[v7,1/2] Driver for TI HDC20x0 humidity and temperature sensors

Commit Message

Eugene Zaikonnikov April 26, 2020, 10:18 p.m. UTC

HDC2010/2080 driver and sysfs documentation for its heater element.

Signed-off-by: Eugene Zaikonnikov <[e-mail]>

Comments

Eugene Zaikonnikov April 26, 2020, 10:26 p.m. UTC | #1

Device tree bindings for the HDC2010/2080 driver.

Signed-off-by: Eugene Zaikonnikov <[e-mail]>

diff -uprN linux-5.3.8/Documentation/devicetree/bindings/iio/humidity/ti,hdc2010.yaml linux-5.3.8_docs/Documentation/devicetree/bindings/iio/humidity/ti,hdc2010.yaml
--- linux-5.3.8/Documentation/devicetree/bindings/iio/humidity/ti,hdc2010.yaml	1970-01-01 01:00:00.000000000 +0100
+++ linux-5.3.8_docs/Documentation/devicetree/bindings/iio/humidity/ti,hdc2010.yaml	2020-04-24 17:50:58.213007228 +0200
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/humidity/ti,hdc2010.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: HDC2010/HDC2080 humidity and temperature iio sensors
+
+maintainers:
+  - Eugene Zaikonnikov <[e-mail]>
+
+description: |
+  Relative humidity and tempereature sensors on I2C bus
+
+  Datasheets are available at:
+    http://www.ti.com/product/HDC2010/datasheet
+    http://www.ti.com/product/HDC2080/datasheet
+
+properties:
+  compatible:
+    enum:
+      - ti,hdc2010
+      - ti,hdc2080
+
+  vdd-supply:
+    maxItems: 1
+
+required:
+  - compatible
+
+examples:
+  - |
+    i2c0 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      humidity@40 {
+          compatible = "ti,hdc2010";
+          reg = <0x40>;
+      };
+    };

Peter Meerwald-Stadler April 26, 2020, 10:35 p.m. UTC | #2

On Sun, 26 Apr 2020, Eugene Zalkonnikov wrote:

> HDC2010/2080 driver and sysfs documentation for its heater element.

