iio: Add tmp006 IR temperature sensor

the TI TMP006 is a non-contact temperature sensor with I2C interface;
it measures the surface temperature of a distance object using a
thermopile to absorb IR energy emitted from the object

the sensor has two channels: IR sensor voltage (16-bit) and reference
temperature of the chip (14-bit); datasheet is here:
http://www.ti.com/lit/ds/symlink/tmp006.pdf

v2 (thanks to Grygorii Strashko, Lars-Peter Clausen, Jonathan Cameron
for review comments):
* power down device on driver remove
* use sign_extend32()
* style cleanup
* add comments what channel raw LSBs mean
* spelling of thermopile

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: LM Sensors <lm-sensors@lm-sensors.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

5 files changed, 314 insertions, 0 deletions

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index 524380c9ae6c..cbea3271c1b1 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -73,5 +73,6 @@ if IIO_TRIGGER
    source "drivers/iio/trigger/Kconfig"
 endif #IIO_TRIGGER
 source "drivers/iio/pressure/Kconfig"
+source "drivers/iio/temperature/Kconfig"
 
 endif # IIO
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index 7a3866c2d2a1..a0547f59e88f 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -21,5 +21,6 @@ obj-y += frequency/
 obj-y += imu/
 obj-y += light/
 obj-y += magnetometer/
+obj-y += temperature/
 obj-y += trigger/
 obj-y += pressure/
diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
new file mode 100644
index 000000000000..372f8fb3085f
--- /dev/null
+++ b/drivers/iio/temperature/Kconfig
@@ -0,0 +1,16 @@
+#
+# Temperature sensor drivers
+#
+menu "Temperature sensors"
+
+config TMP006
+        tristate "TMP006 infrared thermopile sensor"
+        depends on I2C
+        help
+          If you say yes here you get support for the Texas Instruments
+          TMP006 infrared thermopile sensor.
+
+          This driver can also be built as a module. If so, the module will
+          be called tmp006.
+
+endmenu
diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
new file mode 100644
index 000000000000..24d7b602db3e
--- /dev/null
+++ b/drivers/iio/temperature/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for industrial I/O temperature drivers
+#
+
+obj-$(CONFIG_TMP006) += tmp006.o
diff --git a/drivers/iio/temperature/tmp006.c b/drivers/iio/temperature/tmp006.c
new file mode 100644
index 000000000000..64ccde3f1f7a
--- /dev/null
+++ b/drivers/iio/temperature/tmp006.c
@@ -0,0 +1,291 @@
+/*
+ * tmp006.c - Support for TI TMP006 IR thermopile sensor
+ *
+ * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
+ *
+ * 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, changeable via ADR pins)
+ *
+ * TODO: data ready irq
+ */
+
+#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/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define TMP006_VOBJECT 0x00
+#define TMP006_TAMBIENT 0x01
+#define TMP006_CONFIG 0x02
+#define TMP006_MANUFACTURER_ID 0xfe
+#define TMP006_DEVICE_ID 0xff
+
+#define TMP006_TAMBIENT_SHIFT 2
+
+#define TMP006_CONFIG_RESET BIT(15)
+#define TMP006_CONFIG_DRDY_EN BIT(8)
+#define TMP006_CONFIG_DRDY BIT(7)
+
+#define TMP006_CONFIG_MOD_MASK 0x7000
+
+#define TMP006_CONFIG_CR_MASK 0x0e00
+#define TMP006_CONFIG_CR_SHIFT 9
+
+#define MANUFACTURER_MAGIC 0x5449
+#define DEVICE_MAGIC 0x0067
+
+struct tmp006_data {
+        struct i2c_client *client;
+        u16 config;
+};
+
+static int tmp006_read_measurement(struct tmp006_data *data, u8 reg)
+{
+        s32 ret;
+        int tries = 50;
+
+        while (tries-- > 0) {
+                ret = i2c_smbus_read_word_swapped(data->client,
+                        TMP006_CONFIG);
+                if (ret < 0)
+                        return ret;
+                if (ret & TMP006_CONFIG_DRDY)
+                        break;
+                msleep(100);
+        }
+
+        if (tries < 0)
+                return -EIO;
+
+        return i2c_smbus_read_word_swapped(data->client, reg);
+}
+
+static int tmp006_read_raw(struct iio_dev *indio_dev,
+                            struct iio_chan_spec const *channel, int *val,
+                            int *val2, long mask)
+{
+        struct tmp006_data *data = iio_priv(indio_dev);
+        s32 ret;
+
+        switch (mask) {
+        case IIO_CHAN_INFO_RAW:
+                if (channel->type == IIO_VOLTAGE) {
+                        /* LSB is 156.25 nV */
+                        ret = tmp006_read_measurement(data, TMP006_VOBJECT);
+                        if (ret < 0)
+                                return ret;
+                        *val = sign_extend32(ret, 15);
+                } else if (channel->type == IIO_TEMP) {
+                        /* LSB is 0.03125 degrees Celsius */
+                        ret = tmp006_read_measurement(data, TMP006_TAMBIENT);
+                        if (ret < 0)
+                                return ret;
+                        *val = sign_extend32(ret, 15) >> TMP006_TAMBIENT_SHIFT;
+                } else {
+                        break;
+                }
+                return IIO_VAL_INT;
+        case IIO_CHAN_INFO_SCALE:
+                if (channel->type == IIO_VOLTAGE) {
+                        *val = 0;
+                        *val2 = 156250;
+                } else if (channel->type == IIO_TEMP) {
