Messages in this thread | | | Date | Wed, 24 Sep 2014 10:20:29 -0500 | From | David Barksdale <> | Subject | Re: [PATCH v3] IIO: add si7020 driver |
| |
On 09/24/2014 10:15 AM, Daniel Baluta wrote: > On Wed, Sep 24, 2014 at 6:02 PM, David Barksdale <dbarksdale@uplogix.com> 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@uplogix.com> >> >> -- >> 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@uplogix.com> >> + * >> + * 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. >
I just added it a few minutes ago so you spotted it pretty quickly! It's not a problem because we should sleep for at least 15 ms.
| |