Re: [PATCH 2/2] iio: temperature: add driver support for ti tmp117

Lars-Peter Clausen
2021-03-19T22:03:34Z

On 3/19/21 9:30 PM, Puranjay Mohan wrote:
> TMP117 is a Digital temperature sensor with integrated NV memory.
>
> Add support for tmp117 driver in iio subsystem.
>
> Datasheet:-https://www.ti.com/lit/gpn/tmp117
>
> Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>

Hi,

Thanks for the patch, this looks really good. I have a couple of small
comments inline.

And one general comment. What you have implemented as
IIO_CHAN_INFO_OFFSET should be IIO_CHAN_INFO_CALIBBIAS, since it is an
offset for calibration. The IIO_CHAN_INFO_OFFSET property on the other
hand is used to describe how to convert from raw data to SI units.

> ---
> drivers/iio/temperature/Kconfig | 11 ++
> drivers/iio/temperature/Makefile | 1 +
> drivers/iio/temperature/tmp117.c | 196 +++++++++++++++++++++++++++++++
> 3 files changed, 208 insertions(+)
> create mode 100644 drivers/iio/temperature/tmp117.c
>
> diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
> index 3f11ed870..200efc880 100644
> --- a/drivers/iio/temperature/Kconfig
> +++ b/drivers/iio/temperature/Kconfig
> @@ -86,6 +86,17 @@ config TMP007
> This driver can also be built as a module. If so, the module will
> be called tmp007.
>
> +config TMP117
> + tristate "TMP117 Digital temperature sensor with integrated NV memory"
> + depends on I2C
> + help
> + If you say yes here you get support for the Texas Instruments
> + TMP117 Digital temperature sensor with integrated NV memory.
> +
> + This driver can also be built as a module. If so, the module will
> + be called tmp117.
> +
> +
> config TSYS01
> tristate "Measurement Specialties TSYS01 temperature sensor using I2C bus connection"
> depends on I2C
> diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
> index e4e0bad5a..7f2a95ed2 100644
> --- a/drivers/iio/temperature/Makefile
> +++ b/drivers/iio/temperature/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_MLX90614) += mlx90614.o
> obj-$(CONFIG_MLX90632) += mlx90632.o
> obj-$(CONFIG_TMP006) += tmp006.o
> obj-$(CONFIG_TMP007) += tmp007.o
> +obj-$(CONFIG_TMP117) += tmp117.o
> obj-$(CONFIG_TSYS01) += tsys01.o
> obj-$(CONFIG_TSYS02D) += tsys02d.o
> obj-$(CONFIG_LTC2983) += ltc2983.o
> diff --git a/drivers/iio/temperature/tmp117.c b/drivers/iio/temperature/tmp117.c
> new file mode 100644
> index 000000000..15cdf590e
> --- /dev/null
> +++ b/drivers/iio/temperature/tmp117.c
> @@ -0,0 +1,196 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * tmp117.c - Digital temperature sensor with integrated NV memory
> + *
> + * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
> + *
> + * Driver for the Texas Instruments TMP117 Temperature Sensor
> + *
> + * (7-bit I2C slave address (0x48 - 0x4B), changeable via ADD pins)
> + *
> + * Note: This driver assumes that the sensor has been calibrated beforehand.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/pm.h>
> +#include <linux/bitops.h>
> +#include <linux/of.h>
> +#include <linux/irq.h>
> +#include <linux/interrupt.h>

interrupt.h is for consumers, irq.h is for providers. Since this driver
is only a interrupt consumer you only need irq.h.

I believe bitops.h and delay.h are also not needed by this driver.

> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/events.h>
> +
> +#define TMP117_REG_TEMP 0x0
> +#define TMP117_REG_CFGR 0x1
> +#define TMP117_REG_HIGH_LIM 0x2
> +#define TMP117_REG_LOW_LIM 0x3
> +#define TMP117_REG_EEPROM_UL 0x4
> +#define TMP117_REG_EEPROM1 0x5
> +#define TMP117_REG_EEPROM2 0x6
> +#define TMP117_REG_EEPROM3 0x7
> +#define TMP117_REG_TEMP_OFFSET 0x7

You got register 0x7 twice here.

