Re: [PATCH] iio: Add tmp006 IR temperature sensor

[Grygorii Strashko <grygorii.strashko@ti.com>]

Hi Peter,

On 08/04/2013 01:39 PM, Jonathan Cameron wrote:
> On 07/29/13 23:28, Peter Meerwald wrote:
>> the TI TMP006 is a non-contact temperature sensor with I2C interface;
>> it measures the surface temperature of a distance object using a
>> thermophile to absorb IR energy emitted from the object
>>

s/thermophile/Thermopile

Also, it'd nice to add link on DS:
- http://www.ti.com/lit/ds/symlink/tmp006.pdf

Few comments inlined.

>> the sensor has two channels: IR sensor voltage (16-bit) and reference
>> temperature of the chip (14-bit)
> Couple of nitpicks inline.
>
> I've cc'd lmsensors mostly to let them know I'm intending to take this into
> IIO.  It's clearly unconventional enough I would imagine it isn't going
> to get often used for hardware monitoring/
> Best to keep everyone informed (and check no one has strong views on
> this!)  We do have iio-hwmon these days if anyone does need that
> functionality.
>
> Jonathan
>>
>> Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
>> ---
>>   drivers/iio/Kconfig              |   1 +
>>   drivers/iio/Makefile             |   1 +
>>   drivers/iio/temperature/Kconfig  |  16 +++
>>   drivers/iio/temperature/Makefile |   5 +
>>   drivers/iio/temperature/tmp006.c | 288 +++++++++++++++++++++++++++++++++++++++
>>   5 files changed, 311 insertions(+)
>>   create mode 100644 drivers/iio/temperature/Kconfig
>>   create mode 100644 drivers/iio/temperature/Makefile
>>   create mode 100644 drivers/iio/temperature/tmp006.c
>>
>> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
>> index b682f6f..f3a4303 100644
>> --- a/drivers/iio/Kconfig
>> +++ b/drivers/iio/Kconfig
>> @@ -80,5 +80,6 @@ if IIO_TRIGGER
>>      source "drivers/iio/trigger/Kconfig"
>>   endif #IIO_TRIGGER
>>   source "drivers/iio/pressure/Kconfig"
>> +source "drivers/iio/temperature/Kconfig"
>>
>>   endif # IIO
>> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
>> index 6e43e5b..62a08a8 100644
>> --- a/drivers/iio/Makefile
>> +++ b/drivers/iio/Makefile
>> @@ -25,3 +25,4 @@ obj-y += light/
>>   obj-y += magnetometer/
>>   obj-y += trigger/
>>   obj-y += pressure/
>> +obj-y += temperature/
> ouch, we seem to have lost ordering in here...
> Do the best you can (eg. above trigger and we will get pressure moved to the right
> place).
>> diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
>> new file mode 100644
>> index 0000000..85506bb
>> --- /dev/null
>> +++ b/drivers/iio/temperature/Kconfig
>> @@ -0,0 +1,16 @@
>> +#
>> +# Temperature sensor drivers
>> +#
>> +menu "Temperature sensors"
>> +
>> +config TMP006
>> +	tristate "TMP006 infrared thermophile sensor"
>> +	depends on I2C
>> +	help
>> +	  If you say yes here you get support for the Texas Instruments
>> +	  TMP006 infrared thermophile sensor.
>> +
>> +	  This driver can also be built as a module. If so, the module will
>> +	  be called tmp006.
>> +
>> +endmenu
>> diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
