| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Urs Fleisch | 620 | 57.78% | 1 | 6.67% |
| Peter A. Bigot | 354 | 32.99% | 1 | 6.67% |
| Axel Lin | 76 | 7.08% | 2 | 13.33% |
| Guenter Roeck | 10 | 0.93% | 3 | 20.00% |
| Darrick J. Wong | 3 | 0.28% | 1 | 6.67% |
| Jean Delvare | 2 | 0.19% | 1 | 6.67% |
| Randy Dunlap | 2 | 0.19% | 1 | 6.67% |
| Paul Fertser | 2 | 0.19% | 1 | 6.67% |
| Alexander A. Klimov | 1 | 0.09% | 1 | 6.67% |
| Andy Shevchenko | 1 | 0.09% | 1 | 6.67% |
| Thomas Gleixner | 1 | 0.09% | 1 | 6.67% |
| Uwe Kleine-König | 1 | 0.09% | 1 | 6.67% |
| Total | 1073 | 15 |
// SPDX-License-Identifier: GPL-2.0-or-later /* Sensirion SHT21 humidity and temperature sensor driver * * Copyright (C) 2010 Urs Fleisch <urs.fleisch@sensirion.com> * * Data sheet available at https://www.sensirion.com/file/datasheet_sht21 */ #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/jiffies.h> /* I2C command bytes */ #define SHT21_TRIG_T_MEASUREMENT_HM 0xe3 #define SHT21_TRIG_RH_MEASUREMENT_HM 0xe5 #define SHT21_READ_SNB_CMD1 0xFA #define SHT21_READ_SNB_CMD2 0x0F #define SHT21_READ_SNAC_CMD1 0xFC #define SHT21_READ_SNAC_CMD2 0xC9 /** * struct sht21 - SHT21 device specific data * @client: I2C client device * @lock: mutex to protect measurement values * @last_update: time of last update (jiffies) * @temperature: cached temperature measurement value * @humidity: cached humidity measurement value * @valid: only 0 before first measurement is taken * @eic: cached electronic identification code text */ struct sht21 { struct i2c_client *client; struct mutex lock; unsigned long last_update; int temperature; int humidity; bool valid; char eic[18]; }; /** * sht21_temp_ticks_to_millicelsius() - convert raw temperature ticks to * milli celsius * @ticks: temperature ticks value received from sensor */ static inline int sht21_temp_ticks_to_millicelsius(int ticks) { ticks &= ~0x0003; /* clear status bits */ /* * Formula T = -46.85 + 175.72 * ST / 2^16 from data sheet 6.2, * optimized for integer fixed point (3 digits) arithmetic */ return ((21965 * ticks) >> 13) - 46850; } /** * sht21_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 sht21_rh_ticks_to_per_cent_mille(int ticks) { ticks &= ~0x0003; /* clear status bits */ /* * Formula RH = -6 + 125 * SRH / 2^16 from data sheet 6.1, * optimized for integer fixed point (3 digits) arithmetic */ return ((15625 * ticks) >> 13) - 6000; } /** * sht21_update_measurements() - get updated measurements from device * @dev: device * * Returns 0 on success, else negative errno. */ static int sht21_update_measurements(struct device *dev) { int ret = 0; struct sht21 *sht21 = dev_get_drvdata(dev); struct i2c_client *client = sht21->client; mutex_lock(&sht21->lock); /* * Data sheet 2.4: * SHT2x should not be active for more than 10% of the time - e.g. * maximum two measurements per second at 12bit accuracy shall be made. */ if (time_after(jiffies, sht21->last_update + HZ / 2) || !sht21->valid) { ret = i2c_smbus_read_word_swapped(client, SHT21_TRIG_T_MEASUREMENT_HM); if (ret < 0) goto out; sht21->temperature = sht21_temp_ticks_to_millicelsius(ret); ret = i2c_smbus_read_word_swapped(client, SHT21_TRIG_RH_MEASUREMENT_HM); if (ret < 0) goto out; sht21->humidity = sht21_rh_ticks_to_per_cent_mille(ret); sht21->last_update = jiffies; sht21->valid = true; } out: mutex_unlock(&sht21->lock); return ret >= 0 ? 