2019-05-27 09:55:06 +03:00
// SPDX-License-Identifier: GPL-2.0-or-later
2016-06-02 10:59:11 +03:00
/* Sensirion SHT3x-DIS humidity and temperature sensor driver.
* The SHT3x comes in many different versions , this driver is for the
* I2C version only .
*
* Copyright ( C ) 2016 Sensirion AG , Switzerland
* Author : David Frey < david . frey @ sensirion . com >
* Author : Pascal Sachs < pascal . sachs @ sensirion . com >
*/
# include <asm/page.h>
# include <linux/crc8.h>
# include <linux/delay.h>
# include <linux/err.h>
# include <linux/hwmon.h>
# include <linux/hwmon-sysfs.h>
# include <linux/i2c.h>
# include <linux/init.h>
# include <linux/kernel.h>
# include <linux/module.h>
# include <linux/slab.h>
# include <linux/jiffies.h>
# include <linux/platform_data/sht3x.h>
/* commands (high precision mode) */
static const unsigned char sht3x_cmd_measure_blocking_hpm [ ] = { 0x2c , 0x06 } ;
static const unsigned char sht3x_cmd_measure_nonblocking_hpm [ ] = { 0x24 , 0x00 } ;
/* commands (low power mode) */
static const unsigned char sht3x_cmd_measure_blocking_lpm [ ] = { 0x2c , 0x10 } ;
static const unsigned char sht3x_cmd_measure_nonblocking_lpm [ ] = { 0x24 , 0x16 } ;
/* commands for periodic mode */
static const unsigned char sht3x_cmd_measure_periodic_mode [ ] = { 0xe0 , 0x00 } ;
static const unsigned char sht3x_cmd_break [ ] = { 0x30 , 0x93 } ;
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/* commands for heater control */
static const unsigned char sht3x_cmd_heater_on [ ] = { 0x30 , 0x6d } ;
static const unsigned char sht3x_cmd_heater_off [ ] = { 0x30 , 0x66 } ;
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/* other commands */
static const unsigned char sht3x_cmd_read_status_reg [ ] = { 0xf3 , 0x2d } ;
static const unsigned char sht3x_cmd_clear_status_reg [ ] = { 0x30 , 0x41 } ;
/* delays for non-blocking i2c commands, both in us */
# define SHT3X_NONBLOCKING_WAIT_TIME_HPM 15000
# define SHT3X_NONBLOCKING_WAIT_TIME_LPM 4000
# define SHT3X_WORD_LEN 2
# define SHT3X_CMD_LENGTH 2
# define SHT3X_CRC8_LEN 1
# define SHT3X_RESPONSE_LENGTH 6
# define SHT3X_CRC8_POLYNOMIAL 0x31
# define SHT3X_CRC8_INIT 0xFF
# define SHT3X_MIN_TEMPERATURE -45000
# define SHT3X_MAX_TEMPERATURE 130000
# define SHT3X_MIN_HUMIDITY 0
# define SHT3X_MAX_HUMIDITY 100000
enum sht3x_chips {
sht3x ,
sts3x ,
} ;
enum sht3x_limits {
limit_max = 0 ,
limit_max_hyst ,
limit_min ,
limit_min_hyst ,
} ;
DECLARE_CRC8_TABLE ( sht3x_crc8_table ) ;
/* periodic measure commands (high precision mode) */
static const char periodic_measure_commands_hpm [ ] [ SHT3X_CMD_LENGTH ] = {
/* 0.5 measurements per second */
{ 0x20 , 0x32 } ,
/* 1 measurements per second */
{ 0x21 , 0x30 } ,
/* 2 measurements per second */
{ 0x22 , 0x36 } ,
/* 4 measurements per second */
{ 0x23 , 0x34 } ,
/* 10 measurements per second */
{ 0x27 , 0x37 } ,
} ;
/* periodic measure commands (low power mode) */
static const char periodic_measure_commands_lpm [ ] [ SHT3X_CMD_LENGTH ] = {