comments below

> Signed-off-by: Eugene Zaikonnikov <[e-mail]>
> 
> diff -uprN -X linux-5.3.8/Documentation/dontdiff linux-5.3.8/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc2010 linux-5.3.8_hdc2010/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc2010
> --- linux-5.3.8/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc2010	1970-01-01 01:00:00.000000000 +0100
> +++ linux-5.3.8_hdc2010/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc2010	2019-12-02 11:09:25.803326999 +0100
> @@ -0,0 +1,9 @@
> +What:		/sys/bus/iio/devices/iio:deviceX/out_current_heater_raw
> +What:		/sys/bus/iio/devices/iio:deviceX/out_current_heater_raw_available
> +KernelVersion:	5.3.8
> +Contact:	[e-mail]
> +Description:
> +		Controls the heater device within the humidity sensor to get
> +		rid of excess condensation.
> +
> +		Valid control values are 0 = OFF, and 1 = ON.
> diff -uprN -X linux-5.3.8/Documentation/dontdiff linux-5.3.8/drivers/iio/humidity/hdc2010.c linux-5.3.8_hdc2010/drivers/iio/humidity/hdc2010.c
> --- linux-5.3.8/drivers/iio/humidity/hdc2010.c	1970-01-01 01:00:00.000000000 +0100
> +++ linux-5.3.8_hdc2010/drivers/iio/humidity/hdc2010.c	2020-04-24 18:04:48.699251583 +0200
> @@ -0,0 +1,333 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * hdc2010.c - Support for the TI HDC2010 and HDC2080
> + * temperature + relative humidity sensors
> + *
> + * Copyright (C) 2020 Norphonic AS
> + * Author: Eugene Zaikonnikov <[e-mail]>
> + *
> + * Datasheets:
> + * http://www.ti.com/product/HDC2010/datasheet
> + * http://www.ti.com/product/HDC2080/datasheet
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define HDC2010_REG_TEMP_LOW			0x00
> +#define HDC2010_REG_TEMP_HIGH			0x01
> +#define HDC2010_REG_HUMIDITY_LOW		0x02
> +#define HDC2010_REG_HUMIDITY_HIGH		0x03
> +#define HDC2010_REG_INTERRUPT_DRDY		0x04
> +#define HDC2010_REG_TEMP_MAX			0x05
> +#define HDC2010_REG_HUMIDITY_MAX		0x06
> +#define HDC2010_REG_INTERRUPT_EN		0x07
> +#define HDC2010_REG_TEMP_OFFSET_ADJ		0x08
> +#define HDC2010_REG_HUMIDITY_OFFSET_ADJ		0x09
> +#define HDC2010_REG_TEMP_THR_L			0x0a
> +#define HDC2010_REG_TEMP_THR_H			0x0b
> +#define HDC2010_REG_RH_THR_L			0x0c
> +#define HDC2010_REG_RH_THR_H			0x0d
> +#define HDC2010_REG_RESET_DRDY_INT_CONF		0x0e
> +#define HDC2010_REG_MEASUREMENT_CONF		0x0f
> +
> +#define HDC2010_MEAS_CONF			GENMASK(2, 1)
> +#define HDC2010_MEAS_TRIG			BIT(0)
> +#define HDC2010_HEATER_EN			BIT(3)
> +#define HDC2010_AMM				GENMASK(6, 4)
> +
> +struct hdc2010_data {
> +	struct i2c_client *client;
> +	struct mutex lock;
> +	u8 measurement_config;
> +	u8 interrupt_config;
> +	u8 drdy_config;
> +};
> +
> +enum hdc2010_addr_groups {
> +	HDC2010_GROUP_TEMP = 0,
> +	HDC2010_GROUP_HUMIDITY
> +};
> +
> +struct hdc2010_reg_record {
> +	unsigned long primary;
> +	unsigned long peak;
> +};
> +
> +static const struct hdc2010_reg_record hdc2010_reg_translation[] = {
> +	[HDC2010_GROUP_TEMP] = {
> +		.primary = HDC2010_REG_TEMP_LOW,
> +		.peak = HDC2010_REG_TEMP_MAX,
> +	},
> +	[HDC2010_GROUP_HUMIDITY] = {
> +		.primary = HDC2010_REG_HUMIDITY_LOW,
> +		.peak = HDC2010_REG_HUMIDITY_MAX,
> +	},
> +};
> +
> +static IIO_CONST_ATTR(out_current_heater_raw_available,
> +		"0 1");
> +
> +static struct attribute *hdc2010_attributes[] = {
> +	&iio_const_attr_out_current_heater_raw_available.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group hdc2010_attribute_group = {
> +	.attrs = hdc2010_attributes,
> +};
> +
> +static const struct iio_chan_spec hdc2010_channels[] = {
> +	{
> +		.type = IIO_TEMP,
> +		.address = HDC2010_GROUP_TEMP,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +			BIT(IIO_CHAN_INFO_PEAK) |
> +			BIT(IIO_CHAN_INFO_OFFSET) |
> +			BIT(IIO_CHAN_INFO_SCALE),
> +	},
> +	{
> +		.type = IIO_HUMIDITYRELATIVE,
> +		.address = HDC2010_GROUP_HUMIDITY,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +			BIT(IIO_CHAN_INFO_PEAK) |
> +			BIT(IIO_CHAN_INFO_SCALE),
> +	},
> +	{
> +		.type = IIO_CURRENT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> +		.extend_name = "heater",
> +		.output = 1,
> +	},
> +};
> +
> +static int hdc2010_update_drdy_config(struct hdc2010_data *data,
> +					     char mask, char val)
> +{
> +	char tmp = (~mask & data->drdy_config) | val;

maybe u8 instead of char; drdy_config is u8

> +	int ret;
> +
> +	ret = i2c_smbus_write_byte_data(data->client,
> +					HDC2010_REG_RESET_DRDY_INT_CONF, tmp);
> +	if (!ret)
> +		data->drdy_config = tmp;
> +
> +	return ret;
> +}
> +
> +static int hdc2010_get_prim_measurement_word(struct hdc2010_data *data,
> +					     struct iio_chan_spec const *chan)
> +{
> +	struct i2c_client *client = data->client;
> +	s32 ret;
> +
> +	ret = i2c_smbus_read_word_data(client,
> +			hdc2010_reg_translation[chan->address].primary);
> +
> +	if (ret < 0)
> +		dev_err(&client->dev, "Could not read sensor data\n");