0 : ret; } /** * sht21_temperature_show() - 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 sht21_temperature_show(struct device *dev, struct device_attribute *attr, char *buf) { struct sht21 *sht21 = dev_get_drvdata(dev); int ret; ret = sht21_update_measurements(dev); if (ret < 0) return ret; return sprintf(buf, "%d\n", sht21->temperature); } /** * sht21_humidity_show() - 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 sht21_humidity_show(struct device *dev, struct device_attribute *attr, char *buf) { struct sht21 *sht21 = dev_get_drvdata(dev); int ret; ret = sht21_update_measurements(dev); if (ret < 0) return ret; return sprintf(buf, "%d\n", sht21->humidity); } static ssize_t eic_read(struct sht21 *sht21) { struct i2c_client *client = sht21->client; u8 tx[2]; u8 rx[8]; u8 eic[8]; struct i2c_msg msgs[2] = { { .addr = client->addr, .flags = 0, .len = 2, .buf = tx, }, { .addr = client->addr, .flags = I2C_M_RD, .len = 8, .buf = rx, }, }; int ret; tx[0] = SHT21_READ_SNB_CMD1; tx[1] = SHT21_READ_SNB_CMD2; ret = i2c_transfer(client->adapter, msgs, 2); if (ret < 0) goto out; eic[2] = rx[0]; eic[3] = rx[2]; eic[4] = rx[4]; eic[5] = rx[6]; tx[0] = SHT21_READ_SNAC_CMD1; tx[1] = SHT21_READ_SNAC_CMD2; msgs[1].len = 6; ret = i2c_transfer(client->adapter, msgs, 2); if (ret < 0) goto out; eic[0] = rx[3]; eic[1] = rx[4]; eic[6] = rx[0]; eic[7] = rx[1]; ret = snprintf(sht21->eic, sizeof(sht21->eic), "%8phN\n", eic); out: if (ret < 0) sht21->eic[0] = 0; return ret; } /** * eic_show() - show Electronic Identification Code in sysfs * @dev: device * @attr: device attribute * @buf: sysfs buffer (PAGE_SIZE) where EIC is written * * Will be called on read access to eic sysfs attribute. * Returns number of bytes written into buffer, negative errno on error. */ static ssize_t eic_show(struct device *dev, struct device_attribute *attr, char *buf) { struct sht21 *sht21 = dev_get_drvdata(dev); int ret; ret = sizeof(sht21->eic) - 1; mutex_lock(&sht21->lock); if (!sht21->eic[0]) ret = eic_read(sht21); if (ret > 0) memcpy(buf, sht21->eic, ret); mutex_unlock(&sht21->lock); return ret; } /* sysfs attributes */ static SENSOR_DEVICE_ATTR_RO(temp1_input, sht21_temperature, 0); static SENSOR_DEVICE_ATTR_RO(humidity1_input, sht21_humidity, 0); static DEVICE_ATTR_RO(eic); static struct attribute *sht21_attrs[] = { &sensor_dev_attr_temp1_input.dev_attr.attr, &sensor_dev_attr_humidity1_input.dev_attr.attr, &dev_attr_eic.attr, NULL }; ATTRIBUTE_GROUPS(sht21); static int sht21_probe(struct i2c_client *client) { struct device *dev = &client->dev; struct device *hwmon_dev; struct sht21 *sht21; if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) { dev_err(&client->dev, "adapter does not support SMBus word transactions\n"); return -ENODEV; } sht21 = devm_kzalloc(dev, sizeof(*sht21), GFP_KERNEL); if (!sht21) return -ENOMEM; sht21->client = client; mutex_init(&sht21->lock); hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, sht21, sht21_groups); return PTR_ERR_OR_ZERO(hwmon_dev); } /* Device ID table */ static const struct i2c_device_id sht21_id[] = { { "sht21" }, { } }; MODULE_DEVICE_TABLE(i2c, sht21_id); static struct i2c_driver sht21_driver = { .driver.name = "sht21", .probe = sht21_probe, .id_table = sht21_id, }; module_i2c_driver(sht21_driver); MODULE_AUTHOR("Urs Fleisch <urs.fleisch@sensirion.com>"); MODULE_DESCRIPTION("Sensirion SHT21 humidity and temperature sensor driver"); MODULE_LICENSE("GPL");