/* 0.5 measurements per second */
{ 0x20 , 0x2f } ,
/* 1 measurements per second */
{ 0x21 , 0x2d } ,
/* 2 measurements per second */
{ 0x22 , 0x2b } ,
/* 4 measurements per second */
{ 0x23 , 0x29 } ,
/* 10 measurements per second */
{ 0x27 , 0x2a } ,
} ;
struct sht3x_limit_commands {
const char read_command [ SHT3X_CMD_LENGTH ] ;
const char write_command [ SHT3X_CMD_LENGTH ] ;
} ;
static const struct sht3x_limit_commands limit_commands [ ] = {
/* temp1_max, humidity1_max */
[ limit_max ] = { { 0xe1 , 0x1f } , { 0x61 , 0x1d } } ,
/* temp_1_max_hyst, humidity1_max_hyst */
[ limit_max_hyst ] = { { 0xe1 , 0x14 } , { 0x61 , 0x16 } } ,
/* temp1_min, humidity1_min */
[ limit_min ] = { { 0xe1 , 0x02 } , { 0x61 , 0x00 } } ,
/* temp_1_min_hyst, humidity1_min_hyst */
[ limit_min_hyst ] = { { 0xe1 , 0x09 } , { 0x61 , 0x0B } } ,
} ;
# define SHT3X_NUM_LIMIT_CMD ARRAY_SIZE(limit_commands)
static const u16 mode_to_update_interval [ ] = {
0 ,
2000 ,
1000 ,
500 ,
250 ,
100 ,
} ;
struct sht3x_data {
struct i2c_client * client ;
struct mutex i2c_lock ; /* lock for sending i2c commands */
struct mutex data_lock ; /* lock for updating driver data */
u8 mode ;
const unsigned char * command ;
u32 wait_time ; /* in us*/
unsigned long last_update ; /* last update in periodic mode*/
struct sht3x_platform_data setup ;
/*
* cached values for temperature and humidity and limits
* the limits arrays have the following order :
* max , max_hyst , min , min_hyst
*/
int temperature ;
int temperature_limits [ SHT3X_NUM_LIMIT_CMD ] ;
u32 humidity ;
u32 humidity_limits [ SHT3X_NUM_LIMIT_CMD ] ;
} ;
static u8 get_mode_from_update_interval ( u16 value )
{
size_t index ;
u8 number_of_modes = ARRAY_SIZE ( mode_to_update_interval ) ;
if ( value = = 0 )
return 0 ;
/* find next faster update interval */
for ( index = 1 ; index < number_of_modes ; index + + ) {
if ( mode_to_update_interval [ index ] < = value )
return index ;
}
return number_of_modes - 1 ;
}
static int sht3x_read_from_command ( struct i2c_client * client ,
struct sht3x_data * data ,
const char * command ,
char * buf , int length , u32 wait_time )
{
int ret ;
mutex_lock ( & data - > i2c_lock ) ;
ret = i2c_master_send ( client , command , SHT3X_CMD_LENGTH ) ;
if ( ret ! = SHT3X_CMD_LENGTH ) {
ret = ret < 0 ? ret : - EIO ;
goto out ;
}
if ( wait_time )
usleep_range ( wait_time , wait_time + 1000 ) ;
ret = i2c_master_recv ( client , buf , length ) ;
if ( ret ! = length ) {
ret = ret < 0 ? ret : - EIO ;
goto out ;
}
ret = 0 ;
out :
mutex_unlock ( & data - > i2c_lock ) ;
return ret ;
}
static int sht3x_extract_temperature ( u16 raw )
{
/*
* From datasheet :
* T = - 45 + 175 * ST / 2 ^ 16
* Adapted for integer fixed point ( 3 digit ) arithmetic .
*/
return ( ( 21875 * ( int ) raw ) > > 13 ) - 45000 ;
}
static u32 sht3x_extract_humidity ( u16 raw )
{
/*
* From datasheet :
* RH = 100 * SRH / 2 ^ 16
* Adapted for integer fixed point ( 3 digit ) arithmetic .