I suggest to use distinct error messages (if you really need them)

> +
> +	return ret;
> +}
> +
> +static int hdc2010_get_peak_measurement_byte(struct hdc2010_data *data,
> +					     struct iio_chan_spec const *chan)
> +{
> +	struct i2c_client *client = data->client;
> +	s32 ret;
> +
> +	ret = i2c_smbus_read_byte_data(client,
> +			hdc2010_reg_translation[chan->address].peak);
> +
> +	if (ret < 0)
> +		dev_err(&client->dev, "Could not read sensor data\n");
> +
> +	return ret;
> +}
> +
> +static int hdc2010_get_heater_status(struct hdc2010_data *data)

return value should be bool?

> +{
> +	return !!(data->drdy_config & HDC2010_HEATER_EN);
> +}
> +
> +static int hdc2010_read_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan, int *val,
> +			    int *val2, long mask)
> +{
> +	struct hdc2010_data *data = iio_priv(indio_dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW: {
> +		int ret;
> +
> +		if (chan->type == IIO_CURRENT) {
> +			*val = hdc2010_get_heater_status(data);
> +			return IIO_VAL_INT;
> +		}
> +		ret = iio_device_claim_direct_mode(indio_dev);
> +		if (ret)
> +			return ret;
> +		mutex_lock(&data->lock);
> +		ret = hdc2010_get_prim_measurement_word(data, chan);
> +		mutex_unlock(&data->lock);
> +		iio_device_release_direct_mode(indio_dev);
> +		if (ret < 0)
> +			return ret;
> +		*val = ret;
> +		return IIO_VAL_INT;
> +	}
> +	case IIO_CHAN_INFO_PEAK: {
> +		int ret;
> +
> +		ret = iio_device_claim_direct_mode(indio_dev);
> +		if (ret)
> +			return ret;
> +		mutex_lock(&data->lock);
> +		ret = hdc2010_get_peak_measurement_byte(data, chan);
> +		mutex_unlock(&data->lock);
> +		iio_device_release_direct_mode(indio_dev);
> +		if (ret < 0)
> +			return ret;
> +		/* Scaling up the value so we can use same offset as RAW */
> +		*val = ret * 256;

I'd rather have different _SCALEs for peak and raw

> +		return IIO_VAL_INT;
> +	}
> +	case IIO_CHAN_INFO_SCALE:
> +		*val2 = 65536;
> +		if (chan->type == IIO_TEMP)
> +			*val = 165000;
> +		else
> +			*val = 100000;
> +		return IIO_VAL_FRACTIONAL;
> +	case IIO_CHAN_INFO_OFFSET:
> +		*val = -15887;
> +		*val2 = 515151;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int hdc2010_write_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int val, int val2, long mask)
> +{
> +	struct hdc2010_data *data = iio_priv(indio_dev);
> +	int new, ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (chan->type != IIO_CURRENT || val2 != 0)
> +			return -EINVAL;
> +
> +		switch (val) {
> +		case 1:
> +			new = HDC2010_HEATER_EN;
> +			break;
> +		case 0:
> +			new = 0;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +
> +		mutex_lock(&data->lock);
> +		ret = hdc2010_update_drdy_config(data, HDC2010_HEATER_EN, new);
> +		mutex_unlock(&data->lock);
> +		return ret;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static const struct iio_info hdc2010_info = {
> +	.read_raw = hdc2010_read_raw,
> +	.write_raw = hdc2010_write_raw,
> +	.attrs = &hdc2010_attribute_group,
> +};
> +
> +static int hdc2010_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct iio_dev *indio_dev;
> +	struct hdc2010_data *data;
> +	u8 tmp;
> +	int ret;
> +
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
> +				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_I2C))
> +		return -EOPNOTSUPP;
> +
> +	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;
> +	mutex_init(&data->lock);
> +
> +	indio_dev->dev.parent = &client->dev;
> +	/*
> +	 * As DEVICE ID register does not differentiate between
> +	 * HDC2010 and HDC2080, we have the name hardcoded
> +	 */
> +	indio_dev->name = "hdc2010";
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &hdc2010_info;
> +
> +	indio_dev->channels = hdc2010_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(hdc2010_channels);
> +
> +	/* Enable Automatic Measurement Mode at 5Hz */
> +	ret = hdc2010_update_drdy_config(data, HDC2010_AMM, HDC2010_AMM);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * We enable both temp and humidity measurement.
> +	 * However the measurement won't start even in AMM until triggered.
> +	 */
> +	tmp = (u8)(data->measurement_config & ~HDC2010_MEAS_CONF) |
> +		HDC2010_MEAS_TRIG;

