> > > This patch adds support to the Industrial IO subsystem > > > for the Silicon Labs Si701x/2x Relative Humidity and > > > Temperature Sensors. > > > > the name si701x is problematic; the si7015 for example is supported by > > the si7005 driver > > > > how about calling the driver si7020 and stating that it also supports > > si7013, si7021 -- the x notation in driver names always leads to touble... > > Sounds good. > > > the additional features of the si7013 are not supported by the driver > > > > > 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> > > > > > > --- > > > drivers/iio/humidity/Kconfig | 10 +++ > > > drivers/iio/humidity/Makefile | 1 + > > > drivers/iio/humidity/si701x.c | 159 > > > ++++++++++++++++++++++++++++++++++++++++++ > > > 3 files changed, 170 insertions(+) > > > > > > diff --git a/drivers/iio/humidity/Kconfig b/drivers/iio/humidity/Kconfig > > > index e116bd8..ba0ef61 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 SI701X > > > + tristate "Si701x/2x Relative Humidity and Temperature Sensors" > > > + depends on I2C > > > + help > > > + Say yes here to build support for the Silicon Labs Si701x/2x > > > Relative > > > + Humidity and Temperature Sensors. > > > + > > > + To compile this driver as a module, choose M here: the module > > > + will be called si701x. > > > + > > > endmenu > > > diff --git a/drivers/iio/humidity/Makefile b/drivers/iio/humidity/Makefile > > > index e3f3d94..d2e9645 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_SI701X) += si701x.o > > > diff --git a/drivers/iio/humidity/si701x.c b/drivers/iio/humidity/si701x.c > > > new file mode 100644 > > > index 0000000..1a2ee22 > > > --- /dev/null > > > +++ b/drivers/iio/humidity/si701x.c > > > @@ -0,0 +1,159 @@ > > > +/* > > > + * si701x.c - Silicon Labs Si701x/2x Relative Humidity and Temperature > > > 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 Si701x/2x 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/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 */ > > > + SI701XCMD_RH_HOLD = 0xE5, > > > + /* Measure Temperature, Hold Master Mode */ > > > + SI701XCMD_TEMP_HOLD = 0xE3, > > > +}; > > > + > > > +struct si701x_data { > > > + struct i2c_client *client; > > > + struct mutex lock; > > > +}; > > > + > > > +static int si701x_read_raw(struct iio_dev *indio_dev, > > > + struct iio_chan_spec const *chan, int *val, > > > + int *val2, long mask) > > > +{ > > > + struct si701x_data *data = iio_priv(indio_dev); > > > + int ret; > > > + > > > + switch (mask) { > > > + case IIO_CHAN_INFO_RAW: > > > + mutex_lock(&data->lock); > > > > is the locking needed? what is protected? > > I copied this from the si7005 driver. I assumed because calls to read_raw were > not serialized and calls to i2c_smbus_read_word_data on the same client need > to be serialized. reading the si7005 is totally different: start conversion, wait for completion, read data -- this sequence must not be interrupted, hence the lock > > > + ret = i2c_smbus_read_word_data(data->client, > > > + chan->type == IIO_TEMP ? > > > + SI701XCMD_TEMP_HOLD : > > > + SI701XCMD_RH_HOLD); > > > + mutex_unlock(&data->lock); > > > + if (ret < 0) > > > + return ret; > > > + *val = ret; > > > + return IIO_VAL_INT; > > > + case IIO_CHAN_INFO_SCALE: > > > + if (chan->type == IIO_TEMP) { > > > + *val = 175.72 * 1000; > > > > floating-point constants in kernel space makes me nervous > > > > I was trying to make this easy to compare to constants that appear in the data > sheets: 175.72, 125, 65536, -6, and -46.85. I figured the compiler would > transform them to integers, but I suppose that's not a great assumption. I'll > precompute them and explain them in a comment. > > > > + *val2 = 65536; > > > > could set val2 once after the if > > > > > + } else { > > > + *val = 125 * 1000; > > > + *val2 = 65536; > > > + } > > > + return IIO_VAL_FRACTIONAL; > > > + case IIO_CHAN_INFO_OFFSET: > > > + if (chan->type == IIO_TEMP) > > > + *val = -46.85 * 65536 / 175.72; > > > + else > > > + *val = -6 * 65536 / 125; > > > + return IIO_VAL_INT; > > > + default: > > > + break; > > > + } > > > + > > > + return -EINVAL; > > > +} > > > + > > > +static const struct iio_chan_spec si701x_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 si701x_info = { > > > + .read_raw = si701x_read_raw, > > > + .driver_module = THIS_MODULE, > > > +}; > > > + > > > +static int si701x_probe(struct i2c_client *client, > > > + const struct i2c_device_id *id) > > > +{ > > > + struct iio_dev *dev; > > > + struct si701x_data *data; > > > + > > > + if (!i2c_check_functionality(client->adapter, > > > I2C_FUNC_SMBUS_WORD_DATA)) > > > + return -ENODEV; > > > + > > > + dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); > > > + if (!dev) > > > + return -ENOMEM; > > > + > > > + data = iio_priv(dev); > > > + i2c_set_clientdata(client, dev); > > > + data->client = client; > > > + mutex_init(&data->lock); > > > + > > > + dev->dev.parent = &client->dev; > > > + dev->name = dev_name(&client->dev); > > > + dev->modes = INDIO_DIRECT_MODE; > > > + dev->info = &si701x_info; > > > + dev->channels = si701x_channels; > > > + dev->num_channels = ARRAY_SIZE(si701x_channels); > > > + > > > + return devm_iio_device_register(&client->dev, dev); > > > +} > > > + > > > +static const unsigned short si701x_address_list[] = { > > > + 0x40, > > > > the alternate address is 0x41 > > > > Thanks. > > > > + I2C_CLIENT_END > > > +}; > > > + > > > +static const struct i2c_device_id si701x_id[] = { > > > + { "si701x", 0 }, > > > + { } > > > +}; > > > +MODULE_DEVICE_TABLE(i2c, si701x_id); > > > + > > > +static struct i2c_driver si701x_driver = { > > > + .class = I2C_CLASS_HWMON, > > > + .driver.name = "si701x", > > > + .probe = si701x_probe, > > > + .address_list = si701x_address_list, > > > + .id_table = si701x_id, > > > > address_list and I2C_CLASS_HWMON -- what for? > > > > if doing auto-probing, I'd check the chip's ID > > > > Oops. This was originally an hwmon driver but I ported it to iio when I saw > that's where si7005 landed. IIO drivers usually don't fill the I2C address list > > > > +}; > > > + > > > +module_i2c_driver(si701x_driver); > > > +MODULE_DESCRIPTION("Silicon Labs Si701x/2x " > > > + "Relative Humidity and Temperature Sensors"); > > > +MODULE_AUTHOR("David Barksdale <dbarksdale@xxxxxxxxxxx>"); > > > +MODULE_LICENSE("GPL"); > > > + > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- Peter Meerwald +43-664-2444418 (mobile) -- 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