> +#define TMP117_REG_EEPROM4 0x8
> +#define TMP117_REG_DEVICE_ID 0xF
> +
> +#define TMP117_RESOLUTION 78125 /* in tens of uCelsius*/
> +#define TMP117_RESOLUTION_DIV 10000000
> +
> +#define TMP117_DEVICE_ID 0x0117
> +
> +struct tmp117_data {
> + struct i2c_client *client;
> + struct mutex lock;
> +};
> +
> +static int tmp117_read_reg(struct tmp117_data *data, u8 reg)
> +{
> +
Being pedantic: the newline at the top here and also in write_reg are
not needed.
> + return i2c_smbus_read_word_swapped(data->client, reg);
> +}
> +
> +static int tmp117_write_reg(struct tmp117_data *data, u8 reg, int val)
> +{
> +
> + return i2c_smbus_write_word_swapped(data->client, reg, val);
> +}
> +
> +static int tmp117_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *channel, int *val,
> + int *val2, long mask)
> +{
> + struct tmp117_data *data = iio_priv(indio_dev);
> + u16 tmp, off;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_PROCESSED:
> + tmp = tmp117_read_reg(data, TMP117_REG_TEMP);
> + *val = ((int16_t)tmp * (int32_t)TMP117_RESOLUTION) / 10000000;
> + *val2 = ((int16_t)tmp * (int32_t)TMP117_RESOLUTION) % 10000000;
Since this is a linear transform it would be better to report RAW
measurements and then provide the scale attribute for conversion,.
> + return IIO_VAL_INT_PLUS_MICRO;
> +
> + case IIO_CHAN_INFO_OFFSET:
> + off = tmp117_read_reg(data, TMP117_REG_TEMP_OFFSET);
> + *val = ((int16_t)off * (int32_t)TMP117_RESOLUTION) / 10000000;
> + *val2 = ((int16_t)off * (int32_t)TMP117_RESOLUTION) % 10000000;
> + return IIO_VAL_INT_PLUS_MICRO;
> +
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int tmp117_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *channel, int val,
> + int val2, long mask)
> +{
> + struct tmp117_data *data = iio_priv(indio_dev);
> + u16 off;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_OFFSET:
> + off = ((val * 10000000) + (val2 * 10))
> + / (int32_t)TMP117_RESOLUTION;
> + return tmp117_write_reg(data, TMP117_REG_TEMP_OFFSET, off);
> +
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct iio_chan_spec tmp117_channels[] = {
> + {
> + .type = IIO_TEMP,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
> + BIT(IIO_CHAN_INFO_OFFSET),
> + },
> +};
> +
> +static const struct iio_info tmp117_info = {
> + .read_raw = tmp117_read_raw,
> + .write_raw = tmp117_write_raw,
> +};
> +
> +static bool tmp117_identify(struct i2c_client *client)
> +{
> + int dev_id;
> +
> + dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID);
> + if (dev_id < 0)
> + return false;
> +
> + return (dev_id == TMP117_DEVICE_ID);
> +}
> +
> +static int tmp117_probe(struct i2c_client *client,
> + const struct i2c_device_id *tmp117_id)
> +{
> + struct tmp117_data *data;
> + struct iio_dev *indio_dev;
> +
> + if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
> + return -EOPNOTSUPP;
> +
> + if (!tmp117_identify(client)) {
> + dev_err(&client->dev, "TMP117 not found\n");
> + return -ENODEV;
> + }
> +
> + 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);
If you remove the remove() callback the i2c_set_clientdata() here can
also be removed.
> + data->client = client;
> + mutex_init(&data->lock);
> +
> + indio_dev->dev.parent = &client->dev;

The parent assignment is no longer needed in the latest upstream kernel
since it happens in devm_iio_device_alloc().

> + indio_dev->name = "tmp117";
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->info = &tmp117_info;
> +
> + indio_dev->channels = tmp117_channels;
> + indio_dev->num_channels = ARRAY_SIZE(tmp117_channels);
> +
> + return iio_device_register(indio_dev);
devm_iio_device_register(...) and then you can remove the the remove()
callback.
> +}
> +
> …