*/
return ( 12500 * ( u32 ) raw ) > > 13 ;
}
static struct sht3x_data * sht3x_update_client ( struct device * dev )
{
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
struct i2c_client * client = data - > client ;
u16 interval_ms = mode_to_update_interval [ data - > mode ] ;
unsigned long interval_jiffies = msecs_to_jiffies ( interval_ms ) ;
unsigned char buf [ SHT3X_RESPONSE_LENGTH ] ;
u16 val ;
int ret = 0 ;
mutex_lock ( & data - > data_lock ) ;
/*
* Only update cached readings once per update interval in periodic
* mode . In single shot mode the sensor measures values on demand , so
* every time the sysfs interface is called , a measurement is triggered .
* In periodic mode however , the measurement process is handled
* internally by the sensor and reading out sensor values only makes
* sense if a new reading is available .
*/
if ( time_after ( jiffies , data - > last_update + interval_jiffies ) ) {
ret = sht3x_read_from_command ( client , data , data - > command , buf ,
sizeof ( buf ) , data - > wait_time ) ;
if ( ret )
goto out ;
val = be16_to_cpup ( ( __be16 * ) buf ) ;
data - > temperature = sht3x_extract_temperature ( val ) ;
val = be16_to_cpup ( ( __be16 * ) ( buf + 3 ) ) ;
data - > humidity = sht3x_extract_humidity ( val ) ;
data - > last_update = jiffies ;
}
out :
mutex_unlock ( & data - > data_lock ) ;
if ( ret )
return ERR_PTR ( ret ) ;
return data ;
}
/* sysfs attributes */
static ssize_t temp1_input_show ( struct device * dev ,
struct device_attribute * attr , char * buf )
{
struct sht3x_data * data = sht3x_update_client ( dev ) ;
if ( IS_ERR ( data ) )
return PTR_ERR ( data ) ;
return sprintf ( buf , " %d \n " , data - > temperature ) ;
}
static ssize_t humidity1_input_show ( struct device * dev ,
struct device_attribute * attr , char * buf )
{
struct sht3x_data * data = sht3x_update_client ( dev ) ;
if ( IS_ERR ( data ) )
return PTR_ERR ( data ) ;
return sprintf ( buf , " %u \n " , data - > humidity ) ;
}
/*
* limits_update must only be called from probe or with data_lock held
*/
static int limits_update ( struct sht3x_data * data )
{
int ret ;
u8 index ;
int temperature ;
u32 humidity ;
u16 raw ;
char buffer [ SHT3X_RESPONSE_LENGTH ] ;
const struct sht3x_limit_commands * commands ;
struct i2c_client * client = data - > client ;
for ( index = 0 ; index < SHT3X_NUM_LIMIT_CMD ; index + + ) {
commands = & limit_commands [ index ] ;
ret = sht3x_read_from_command ( client , data ,
commands - > read_command , buffer ,
SHT3X_RESPONSE_LENGTH , 0 ) ;
if ( ret )
return ret ;
raw = be16_to_cpup ( ( __be16 * ) buffer ) ;
temperature = sht3x_extract_temperature ( ( raw & 0x01ff ) < < 7 ) ;
humidity = sht3x_extract_humidity ( raw & 0xfe00 ) ;
data - > temperature_limits [ index ] = temperature ;
data - > humidity_limits [ index ] = humidity ;
}
return ret ;
}
static ssize_t temp1_limit_show ( struct device * dev ,
struct device_attribute * attr ,
char * buf )
{
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
u8 index = to_sensor_dev_attr ( attr ) - > index ;
int temperature_limit = data - > temperature_limits [ index ] ;
return scnprintf ( buf , PAGE_SIZE , " %d \n " , temperature_limit ) ;
}
