
> > +
> > +static struct spi_driver max6675_driver = {
> > + .driver = {
> > + .name = "max6675",
> > + .owner = THIS_MODULE,
> > + .acpi_match_table = ACPI_PTR(max6675_acpi_ids),
> > + .of_match_table = of_match_ptr(max6675_dt_ids),
> > + },
> > + .probe = max6675_probe,
> > + .remove = max6675_remove,
> > + .id_table = max6675_spi_ids,
> > +};
> > +module_spi_driver(max6675_driver);
> > +
> > +MODULE_AUTHOR("Matt Porter <mporter@...sulko.com>");
> > +MODULE_DESCRIPTION("MAX6675 thermocouple converter driver");
> > +MODULE_LICENSE("GPL");
> > +MODULE_ALIAS("spi:max6675");
> >
>
> --
>
> Peter Meerwald
> +43-664-2444418 (mobile)
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