On Wed, Jun 20, 2012 at 02:58:15PM +0000, Iain Paton wrote: > Hi, > > This is a new driver for the Honeywell Humidicon HIH-6130 humidity sensor. > > I don't claim originality, the driver is mostly identical to the existing Sensiron sht21 > driver with the necessary changes to the probe, update_measurements and conversion functions > necessary to use the Honeywell sensors. > > My first kernel patch, please go easy on me as I'm bound to be doing something stupid :) > Hi Iain, It is pretty good, actually, especially for a first patch. Just a bunch of nitpicks. Please run the patch through checkpatch and fix the warnings and errors (too long lines and missing sign-off). Please provide Documentation/hwmon/hih613x (or, rather, hih6130 - see next paragraph). Please spell out the chip types. "hih613x" could include anything from HIH6130 to HIH6139 (or even HIH613Z); if any of those is ever released, things would get confusing. I would suggest to name the driver hih6130 and refer to the chips as HIH6130/6131 as in the data sheet. > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 6f1d167..2b13375 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -433,6 +433,16 @@ config SENSORS_GPIO_FAN > This driver can also be built as a module. If so, the module > will be called gpio-fan. > > +config SENSORS_HIH613X > + tristate "Honeywell Humidicon HIH-613x humidity/temperature sensor" > + depends on I2C && EXPERIMENTAL, at least for a couple of releases. > + help > + If you say yes here you get support for Honeywell HIH-613x > + Humidicon humidity sensors. > + > + This driver can also be built as a module. If so, the module > + will be called hih613x. > + > config SENSORS_CORETEMP > tristate "Intel Core/Core2/Atom temperature sensor" > depends on X86 && PCI && EXPERIMENTAL > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index e1eeac1..b92447c 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -58,6 +58,7 @@ obj-$(CONFIG_SENSORS_G760A) += g760a.o > obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o > obj-$(CONFIG_SENSORS_GL520SM) += gl520sm.o > obj-$(CONFIG_SENSORS_GPIO_FAN) += gpio-fan.o > +obj-$(CONFIG_SENSORS_HIH613X) += hih613x.o > obj-$(CONFIG_SENSORS_ULTRA45) += ultra45_env.o > obj-$(CONFIG_SENSORS_I5K_AMB) += i5k_amb.o > obj-$(CONFIG_SENSORS_IBMAEM) += ibmaem.o > diff --git a/drivers/hwmon/hih613x.c b/drivers/hwmon/hih613x.c > new file mode 100644 > index 0000000..0c8693c > --- /dev/null > +++ b/drivers/hwmon/hih613x.c > @@ -0,0 +1,297 @@ > +/* Honeywell HIH-613x humidity and temperature sensor driver > + * > + * Copyright (C) 2012 Iain Paton <ipaton0@xxxxxxxxx> > + * > + * heavily based on the sht21 driver > + * Copyright (C) 2010 Urs Fleisch <urs.fleisch@xxxxxxxxxxxxx> > + * > + * 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. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA > + * > + * Data sheets available (6/2012) at > + * http://sensing.honeywell.com/index.php?ci_id=3106&la_id=1&defId=44872 > + */ > + > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/slab.h> > +#include <linux/i2c.h> > +#include <linux/hwmon.h> > +#include <linux/hwmon-sysfs.h> > +#include <linux/err.h> > +#include <linux/mutex.h> > +#include <linux/device.h> > +#include <linux/delay.h> > + > +/** > + * struct hih613x - HIH-613x device specific data > + * @hwmon_dev: device registered with hwmon > + * @lock: mutex to protect measurement values > + * @valid: only 0 before first measurement is taken > + * @last_update: time of last update (jiffies) > + * @temperature: cached temperature measurement value > + * @humidity: cached humidity measurement value > + */ > +struct hih613x { > + struct device *hwmon_dev; > + struct mutex lock; > + char valid; char is more expensive than bool on many platforms. I would suggest to use bool instead. > + unsigned long last_update; > + int temperature; > + int humidity; > +}; > + > +/** > + * hih613x_temp_ticks_to_millicelsius() - convert raw temperature ticks to > + * milli celsius > + * @ticks: temperature ticks value