static ssize_t humidity1_limit_show ( struct device * dev ,
struct device_attribute * attr ,
char * buf )
{
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
u8 index = to_sensor_dev_attr ( attr ) - > index ;
u32 humidity_limit = data - > humidity_limits [ index ] ;
return scnprintf ( buf , PAGE_SIZE , " %u \n " , humidity_limit ) ;
}
/*
* limit_store must only be called with data_lock held
*/
static size_t limit_store ( struct device * dev ,
size_t count ,
u8 index ,
int temperature ,
u32 humidity )
{
char buffer [ SHT3X_CMD_LENGTH + SHT3X_WORD_LEN + SHT3X_CRC8_LEN ] ;
char * position = buffer ;
int ret ;
u16 raw ;
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
struct i2c_client * client = data - > client ;
const struct sht3x_limit_commands * commands ;
commands = & limit_commands [ index ] ;
memcpy ( position , commands - > write_command , SHT3X_CMD_LENGTH ) ;
position + = SHT3X_CMD_LENGTH ;
/*
* ST = ( T + 45 ) / 175 * 2 ^ 16
* SRH = RH / 100 * 2 ^ 16
* adapted for fixed point arithmetic and packed the same as
* in limit_show ( )
*/
raw = ( ( u32 ) ( temperature + 45000 ) * 24543 ) > > ( 16 + 7 ) ;
raw | = ( ( humidity * 42950 ) > > 16 ) & 0xfe00 ;
* ( ( __be16 * ) position ) = cpu_to_be16 ( raw ) ;
position + = SHT3X_WORD_LEN ;
* position = crc8 ( sht3x_crc8_table ,
position - SHT3X_WORD_LEN ,
SHT3X_WORD_LEN ,
SHT3X_CRC8_INIT ) ;
mutex_lock ( & data - > i2c_lock ) ;
ret = i2c_master_send ( client , buffer , sizeof ( buffer ) ) ;
mutex_unlock ( & data - > i2c_lock ) ;
if ( ret ! = sizeof ( buffer ) )
return ret < 0 ? ret : - EIO ;
data - > temperature_limits [ index ] = temperature ;
data - > humidity_limits [ index ] = humidity ;
return count ;
}
static ssize_t temp1_limit_store ( struct device * dev ,
struct device_attribute * attr ,
const char * buf ,
size_t count )
{
int temperature ;
int ret ;
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
u8 index = to_sensor_dev_attr ( attr ) - > index ;
ret = kstrtoint ( buf , 0 , & temperature ) ;
if ( ret )
return ret ;
temperature = clamp_val ( temperature , SHT3X_MIN_TEMPERATURE ,
SHT3X_MAX_TEMPERATURE ) ;
mutex_lock ( & data - > data_lock ) ;
ret = limit_store ( dev , count , index , temperature ,
data - > humidity_limits [ index ] ) ;
mutex_unlock ( & data - > data_lock ) ;
return ret ;
}
static ssize_t humidity1_limit_store ( struct device * dev ,
struct device_attribute * attr ,
const char * buf ,
size_t count )
{
u32 humidity ;
int ret ;
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
u8 index = to_sensor_dev_attr ( attr ) - > index ;
ret = kstrtou32 ( buf , 0 , & humidity ) ;
if ( ret )
return ret ;
humidity = clamp_val ( humidity , SHT3X_MIN_HUMIDITY , SHT3X_MAX_HUMIDITY ) ;
mutex_lock ( & data - > data_lock ) ;
ret = limit_store ( dev , count , index , data - > temperature_limits [ index ] ,
humidity ) ;
mutex_unlock ( & data - > data_lock ) ;
return ret ;
}
static void sht3x_select_command ( struct sht3x_data * data )
{
/*
* In blocking mode ( clock stretching mode ) the I2C bus
* is blocked for other traffic , thus the call to i2c_master_recv ( )
* will wait until the data is ready . For non blocking mode , we
* have to wait ourselves .