shouldn't this be disabled when the driver is unloaded?

> +	ret = i2c_smbus_write_byte_data(client,
> +					HDC2010_REG_MEASUREMENT_CONF, tmp);
> +	if (ret)
> +		return ret;
> +	data->measurement_config = tmp;
> +
> +	return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +static const struct i2c_device_id hdc2010_id[] = {
> +	{ "hdc2010" },
> +	{ "hdc2080" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, hdc2010_id);
> +
> +static const struct of_device_id hdc2010_dt_ids[] = {
> +	{ .compatible = "ti,hdc2010" },
> +	{ .compatible = "ti,hdc2080" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, hdc2010_dt_ids);
> +
> +static struct i2c_driver hdc2010_driver = {
> +	.driver = {
> +		.name	= "hdc2010",
> +		.of_match_table = hdc2010_dt_ids,
> +	},
> +	.probe = hdc2010_probe,
> +	.id_table = hdc2010_id,
> +};
> +module_i2c_driver(hdc2010_driver);
> +
> +MODULE_AUTHOR("Eugene Zaikonnikov <[e-mail]>");
> +MODULE_DESCRIPTION("TI HDC2010 humidity and temperature sensor driver");
> +MODULE_LICENSE("GPL");
> diff -uprN -X linux-5.3.8/Documentation/dontdiff linux-5.3.8/drivers/iio/humidity/Kconfig linux-5.3.8_hdc2010/drivers/iio/humidity/Kconfig
> --- linux-5.3.8/drivers/iio/humidity/Kconfig	2019-10-29 09:22:48.000000000 +0100
> +++ linux-5.3.8_hdc2010/drivers/iio/humidity/Kconfig	2019-11-28 14:31:27.794242693 +0100
> @@ -38,6 +38,16 @@ config HDC100X
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called hdc100x.
>  
> +config HDC2010
> +	tristate "TI HDC2010 relative humidity and temperature sensor"
> +	depends on I2C
> +	help
> +	  Say yes here to build support for the Texas Instruments
> +	  HDC2010 and HDC2080 relative humidity and temperature sensors.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called hdc2010.
> +
>  config HID_SENSOR_HUMIDITY
>  	tristate "HID Environmental humidity sensor"
>  	depends on HID_SENSOR_HUB
> diff -uprN -X linux-5.3.8/Documentation/dontdiff linux-5.3.8/drivers/iio/humidity/Makefile linux-5.3.8_hdc2010/drivers/iio/humidity/Makefile
> --- linux-5.3.8/drivers/iio/humidity/Makefile	2019-10-29 09:22:48.000000000 +0100
> +++ linux-5.3.8_hdc2010/drivers/iio/humidity/Makefile	2019-11-28 14:30:40.609892061 +0100
> @@ -6,6 +6,7 @@
>  obj-$(CONFIG_AM2315) += am2315.o
>  obj-$(CONFIG_DHT11) += dht11.o
>  obj-$(CONFIG_HDC100X) += hdc100x.o
> +obj-$(CONFIG_HDC2010) += hdc2010.o
>  obj-$(CONFIG_HID_SENSOR_HUMIDITY) += hid-sensor-humidity.o
>  
>  hts221-y := hts221_core.o \
>

