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Diffstat (limited to 'Documentation/ABI/testing/sysfs-driver-w1_therm')
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diff --git a/Documentation/ABI/testing/sysfs-driver-w1_therm b/Documentation/ABI/testing/sysfs-driver-w1_therm new file mode 100644 index 000000000..6a37dc33f --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-w1_therm @@ -0,0 +1,190 @@ +What: /sys/bus/w1/devices/.../alarms +Date: May 2020 +Contact: Akira Shimahara <akira215corp@gmail.com> +Description: + (RW) read or write TH and TL (Temperature High an Low) alarms. + Values shall be space separated and in the device range + (typical -55 degC to 125 degC), if not values will be trimmed + 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 + detailed information +Users: any user space application which wants to communicate with + w1_term device + + +What: /sys/bus/w1/devices/.../eeprom +Date: May 2020 +Contact: Akira Shimahara <akira215corp@gmail.com> +Description: + (WO) writing that file will either trigger a save of the + 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 + + +What: /sys/bus/w1/devices/.../ext_power +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 + + +What: /sys/bus/w1/devices/.../resolution +Date: May 2020 +Contact: Akira Shimahara <akira215corp@gmail.com> +Description: + (RW) get or set the device resolution (on supported devices, + if not, this entry is not present). Note that the resolution + 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..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 + + +What: /sys/bus/w1/devices/.../temperature +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. + * 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. + +Users: any user space application which wants to communicate with + w1_term device + + +What: /sys/bus/w1/devices/.../w1_slave +Date: May 2020 +Contact: Akira Shimahara <akira215corp@gmail.com> +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*: + + * '0' : save the 2 or 3 bytes to the device EEPROM + (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 + w1_term device + + +What: /sys/bus/w1/devices/w1_bus_masterXX/therm_bulk_read +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 + value has not been read yet + * '0' : + no bulk operation. Reading temperature will + trigger a conversion on each device + + *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 |