+                        *val = 31;
+                        *val2 = 250000;
+                } else {
+                        break;
+                }
+                return IIO_VAL_INT_PLUS_MICRO;
+        default:
+                break;
+        }
+
+        return -EINVAL;
+}
+
+static const char * const tmp006_freqs[] = { "4", "2", "1", "0.5", "0.25" };
+
+static ssize_t tmp006_show_freq(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+        struct tmp006_data *data = iio_priv(dev_to_iio_dev(dev));
+        int cr = (data->config & TMP006_CONFIG_CR_MASK)
+                >> TMP006_CONFIG_CR_SHIFT;
+        return sprintf(buf, "%s\n", tmp006_freqs[cr]);
+}
+
+static ssize_t tmp006_store_freq(struct device *dev,
+                                 struct device_attribute *attr,
+                                 const char *buf, size_t len)
+{
+        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+        struct tmp006_data *data = iio_priv(indio_dev);
+        int i;
+        bool found = false;
+
+        for (i = 0; i < ARRAY_SIZE(tmp006_freqs); i++)
+                if (sysfs_streq(buf, tmp006_freqs[i])) {
+                        found = true;
+                        break;
+                }
+        if (!found)
+                return -EINVAL;
+
+        data->config &= ~TMP006_CONFIG_CR_MASK;
+        data->config |= i << TMP006_CONFIG_CR_SHIFT;
+
+        return i2c_smbus_write_word_swapped(data->client, TMP006_CONFIG,
+                data->config);
+}
+
+static IIO_DEV_ATTR_SAMP_FREQ(S_IRUGO | S_IWUSR,
+                        tmp006_show_freq, tmp006_store_freq);
+
+static IIO_CONST_ATTR(sampling_frequency_available, "4 2 1 0.5 0.25");
+
+static struct attribute *tmp006_attributes[] = {
+        &iio_dev_attr_sampling_frequency.dev_attr.attr,
+        &iio_const_attr_sampling_frequency_available.dev_attr.attr,
+        NULL
+};
+
+static const struct attribute_group tmp006_attribute_group = {
+        .attrs = tmp006_attributes,
+};
+
+static const struct iio_chan_spec tmp006_channels[] = {
+        {
+                .type = IIO_VOLTAGE,
+                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                        BIT(IIO_CHAN_INFO_SCALE),
+        },
+        {
+                .type = IIO_TEMP,
+                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                        BIT(IIO_CHAN_INFO_SCALE),
+        }
+};
+
+static const struct iio_info tmp006_info = {
+        .read_raw = tmp006_read_raw,
+        .attrs = &tmp006_attribute_group,
+        .driver_module = THIS_MODULE,
+};
+
+static bool tmp006_check_identification(struct i2c_client *client)
+{
+        int mid, did;
+
+        mid = i2c_smbus_read_word_swapped(client, TMP006_MANUFACTURER_ID);
+        if (mid < 0)
+                return false;
+
+        did = i2c_smbus_read_word_swapped(client, TMP006_DEVICE_ID);
+        if (did < 0)
+                return false;
+
+        return mid == MANUFACTURER_MAGIC && did == DEVICE_MAGIC;
+}
+
+static int tmp006_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+        struct iio_dev *indio_dev;
+        struct tmp006_data *data;
+        int ret;
+
+        if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+                return -ENODEV;
+
+        if (!tmp006_check_identification(client)) {
+                dev_err(&client->dev, "no TMP006 sensor\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 = &tmp006_info;
+
+        indio_dev->channels = tmp006_channels;
+        indio_dev->num_channels = ARRAY_SIZE(tmp006_channels);
+
+        ret = i2c_smbus_read_word_swapped(data->client, TMP006_CONFIG);
+        if (ret < 0)
+                return ret;
+        data->config = ret;
+
+        return iio_device_register(indio_dev);
+}
+
+static int tmp006_powerdown(struct tmp006_data *data)
+{
+        return i2c_smbus_write_word_swapped(data->client, TMP006_CONFIG,
+                data->config & ~TMP006_CONFIG_MOD_MASK);
+}
+
+static int tmp006_remove(struct i2c_client *client)
+{
+        struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+        iio_device_unregister(indio_dev);
+        tmp006_powerdown(iio_priv(indio_dev));
+
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tmp006_suspend(struct device *dev)
+{
+        return tmp006_powerdown(iio_priv(dev_to_iio_dev(dev)));
+}
+
+static int tmp006_resume(struct device *dev)
+{
+        struct tmp006_data *data = iio_priv(dev_to_iio_dev(dev));
+        return i2c_smbus_write_word_swapped(data->client, TMP006_CONFIG,
+                data->config | TMP006_CONFIG_MOD_MASK);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(tmp006_pm_ops, tmp006_suspend, tmp006_resume);
+
+static const struct i2c_device_id tmp006_id[] = {
+        { "tmp006", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, tmp006_id);
+
+static struct i2c_driver tmp006_driver = {
+        .driver = {
+                .name   = "tmp006",
+                .pm     = &tmp006_pm_ops,
+                .owner  = THIS_MODULE,
+        },
+        .probe = tmp006_probe,
+        .remove = tmp006_remove,
+        .id_table = tmp006_id,
+};
+module_i2c_driver(tmp006_driver);
+
+MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("TI TMP006 IR thermopile sensor driver");
+MODULE_LICENSE("GPL");