Eugene Zaikonnikov April 27, 2020, 7:57 a.m. UTC | #3

Hi Peter,


On 27.04.2020 00:35, Peter Meerwald-Stadler wrote:
>> +{
>> +	struct i2c_client *client = data->client;
>> +	s32 ret;
>> +
>> +	ret = i2c_smbus_read_byte_data(client,
>> +			hdc2010_reg_translation[chan->address].peak);
>> +
>> +	if (ret < 0)
>> +		dev_err(&client->dev, "Could not read sensor data\n");
>> +
>> +	return ret;
>> +}
>> +
>> +static int hdc2010_get_heater_status(struct hdc2010_data *data)
> return value should be bool?

No idea. It is an int in hdc100x hdc heater sysfs and I try to stick to existing practices.

Should those be bools?

>
>> +	case IIO_CHAN_INFO_PEAK: {
>> +		int ret;
>> +
>> +		ret = iio_device_claim_direct_mode(indio_dev);
>> +		if (ret)
>> +			return ret;
>> +		mutex_lock(&data->lock);
>> +		ret = hdc2010_get_peak_measurement_byte(data, chan);
>> +		mutex_unlock(&data->lock);
>> +		iio_device_release_direct_mode(indio_dev);
>> +		if (ret < 0)
>> +			return ret;
>> +		/* Scaling up the value so we can use same offset as RAW */
>> +		*val = ret * 256;
> I'd rather have different _SCALEs for peak and raw

They are made shared per Jonathan's suggestion early on, as the offsets for the channels don't match.


Regards,

   Eugene.

Jonathan Cameron May 2, 2020, 6:21 p.m. UTC | #4

On Mon, 27 Apr 2020 09:57:49 +0200
Eugene Zaikonnikov <[e-mail]> wrote:

> Hi Peter,
> 
> 
> On 27.04.2020 00:35, Peter Meerwald-Stadler wrote:
> >> +{
> >> +	struct i2c_client *client = data->client;
> >> +	s32 ret;
> >> +
> >> +	ret = i2c_smbus_read_byte_data(client,
> >> +			hdc2010_reg_translation[chan->address].peak);
> >> +
> >> +	if (ret < 0)
> >> +		dev_err(&client->dev, "Could not read sensor data\n");
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static int hdc2010_get_heater_status(struct hdc2010_data *data)  
> > return value should be bool?  
> 
> No idea. It is an int in hdc100x hdc heater sysfs and I try to stick to existing practices.
> 
> Should those be bools?

Locally it would make sense, but then we write them into an int where
they are used, so little point. Probably best to leave them as they are.

> 
> >  
> >> +	case IIO_CHAN_INFO_PEAK: {
> >> +		int ret;
> >> +
> >> +		ret = iio_device_claim_direct_mode(indio_dev);
> >> +		if (ret)
> >> +			return ret;
> >> +		mutex_lock(&data->lock);
> >> +		ret = hdc2010_get_peak_measurement_byte(data, chan);
> >> +		mutex_unlock(&data->lock);
> >> +		iio_device_release_direct_mode(indio_dev);
> >> +		if (ret < 0)
> >> +			return ret;
> >> +		/* Scaling up the value so we can use same offset as RAW */
> >> +		*val = ret * 256;  
> > I'd rather have different _SCALEs for peak and raw  
> 
> They are made shared per Jonathan's suggestion early on, as the offsets for the channels don't match.

Yup. There is no standard ABI to deal with different scales for peak and
raw and I wasn't keen that we introduce it for this relatively rare
corner case.

