iio:temperature: Add support for TI TMP007 sensor

This patch adds support for TI TMP007 - 16 bit IR thermopile sensor with integrated Math engine.
Sensor takes care of calculating the object temperature with the help of calibrated constants stored in non-volatile memory,
thereby reducing the calculation overhead.

Signed-off-by: Manivannan Sadhasivam <manivannanece23@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/devicetree/bindings/iio/temperature/tmp007.txt

@@ -0,0 +1,27 @@
+* TI TMP007 - IR thermopile sensor with integrated math engine
+
+Link to datasheet: http://www.ti.com/lit/ds/symlink/tmp007.pdf
+
+Required properties:
+
+  - compatible: should be "ti,tmp007"
+  - reg: the I2C address of the sensor (changeable via ADR pins)
+		------------------------------
+		|ADR1 | ADR0 | Device Address|
+		------------------------------
+		   0      0        0x40
+		   0	  1	   0x41
+		   0	 SDA       0x42
+		   0     SCL       0x43
+		   1      0        0x44
+		   1      1        0x45
+		   1	 SDA	   0x46
+		   1     SCL       0x47
+
+Example:
+
+tmp007@40 {
+        compatible = "ti,tmp007";
+        reg = <0x40>;
+};
+

drivers/iio/temperature/Kconfig

@@ -39,6 +39,16 @@ config TMP006
 	  This driver can also be built as a module. If so, the module will
 	  be called tmp006.
 
+config TMP007
+        tristate "TMP007 infrared thermopile sensor with Integrated Math Engine"
+        depends on I2C
+        help
+          If you say yes here you get support for the Texas Instruments
+          TMP007 infrared thermopile sensor with Integrated Math Engine.
+
+          This driver can also be built as a module. If so, the module will
+          be called tmp007.
+
 config TSYS01
 	tristate "Measurement Specialties TSYS01 temperature sensor using I2C bus connection"
 	depends on I2C

drivers/iio/temperature/Makefile

@@ -5,5 +5,6 @@
 obj-$(CONFIG_MAXIM_THERMOCOUPLE) += maxim_thermocouple.o
 obj-$(CONFIG_MLX90614) += mlx90614.o
 obj-$(CONFIG_TMP006) += tmp006.o
+obj-$(CONFIG_TMP007) += tmp007.o
 obj-$(CONFIG_TSYS01) += tsys01.o
 obj-$(CONFIG_TSYS02D) += tsys02d.o