>> new file mode 100644
>> index 0000000..24d7b60
>> --- /dev/null
>> +++ b/drivers/iio/temperature/Makefile
>> @@ -0,0 +1,5 @@
>> +#
>> +# Makefile for industrial I/O temperature drivers
>> +#
>> +
>> +obj-$(CONFIG_TMP006) += tmp006.o
>> diff --git a/drivers/iio/temperature/tmp006.c b/drivers/iio/temperature/tmp006.c
>> new file mode 100644
>> index 0000000..fca1ca0
>> --- /dev/null
>> +++ b/drivers/iio/temperature/tmp006.c
>> @@ -0,0 +1,288 @@
>> +/*
>> + * tmp006.c - Support for TI TMP006 IR thermophile sensor
>> + *
>> + * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
>> + *
>> + * This file is subject to the terms and conditions of version 2 of
>> + * the GNU General Public License.  See the file COPYING in the main
>> + * directory of this archive for more details.
>> + *
>> + * Driver for the Texas Instruments I2C 16-bit IR thermophile sensor
>> + *
>> + * (7-bit I2C slave address 0x40, changeable via ADR pins)
>> + *
>> + * TODO: data ready irq
>> + */
>> +
>> +#include <linux/err.h>
>> +#include <linux/i2c.h>
>> +#include <linux/delay.h>
>> +#include <linux/module.h>
>> +
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/sysfs.h>
>> +
>> +#define TMP006_VOBJECT 0x00
>> +#define TMP006_TAMBIENT 0x01
>> +#define TMP006_CONFIG 0x02
>> +#define TMP006_MANUFACTURER_ID 0xfe
>> +#define TMP006_DEVICE_ID 0xff
>> +
>> +#define TMP006_CONFIG_RESET BIT(15)
>> +#define TMP006_CONFIG_DRDY_EN BIT(8)
>> +#define TMP006_CONFIG_DRDY BIT(7)
>> +
>> +#define TMP006_CONFIG_MOD_MASK 0x7000
>> +
>> +#define TMP006_CONFIG_CR_MASK 0x0e00
>> +#define TMP006_CONFIG_CR_SHIFT 9
>> +
>> +#define MANUFACTURER_MAGIC 0x5449
>> +#define DEVICE_MAGIC 0x0067
>> +
>> +struct tmp006_data {
>> +	struct i2c_client *client;
>> +	u16 config;
>> +};
>> +
>> +static int tmp006_read_measurement(struct tmp006_data *data, u8 reg)
>> +{
>> +	s32 ret;
>> +	int tries = 50;
>> +
>> +	while (tries-- > 0) {
>> +		ret = i2c_smbus_read_word_swapped(data->client,
>> +			TMP006_CONFIG);
>> +		if (ret < 0)
>> +			return ret;
>> +		if (ret & TMP006_CONFIG_DRDY)
>> +			break;
>> +		msleep(100);
>> +	}
>> +
>> +	if (tries < 0)
>> +		return -EIO;
>> +
>> +	return i2c_smbus_read_word_swapped(data->client, reg);
>> +}
>> +
>> +static int tmp006_read_raw(struct iio_dev *indio_dev,
>> +			    struct iio_chan_spec const *channel, int *val,
>> +			    int *val2, long mask)
>> +{
>> +	struct tmp006_data *data = iio_priv(indio_dev);
>> +	s32 ret;
>> +
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_RAW:
>> +		if (channel->type == IIO_VOLTAGE) {
>> +			ret = tmp006_read_measurement(data, TMP006_VOBJECT);
>> +			if (ret < 0)
>> +				return ret;
>> +			*val = (s16) ret;
> I would marginally prefer you used sign_extend32 to do this (little
> bit clearer what is going on).
>> +		} else if (channel->type == IIO_TEMP) {
>> +			ret = tmp006_read_measurement(data, TMP006_TAMBIENT);
>> +			if (ret < 0)
>> +				return ret;
>> +			*val = (s16) ret >> 2;

Could you use define TMP006_TEMP_VAL_SHIFT instead of magic number
here, pls?

