--- /dev/null
+/*
+ * htu21.c - Support for Measurement-Specialties
+ * htu21 temperature & humidity sensor
+ *
+ * Copyright (c) 2014 Measurement-Specialties
+ *
+ * Licensed under the GPL-2.
+ *
+ * (7-bit I2C slave address 0x40)
+ *
+ * Datasheet:
+ * http://www.meas-spec.com/downloads/HTU21D.pdf
+ */
+
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/stat.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#include "../common/ms_sensors/ms_sensors_i2c.h"
+
+#define HTU21_RESET 0xFE
+
+static const int htu21_samp_freq[4] = { 20, 40, 70, 120 };
+/* String copy of the above const for readability purpose */
+static const char htu21_show_samp_freq[] = "20 40 70 120";
+
+static int htu21_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *channel, int *val,
+ int *val2, long mask)
+{
+ int ret, temperature;
+ unsigned int humidity;
+ struct ms_ht_dev *dev_data = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_PROCESSED:
+ switch (channel->type) {
+ case IIO_TEMP: /* in milli °C */
+ ret = ms_sensors_ht_read_temperature(dev_data,
+ &temperature);
+ if (ret)
+ return ret;
+ *val = temperature;
+
+ return IIO_VAL_INT;
+ case IIO_HUMIDITYRELATIVE: /* in milli %RH */
+ ret = ms_sensors_ht_read_humidity(dev_data,
+ &humidity);
+ if (ret)
+ return ret;
+ *val = humidity;
+
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = htu21_samp_freq[dev_data->res_index];
+
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int htu21_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct ms_ht_dev *dev_data = iio_priv(indio_dev);
+ int i, ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ i = ARRAY_SIZE(htu21_samp_freq);
+ while (i-- > 0)
+ if (val == htu21_samp_freq[i])
+ break;
+ if (i < 0)
+ return -EINVAL;
+ mutex_lock(&dev_data->lock);
+ dev_data->res_index = i;
+ ret = ms_sensors_write_resolution(dev_data, i);
+ mutex_unlock(&dev_data->lock);
+
+ return ret;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_chan_spec htu21_channels[] = {
+ {
+ .type = IIO_TEMP,
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ },
+ {
+ .type = IIO_HUMIDITYRELATIVE,
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ }
+};
+
+static ssize_t htu21_show_battery_low(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct ms_ht_dev *dev_data = iio_priv(indio_dev);
+
+ return ms_sensors_show_battery_low(dev_data, buf);
+}
+
+static ssize_t htu21_show_heater(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct ms_ht_dev *dev_data = iio_priv(indio_dev);
+
+ return ms_sensors_show_heater(dev_data, buf);
+}
+
+static ssize_t htu21_write_heater(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct ms_ht_dev *dev_data = iio_priv(indio_dev);
+
+ return ms_sensors_write_heater(dev_data, buf, len);
+}
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(htu21_show_samp_freq);
+static IIO_DEVICE_ATTR(battery_low, S_IRUGO,
+ htu21_show_battery_low, NULL, 0);
+static IIO_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR,
+ htu21_show_heater, htu21_write_heater, 0);
+
+static struct attribute *htu21_attributes[] = {
+ &iio_const_attr_sampling_frequency_available.dev_attr.attr,
+ &iio_dev_attr_battery_low.dev_attr.attr,
+ &iio_dev_attr_heater_enable.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group htu21_attribute_group = {
+ .attrs = htu21_attributes,
+};
+
+static const struct iio_info htu21_info = {
+ .read_raw = htu21_read_raw,
+ .write_raw = htu21_write_raw,
+ .attrs = &htu21_attribute_group,
+ .driver_module = THIS_MODULE,
+};
+
+static int htu21_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct ms_ht_dev *dev_data;
+ struct iio_dev *indio_dev;
+ int ret;
+ u64 serial_number;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+ I2C_FUNC_SMBUS_WRITE_BYTE |
+ I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+ dev_err(&client->dev,
+ "Adapter does not support some i2c transaction\n");
+ return -ENODEV;
+ }
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ dev_data = iio_priv(indio_dev);
+ dev_data->client = client;
+ dev_data->res_index = 0;
+ mutex_init(&dev_data->lock);
+
+ indio_dev->info = &htu21_info;
+ indio_dev->name = id->name;
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = htu21_channels;
+ indio_dev->num_channels = ARRAY_SIZE(htu21_channels);
+
+ i2c_set_clientdata(client, indio_dev);
+
+ ret = ms_sensors_reset(client, HTU21_RESET, 15000);
+ if (ret)
+ return ret;
+
+ ret = ms_sensors_read_serial(client, &serial_number);
+ if (ret)
+ return ret;
+ dev_info(&client->dev, "Serial number : %llx", serial_number);
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id htu21_id[] = {
+ {"htu21", 0},
+ {}
+};
+
+static struct i2c_driver htu21_driver = {
+ .probe = htu21_probe,
+ .id_table = htu21_id,
+ .driver = {
+ .name = "htu21",
+ },
+};
+
+module_i2c_driver(htu21_driver);
+
+MODULE_DESCRIPTION("Measurement-Specialties htu21 temperature and humidity driver");
+MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
+MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
+MODULE_LICENSE("GPL v2");
projects / karo-tx-linux.git / commitdiff