[PATCH v3 0/2] iio: temperature: add support for tmp117

[PATCH v3 0/2] iio: temperature: add support for tmp117

[Puranjay Mohan]

Add the dt-bindings and the driver for tmp117 sensor.

Changes since v2:
1. Made Calibbias read and write in same units.
2. Add missing includes.
3. Clamp the values before writing to calibbias.
4. Add i2c description to dt-binding example.
5. Remove explicit casting at different places.
Changes since v1:
1. Remove unused headers
2. Add error checking in i2c read/write.
3. Correct DT bindings.
4. Correct implementation to return tmp in milli celcius.
5. Remove unused mutex lock.
6. Modify MAINTAINERS.
Changes since v0:
1. Correct Yaml syntax.
2. Change IIO_CHAN_INFO_OFFSET to IIO_CHAN_INFO_CALIBBIAS.
3. Implement IIO_CHAN_INFO_SCALE.
4. Use devm_iio_device_register().
5. Remove unused headers like delay.h

Puranjay Mohan (2):
  dt-bindings: iio: temperature: Add DT bindings for TMP117
  iio: temperature: add driver support for ti tmp117

 .../bindings/iio/temperature/ti,tmp117.yaml   |  41 ++++
 MAINTAINERS                                   |   7 +
 drivers/iio/temperature/Kconfig               |  10 +
 drivers/iio/temperature/Makefile              |   1 +
 drivers/iio/temperature/tmp117.c              | 182 ++++++++++++++++++
 5 files changed, 241 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml
 create mode 100644 drivers/iio/temperature/tmp117.c

-- 
2.30.1

[PATCH v3 1/2] dt-bindings: iio: temperature: Add DT bindings for TMP117

[Puranjay Mohan]

Add devicetree binding document for TMP117, a digital temperature sensor.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
---
 .../bindings/iio/temperature/ti,tmp117.yaml   | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml

diff --git a/Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml b/Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml
new file mode 100644
index 000000000..347bc16a4
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/iio/temperature/ti,tmp117.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: "TI TMP117 - Digital temperature sensor with integrated NV memory"
+
+description: |
+    TI TMP117 - Digital temperature sensor with integrated NV memory that supports
+    I2C interface.
+      https://www.ti.com/lit/gpn/tmp1
+
+maintainers:
+  - Puranjay Mohan <puranjay12@gmail.com>
+
+properties:
+  compatible:
+    enum:
+      - ti,tmp117
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        tmp117@48 {
+             compatible = "ti,tmp117";
+             reg = <0x48>;
+        };
+    };
-- 
2.30.1

[PATCH v3 2/2] iio: temperature: add driver support for ti tmp117

[Puranjay Mohan]

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>
---
 MAINTAINERS                      |   7 ++
 drivers/iio/temperature/Kconfig  |  10 ++
 drivers/iio/temperature/Makefile |   1 +
 drivers/iio/temperature/tmp117.c | 182 +++++++++++++++++++++++++++++++
 4 files changed, 200 insertions(+)
 create mode 100644 drivers/iio/temperature/tmp117.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 60ed2963e..c9b806b63 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16666,6 +16666,13 @@ F:	include/dt-bindings/soc/ti,sci_pm_domain.h
 F:	include/linux/soc/ti/ti_sci_inta_msi.h
 F:	include/linux/soc/ti/ti_sci_protocol.h
 
