--- /dev/null
+/*
+ * 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");