iio: humidity: add HDC100x support
authorMatt Ranostay <mranostay@gmail.com>
Sun, 6 Sep 2015 20:27:39 +0000 (13:27 -0700)
committerJonathan Cameron <jic23@kernel.org>
Wed, 23 Sep 2015 19:23:19 +0000 (20:23 +0100)
Add support for the HDC100x temperature and humidity sensors
including the resistive heater element.

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc100x [new file with mode: 0644]
drivers/iio/humidity/Kconfig
drivers/iio/humidity/Makefile
drivers/iio/humidity/hdc100x.c [new file with mode: 0644]

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc100x b/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc100x
new file mode 100644 (file)
index 0000000..b72bb62
--- /dev/null
@@ -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: 4.3
+Contact:       linux-iio@vger.kernel.org
+Description:
+               Controls the heater device within the humidity sensor to get
+               rid of excess condensation.
+
+               Valid control values are 0 = OFF, and 1 = ON.
index 688c0d1cb47dea363df8b5dcc395797a575e9445..353ee9ade95dd1a9d6ae76b08af74a43c50abcca 100644 (file)
@@ -12,6 +12,16 @@ config DHT11
          Other sensors should work as well as long as they speak the
          same protocol.
 
+config HDC100X
+       tristate "TI HDC100x relative humidity and temperature sensor"
+       depends on I2C
+       help
+        Say yes here to build support for the TI HDC100x series of
+        relative humidity and temperature sensors.
+
+        To compile this driver as a module, choose M here: the module
+        will be called hdc100x.
+
 config SI7005
        tristate "SI7005 relative humidity and temperature sensor"
        depends on I2C
index 86e2d26e9f4dd8edbfcaa3e4c3b24f5651dcfc91..3e62c0a12d5e02ab3d129bd6952c5c4fca4dab6c 100644 (file)
@@ -3,5 +3,6 @@
 #
 
 obj-$(CONFIG_DHT11) += dht11.o
+obj-$(CONFIG_HDC100X) += hdc100x.o
 obj-$(CONFIG_SI7005) += si7005.o
 obj-$(CONFIG_SI7020) += si7020.o
diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c
new file mode 100644 (file)
index 0000000..2824578
--- /dev/null
@@ -0,0 +1,319 @@
+/*
+ * hdc100x.c - Support for the TI HDC100x temperature + humidity sensors
+ *
+ * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define HDC100X_REG_TEMP                       0x00
+#define HDC100X_REG_HUMIDITY                   0x01
+
+#define HDC100X_REG_CONFIG                     0x02
+#define HDC100X_REG_CONFIG_HEATER_EN           BIT(13)
+
+struct hdc100x_data {
+       struct i2c_client *client;
+       struct mutex lock;
+       u16 config;
+
+       /* integration time of the sensor */
+       int adc_int_us[2];
+};
+
+/* integration time in us */
+static const int hdc100x_int_time[][3] = {
+       { 6350, 3650, 0 },      /* IIO_TEMP channel*/
+       { 6500, 3850, 2500 },   /* IIO_HUMIDITYRELATIVE channel */
+};
+
+/* HDC100X_REG_CONFIG shift and mask values */
+static const struct {
+       int shift;
+       int mask;
+} hdc100x_resolution_shift[2] = {
+       { /* IIO_TEMP channel */
+               .shift = 10,
+               .mask = 1
+       },
+       { /* IIO_HUMIDITYRELATIVE channel */
+               .shift = 8,
+               .mask = 2,
+       },
+};
+
+static IIO_CONST_ATTR(temp_integration_time_available,
