On Wed, Sep 24, 2014 at 6:02 PM, David Barksdale <dbarksdale@xxxxxxxxxxx> wrote: > This patch adds support to the Industrial IO subsystem > for the Silicon Labs Si7013/20/21 Relative Humidity and > Temperature Sensors. > > Website: http://www.silabs.com/products/sensors/humidity-sensors/Pages/si7013-20-21.aspx > > These are i2c devices which measure relative humidity > and temperature and all use the same protocol. The > Si7013 has an additional input with programmable > linearization which is not supported because that's > complicated and I didn't need it. > > Signed-off-by: David Barksdale <dbarksdale@xxxxxxxxxxx> > > -- > Changes since v1: > * Renamed to si7020 and replaced Si701x/2x with Si7013/20/21. > * Removed unneeded mutex. > * Pre-computed floating-point constant expressions. > * Removed address_list and I2C_CLASS_HWMON. > > Changes since v2: > * Return correct raw sensor values. > * Rename dev variable to indio_dev. > * Issue a software reset command during probe. > * Un-broke string literal. > > --- > drivers/iio/humidity/Kconfig | 10 +++ > drivers/iio/humidity/Makefile | 1 + > drivers/iio/humidity/si7020.c | 165 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 176 insertions(+) > > diff --git a/drivers/iio/humidity/Kconfig b/drivers/iio/humidity/Kconfig > index e116bd8..4813b79 100644 > --- a/drivers/iio/humidity/Kconfig > +++ b/drivers/iio/humidity/Kconfig > @@ -22,4 +22,14 @@ config SI7005 > To compile this driver as a module, choose M here: the module > will be called si7005. > > +config SI7020 > + tristate "Si7013/20/21 Relative Humidity and Temperature Sensors" > + depends on I2C > + help > + Say yes here to build support for the Silicon Labs Si7013/20/21 > + Relative Humidity and Temperature Sensors. > + > + To compile this driver as a module, choose M here: the module > + will be called si7020. > + > endmenu > diff --git a/drivers/iio/humidity/Makefile b/drivers/iio/humidity/Makefile > index e3f3d94..86e2d26 100644 > --- a/drivers/iio/humidity/Makefile > +++ b/drivers/iio/humidity/Makefile > @@ -4,3 +4,4 @@ > > obj-$(CONFIG_DHT11) += dht11.o > obj-$(CONFIG_SI7005) += si7005.o > +obj-$(CONFIG_SI7020) += si7020.o > diff --git a/drivers/iio/humidity/si7020.c b/drivers/iio/humidity/si7020.c > new file mode 100644 > index 0000000..4aacb55 > --- /dev/null > +++ b/drivers/iio/humidity/si7020.c > @@ -0,0 +1,165 @@ > +/* > + * si7020.c - Silicon Labs Si7013/20/21 Relative Humidity and Temp Sensors > + * Copyright (c) 2013,2014 Uplogix, Inc. > + * David Barksdale <dbarksdale@xxxxxxxxxxx> > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * 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. > + */ > + > +/* > + * The Silicon Labs Si7013/20/21 Relative Humidity and Temperature Sensors > + * are i2c devices which have an identical programming interface for > + * measuring relative humidity and temperature. The Si7013 has an additional > + * temperature input which this driver does not support. > + * > + * Data Sheets: > + * Si7013: http://www.silabs.com/Support%20Documents/TechnicalDocs/Si7013.pdf > + * Si7020: http://www.silabs.com/Support%20Documents/TechnicalDocs/Si7020.pdf > + * Si7021: http://www.silabs.com/Support%20Documents/TechnicalDocs/Si7021.pdf > + */ > + > +#include <linux/delay.h> > +#include <linux/i2c.h> > +#include <linux/module.h> > +#include <linux/slab.h> > +#include <linux/sysfs.h> > + > +#include <linux/iio/iio.h> > +#include <linux/iio/sysfs.h> > + > +enum { > + /* Measure Relative Humidity, Hold Master Mode */ > + SI7020CMD_RH_HOLD = 0xE5, > + /* Measure Temperature, Hold Master Mode */ > + SI7020CMD_TEMP_HOLD = 0xE3, > + /* Software Reset */ > + SI7020CMD_RESET = 0xFE, > +}; > + > +static int si7020_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, int *val, > + int *val2, long mask) > +{ > + struct i2c_client **client = iio_priv(indio_dev); > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + ret = i2c_smbus_read_word_data(*client, > + chan->type == IIO_TEMP ? > + SI7020CMD_TEMP_HOLD : > + SI7020CMD_RH_HOLD); > + if (ret < 0) > + return ret; > + if (chan->type == IIO_TEMP) > + *val = ret >> 2; > + else > + *val = (ret & 0x3FFF) >> 2; > + return IIO_VAL_INT; > + case IIO_CHAN_INFO_SCALE: > + if (chan->type == IIO_TEMP) > + *val = 175720; /* = 175.72 * 1000 */ > + else > + *val = 125 * 1000; > + *val2 = 65536 >> 2; > + return IIO_VAL_FRACTIONAL; > + case IIO_CHAN_INFO_OFFSET: > + /* Since iio_convert_raw_to_processed_unlocked assumes offset > + * is an integer we have to round these values and lose > + * accuracy. > + * Relative humidity will be 0.0032959% too high and > + * temperature will be 0.00277344 degrees too high. > + * This is no big deal because it's within the accuracy of the > + * sensor. > + */ > + if (chan->type == IIO_TEMP) > + *val = -4368; /* = -46.85 * (65536 >> 2) / 175.72 */ > + else > + *val = -786; /* = -6 * (65536 >> 2) / 125 */ > + return IIO_VAL_INT; > + default: > + break; > + } > + > + return -EINVAL; > +} > + > +static const struct iio_chan_spec si7020_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 si7020_info = { > + .read_raw = si7020_read_raw, > + .driver_module = THIS_MODULE, > +}; > + > +static int si7020_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct iio_dev *indio_dev; > + struct i2c_client **data; > + int ret; > + > + if (!i2c_check_functionality(client->adapter, > + I2C_FUNC_SMBUS_WRITE_BYTE | > + I2C_FUNC_SMBUS_READ_WORD_DATA)) > + return -ENODEV; > + > + /* Reset device, loads default settings. */ > + ret = i2c_smbus_write_byte(client, SI7020CMD_RESET); > + if (ret < 0) > + return ret; > + /* Wait the maximum power-up time after software reset. */ > + msleep(15); Nit: checkpatch.pl says: WARNING: msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt #155: FILE: drivers/iio/humidity/si7020.c:129: + msleep(15); Sorry for spotting this so late in the review. I don't now if this is a real problem. thanks, Daniel. -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