*/
if ( data - > mode > 0 ) {
data - > command = sht3x_cmd_measure_periodic_mode ;
data - > wait_time = 0 ;
} else if ( data - > setup . blocking_io ) {
data - > command = data - > setup . high_precision ?
sht3x_cmd_measure_blocking_hpm :
sht3x_cmd_measure_blocking_lpm ;
data - > wait_time = 0 ;
} else {
if ( data - > setup . high_precision ) {
data - > command = sht3x_cmd_measure_nonblocking_hpm ;
data - > wait_time = SHT3X_NONBLOCKING_WAIT_TIME_HPM ;
} else {
data - > command = sht3x_cmd_measure_nonblocking_lpm ;
data - > wait_time = SHT3X_NONBLOCKING_WAIT_TIME_LPM ;
}
}
}
static int status_register_read ( struct device * dev ,
struct device_attribute * attr ,
char * buffer , int length )
{
int ret ;
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
struct i2c_client * client = data - > client ;
ret = sht3x_read_from_command ( client , data , sht3x_cmd_read_status_reg ,
buffer , length , 0 ) ;
return ret ;
}
static ssize_t temp1_alarm_show ( struct device * dev ,
struct device_attribute * attr ,
char * buf )
{
char buffer [ SHT3X_WORD_LEN + SHT3X_CRC8_LEN ] ;
int ret ;
ret = status_register_read ( dev , attr , buffer ,
SHT3X_WORD_LEN + SHT3X_CRC8_LEN ) ;
if ( ret )
return ret ;
return scnprintf ( buf , PAGE_SIZE , " %d \n " , ! ! ( buffer [ 0 ] & 0x04 ) ) ;
}
static ssize_t humidity1_alarm_show ( struct device * dev ,
struct device_attribute * attr ,
char * buf )
{
char buffer [ SHT3X_WORD_LEN + SHT3X_CRC8_LEN ] ;
int ret ;
ret = status_register_read ( dev , attr , buffer ,
SHT3X_WORD_LEN + SHT3X_CRC8_LEN ) ;
if ( ret )
return ret ;
return scnprintf ( buf , PAGE_SIZE , " %d \n " , ! ! ( buffer [ 0 ] & 0x08 ) ) ;
}
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static ssize_t heater_enable_show ( struct device * dev ,
struct device_attribute * attr ,
char * buf )
{
char buffer [ SHT3X_WORD_LEN + SHT3X_CRC8_LEN ] ;
int ret ;
ret = status_register_read ( dev , attr , buffer ,
SHT3X_WORD_LEN + SHT3X_CRC8_LEN ) ;
if ( ret )
return ret ;
return scnprintf ( buf , PAGE_SIZE , " %d \n " , ! ! ( buffer [ 0 ] & 0x20 ) ) ;
}
static ssize_t heater_enable_store ( struct device * dev ,
struct device_attribute * attr ,
const char * buf ,
size_t count )
{
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
struct i2c_client * client = data - > client ;
int ret ;
bool status ;
ret = kstrtobool ( buf , & status ) ;
if ( ret )
return ret ;
mutex_lock ( & data - > i2c_lock ) ;
if ( status )
ret = i2c_master_send ( client , ( char * ) & sht3x_cmd_heater_on ,
SHT3X_CMD_LENGTH ) ;
else
ret = i2c_master_send ( client , ( char * ) & sht3x_cmd_heater_off ,
SHT3X_CMD_LENGTH ) ;
mutex_unlock ( & data - > i2c_lock ) ;
return ret ;
}
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static ssize_t update_interval_show ( struct device * dev ,
struct device_attribute * attr ,
char * buf )
{
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
return scnprintf ( buf , PAGE_SIZE , " %u \n " ,
mode_to_update_interval [ data - > mode ] ) ;
}
static ssize_t update_interval_store ( struct device * dev ,
struct device_attribute * attr ,
const char * buf ,
size_t count )
{
u16 update_interval ;
u8 mode ;
int ret ;
const char * command ;
struct sht3x_data * data = dev_get_drvdata ( dev ) ;
struct i2c_client * client = data - > client ;
ret = kstrtou16 ( buf , 0 , & update_interval ) ;
if ( ret )
return ret ;
mode = get_mode_from_update_interval ( update_interval ) ;
mutex_lock ( & data - > data_lock ) ;
/* mode did not change */
if ( mode = = data - > mode ) {
mutex_unlock ( & data - > data_lock ) ;
return count ;
}
mutex_lock ( & data - > i2c_lock ) ;
/*
* Abort periodic measure mode .