received from sensor > + */ > +static inline int hih613x_temp_ticks_to_millicelsius(int ticks) > +{ > + > + ticks &= ~0x0003; /* clear unused bits */ The above code is unnecessary; the shift gets rid of the unused bits. > + ticks = ticks >> 2; > + /* > + * Formula T = ( ticks / ( 2^14 - 2 ) ) * 165 -40 from data sheet section 5.0, > + */ > + return ((ticks * 165000) / 16382) - 40000; Would DIV_ROUND_CLOSEST make sense here ? Also, is it guaranteed that you don't get an integer overflow ? > +} > + > +/** > + * hih613x_rh_ticks_to_per_cent_mille() - convert raw humidity ticks to > + * one-thousandths of a percent relative humidity > + * @ticks: humidity ticks value received from sensor > + */ > +static inline int hih613x_rh_ticks_to_per_cent_mille(int ticks) > +{ > + > + ticks &= ~0xC000; /* clear status bits */ > + /* > + * Formula RH = ( ticks / ( 2^14 -2 ) ) * 100 from data sheet section 4.0, > + */ > + return (ticks * 100000) / 16382; Would DIV_ROUND_CLOSEST make sense here ? Is it guaranteed that there won't be an integer overflow ? > +} > + > +/** > + * hih613x_update_measurements() - get updated measurements from device > + * @client: I2C client device > + * > + * Returns 0 on success, else negative errno. > + */ > +static int hih613x_update_measurements(struct i2c_client *client) > +{ > + int ret = 0; > + int t; > + struct hih613x *hih613x = i2c_get_clientdata(client); > + This empty line is not really needed. > + unsigned char tmp[4]; > + struct i2c_msg msgs[1] = { > + { > + .addr = client->addr, > + .flags = I2C_M_RD, > + .len = 4, > + .buf = tmp, > + } > + }; > + > + mutex_lock(&hih613x->lock); > + > + /* > + * Unlike the SHT2x the HIH-613x datasheet doesn't give limits on the number of > + * measurements per second we can make. However it makes no sense to allow polling > + * for humidity or temperature more than a couple of times a second anyway. > + */ It isn't really relevant what SHT2x does here. More important would be to mention that a measurement takes a long time, so you want to limit it. Since a measurement cycle takes 40 ms, you might actually want to consider increasing the timeout to HZ or even HZ + HZ/2. > + if (time_after(jiffies, hih613x->last_update + HZ / 2) || !hih613x->valid) { > + > + /* write to slave address, no data, to request a measurement */ > + ret = i2c_master_send(client, tmp, 0); > + if (ret < 0) > + goto out; > + > + /* for default 14 bit accuracy the measurement cycle time is ~36.65msec > + * we can either simply wait, or could loop polling the status bits > + */ Multi-line comment style. Also, is there another accuracy ? I didn't find it in the documentation. If the measurement cycle can be longer based on the configuration, reading the measurement results might always fail, which would be bad. > + msleep(40); > + > + ret = i2c_transfer(client->adapter, msgs, 1); > + if (ret < 0) > + goto out; > + > + if ((tmp[0] & 0xC0) != 0) { > + dev_err(&client->dev, "Error while reading measurement result\n"); > + ret = -EIO; > + goto out; > + } > + > + t = (tmp[0]<<8) + tmp[1]; Coding style: spaces before and after << > + hih613x->humidity = hih613x_rh_ticks_to_per_cent_mille(t); > + > + t = (tmp[2]<<8) + tmp[3]; Coding style: spaces before and after << > + hih613x->temperature = hih613x_temp_ticks_to_millicelsius(t); > + > + hih613x->last_update = jiffies; > + hih613x->valid = 1; > + Unnecessary empty line > + } > +out: > + mutex_unlock(&hih613x->lock); > + > + return ret >= 0 ? 