Jonathan

> 
> 
> Regards,
> 
>    Eugene.
>

Patch

diff -uprN -X linux-5.3.8/Documentation/dontdiff linux-5.3.8/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc2010 linux-5.3.8_hdc2010/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc2010
--- linux-5.3.8/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc2010	1970-01-01 01:00:00.000000000 +0100
+++ linux-5.3.8_hdc2010/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc2010	2019-12-02 11:09:25.803326999 +0100
@@ -0,0 +1,9 @@ 
+What:		/sys/bus/iio/devices/iio:deviceX/out_current_heater_raw
+What:		/sys/bus/iio/devices/iio:deviceX/out_current_heater_raw_available
+KernelVersion:	5.3.8
+Contact:	[e-mail]
+Description:
+		Controls the heater device within the humidity sensor to get
+		rid of excess condensation.
+
+		Valid control values are 0 = OFF, and 1 = ON.
diff -uprN -X linux-5.3.8/Documentation/dontdiff linux-5.3.8/drivers/iio/humidity/hdc2010.c linux-5.3.8_hdc2010/drivers/iio/humidity/hdc2010.c
--- linux-5.3.8/drivers/iio/humidity/hdc2010.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-5.3.8_hdc2010/drivers/iio/humidity/hdc2010.c	2020-04-24 18:04:48.699251583 +0200
@@ -0,0 +1,333 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * hdc2010.c - Support for the TI HDC2010 and HDC2080
+ * temperature + relative humidity sensors
+ *
+ * Copyright (C) 2020 Norphonic AS
+ * Author: Eugene Zaikonnikov <[e-mail]>
+ *
+ * Datasheets:
+ * http://www.ti.com/product/HDC2010/datasheet
+ * http://www.ti.com/product/HDC2080/datasheet
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define HDC2010_REG_TEMP_LOW			0x00
+#define HDC2010_REG_TEMP_HIGH			0x01
+#define HDC2010_REG_HUMIDITY_LOW		0x02
+#define HDC2010_REG_HUMIDITY_HIGH		0x03
+#define HDC2010_REG_INTERRUPT_DRDY		0x04
+#define HDC2010_REG_TEMP_MAX			0x05
+#define HDC2010_REG_HUMIDITY_MAX		0x06
+#define HDC2010_REG_INTERRUPT_EN		0x07
+#define HDC2010_REG_TEMP_OFFSET_ADJ		0x08
+#define HDC2010_REG_HUMIDITY_OFFSET_ADJ		0x09
+#define HDC2010_REG_TEMP_THR_L			0x0a
+#define HDC2010_REG_TEMP_THR_H			0x0b
+#define HDC2010_REG_RH_THR_L			0x0c
+#define HDC2010_REG_RH_THR_H			0x0d
+#define HDC2010_REG_RESET_DRDY_INT_CONF		0x0e
+#define HDC2010_REG_MEASUREMENT_CONF		0x0f
+
+#define HDC2010_MEAS_CONF			GENMASK(2, 1)
+#define HDC2010_MEAS_TRIG			BIT(0)
+#define HDC2010_HEATER_EN			BIT(3)
+#define HDC2010_AMM				GENMASK(6, 4)
+
+struct hdc2010_data {
+	struct i2c_client *client;
+	struct mutex lock;
+	u8 measurement_config;
+	u8 interrupt_config;
+	u8 drdy_config;
+};
+
+enum hdc2010_addr_groups {
+	HDC2010_GROUP_TEMP = 0,
+	HDC2010_GROUP_HUMIDITY
+};
+
+struct hdc2010_reg_record {
+	unsigned long primary;
+	unsigned long peak;
+};
+
+static const struct hdc2010_reg_record hdc2010_reg_translation[] = {
+	[HDC2010_GROUP_TEMP] = {
+		.primary = HDC2010_REG_TEMP_LOW,
+		.peak = HDC2010_REG_TEMP_MAX,
+	},
+	[HDC2010_GROUP_HUMIDITY] = {
+		.primary = HDC2010_REG_HUMIDITY_LOW,
+		.peak = HDC2010_REG_HUMIDITY_MAX,
+	},
+};
+
+static IIO_CONST_ATTR(out_current_heater_raw_available,
+		"0 1");
+
+static struct attribute *hdc2010_attributes[] = {
+	&iio_const_attr_out_current_heater_raw_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group hdc2010_attribute_group = {
+	.attrs = hdc2010_attributes,
+};
+
+static const struct iio_chan_spec hdc2010_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.address = HDC2010_GROUP_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_PEAK) |
+			BIT(IIO_CHAN_INFO_OFFSET) |
+			BIT(IIO_CHAN_INFO_SCALE),
+	},
+	{
+		.type = IIO_HUMIDITYRELATIVE,
+		.address = HDC2010_GROUP_HUMIDITY,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_PEAK) |
+			BIT(IIO_CHAN_INFO_SCALE),
+	},
+	{
+		.type = IIO_CURRENT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.extend_name = "heater",
+		.output = 1,
+	},
+};
+
+static int hdc2010_update_drdy_config(struct hdc2010_data *data,
+					     char mask, char val)
+{
+	char tmp = (~mask & data->drdy_config) | val;
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(data->client,
+					HDC2010_REG_RESET_DRDY_INT_CONF, tmp);
+	if (!ret)
+		data->drdy_config = tmp;
+
+	return ret;
+}
+
+static int hdc2010_get_prim_measurement_word(struct hdc2010_data *data,
+					     struct iio_chan_spec const *chan)
+{
+	struct i2c_client *client = data->client;
+	s32 ret;
+
+	ret = i2c_smbus_read_word_data(client,
+			hdc2010_reg_translation[chan->address].primary);
+
+	if (ret < 0)
+		dev_err(&client->dev, "Could not read sensor data\n");
+
+	return ret;
+}
+
+static int hdc2010_get_peak_measurement_byte(struct hdc2010_data *data,
+					     struct iio_chan_spec const *chan)
+{
+	struct i2c_client *client = data->client;