* To do any changes to the configuration while in periodic mode , we
* have to send a break command to the sensor , which then falls back
* to single shot ( mode = 0 ) .
*/
if ( data - > mode > 0 ) {
ret = i2c_master_send ( client , sht3x_cmd_break ,
SHT3X_CMD_LENGTH ) ;
if ( ret ! = SHT3X_CMD_LENGTH )
goto out ;
data - > mode = 0 ;
}
if ( mode > 0 ) {
if ( data - > setup . high_precision )
command = periodic_measure_commands_hpm [ mode - 1 ] ;
else
command = periodic_measure_commands_lpm [ mode - 1 ] ;
/* select mode */
ret = i2c_master_send ( client , command , SHT3X_CMD_LENGTH ) ;
if ( ret ! = SHT3X_CMD_LENGTH )
goto out ;
}
/* select mode and command */
data - > mode = mode ;
sht3x_select_command ( data ) ;
out :
mutex_unlock ( & data - > i2c_lock ) ;
mutex_unlock ( & data - > data_lock ) ;
if ( ret ! = SHT3X_CMD_LENGTH )
return ret < 0 ? ret : - EIO ;
return count ;
}
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static SENSOR_DEVICE_ATTR_RO ( temp1_input , temp1_input , 0 ) ;
static SENSOR_DEVICE_ATTR_RO ( humidity1_input , humidity1_input , 0 ) ;
static SENSOR_DEVICE_ATTR_RW ( temp1_max , temp1_limit , limit_max ) ;
static SENSOR_DEVICE_ATTR_RW ( humidity1_max , humidity1_limit , limit_max ) ;
static SENSOR_DEVICE_ATTR_RW ( temp1_max_hyst , temp1_limit , limit_max_hyst ) ;
static SENSOR_DEVICE_ATTR_RW ( humidity1_max_hyst , humidity1_limit ,
limit_max_hyst ) ;
static SENSOR_DEVICE_ATTR_RW ( temp1_min , temp1_limit , limit_min ) ;
static SENSOR_DEVICE_ATTR_RW ( humidity1_min , humidity1_limit , limit_min ) ;
static SENSOR_DEVICE_ATTR_RW ( temp1_min_hyst , temp1_limit , limit_min_hyst ) ;
static SENSOR_DEVICE_ATTR_RW ( humidity1_min_hyst , humidity1_limit ,
limit_min_hyst ) ;
static SENSOR_DEVICE_ATTR_RO ( temp1_alarm , temp1_alarm , 0 ) ;
static SENSOR_DEVICE_ATTR_RO ( humidity1_alarm , humidity1_alarm , 0 ) ;
static SENSOR_DEVICE_ATTR_RW ( heater_enable , heater_enable , 0 ) ;
static SENSOR_DEVICE_ATTR_RW ( update_interval , update_interval , 0 ) ;
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static struct attribute * sht3x_attrs [ ] = {
& sensor_dev_attr_temp1_input . dev_attr . attr ,
& sensor_dev_attr_humidity1_input . dev_attr . attr ,
& sensor_dev_attr_temp1_max . dev_attr . attr ,
& sensor_dev_attr_temp1_max_hyst . dev_attr . attr ,
& sensor_dev_attr_humidity1_max . dev_attr . attr ,
& sensor_dev_attr_humidity1_max_hyst . dev_attr . attr ,
& sensor_dev_attr_temp1_min . dev_attr . attr ,
& sensor_dev_attr_temp1_min_hyst . dev_attr . attr ,
& sensor_dev_attr_humidity1_min . dev_attr . attr ,
& sensor_dev_attr_humidity1_min_hyst . dev_attr . attr ,
& sensor_dev_attr_temp1_alarm . dev_attr . attr ,
& sensor_dev_attr_humidity1_alarm . dev_attr . attr ,
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& sensor_dev_attr_heater_enable . dev_attr . attr ,
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& sensor_dev_attr_update_interval . dev_attr . attr ,
NULL
} ;
static struct attribute * sts3x_attrs [ ] = {
& sensor_dev_attr_temp1_input . dev_attr . attr ,
NULL
} ;
