diff options
Diffstat (limited to 'drivers/iio/humidity/hdc100x.c')
| -rw-r--r-- | drivers/iio/humidity/hdc100x.c | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c new file mode 100644 index 000000000..a7f61e881 --- /dev/null +++ b/drivers/iio/humidity/hdc100x.c @@ -0,0 +1,320 @@ +/* + * 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 = -3971; + *val2 = 879096; + return IIO_VAL_INT_PLUS_MICRO; + 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"); |