| Message ID | 1459936986-2839-1-git-send-email-ldewangan@nvidia.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Eduardo Valentin |
| Headers | show |
On Wed, Apr 06, 2016 at 03:33:05PM +0530, Laxman Dewangan wrote: > Sometimes, thermal sensors like NCT thermistors are connected to > the ADC channel. The temperature is read by reading the voltage > across the sensor resistance via ADC and referring the lookup > table for ADC value to temperature. The ADC interface is provided > through the IIO framework. > > Add DT binding doc for the adc based thermal sensor driver to detail > the DT property and provide the example for how to use it. > > Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> > --- > .../bindings/thermal/thermal-generic-adc.txt | 86 ++++++++++++++++++++++ > 1 file changed, 86 insertions(+) > create mode 100644 Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt > > diff --git a/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt b/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt > new file mode 100644 > index 0000000..6b3e715 > --- /dev/null > +++ b/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt > @@ -0,0 +1,86 @@ > +General Purpose Analog To Digital Converter (ADC) based thermal sensor > + > +On some of platforms, thermal sensor like thermistors are connected to > +one of ADC channel and sensor resistance is read via voltage across the > +sensor. The voltage read across the sensor is mapped to temperature using > +voltage-temperature lookup table. > + > +This driver provides the interface to sensor-ADC interconnection and > +the relation ship between ADC read value and temperature. > + > +Required properties: > +=================== > +- compatible: Must be "generic-adc-thermal". > +- lower-temperature: Lower temperature for the lookup table > + in millicelsius. > +- upper-temperature: Upper temperature for the lookup table > + in millicelsius. > +- step-temperature: The temperature steps for the reading ADC > + value in millicelsius. How about when you have a sensor that does not have a nice linear stepping correlation ? > +- temperature-lookup-table: The ADC reading value on each step of the > + temperature starting from lower temperature > + to upper temperature. > + When ADC is read, the value is looked up on the > + table to get the equivalent temperature. I would say, we would need to support a two dimensional table here.. > +- #thermal-sensor-cells: Should be 1. See ./thermal.txt for a description > + of this property. > + > +Example : > +#include <dt-bindings/thermal/thermal.h> > + > +i2c@7000c400 { > + ads1015: ads1015@4a { > + reg = <0x4a>; > + compatible = "ads1015"; > + sampling-frequency = <3300>; > + #io-channel-cells = <1>; > + }; > +}; > + > +thermal-sensor@1 { > + compatible = "generic-adc-thermal"; > + #thermal-sensor-cells = <0>; > + io-channels = <&ads1015 1>; > + io-channel-names = "sensor-channel"; > + lower-temperature = <(-40000)>; > + upper-temperature = <125000>; > + step-temperature = <1000>; > + temperature-lookup-table = <2578 2577 2576 2575 2574 > + 2573 2572 2571 2569 2568 > + 2567 2565 2563 2561 2559 > + :::::::::: > + 254 247 240 233 226 220 > + 214 208>; > +}; > + > +dummy_cool_dev: dummy-cool-dev { > + compatible = "dummy-cooling-dev"; > + #cooling-cells = <2>; /* min followed by max */ > +}; > + > +thermal-zones { > + Tboard { > + polling-delay = <15000>; /* milliseconds */ > + polling-delay-passive = <0>; /* milliseconds */ > + thermal-sensors = <&tboard_thermistor>; > + > + trips { > + therm_est_trip: therm_est_trip { > + temperature = <40000>; > + type = "active"; > + hysteresis = <1000>; > + writable; Not sure about writable property, where is it described? > + }; > + }; > + > + cooling-maps { > + map0 { > + trip = <&therm_est_trip>; > + cooling-device = <&dummy_cool_dev THERMAL_NO_LIMIT THERMAL_NO_LIMIT>; > + contribution = <100>; > + cdev-type = "therm_est_activ"; Not sure about cdev-type property, where is it described? > + }; > + }; > + > + }; > +}; > -- > 2.1.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Eduardo, Thanks for review. On Wednesday 06 April 2016 09:31 PM, Eduardo Valentin wrote: > On Wed, Apr 06, 2016 at 03:33:05PM +0530, Laxman Dewangan wrote: >> +- step-temperature: The temperature steps for the reading ADC >> + value in millicelsius. > How about when you have a sensor that does not have a nice linear > stepping correlation ? Here just temp is stepping but ADC reading is not in linear. So temp vs adc value is not linear. Just making the table that temp vs adc value where temp is in equally stepped. if something is not possible for few steps than that can be intrapolate here to get this. Other way as you said: two dimensional. You mean <temp ADC-value> pair for the table? This is also possible and on this case, we will not need lower/upper and step temperature. Table will provide all the information. Also, I assume that sensor is negative coefficients. Temp increases->ADC read value decreases. Should we also support positive coefficient relation? > + writable; > Not sure about writable property, where is it described? It is from my testing, not standard. I will remove it. >> + }; >> + }; >> + >> + cooling-maps { >> + map0 { >> + trip = <&therm_est_trip>; >> + cooling-device = <&dummy_cool_dev THERMAL_NO_LIMIT THERMAL_NO_LIMIT>; >> + contribution = <100>; >> + cdev-type = "therm_est_activ"; > > Not sure about cdev-type property, where is it described? From my testing only. Will remove it. