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path: root/drivers/iio/humidity/si7005.c
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Diffstat (limited to 'drivers/iio/humidity/si7005.c')
-rw-r--r--drivers/iio/humidity/si7005.c189
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/iio/humidity/si7005.c b/drivers/iio/humidity/si7005.c
new file mode 100644
index 000000000000..bdd586e6d955
--- /dev/null
+++ b/drivers/iio/humidity/si7005.c
@@ -0,0 +1,189 @@
+/*
+ * si7005.c - Support for Silabs Si7005 humidity and temperature sensor
+ *
+ * Copyright (c) 2014 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.
+ *
+ * (7-bit I2C slave address 0x40)
+ *
+ * TODO: heater, fast mode, processed mode (temp. / linearity compensation)
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define SI7005_STATUS 0x00
+#define SI7005_DATA 0x01 /* 16-bit, MSB */
+#define SI7005_CONFIG 0x03
+#define SI7005_ID 0x11
+
+#define SI7005_STATUS_NRDY BIT(0)
+#define SI7005_CONFIG_TEMP BIT(4)
+#define SI7005_CONFIG_START BIT(0)
+
+#define SI7005_ID_7005 0x50
+#define SI7005_ID_7015 0xf0
+
+struct si7005_data {
+ struct i2c_client *client;
+ struct mutex lock;
+ u8 config;
+};
+
+static int si7005_read_measurement(struct si7005_data *data, bool temp)
+{
+ int tries = 50;
+ int ret;
+
+ mutex_lock(&data->lock);
+
+ ret = i2c_smbus_write_byte_data(data->client, SI7005_CONFIG,
+ data->config | SI7005_CONFIG_START |
+ (temp ? SI7005_CONFIG_TEMP : 0));
+ if (ret < 0)
+ goto done;
+
+ while (tries-- > 0) {
+ msleep(20);
+ ret = i2c_smbus_read_byte_data(data->client, SI7005_STATUS);
+ if (ret < 0)
+ goto done;
+ if (!(ret & SI7005_STATUS_NRDY))
+ break;
+ }
+ if (tries < 0) {
+ ret = -EIO;
+ goto done;
+ }
+
+ ret = i2c_smbus_read_word_swapped(data->client, SI7005_DATA);
+
+done:
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static int si7005_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct si7005_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = si7005_read_measurement(data, chan->type == IIO_TEMP);
+ if (ret < 0)
+ return ret;
+ *val = ret;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ if (chan->type == IIO_TEMP) {
+ *val = 7;
+ *val2 = 812500;
+ } else {
+ *val = 3;
+ *val2 = 906250;
+ }
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CHAN_INFO_OFFSET:
+ if (chan->type == IIO_TEMP)
+ *val = -50 * 32 * 4;
+ else
+ *val = -24 * 16 * 16;
+ return IIO_VAL_INT;
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_chan_spec si7005_channels[] = {
+ {
+ .type = IIO_HUMIDITYRELATIVE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
+ },
+ {
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
+ }
+};
+
+static const struct iio_info si7005_info = {
+ .read_raw = si7005_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int si7005_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct iio_dev *indio_dev;
+ struct si7005_data *data;
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+ 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 = &si7005_info;
+
+ indio_dev->channels = si7005_channels;
+ indio_dev->num_channels = ARRAY_SIZE(si7005_channels);
+
+ ret = i2c_smbus_read_byte_data(client, SI7005_ID);
+ if (ret < 0)
+ return ret;
+ if (ret != SI7005_ID_7005 && ret != SI7005_ID_7015)
+ return -ENODEV;
+
+ ret = i2c_smbus_read_byte_data(client, SI7005_CONFIG);
+ if (ret < 0)
+ return ret;
+ data->config = ret;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id si7005_id[] = {
+ { "si7005", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, si7005_id);
+
+static struct i2c_driver si7005_driver = {
+ .driver = {
+ .name = "si7005",
+ .owner = THIS_MODULE,
+ },
+ .probe = si7005_probe,
+ .id_table = si7005_id,
+};
+module_i2c_driver(si7005_driver);
+
+MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("Silabs Si7005 humidity and temperature sensor driver");
+MODULE_LICENSE("GPL");