+               "0.00365 0.00635");
+
+static IIO_CONST_ATTR(humidityrelative_integration_time_available,
+               "0.0025 0.00385 0.0065");
+
+static IIO_CONST_ATTR(out_current_heater_raw_available,
+               "0 1");
+
+static struct attribute *hdc100x_attributes[] = {
+       &iio_const_attr_temp_integration_time_available.dev_attr.attr,
+       &iio_const_attr_humidityrelative_integration_time_available.dev_attr.attr,
+       &iio_const_attr_out_current_heater_raw_available.dev_attr.attr,
+       NULL
+};
+
+static struct attribute_group hdc100x_attribute_group = {
+       .attrs = hdc100x_attributes,
+};
+
+static const struct iio_chan_spec hdc100x_channels[] = {
+       {
+               .type = IIO_TEMP,
+               .address = HDC100X_REG_TEMP,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                       BIT(IIO_CHAN_INFO_SCALE) |
+                       BIT(IIO_CHAN_INFO_INT_TIME) |
+                       BIT(IIO_CHAN_INFO_OFFSET),
+       },
+       {
+               .type = IIO_HUMIDITYRELATIVE,
+               .address = HDC100X_REG_HUMIDITY,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                       BIT(IIO_CHAN_INFO_SCALE) |
+                       BIT(IIO_CHAN_INFO_INT_TIME)
+       },
+       {
+               .type = IIO_CURRENT,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+               .extend_name = "heater",
+               .output = 1,
+       },
+};
+
+static int hdc100x_update_config(struct hdc100x_data *data, int mask, int val)
+{
+       int tmp = (~mask & data->config) | val;
+       int ret;
+
+       ret = i2c_smbus_write_word_swapped(data->client,
+                                               HDC100X_REG_CONFIG, tmp);
+       if (!ret)
+               data->config = tmp;
+
+       return ret;
+}
+
+static int hdc100x_set_it_time(struct hdc100x_data *data, int chan, int val2)
+{
+       int shift = hdc100x_resolution_shift[chan].shift;
+       int ret = -EINVAL;
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(hdc100x_int_time[chan]); i++) {
+               if (val2 && val2 == hdc100x_int_time[chan][i]) {
+                       ret = hdc100x_update_config(data,
+                               hdc100x_resolution_shift[chan].mask << shift,
+                               i << shift);
+                       if (!ret)
+                               data->adc_int_us[chan] = val2;
+                       break;
+               }
+       }
+
+       return ret;
+}
+
+static int hdc100x_get_measurement(struct hdc100x_data *data,
+                                  struct iio_chan_spec const *chan)
+{
+       struct i2c_client *client = data->client;
+       int delay = data->adc_int_us[chan->address];
+       int ret;
+       int val;
+
+       /* start measurement */
+       ret = i2c_smbus_write_byte(client, chan->address);
+       if (ret < 0) {
+               dev_err(&client->dev, "cannot start measurement");
+               return ret;
+       }
+
+       /* wait for integration time to pass */
+       usleep_range(delay, delay + 1000);
+
+       /*
+        * i2c_smbus_read_word_data cannot() be used here due to the command
+        * value not being understood and causes NAKs preventing any reading
+        * from being accessed.