>> +		} else
>> +			break;
>> +		return IIO_VAL_INT;
>> +	case IIO_CHAN_INFO_SCALE:
>> +		if (channel->type == IIO_VOLTAGE) {
>> +			*val = 0;
>> +			*val2 = 156250;
>> +		} else if (channel->type == IIO_TEMP) {
>> +			*val = 31;
>> +			*val2 = 250000;
>> +		} else
>> +			break;

I think, it'd good to have some information here (or in the commit
message) about Raw to Scaled values conversation.

Smth. like this, T_RAW_LSB=0.03125C degrees Celsius
T_Scaled = T_RAW * 31 + T_RAW * 250000 / 1000000 milli degrees Celsius

>> +		return IIO_VAL_INT_PLUS_MICRO;
>> +	default:
>> +		break;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static const char * const tmp006_freqs[] = { "4", "2", "1", "0.5", "0.25" };
>> +
>> +static ssize_t tmp006_show_freq(struct device *dev,
>> +				struct device_attribute *attr, char *buf)
>> +{
>> +	struct tmp006_data *data = iio_priv(dev_to_iio_dev(dev));
>> +	int cr = (data->config & TMP006_CONFIG_CR_MASK)
>> +		>> TMP006_CONFIG_CR_SHIFT;
>> +	return sprintf(buf, "%s\n", tmp006_freqs[cr]);
>> +}
>> +
>> +static ssize_t tmp006_store_freq(struct device *dev,
>> +				 struct device_attribute *attr,
>> +				 const char *buf, size_t len)
>> +{
>> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>> +	struct tmp006_data *data = iio_priv(indio_dev);
>> +	int i;
>> +	bool found = false;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(tmp006_freqs); i++)
>> +		if (sysfs_streq(buf, tmp006_freqs[i])) {
>> +			found = true;
>> +			break;
>> +		}
>> +	if (!found)
>> +		return -EINVAL;
>> +
>> +	data->config &= ~TMP006_CONFIG_CR_MASK;
>> +	data->config |= i << TMP006_CONFIG_CR_SHIFT;
>> +
>> +	return i2c_smbus_write_word_swapped(data->client, TMP006_CONFIG,
>> +		data->config);
>> +}
>> +
>> +static IIO_DEV_ATTR_SAMP_FREQ(S_IRUGO | S_IWUSR,
>> +			tmp006_show_freq, tmp006_store_freq);
>> +
>> +static IIO_CONST_ATTR(sampling_frequency_available, "4 2 1 0.5 0.25");
>> +
>> +static struct attribute *tmp006_attributes[] = {
>> +	&iio_dev_attr_sampling_frequency.dev_attr.attr,
>> +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
>> +	NULL
>> +};
>> +
>> +static const struct attribute_group tmp006_attribute_group = {
>> +	.attrs = tmp006_attributes,
>> +};
>> +
>> +static const struct iio_chan_spec tmp006_channels[] = {
>> +	{
>> +		.type = IIO_VOLTAGE,
>> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>> +			BIT(IIO_CHAN_INFO_SCALE),
>> +	},
> }, { is slightly more compact with no loss of readability.
>> +	{
>> +		.type = IIO_TEMP,
>> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>> +			BIT(IIO_CHAN_INFO_SCALE),
>> +	}
>> +};
>> +
>> +static const struct iio_info tmp006_info = {
>> +	.read_raw = tmp006_read_raw,
>> +	.attrs = &tmp006_attribute_group,
>> +	.driver_module = THIS_MODULE,
>> +};
>> +
>> +static bool tmp006_check_identification(struct tmp006_data *data)
>> +{
>> +	int mid, did;
>> +
>> +	mid = i2c_smbus_read_word_swapped(data->client,
>> +		TMP006_MANUFACTURER_ID);
>> +	if (mid < 0)
>> +		return false;
>> +
>> +	did = i2c_smbus_read_word_swapped(data->client, TMP006_DEVICE_ID);
>> +	if (did < 0)
>> +		return false;
>> +
>> +	if (mid != MANUFACTURER_MAGIC || did != DEVICE_MAGIC)
>> +		return false;
>> +
>> +	return true;
>> +}
>> +
>> +static int tmp006_probe(struct i2c_client *client,
>> +			 const struct i2c_device_id *id)
>> +{
>> +	struct iio_dev *indio_dev;
>> +	struct tmp006_data *data;
>> +	int ret;
>> +
>> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
>> +		return -ENODEV;

In case, if tmp006_check_identification() will accept "struct 
i2c_client" instead of "struct tmp006_data" you'd be able to move tmp006 
identification code here and in such way skip some initialization steps 
in case if tmp106 isn't detected.