+	s32 ret;
+
+	ret = i2c_smbus_read_byte_data(client,
+			hdc2010_reg_translation[chan->address].peak);
+
+	if (ret < 0)
+		dev_err(&client->dev, "Could not read sensor data\n");
+
+	return ret;
+}
+
+static int hdc2010_get_heater_status(struct hdc2010_data *data)
+{
+	return !!(data->drdy_config & HDC2010_HEATER_EN);
+}
+
+static int hdc2010_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	struct hdc2010_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW: {
+		int ret;
+
+		if (chan->type == IIO_CURRENT) {
+			*val = hdc2010_get_heater_status(data);
+			return IIO_VAL_INT;
+		}
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+		mutex_lock(&data->lock);
+		ret = hdc2010_get_prim_measurement_word(data, chan);
+		mutex_unlock(&data->lock);
+		iio_device_release_direct_mode(indio_dev);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	}
+	case IIO_CHAN_INFO_PEAK: {
+		int ret;
+
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+		mutex_lock(&data->lock);
+		ret = hdc2010_get_peak_measurement_byte(data, chan);
+		mutex_unlock(&data->lock);
+		iio_device_release_direct_mode(indio_dev);
+		if (ret < 0)
+			return ret;
+		/* Scaling up the value so we can use same offset as RAW */
+		*val = ret * 256;
+		return IIO_VAL_INT;
+	}
+	case IIO_CHAN_INFO_SCALE:
+		*val2 = 65536;
+		if (chan->type == IIO_TEMP)
+			*val = 165000;
+		else
+			*val = 100000;
+		return IIO_VAL_FRACTIONAL;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = -15887;
+		*val2 = 515151;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int hdc2010_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct hdc2010_data *data = iio_priv(indio_dev);
+	int new, ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type != IIO_CURRENT || val2 != 0)
+			return -EINVAL;
+
+		switch (val) {
+		case 1:
+			new = HDC2010_HEATER_EN;
+			break;
+		case 0:
+			new = 0;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		mutex_lock(&data->lock);
+		ret = hdc2010_update_drdy_config(data, HDC2010_HEATER_EN, new);
+		mutex_unlock(&data->lock);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info hdc2010_info = {
+	.read_raw = hdc2010_read_raw,
+	.write_raw = hdc2010_write_raw,
+	.attrs = &hdc2010_attribute_group,
+};
+
+static int hdc2010_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct iio_dev *indio_dev;
+	struct hdc2010_data *data;
+	u8 tmp;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
+				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_I2C))
+		return -EOPNOTSUPP;
+
+	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;
+	mutex_init(&data->lock);
+
+	indio_dev->dev.parent = &client->dev;
+	/*
+	 * As DEVICE ID register does not differentiate between
+	 * HDC2010 and HDC2080, we have the name hardcoded
+	 */
+	indio_dev->name = "hdc2010";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &hdc2010_info;
+
+	indio_dev->channels = hdc2010_channels;
+	indio_dev->num_channels = ARRAY_SIZE(hdc2010_channels);
+
+	/* Enable Automatic Measurement Mode at 5Hz */
+	ret = hdc2010_update_drdy_config(data, HDC2010_AMM, HDC2010_AMM);
+	if (ret)
+		return ret;
+
+	/*
+	 * We enable both temp and humidity measurement.
+	 * However the measurement won't start even in AMM until triggered.
+	 */
+	tmp = (u8)(data->measurement_config & ~HDC2010_MEAS_CONF) |
+		HDC2010_MEAS_TRIG;
+
+	ret = i2c_smbus_write_byte_data(client,
+					HDC2010_REG_MEASUREMENT_CONF, tmp);
+	if (ret)
+		return ret;
+	data->measurement_config = tmp;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id hdc2010_id[] = {
+	{ "hdc2010" },
+	{ "hdc2080" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, hdc2010_id);
+
+static const struct of_device_id hdc2010_dt_ids[] = {
+	{ .compatible = "ti,hdc2010" },
+	{ .compatible = "ti,hdc2080" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, hdc2010_dt_ids);
+
+static struct i2c_driver hdc2010_driver = {
+	.driver = {
+		.name	= "hdc2010",
+		.of_match_table = hdc2010_dt_ids,
+	},
+	.probe = hdc2010_probe,
+	.id_table = hdc2010_id,
+};
+module_i2c_driver(hdc2010_driver);
+
+MODULE_AUTHOR("Eugene Zaikonnikov <[e-mail]>");
+MODULE_DESCRIPTION("TI HDC2010 humidity and temperature sensor driver");
+MODULE_LICENSE("GPL");
diff -uprN -X linux-5.3.8/Documentation/dontdiff linux-5.3.8/drivers/iio/humidity/Kconfig linux-5.3.8_hdc2010/drivers/iio/humidity/Kconfig
--- linux-5.3.8/drivers/iio/humidity/Kconfig	2019-10-29 09:22:48.000000000 +0100
+++ linux-5.3.8_hdc2010/drivers/iio/humidity/Kconfig	2019-11-28 14:31:27.794242693 +0100
@@ -38,6 +38,16 @@  config HDC100X
 	  To compile this driver as a module, choose M here: the module
 	  will be called hdc100x.
 