+        */
+       ret = i2c_smbus_read_byte(client);
+       if (ret < 0) {
+               dev_err(&client->dev, "cannot read high byte measurement");
+               return ret;
+       }
+       val = ret << 6;
+
+       ret = i2c_smbus_read_byte(client);
+       if (ret < 0) {
+               dev_err(&client->dev, "cannot read low byte measurement");
+               return ret;
+       }
+       val |= ret >> 2;
+
+       return val;
+}
+
+static int hdc100x_get_heater_status(struct hdc100x_data *data)
+{
+       return !!(data->config & HDC100X_REG_CONFIG_HEATER_EN);
+}
+
+static int hdc100x_read_raw(struct iio_dev *indio_dev,
+                           struct iio_chan_spec const *chan, int *val,
+                           int *val2, long mask)
+{
+       struct hdc100x_data *data = iio_priv(indio_dev);
+
+       switch (mask) {
+       case IIO_CHAN_INFO_RAW: {
+               int ret;
+
+               mutex_lock(&data->lock);
+               if (chan->type == IIO_CURRENT) {
+                       *val = hdc100x_get_heater_status(data);
+                       ret = IIO_VAL_INT;
+               } else {
+                       ret = hdc100x_get_measurement(data, chan);
+                       if (ret >= 0) {
+                               *val = ret;
+                               ret = IIO_VAL_INT;
+                       }
+               }
+               mutex_unlock(&data->lock);
+               return ret;
+       }
+       case IIO_CHAN_INFO_INT_TIME:
+               *val = 0;
+               *val2 = data->adc_int_us[chan->address];
+               return IIO_VAL_INT_PLUS_MICRO;
+       case IIO_CHAN_INFO_SCALE:
+               if (chan->type == IIO_TEMP) {
+                       *val = 165;
+                       *val2 = 65536 >> 2;
+                       return IIO_VAL_FRACTIONAL;
+               } else {
+                       *val = 0;
+                       *val2 = 10000;
+                       return IIO_VAL_INT_PLUS_MICRO;
+               }
+               break;
+       case IIO_CHAN_INFO_OFFSET:
+               *val = -40;
+               return IIO_VAL_INT;
+       default:
+               return -EINVAL;
+       }
+}
+
+static int hdc100x_write_raw(struct iio_dev *indio_dev,
+                            struct iio_chan_spec const *chan,
+                            int val, int val2, long mask)
+{
+       struct hdc100x_data *data = iio_priv(indio_dev);
+       int ret = -EINVAL;
+
+       switch (mask) {
+       case IIO_CHAN_INFO_INT_TIME:
+               if (val != 0)
+                       return -EINVAL;
+
+               mutex_lock(&data->lock);
+               ret = hdc100x_set_it_time(data, chan->address, val2);
+               mutex_unlock(&data->lock);
+               return ret;
+       case IIO_CHAN_INFO_RAW:
+               if (chan->type != IIO_CURRENT || val2 != 0)
+                       return -EINVAL;
+
+               mutex_lock(&data->lock);
+               ret = hdc100x_update_config(data, HDC100X_REG_CONFIG_HEATER_EN,
+                                       val ? HDC100X_REG_CONFIG_HEATER_EN : 0);
+               mutex_unlock(&data->lock);
+               return ret;
+       default:
+               return -EINVAL;
+       }
+}
+
+static const struct iio_info hdc100x_info = {
+       .read_raw = hdc100x_read_raw,
+       .write_raw = hdc100x_write_raw,
+       .attrs = &hdc100x_attribute_group,
+       .driver_module = THIS_MODULE,
+};
+
+static int hdc100x_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+       struct iio_dev *indio_dev;
+       struct hdc100x_data *data;
+
+       if (!i2c_check_functionality(client->adapter,
+                               I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))
+               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;
+       mutex_init(&data->lock);
+
+       indio_dev->dev.parent = &client->dev;
+       indio_dev->name = dev_name(&client->dev);
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->info = &hdc100x_info;
+
+       indio_dev->channels = hdc100x_channels;
+       indio_dev->num_channels = ARRAY_SIZE(hdc100x_channels);
+
+       /* be sure we are in a known state */
+       hdc100x_set_it_time(data, 0, hdc100x_int_time[0][0]);
+       hdc100x_set_it_time(data, 1, hdc100x_int_time[1][0]);
+
+       return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id hdc100x_id[] = {
+       { "hdc100x", 0 },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, hdc100x_id);
+
+static struct i2c_driver hdc100x_driver = {
+       .driver = {
+               .name   = "hdc100x",
+       },
+       .probe = hdc100x_probe,
+       .id_table = hdc100x_id,
+};
+module_i2c_driver(hdc100x_driver);
+
+MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
+MODULE_DESCRIPTION("TI HDC100x humidity and temperature sensor driver");
+MODULE_LICENSE("GPL");