>> +
>> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>> +	if (!indio_dev)
>> +		return -ENOMEM;
>> +
>> +	data = iio_priv(indio_dev);
>> +	i2c_set_clientdata(client, indio_dev);
>> +	data->client = client;
>> +
>> +	indio_dev->dev.parent = &client->dev;
>> +	indio_dev->name = dev_name(&client->dev);
>> +	indio_dev->modes = INDIO_DIRECT_MODE;
>> +	indio_dev->info = &tmp006_info;
>> +
>> +	indio_dev->channels = tmp006_channels;
>> +	indio_dev->num_channels = ARRAY_SIZE(tmp006_channels);
>> +
>> +	if (!tmp006_check_identification(data)) {
>> +		dev_err(&client->dev, "no TMP006 sensor\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	dev_info(&client->dev, "TMP006 IR thermophile sensor\n");
>> +
>> +	ret = i2c_smbus_read_word_swapped(data->client, TMP006_CONFIG);
>> +	if (ret < 0)
>> +		return ret;
>> +	data->config = ret;
>> +
>> +	ret = iio_device_register(indio_dev);
>> +	if (ret < 0)
>> +		return ret;
> Return ret instead of 0 below and loose this final test.
>> +
>> +	return 0;
>> +}
>> +
>> +static int tmp006_remove(struct i2c_client *client)
>> +{
>> +	iio_device_unregister(i2c_get_clientdata(client));
> blank line.

Power-down??


>> +	return 0;
>> +}
>> +
>> +#ifdef CONFIG_PM_SLEEP
>> +static int tmp006_suspend(struct device *dev)
>> +{
>> +	struct tmp006_data *data = iio_priv(dev_to_iio_dev(dev));
>> +	return i2c_smbus_write_word_swapped(data->client, TMP006_CONFIG,
>> +		data->config & ~TMP006_CONFIG_MOD_MASK);
>> +}
>> +
>> +static int tmp006_resume(struct device *dev)
>> +{
>> +	struct tmp006_data *data = iio_priv(dev_to_iio_dev(dev));
>> +	return i2c_smbus_write_word_swapped(data->client, TMP006_CONFIG,
>> +		data->config | TMP006_CONFIG_MOD_MASK);
>> +}
>> +
>> +static SIMPLE_DEV_PM_OPS(tmp006_pm_ops, tmp006_suspend, tmp006_resume);
>> +#define TMP006_PM_OPS (&tmp006_pm_ops)
>> +#else
>> +#define TMP006_PM_OPS NULL
>> +#endif
>> +
>> +static const struct i2c_device_id tmp006_id[] = {
>> +	{ "tmp006", 0 },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, tmp006_id);
>> +
>> +static struct i2c_driver tmp006_driver = {
>> +	.driver = {
>> +		.name = "tmp006",
>> +		.pm = TMP006_PM_OPS,
>> +		.owner = THIS_MODULE,
>> +	},
>> +	.probe = tmp006_probe,
>> +	.remove = tmp006_remove,
>> +	.id_table = tmp006_id,
>> +};
>> +module_i2c_driver(tmp006_driver);
>> +
>> +MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
>> +MODULE_DESCRIPTION("TI TMP006 IR thermophile sensor driver");
>> +MODULE_LICENSE("GPL");
>>
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Regards,
- grygorii