+TEXAS INSTRUMENTS' TMP117 TEMPERATURE SENSOR DRIVER
+M:	Puranjay Mohan <puranjay12@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml
+F:	drivers/iio/temperature/tmp117.c
+
 THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER
 M:	Hans Verkuil <hverkuil@xs4all.nl>
 L:	linux-media@vger.kernel.org
diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
index f1f2a1499..c5482983f 100644
--- a/drivers/iio/temperature/Kconfig
+++ b/drivers/iio/temperature/Kconfig
@@ -97,6 +97,16 @@ 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 90c113115..e3392c4b2 100644
--- a/drivers/iio/temperature/Makefile
+++ b/drivers/iio/temperature/Makefile
@@ -12,5 +12,6 @@ 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
diff --git a/drivers/iio/temperature/tmp117.c b/drivers/iio/temperature/tmp117.c
new file mode 100644
index 000000000..c3ff2913b
--- /dev/null
+++ b/drivers/iio/temperature/tmp117.c
@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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/module.h>
+#include <linux/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+
+#include <linux/iio/iio.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_TEMP_OFFSET		0x7
+#define TMP117_REG_EEPROM3		0x8
+#define TMP117_REG_DEVICE_ID		0xF
+
+#define TMP117_RESOLUTION_10UC		78125
+#define TMP117_DEVICE_ID		0x0117
+#define MICRODEGREE_PER_10MILLIDEGREE	10000
+
+struct tmp117_data {
+	struct i2c_client *client;
+	s16 calibbias;
+};
+
+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);
+	s32 ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = i2c_smbus_read_word_swapped(data->client,
+						TMP117_REG_TEMP);
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(ret, 15);
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_CALIBBIAS:
+		ret = i2c_smbus_read_word_swapped(data->client,
+					TMP117_REG_TEMP_OFFSET);
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(ret, 15);
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		/* Conversion from 10s of uC to mC
+		 * as IIO reports temperature in mC
+		 */
+		*val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE;
+		*val2 = (TMP117_RESOLUTION_10UC %
+					MICRODEGREE_PER_10MILLIDEGREE) * 100;
+
+		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);
+	s16 off;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_CALIBBIAS:
+		off = clamp(val, -32768, 32767);
+		if (off == data->calibbias)
+			return 0;
+		return i2c_smbus_write_word_swapped(data->client,
+						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_RAW) |
+			BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_SCALE),
+	},
+};
+
+static const struct iio_info tmp117_info = {
+	.read_raw = tmp117_read_raw,
+	.write_raw = tmp117_write_raw,
+};
+
+static int 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 dev_id;
+	if (dev_id != TMP117_DEVICE_ID) {
+		dev_err(&client->dev, "TMP117 not found\n");
+		return -ENODEV;
+	}
+	return 0;
+}
+
+static int tmp117_probe(struct i2c_client *client)
+{
+	struct tmp117_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+		return -EOPNOTSUPP;
+
+	ret = tmp117_identify(client);
+	if (ret < 0)
+		return ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+	data->calibbias = 0;
+
+	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 devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct of_device_id tmp117_of_match[] = {
+	{ .compatible = "ti,tmp117", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tmp117_of_match);
+
+static const struct i2c_device_id tmp117_id[] = {
+	{ "tmp117", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tmp117_id);
+
+static struct i2c_driver tmp117_driver = {
+	.driver = {
+		.name	= "tmp117",
+		.of_match_table = tmp117_of_match,
+	},
+	.probe_new	= tmp117_probe,
+	.id_table	= tmp117_id,
+};
+module_i2c_driver(tmp117_driver);
+
+MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
+MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver");
+MODULE_LICENSE("GPL");
-- 
2.30.1

Re: [PATCH v3 2/2] iio: temperature: add driver support for ti tmp117

[Lars-Peter Clausen]

On 4/6/21 8:28 PM, Puranjay Mohan wrote:
> +
> +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);
> +	s16 off;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_CALIBBIAS:
> +		off = clamp(val, -32768, 32767);
> +		if (off == data->calibbias)

data->calibbias is only set in probe() and always 0. I'm not sure we 
need to cache the value. Reading it back from the device seems fine.

> +			return 0;
> +		return i2c_smbus_write_word_swapped(data->client,
> +						TMP117_REG_TEMP_OFFSET, off);
> +
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +

Re: [PATCH v3 2/2] iio: temperature: add driver support for ti tmp117

[Puranjay Mohan]

On Wed, Apr 7, 2021 at 10:26 AM Lars-Peter Clausen <lars@metafoo.de> wrote:
>
> On 4/6/21 8:28 PM, Puranjay Mohan wrote:
> > +
> > +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);
> > +     s16 off;
> > +
> > +     switch (mask) {
> > +     case IIO_CHAN_INFO_CALIBBIAS:
> > +             off = clamp(val, -32768, 32767);
> > +             if (off == data->calibbias)
>
> data->calibbias is only set in probe() and always 0. I'm not sure we
> need to cache the value. Reading it back from the device seems fine.
I forgot to update it, thanks for finding the bug.
Actually, I wanted to update the calibbias register only if a
different value is being written.
If the same value is written to the device repeatedly then we can save
some I2C writes using this.

and while reading the calibbias, it is read from the device only.
I will fix the bug in the next revision.

>
> > +                     return 0;
> > +             return i2c_smbus_write_word_swapped(data->client,
> > +                                             TMP117_REG_TEMP_OFFSET, off);
> > +
> > +     default:
> > +             return -EINVAL;
> > +     }
> > +}
> > +
>


-- 
Thanks and Regards

Yours Truly,

Puranjay Mohan