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

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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@xxxxxxxxx>

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@xxxxxxxxx>
+ *
+ * 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.
+}
+
[...]





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