diff options
Diffstat (limited to 'Documentation/ABI/testing/sysfs-driver-w1_therm')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-driver-w1_therm | 114 |
1 files changed, 94 insertions, 20 deletions
diff --git a/Documentation/ABI/testing/sysfs-driver-w1_therm b/Documentation/ABI/testing/sysfs-driver-w1_therm index 076659d506f2..74642c73d29c 100644 --- a/Documentation/ABI/testing/sysfs-driver-w1_therm +++ b/Documentation/ABI/testing/sysfs-driver-w1_therm @@ -8,13 +8,13 @@ Description: to device min/max capabilities. Values are integer as they are stored in a 8bit register in the device. Lowest value is automatically put to TL. Once set, alarms could be search at - master level, refer to Documentation/w1/w1_generic.rst for + master level, refer to Documentation/w1/w1-generic.rst for detailed information Users: any user space application which wants to communicate with w1_term device -What: /sys/bus/w1/devices/.../eeprom +What: /sys/bus/w1/devices/.../eeprom_cmd Date: May 2020 Contact: Akira Shimahara <akira215corp@gmail.com> Description: @@ -22,8 +22,10 @@ Description: device data to its embedded EEPROM, either restore data embedded in device EEPROM. Be aware that devices support limited EEPROM writing cycles (typical 50k) + * 'save': save device RAM to EEPROM * 'restore': restore EEPROM data in device RAM + Users: any user space application which wants to communicate with w1_term device @@ -33,9 +35,11 @@ Date: May 2020 Contact: Akira Shimahara <akira215corp@gmail.com> Description: (RO) return the power status by asking the device + * '0': device parasite powered * '1': device externally powered * '-xx': xx is kernel error when reading power status + Users: any user space application which wants to communicate with w1_term device @@ -49,10 +53,15 @@ Description: will be changed only in device RAM, so it will be cleared when power is lost. Trigger a 'save' to EEPROM command to keep values after power-on. Read or write are : - * '9..12': device resolution in bit - or resolution to set in bit + + * '9..14': device resolution in bit + or resolution to set in bit * '-xx': xx is kernel error when reading the resolution * Anything else: do nothing + + Some DS18B20 clones are fixed in 12-bit resolution, so the + actual resolution is read back from the chip and verified. Error + is reported if the results differ. Users: any user space application which wants to communicate with w1_term device @@ -62,16 +71,18 @@ Date: May 2020 Contact: Akira Shimahara <akira215corp@gmail.com> Description: (RO) return the temperature in 1/1000 degC. + * If a bulk read has been triggered, it will directly - return the temperature computed when the bulk read - occurred, if available. If not yet available, nothing - is returned (a debug kernel message is sent), you - should retry later on. + return the temperature computed when the bulk read + occurred, if available. If not yet available, nothing + is returned (a debug kernel message is sent), you + should retry later on. * If no bulk read has been triggered, it will trigger - a conversion and send the result. Note that the - conversion duration depend on the resolution (if - device support this feature). It takes 94ms in 9bits - resolution, 750ms for 12bits. + a conversion and send the result. Note that the + conversion duration depend on the resolution (if + device support this feature). It takes 94ms in 9bits + resolution, 750ms for 12bits. + Users: any user space application which wants to communicate with w1_term device @@ -83,12 +94,14 @@ Description: (RW) return the temperature in 1/1000 degC. *read*: return 2 lines with the hexa output data sent on the bus, return the CRC check and temperature in 1/1000 degC - *write* : + *write*: + * '0' : save the 2 or 3 bytes to the device EEPROM - (i.e. TH, TL and config register) - * '9..12' : set the device resolution in RAM - (if supported) + (i.e. TH, TL and config register) + * '9..14' : set the device resolution in RAM + (if supported) * Anything else: do nothing + refer to Documentation/w1/slaves/w1_therm.rst for detailed information. Users: any user space application which wants to communicate with @@ -100,17 +113,78 @@ Date: May 2020 Contact: Akira Shimahara <akira215corp@gmail.com> Description: (RW) trigger a bulk read conversion. read the status + *read*: - * '-1': conversion in progress on at least 1 sensor - * '1' : conversion complete but at least one sensor + * '-1': + conversion in progress on at least 1 sensor + * '1' : + conversion complete but at least one sensor value has not been read yet - * '0' : no bulk operation. Reading temperature will + * '0' : + no bulk operation. Reading temperature will trigger a conversion on each device - *write*: 'trigger': trigger a bulk read on all supporting + + *write*: + 'trigger': trigger a bulk read on all supporting devices on the bus + Note that if a bulk read is sent but one sensor is not read immediately, the next access to temperature on this device will return the temperature measured at the time of issue of the bulk read command (not the current temperature). Users: any user space application which wants to communicate with w1_term device + + +What: /sys/bus/w1/devices/.../conv_time +Date: July 2020 +Contact: Ivan Zaentsev <ivan.zaentsev@wirenboard.ru> +Description: + (RW) Get, set, or measure a temperature conversion time. The + setting remains active until a resolution change. Then it is + reset to default (datasheet) conversion time for a new + resolution. + + *read*: + Actual conversion time in milliseconds. + + *write*: + * '0': + Set the default conversion time from the datasheet. + * '1': + Measure and set the conversion time. Make a single + temperature conversion, measure an actual value. + Increase it by 20% for temperature range. A new + conversion time can be obtained by reading this + same attribute. + * other positive value: + Set the conversion time in milliseconds. + +Users: An application using the w1_term device + + +What: /sys/bus/w1/devices/.../features +Date: July 2020 +Contact: Ivan Zaentsev <ivan.zaentsev@wirenboard.ru> +Description: + (RW) Control optional driver settings. + Bit masks to read/write (bitwise OR): + + == ============================================================ + 1 Enable check for conversion success. If byte 6 of + scratchpad memory is 0xC after conversion, and + temperature reads 85.00 (powerup value) or 127.94 + (insufficient power) - return a conversion error. + + 2 Enable poll for conversion completion. Generate read cycles + after the conversion start and wait for 1's. In parasite + power mode this feature is not available. + == ============================================================ + + *read*: + Currently selected features. + + *write*: + Select features. + +Users: An application using the w1_term device |