hwmon: (sht21) Add Electronic Identification Code retrieval (53e678d7) · Commits · e / devices / android_kernel_oneplus_sm8150

Documentation/hwmon/sht21

+3 −2

Original line number	Original line	Diff line number	Diff line
	@@ -35,6 +35,7 @@ sysfs-Interface

	temp1_input - temperature input		temp1_input - temperature input
	humidity1_input - humidity input		humidity1_input - humidity input
			eic - Electronic Identification Code

	Notes		Notes
	-----		-----
	@@ -45,5 +46,5 @@ humidity and 66 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,		Celsius, the device should not be active for more than 10% of the time,
	e.g. maximum two measurements per second at the given resolution.		e.g. maximum two measurements per second at the given resolution.

	Different resolutions, the on-chip heater, using the CRC checksum and reading		Different resolutions, the on-chip heater, and using the CRC checksum
	the serial number are not supported yet.		are not supported yet.

drivers/hwmon/sht21.c

+90 −2

Original line number	Original line	Diff line number	Diff line
	@@ -34,23 +34,29 @@
	/* I2C command bytes */		/* I2C command bytes */
	#define SHT21_TRIG_T_MEASUREMENT_HM 0xe3		#define SHT21_TRIG_T_MEASUREMENT_HM 0xe3
	#define SHT21_TRIG_RH_MEASUREMENT_HM 0xe5		#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		* struct sht21 - SHT21 device specific data
	* @hwmon_dev: device registered with hwmon		* @hwmon_dev: device registered with hwmon
	* @lock: mutex to protect measurement values		* @lock: mutex to protect measurement values
	* @valid: only 0 before first measurement is taken
	* @last_update: time of last update (jiffies)		* @last_update: time of last update (jiffies)
	* @temperature: cached temperature measurement value		* @temperature: cached temperature measurement value
	* @humidity: cached humidity measurement value		* @humidity: cached humidity measurement value
			* @valid: only 0 before first measurement is taken
			* @eic: cached electronic identification code text
	*/		*/
	struct sht21 {		struct sht21 {
	struct i2c_client *client;		struct i2c_client *client;
	struct mutex lock;		struct mutex lock;
	char valid;
	unsigned long last_update;		unsigned long last_update;
	int temperature;		int temperature;
	int humidity;		int humidity;
			char valid;
			char eic[18];
	};		};

	/**		/**
	@@ -165,15 +171,97 @@ static ssize_t sht21_show_humidity(struct device *dev,
	return sprintf(buf, "%d\n", sht21->humidity);		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),
			"%02x%02x%02x%02x%02x%02x%02x%02x\n",
			eic[0], eic[1], eic[2], eic[3],
			eic[4], eic[5], eic[6], eic[7]);
			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 */		/* sysfs attributes */
	static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, sht21_show_temperature,		static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, sht21_show_temperature,
	NULL, 0);		NULL, 0);
	static SENSOR_DEVICE_ATTR(humidity1_input, S_IRUGO, sht21_show_humidity,		static SENSOR_DEVICE_ATTR(humidity1_input, S_IRUGO, sht21_show_humidity,
	NULL, 0);		NULL, 0);
			static DEVICE_ATTR_RO(eic);

	static struct attribute *sht21_attrs[] = {		static struct attribute *sht21_attrs[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,		&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_humidity1_input.dev_attr.attr,		&sensor_dev_attr_humidity1_input.dev_attr.attr,
			&dev_attr_eic.attr,
	NULL		NULL
	};		};