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hwmon: (shtc1) add support for the SHTC3 sensor 

Add support for the Sensirion SHTC3 humidity and temperature sensor to
the shtc1 module.

Signed-off-by: Dan Robertson <dan@dlrobertson.com>
Link: https://lore.kernel.org/r/20190905014554.21658-2-dan@dlrobertson.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Dan Robertson 2019-09-05 01:45:53 +00:00 committed by Guenter Roeck
parent fdc7d8e829
commit ffd96868ac
3 changed files with 59 additions and 21 deletions
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19
Documentation/hwmon/shtc1.rst
View File

@ -19,7 +19,17 @@ Supported chips:
Addresses scanned: none
Datasheet: Not publicly available
Datasheet: http://www.sensirion.com/file/datasheet_shtw1
* Sensirion SHTC3
Prefix: 'shtc3'
Addresses scanned: none
Datasheet: http://www.sensirion.com/file/datasheet_shtc3
@ -30,10 +40,9 @@ Author:
Description
-----------
This driver implements support for the Sensirion SHTC1 chip, a humidity and
temperature sensor. Temperature is measured in degrees celsius, relative
humidity is expressed as a percentage. Driver can be used as well for SHTW1
chip, which has the same electrical interface.
This driver implements support for the Sensirion SHTC1, SHTW1, and SHTC3
chips, a humidity and temperature sensor. Temperature is measured in degrees
celsius, relative humidity is expressed as a percentage.
The device communicates with the I2C protocol. All sensors are set to I2C
address 0x70. See Documentation/i2c/instantiating-devices for methods to

4
drivers/hwmon/Kconfig
View File

@ -1392,8 +1392,8 @@ config SENSORS_SHTC1
tristate "Sensiron humidity and temperature sensors. SHTC1 and compat."
depends on I2C
help
If you say yes here you get support for the Sensiron SHTC1 and SHTW1
humidity and temperature sensors.
If you say yes here you get support for the Sensiron SHTC1, SHTW1,
and SHTC3 humidity and temperature sensors.
This driver can also be built as a module. If so, the module
will be called shtc1.

57
drivers/hwmon/shtc1.c
View File

@ -24,19 +24,33 @@ static const unsigned char shtc1_cmd_measure_blocking_lpm[] = { 0x64, 0x58 };
static const unsigned char shtc1_cmd_measure_nonblocking_lpm[] = { 0x60, 0x9c };
/* command for reading the ID register */
static const unsigned char shtc1_cmd_read_id_reg[] = { 0xef, 0xc8 };
static const unsigned char shtc1_cmd_read_id_reg[] = { 0xef, 0xc8 };
/* constants for reading the ID register */
#define SHTC1_ID 0x07
#define SHTC1_ID_REG_MASK 0x3f
/*
* constants for reading the ID register
* SHTC1: 0x0007 with mask 0x003f
* SHTW1: 0x0007 with mask 0x003f
* SHTC3: 0x0807 with mask 0x083f
*/
#define SHTC3_ID 0x0807
#define SHTC3_ID_MASK 0x083f
#define SHTC1_ID 0x0007
#define SHTC1_ID_MASK 0x003f
/* delays for non-blocking i2c commands, both in us */
#define SHTC1_NONBLOCKING_WAIT_TIME_HPM 14400
#define SHTC1_NONBLOCKING_WAIT_TIME_LPM 1000
#define SHTC3_NONBLOCKING_WAIT_TIME_HPM 12100
#define SHTC3_NONBLOCKING_WAIT_TIME_LPM 800
#define SHTC1_CMD_LENGTH 2
#define SHTC1_RESPONSE_LENGTH 6
enum shtcx_chips {
shtc1,
shtc3,
};
struct shtc1_data {
struct i2c_client *client;
struct mutex update_lock;
@ -47,6 +61,7 @@ struct shtc1_data {
unsigned int nonblocking_wait_time; /* in us */
struct shtc1_platform_data setup;
enum shtcx_chips chip;
int temperature; /* 1000 * temperature in dgr C */
int humidity; /* 1000 * relative humidity in %RH */
@ -157,13 +172,16 @@ static void shtc1_select_command(struct shtc1_data *data)
data->command = data->setup.blocking_io ?
shtc1_cmd_measure_blocking_hpm :
shtc1_cmd_measure_nonblocking_hpm;
data->nonblocking_wait_time = SHTC1_NONBLOCKING_WAIT_TIME_HPM;
data->nonblocking_wait_time = (data->chip == shtc1) ?
SHTC1_NONBLOCKING_WAIT_TIME_HPM :
SHTC3_NONBLOCKING_WAIT_TIME_HPM;
} else {
data->command = data->setup.blocking_io ?
shtc1_cmd_measure_blocking_lpm :
shtc1_cmd_measure_nonblocking_lpm;
data->nonblocking_wait_time = SHTC1_NONBLOCKING_WAIT_TIME_LPM;
data->nonblocking_wait_time = (data->chip == shtc1) ?
SHTC1_NONBLOCKING_WAIT_TIME_LPM :
SHTC3_NONBLOCKING_WAIT_TIME_LPM;
}
}
@ -171,9 +189,11 @@ static int shtc1_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int ret;
char id_reg[2];
u16 id_reg;
char id_reg_buf[2];
struct shtc1_data *data;
struct device *hwmon_dev;
enum shtcx_chips chip = id->driver_data;
struct i2c_adapter *adap = client->adapter;
struct device *dev = &client->dev;
@ -187,13 +207,20 @@ static int shtc1_probe(struct i2c_client *client,
dev_err(dev, "could not send read_id_reg command: %d\n", ret);
return ret < 0 ? ret : -ENODEV;
}
ret = i2c_master_recv(client, id_reg, sizeof(id_reg));
if (ret != sizeof(id_reg)) {
ret = i2c_master_recv(client, id_reg_buf, sizeof(id_reg_buf));
if (ret != sizeof(id_reg_buf)) {
dev_err(dev, "could not read ID register: %d\n", ret);
return -ENODEV;
}
if ((id_reg[1] & SHTC1_ID_REG_MASK) != SHTC1_ID) {
dev_err(dev, "ID register doesn't match\n");
id_reg = be16_to_cpup((__be16 *)id_reg_buf);
if (chip == shtc3) {
if ((id_reg & SHTC3_ID_MASK) != SHTC3_ID) {
dev_err(dev, "SHTC3 ID register does not match\n");
return -ENODEV;
}
} else if ((id_reg & SHTC1_ID_MASK) != SHTC1_ID) {
dev_err(dev, "SHTC1 ID register does not match\n");
return -ENODEV;
}
@ -204,6 +231,7 @@ static int shtc1_probe(struct i2c_client *client,
data->setup.blocking_io = false;
data->setup.high_precision = true;
data->client = client;
data->chip = chip;
if (client->dev.platform_data)
data->setup = *(struct shtc1_platform_data *)dev->platform_data;
@ -222,8 +250,9 @@ static int shtc1_probe(struct i2c_client *client,
/* device ID table */
static const struct i2c_device_id shtc1_id[] = {
{ "shtc1", 0 },
{ "shtw1", 0 },
{ "shtc1", shtc1 },
{ "shtw1", shtc1 },
{ "shtc3", shtc3 },
{ }
};
MODULE_DEVICE_TABLE(i2c, shtc1_id);