drivers/iio/temperature/tmp007.c

@@ -0,0 +1,345 @@
+/*
+ * tmp007.c - Support for TI TMP007 IR thermopile sensor with integrated math engine
+ *
+ * Copyright (c) 2017 Manivannan Sadhasivam <manivannanece23@gmail.com>
+ *
+ * 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 thermopile sensor
+ *
+ * (7-bit I2C slave address (0x40 - 0x47), changeable via ADR pins)
+ *
+ * Note: This driver assumes that the sensor has been calibrated beforehand
+ *
+ * TODO: ALERT irq, limit threshold events
+ *
+ */
+
+#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/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define TMP007_TDIE 0x01
+#define TMP007_CONFIG 0x02
+#define TMP007_TOBJECT 0x03
+#define TMP007_STATUS 0x04
+#define TMP007_STATUS_MASK 0x05
+#define TMP007_MANUFACTURER_ID 0x1e
+#define TMP007_DEVICE_ID 0x1f
+
+#define TMP007_CONFIG_CONV_EN BIT(12)
+#define TMP007_CONFIG_COMP_EN BIT(5)
+#define TMP007_CONFIG_TC_EN BIT(6)
+#define TMP007_CONFIG_CR_MASK GENMASK(11, 9)
+#define TMP007_CONFIG_CR_SHIFT 9
+
+#define TMP007_STATUS_CONV_READY BIT(14)
+#define TMP007_STATUS_DATA_VALID BIT(9)
+
+#define TMP007_MANUFACTURER_MAGIC 0x5449
+#define TMP007_DEVICE_MAGIC 0x0078
+
+#define TMP007_TEMP_SHIFT 2
+
+struct tmp007_data {
+	struct i2c_client *client;
+	u16 config;
+};
+
+static const int tmp007_avgs[5][2] = { {4, 0}, {2, 0}, {1, 0},
+					{0, 500000}, {0, 250000} };
+
+static int tmp007_read_temperature(struct tmp007_data *data, u8 reg)
+{
+	s32 ret;
+	int tries = 50;
+
+	while (tries-- > 0) {
+		ret = i2c_smbus_read_word_swapped(data->client,
+			TMP007_STATUS);
+		if (ret < 0)
+			return ret;
+		if ((ret & TMP007_STATUS_CONV_READY) &&
+			!(ret & TMP007_STATUS_DATA_VALID))
+				break;
+		msleep(100);
+	}
+
+	if (tries < 0)
+		return -EIO;
+
+	return i2c_smbus_read_word_swapped(data->client, reg);
+}
+
+static int tmp007_powerdown(struct tmp007_data *data)
+{
+	return i2c_smbus_write_word_swapped(data->client, TMP007_CONFIG,
+			data->config & ~TMP007_CONFIG_CONV_EN);
+}
+
+static int tmp007_read_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *channel, int *val,
+		int *val2, long mask)
+{
+	struct tmp007_data *data = iio_priv(indio_dev);
+	s32 ret;
+	int conv_rate;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (channel->channel2) {
+		case IIO_MOD_TEMP_AMBIENT: /* LSB: 0.03125 degree Celsius */
+			ret = i2c_smbus_read_word_swapped(data->client, TMP007_TDIE);
+			if (ret < 0)
+				return ret;
+			break;
+		case IIO_MOD_TEMP_OBJECT:
+			ret = tmp007_read_temperature(data, TMP007_TOBJECT);
+			if (ret < 0)
+				return ret;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		*val = sign_extend32(ret, 15) >> TMP007_TEMP_SHIFT;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 31;
+		*val2 = 250000;
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		conv_rate = (data->config & TMP007_CONFIG_CR_MASK)
+				>> TMP007_CONFIG_CR_SHIFT;
+		*val = tmp007_avgs[conv_rate][0];
+		*val2 = tmp007_avgs[conv_rate][1];
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int tmp007_write_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *channel, int val,
+		int val2, long mask)
+{
+	struct tmp007_data *data = iio_priv(indio_dev);
+	int i;
+	u16 tmp;
+
+	if (mask == IIO_CHAN_INFO_SAMP_FREQ) {
+		for (i = 0; i < ARRAY_SIZE(tmp007_avgs); i++) {
+			if ((val == tmp007_avgs[i][0]) &&
+			(val2 == tmp007_avgs[i][1])) {
+				tmp = data->config & ~TMP007_CONFIG_CR_MASK;
+				tmp |= (i << TMP007_CONFIG_CR_SHIFT);
+
+				return i2c_smbus_write_word_swapped(data->client,
+								TMP007_CONFIG,
+								data->config = tmp);
+			}
+		}
+	}
+
+	return -EINVAL;
+}
+
+static IIO_CONST_ATTR(sampling_frequency_available, "4 2 1 0.5 0.25");
+
+static struct attribute *tmp007_attributes[] = {
+	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group tmp007_attribute_group = {
+	.attrs = tmp007_attributes,
+};
+