+config HDC2010
+	tristate "TI HDC2010 relative humidity and temperature sensor"
+	depends on I2C
+	help
+	  Say yes here to build support for the Texas Instruments
+	  HDC2010 and HDC2080 relative humidity and temperature sensors.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called hdc2010.
+
 config HID_SENSOR_HUMIDITY
 	tristate "HID Environmental humidity sensor"
 	depends on HID_SENSOR_HUB
diff -uprN -X linux-5.3.8/Documentation/dontdiff linux-5.3.8/drivers/iio/humidity/Makefile linux-5.3.8_hdc2010/drivers/iio/humidity/Makefile
--- linux-5.3.8/drivers/iio/humidity/Makefile	2019-10-29 09:22:48.000000000 +0100
+++ linux-5.3.8_hdc2010/drivers/iio/humidity/Makefile	2019-11-28 14:30:40.609892061 +0100
@@ -6,6 +6,7 @@ 
 obj-$(CONFIG_AM2315) += am2315.o
 obj-$(CONFIG_DHT11) += dht11.o
 obj-$(CONFIG_HDC100X) += hdc100x.o
+obj-$(CONFIG_HDC2010) += hdc2010.o
 obj-$(CONFIG_HID_SENSOR_HUMIDITY) += hid-sensor-humidity.o
 
 hts221-y := hts221_core.o \