Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752770Ab3H3DfS (ORCPT ); Thu, 29 Aug 2013 23:35:18 -0400 Received: from mail.active-venture.com ([67.228.131.205]:53290 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751941Ab3H3DfQ (ORCPT ); Thu, 29 Aug 2013 23:35:16 -0400 X-Originating-IP: 108.223.40.66 Message-ID: <522012F1.5040309@roeck-us.net> Date: Thu, 29 Aug 2013 20:35:13 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130803 Thunderbird/17.0.8 MIME-Version: 1.0 To: "Markezana, William" CC: khali@linux-fr.org, lm-sensors@lm-sensors.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] hwmon: (htu21) Add Measurement Specialties HTU21D support References: <20130828161804.GB5278@roeck-us.net> <20130829094052.GA19239@roeck-us.net> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10511 Lines: 311 On 08/29/2013 04:51 AM, Markezana, William wrote: > From: William Markezana > > hwmon: (htu21) Add Measurement Specialties HTU21D support > Signed-off-by: William Markezana > --- Applied [ with minor formatting changes ] to -next. Thanks, Guenter > diff --git a/Documentation/hwmon/htu21 b/Documentation/hwmon/htu21 > new file mode 100644 > index 0000000..8082879 > --- /dev/null > +++ b/Documentation/hwmon/htu21 > @@ -0,0 +1,46 @@ > +Kernel driver htu21 > +=================== > + > +Supported chips: > + * Measurement Specialties HTU21D > + Prefix: 'htu21' > + Addresses scanned: none > + Datasheet: Publicly available at the Measurement Specialties website > + http://www.meas-spec.com/downloads/HTU21D.pdf > + > + > +Author: > + William Markezana > + > +Description > +----------- > + > +The HTU21D is a humidity and temperature sensor in a DFN package of > +only 3 x 3 mm footprint and 0.9 mm height. > + > +The devices communicate with the I2C protocol. All sensors are set to the > +same I2C address 0x40, so an entry with I2C_BOARD_INFO("htu21", 0x40) can > +be used in the board setup code. > + > +This driver does not auto-detect devices. You will have to instantiate the > +devices explicitly. Please see Documentation/i2c/instantiating-devices > +for details." > + > +sysfs-Interface > +--------------- > + > +temp1_input - temperature input > +humidity1_input - humidity input > + > +Notes > +----- > + > +The driver uses the default resolution settings of 12 bit for humidity and 14 > +bit for temperature, which results in typical measurement times of 11 ms for > +humidity and 44 ms for temperature. To keep self heating below 0.1 degree > +Celsius, the device should not be active for more than 10% of the time. For > +this reason, the driver performs no more than two measurements per second and > +reports cached information if polled more frequently. > + > +Different resolutions, the on-chip heater, using the CRC checksum and reading > +the serial number are not supported yet. > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index e989f7f..55973cd 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -511,6 +511,16 @@ config SENSORS_HIH6130 > This driver can also be built as a module. If so, the module > will be called hih6130. > > +config SENSORS_HTU21 > + tristate "Measurement Specialties HTU21D humidity/temperature sensors" > + depends on I2C > + help > + If you say yes here you get support for the Measurement Specialties > + HTU21D humidity and temperature sensors. > + > + This driver can also be built as a module. If so, the module > + will be called htu21. > + > config SENSORS_CORETEMP > tristate "Intel Core/Core2/Atom temperature sensor" > depends on X86 > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index 4f0fb52..ec7cde0 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -65,6 +65,7 @@ obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o > obj-$(CONFIG_SENSORS_GL520SM) += gl520sm.o > obj-$(CONFIG_SENSORS_GPIO_FAN) += gpio-fan.o > obj-$(CONFIG_SENSORS_HIH6130) += hih6130.o > +obj-$(CONFIG_SENSORS_HTU21) += htu21.o > obj-$(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/htu21.c b/drivers/hwmon/htu21.c > new file mode 100644 > index 0000000..743bf32 > --- /dev/null > +++ b/drivers/hwmon/htu21.c > @@ -0,0 +1,201 @@ > +/* > + * Measurement Specialties HTU21D humidity and temperature sensor driver > + * > + * Copyright (C) 2013 William Markezana > + * > + * 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 > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/* HTU21 Commands */ > +#define HTU21_T_MEASUREMENT_HM 0xE3 > +#define