ATTRIBUTE_GROUPS ( sht3x ) ;
ATTRIBUTE_GROUPS ( sts3x ) ;
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static const struct i2c_device_id sht3x_ids [ ] ;
static int sht3x_probe ( struct i2c_client * client )
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{
int ret ;
struct sht3x_data * data ;
struct device * hwmon_dev ;
struct i2c_adapter * adap = client - > adapter ;
struct device * dev = & client - > dev ;
const struct attribute_group * * attribute_groups ;
/*
* we require full i2c support since the sht3x uses multi - byte read and
* writes as well as multi - byte commands which are not supported by
* the smbus protocol
*/
if ( ! i2c_check_functionality ( adap , I2C_FUNC_I2C ) )
return - ENODEV ;
ret = i2c_master_send ( client , sht3x_cmd_clear_status_reg ,
SHT3X_CMD_LENGTH ) ;
if ( ret ! = SHT3X_CMD_LENGTH )
return ret < 0 ? ret : - ENODEV ;
data = devm_kzalloc ( dev , sizeof ( * data ) , GFP_KERNEL ) ;
if ( ! data )
return - ENOMEM ;
data - > setup . blocking_io = false ;
data - > setup . high_precision = true ;
data - > mode = 0 ;
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data - > last_update = jiffies - msecs_to_jiffies ( 3000 ) ;
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data - > client = client ;
crc8_populate_msb ( sht3x_crc8_table , SHT3X_CRC8_POLYNOMIAL ) ;
if ( client - > dev . platform_data )
data - > setup = * ( struct sht3x_platform_data * ) dev - > platform_data ;
sht3x_select_command ( data ) ;
mutex_init ( & data - > i2c_lock ) ;
mutex_init ( & data - > data_lock ) ;
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/*
* An attempt to read limits register too early
* causes a NACK response from the chip .
* Waiting for an empirical delay of 500 us solves the issue .
*/
usleep_range ( 500 , 600 ) ;
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ret = limits_update ( data ) ;
if ( ret )
return ret ;
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if ( i2c_match_id ( sht3x_ids , client ) - > driver_data = = sts3x )
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attribute_groups = sts3x_groups ;
else
attribute_groups = sht3x_groups ;
hwmon_dev = devm_hwmon_device_register_with_groups ( dev ,
client - > name ,
data ,
attribute_groups ) ;
if ( IS_ERR ( hwmon_dev ) )
dev_dbg ( dev , " unable to register hwmon device \n " ) ;
return PTR_ERR_OR_ZERO ( hwmon_dev ) ;
}
/* device ID table */
static const struct i2c_device_id sht3x_ids [ ] = {
{ " sht3x " , sht3x } ,
{ " sts3x " , sts3x } ,
{ }
} ;
MODULE_DEVICE_TABLE ( i2c , sht3x_ids ) ;
static struct i2c_driver sht3x_i2c_driver = {
. driver . name = " sht3x " ,
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. probe_new = sht3x_probe ,
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. id_table = sht3x_ids ,
} ;
module_i2c_driver ( sht3x_i2c_driver ) ;
MODULE_AUTHOR ( " David Frey <david.frey@sensirion.com> " ) ;
MODULE_AUTHOR ( " Pascal Sachs <pascal.sachs@sensirion.com> " ) ;
MODULE_DESCRIPTION ( " Sensirion SHT3x humidity and temperature sensor driver " ) ;
MODULE_LICENSE ( " GPL " ) ;