0 : ret; > +} > + > +/** > + * hih613x_show_temperature() - show temperature measurement value in sysfs > + * @dev: device > + * @attr: device attribute > + * @buf: sysfs buffer (PAGE_SIZE) where measurement values are written to > + * > + * Will be called on read access to temp1_input sysfs attribute. > + * Returns number of bytes written into buffer, negative errno on error. > + */ > +static ssize_t hih613x_show_temperature(struct device *dev, > + struct device_attribute *attr, > + char *buf) I don't really like the alignment here. I would suggest to align with (, and use one less line. > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct hih613x *hih613x = i2c_get_clientdata(client); > + int ret = hih613x_update_measurements(client); > + if (ret < 0) > + return ret; > + return sprintf(buf, "%d\n", hih613x->temperature); > +} > + > +/** > + * hih613x_show_humidity() - show humidity measurement value in sysfs > + * @dev: device > + * @attr: device attribute > + * @buf: sysfs buffer (PAGE_SIZE) where measurement values are written to > + * > + * Will be called on read access to humidity1_input sysfs attribute. > + * Returns number of bytes written into buffer, negative errno on error. > + */ > +static ssize_t hih613x_show_humidity(struct device *dev, > + struct device_attribute *attr, > + char *buf) Same here. > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct hih613x *hih613x = i2c_get_clientdata(client); > + int ret = hih613x_update_measurements(client); > + if (ret < 0) > + return ret; > + return sprintf(buf, "%d\n", hih613x->humidity); > +} > + > +/* sysfs attributes */ > +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, hih613x_show_temperature, > + NULL, 0); > +static SENSOR_DEVICE_ATTR(humidity1_input, S_IRUGO, hih613x_show_humidity, > + NULL, 0); > + > +static struct attribute *hih613x_attributes[] = { > + &sensor_dev_attr_temp1_input.dev_attr.attr, > + &sensor_dev_attr_humidity1_input.dev_attr.attr, > + NULL > +}; > + > +static const struct attribute_group hih613x_attr_group = { > + .attrs = hih613x_attributes, > +}; > + > +/** > + * hih613x_probe() - probe device > + * @client: I2C client device > + * @id: device ID > + * > + * Called by the I2C core when an entry in the ID table matches a > + * device's name. > + * Returns 0 on success. > + */ > +static int __devinit hih613x_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct hih613x *hih613x; > + int err; > + > + if (!i2c_check_functionality(client->adapter, > + I2C_FUNC_I2C)) { This does not need two lines. > + dev_err(&client->dev, > + "adapter does not support true I2C\n"); Does not need two lines. > + return -ENODEV; > + } > + > + hih613x = devm_kzalloc(&client->dev, sizeof(*hih613x), GFP_KERNEL); > + if (!hih613x) { > + dev_dbg(&client->dev, "devm_kzalloc failed\n"); The calling code dumps a message, so this dev_dbg is unnecessary. > + return -ENOMEM; > + } > + > + i2c_set_clientdata(client, hih613x); > + > + mutex_init(&hih613x->lock); > + > + err = sysfs_create_group(&client->dev.kobj, &hih613x_attr_group); > + if (err) { > + dev_dbg(&client->dev, "could not create sysfs files\n"); > + return err; > + } > + > + hih613x->hwmon_dev = hwmon_device_register(&client->dev); > + if (IS_ERR(hih613x->hwmon_dev)) { > + dev_dbg(&client->dev, "unable to register hwmon device\n"); > + err = PTR_ERR(hih613x->hwmon_dev); > + goto fail_remove_sysfs; > + } > + > + dev_info(&client->dev, "initialized\n"); Is this valuable or just noise ? > + > + return 0; > + > +fail_remove_sysfs: > + sysfs_remove_group(&client->dev.kobj, &hih613x_attr_group); > + return err; > +} > + > +/** > + * hih613x_remove() - remove device > + * @client: I2C client device > + */ > +static int __devexit hih613x_remove(struct i2c_client *client) > +{ > + struct hih613x *hih613x = i2c_get_clientdata(client); > + > + hwmon_device_unregister(hih613x->hwmon_dev); > + sysfs_remove_group(&client->dev.kobj, &hih613x_attr_group); > + > + return 0; > +} > + > +/* Device ID table */ > +static const struct i2c_device_id hih613x_id[] = { > + { "hih613x", 0 }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, hih613x_id); > + > +static struct i2c_driver hih613x_driver = { > + .driver.name = "hih613x", > + .probe = hih613x_probe, > + .remove = __devexit_p(hih613x_remove), > + .id_table = hih613x_id, > +}; > + > +module_i2c_driver(hih613x_driver); > + > +MODULE_AUTHOR("Iain Paton <ipaton0@xxxxxxxxx>"); > +MODULE_DESCRIPTION("Honeywell HIH-613x humidity and temperature sensor driver"); > +MODULE_LICENSE("GPL"); > _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