HTU21_RH_MEASUREMENT_HM 0xE5 > + > +struct htu21 { > + struct device *hwmon_dev; > + struct mutex lock; > + bool valid; > + unsigned long last_update; > + int temperature; > + int humidity; > +}; > + > +static inline int htu21_temp_ticks_to_millicelsius(int ticks) > +{ > + ticks &= ~0x0003; /* clear status bits */ > + /* > + * Formula T = -46.85 + 175.72 * ST / 2^16 from datasheet p14, > + * optimized for integer fixed point (3 digits) arithmetic > + */ > + return ((21965 * ticks) >> 13) - 46850; > +} > + > +static inline int htu21_rh_ticks_to_per_cent_mille(int ticks) > +{ > + ticks &= ~0x0003; /* clear status bits */ > + /* > + * Formula RH = -6 + 125 * SRH / 2^16 from datasheet p14, > + * optimized for integer fixed point (3 digits) arithmetic > + */ > + return ((15625 * ticks) >> 13) - 6000; > +} > + > +static int htu21_update_measurements(struct i2c_client *client) > +{ > + int ret = 0; > + struct htu21 *htu21 = i2c_get_clientdata(client); > + > + mutex_lock(&htu21->lock); > + > + if (time_after(jiffies, htu21->last_update + HZ / 2) || > + !htu21->valid) { > + ret = i2c_smbus_read_word_swapped(client, > + HTU21_T_MEASUREMENT_HM); > + if (ret < 0) > + goto out; > + htu21->temperature = htu21_temp_ticks_to_millicelsius(ret); > + ret = i2c_smbus_read_word_swapped(client, > + HTU21_RH_MEASUREMENT_HM); > + if (ret < 0) > + goto out; > + htu21->humidity = htu21_rh_ticks_to_per_cent_mille(ret); > + htu21->last_update = jiffies; > + htu21->valid = true; > + } > +out: > + mutex_unlock(&htu21->lock); > + > + return ret >= 0 ? 0 : ret; > +} > + > +static ssize_t htu21_show_temperature(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct htu21 *htu21 = i2c_get_clientdata(client); > + int ret = htu21_update_measurements(client); > + if (ret < 0) > + return ret; > + return sprintf(buf, "%d\n", htu21->temperature); > +} > + > +static ssize_t htu21_show_humidity(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct htu21 *htu21 = i2c_get_clientdata(client); > + int ret = htu21_update_measurements(client); > + if (ret < 0) > + return ret; > + return sprintf(buf, "%d\n", htu21->humidity); > +} > + > +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, > + htu21_show_temperature, NULL, 0); > +static SENSOR_DEVICE_ATTR(humidity1_input, S_IRUGO, > + htu21_show_humidity, NULL, 0); > + > +static struct attribute *htu21_attributes[] = { > + &sensor_dev_attr_temp1_input.dev_attr.attr, > + &sensor_dev_attr_humidity1_input.dev_attr.attr, > + NULL > +}; > + > +static const struct attribute_group htu21_group = { > + .attrs = htu21_attributes, > +}; > + > +static int htu21_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct htu21 *htu21; > + int err; > + > + if (!i2c_check_functionality(client->adapter, > + I2C_FUNC_SMBUS_READ_WORD_DATA)) { > + dev_err(&client->dev, > + "adapter does not support SMBus word transactions\n"); > + return -ENODEV; > + } > + > + htu21 = devm_kzalloc(&client->dev, sizeof(*htu21), GFP_KERNEL); > + if (!htu21) > + return -ENOMEM; > + > + i2c_set_clientdata(client, htu21); > + > + mutex_init(&htu21->lock); > + > + err = sysfs_create_group(&client->dev.kobj, &htu21_group); > + if (err) { > + dev_dbg(&client->dev, "could not create sysfs files\n"); > + return err; > + } > + htu21->hwmon_dev = hwmon_device_register(&client->dev); > + if (IS_ERR(htu21->hwmon_dev)) { > + dev_dbg(&client->dev, "unable to register hwmon device\n"); > + err = PTR_ERR(htu21->hwmon_dev); > + goto error; > + } > + > + dev_info(&client->dev, "initialized\n"); > + > + return 0; > + > +error: > + sysfs_remove_group(&client->dev.kobj, &htu21_group); > + return err; > +} > + > +static int htu21_remove(struct i2c_client *client) > +{ > + struct htu21 *htu21 = i2c_get_clientdata(client); > + > + hwmon_device_unregister(htu21->hwmon_dev); > + sysfs_remove_group(&client->dev.kobj, &htu21_group); > + > + return 0; > +} > + > +static const struct i2c_device_id htu21_id[] = { > + { "htu21", 0 }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, htu21_id); > + > +static struct i2c_driver htu21_driver = { > + .class = I2C_CLASS_HWMON, > + .driver = { > + .name = "htu21", > + }, > + .probe = htu21_probe, > + .remove = htu21_remove, > + .id_table = htu21_id, > +}; > + > +module_i2c_driver(htu21_driver); > + > +MODULE_AUTHOR("William Markezana "); > +MODULE_DESCRIPTION("MEAS HTU21D humidity and temperature sensor driver"); > +MODULE_LICENSE("GPL"); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/