+static const struct iio_chan_spec tmp007_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.modified = 1,
+		.channel2 = IIO_MOD_TEMP_AMBIENT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	},
+	{
+		.type = IIO_TEMP,
+		.modified = 1,
+		.channel2 = IIO_MOD_TEMP_OBJECT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	}
+};
+
+static const struct iio_info tmp007_info = {
+	.read_raw = tmp007_read_raw,
+	.write_raw = tmp007_write_raw,
+	.attrs = &tmp007_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static bool tmp007_identify(struct i2c_client *client)
+{
+	int manf_id, dev_id;
+
+	manf_id = i2c_smbus_read_word_swapped(client, TMP007_MANUFACTURER_ID);
+	if (manf_id < 0)
+		return false;
+
+	dev_id = i2c_smbus_read_word_swapped(client, TMP007_DEVICE_ID);
+	if (dev_id < 0)
+		return false;
+
+	return (manf_id == TMP007_MANUFACTURER_MAGIC && dev_id == TMP007_DEVICE_MAGIC);
+}
+
+static int tmp007_probe(struct i2c_client *client,
+			const struct i2c_device_id *tmp007_id)
+{
+	struct tmp007_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+	u16  status;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+		return -EOPNOTSUPP;
+
+	if (!tmp007_identify(client)) {
+		dev_err(&client->dev, "TMP007 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);
+	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 = &tmp007_info;
+
+	indio_dev->channels = tmp007_channels;
+	indio_dev->num_channels = ARRAY_SIZE(tmp007_channels);
+
+	/*
+	 * Set Configuration register:
+	 * 1. Conversion ON
+	 * 2. Comparator mode
+	 * 3. Transient correction enable
+	 */
+
+	ret = i2c_smbus_read_word_swapped(data->client, TMP007_CONFIG);
+	if (ret < 0)
+		return ret;
+
+	data->config = ret;
+	data->config |= (TMP007_CONFIG_CONV_EN | TMP007_CONFIG_COMP_EN | TMP007_CONFIG_TC_EN);
+
+	ret = i2c_smbus_write_word_swapped(data->client, TMP007_CONFIG,
+					data->config);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Set Status Mask register:
+	 * 1. Conversion ready enable
+	 * 2. Data valid enable
+	 */
+
+	ret = i2c_smbus_read_word_swapped(data->client, TMP007_STATUS_MASK);
+	if (ret < 0)
+		goto error_powerdown;
+
+	status = ret;
+	status |= (TMP007_STATUS_CONV_READY | TMP007_STATUS_DATA_VALID);
+
+	ret = i2c_smbus_write_word_swapped(data->client, TMP007_STATUS_MASK, status);
+	if (ret < 0)
+		goto error_powerdown;
+
+	return iio_device_register(indio_dev);
+
+error_powerdown:
+	tmp007_powerdown(data);
+
+	return ret;
+}
+
+static int tmp007_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct tmp007_data *data = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+	tmp007_powerdown(data);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tmp007_suspend(struct device *dev)
+{
+	struct tmp007_data *data = iio_priv(i2c_get_clientdata(
+			to_i2c_client(dev)));
+
+	return tmp007_powerdown(data);
+}
+
+static int tmp007_resume(struct device *dev)
+{
+	struct tmp007_data *data = iio_priv(i2c_get_clientdata(
+			to_i2c_client(dev)));
+
+	return i2c_smbus_write_word_swapped(data->client, TMP007_CONFIG,
+			data->config | TMP007_CONFIG_CONV_EN);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(tmp007_pm_ops, tmp007_suspend, tmp007_resume);
+
+static const struct of_device_id tmp007_of_match[] = {
+	{ .compatible = "ti,tmp007", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, tmp007_of_match);
+
+static const struct i2c_device_id tmp007_id[] = {
+	{ "tmp007", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tmp007_id);
+
+static struct i2c_driver tmp007_driver = {
+	.driver = {
+		.name	= "tmp007",
+		.of_match_table = of_match_ptr(tmp007_of_match),
+		.pm	= &tmp007_pm_ops,
+	},
+	.probe		= tmp007_probe,
+	.remove		= tmp007_remove,
+	.id_table	= tmp007_id,
+};
+module_i2c_driver(tmp007_driver);
+
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannanece23@gmail.com>");
+MODULE_DESCRIPTION("TI TMP007 IR thermopile sensor driver");
+MODULE_LICENSE("GPL");