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Apr 06, 2016 at 03:33:05PM +0530, Laxman Dewangan wrote: > Sometimes, thermal sensors like NCT thermistors are connected to > the ADC channel. The temperature is read by reading the voltage > across the sensor resistance via ADC and referring the lookup > table for ADC value to temperature. The ADC interface is provided > through the IIO framework. IIO framework is a detail not relevant to the binding. > > Add DT binding doc for the adc based thermal sensor driver to detail > the DT property and provide the example for how to use it. > > Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> > --- > .../bindings/thermal/thermal-generic-adc.txt | 86 ++++++++++++++++++++++ > 1 file changed, 86 insertions(+) > create mode 100644 Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt > > diff --git a/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt b/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt > new file mode 100644 > index 0000000..6b3e715 > --- /dev/null > +++ b/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt > @@ -0,0 +1,86 @@ > +General Purpose Analog To Digital Converter (ADC) based thermal sensor > + > +On some of platforms, thermal sensor like thermistors are connected to > +one of ADC channel and sensor resistance is read via voltage across the > +sensor. The voltage read across the sensor is mapped to temperature using > +voltage-temperature lookup table. > + > +This driver provides the interface to sensor-ADC interconnection and > +the relation ship between ADC read value and temperature. Bindings don't describe drivers. > + > +Required properties: > +=================== > +- compatible: Must be "generic-adc-thermal". > +- lower-temperature: Lower temperature for the lookup table > + in millicelsius. > +- upper-temperature: Upper temperature for the lookup table > + in millicelsius. > +- step-temperature: The temperature steps for the reading ADC > + value in millicelsius. > +- temperature-lookup-table: The ADC reading value on each step of the > + temperature starting from lower temperature > + to upper temperature. > + When ADC is read, the value is looked up on the > + table to get the equivalent temperature. > +- #thermal-sensor-cells: Should be 1. See ./thermal.txt for a description > + of this property. > + > +Example : > +#include <dt-bindings/thermal/thermal.h> > + > +i2c@7000c400 { > + ads1015: ads1015@4a { > + reg = <0x4a>; > + compatible = "ads1015"; > + sampling-frequency = <3300>; > + #io-channel-cells = <1>; > + }; > +}; > + > +thermal-sensor@1 { > + compatible = "generic-adc-thermal"; > + #thermal-sensor-cells = <0>; > + io-channels = <&ads1015 1>; > + io-channel-names = "sensor-channel"; > + lower-temperature = <(-40000)>; > + upper-temperature = <125000>; > + step-temperature = <1000>; > + temperature-lookup-table = <2578 2577 2576 2575 2574 > + 2573 2572 2571 2569 2568 > + 2567 2565 2563 2561 2559 > + :::::::::: > + 254 247 240 233 226 220 > + 214 208>; > +}; > + > +dummy_cool_dev: dummy-cool-dev { > + compatible = "dummy-cooling-dev"; > + #cooling-cells = <2>; /* min followed by max */ > +}; > + > +thermal-zones { > + Tboard { > + polling-delay = <15000>; /* milliseconds */ > + polling-delay-passive = <0>; /* milliseconds */ > + thermal-sensors = <&tboard_thermistor>; Missing a label? > + > + trips { > + therm_est_trip: therm_est_trip { > + temperature = <40000>; > + type = "active"; > + hysteresis = <1000>; > + writable; Missing indentation and closing brace. > + }; > + }; > + > + cooling-maps { > + map0 { > + trip = <&therm_est_trip>; > + cooling-device = <&dummy_cool_dev THERMAL_NO_LIMIT THERMAL_NO_LIMIT>; > + contribution = <100>; > + cdev-type = "therm_est_activ"; > + }; Here's your missing brace... > + }; > + > + }; > +}; > -- > 2.1.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt b/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt new file mode 100644 index 0000000..6b3e715 --- /dev/null +++ b/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt @@ -0,0 +1,86 @@ +General Purpose Analog To Digital Converter (ADC) based thermal sensor + +On some of platforms, thermal sensor like thermistors are connected to +one of ADC channel and sensor resistance is read via voltage across the +sensor. The voltage read across the sensor is mapped to temperature using +voltage-temperature lookup table. + +This driver provides the interface to sensor-ADC interconnection and +the relation ship between ADC read value and temperature. + +Required properties: +=================== +- compatible: Must be "generic-adc-thermal". +- lower-temperature: Lower temperature for the lookup table + in millicelsius. +- upper-temperature: Upper temperature for the lookup table + in millicelsius. +- step-temperature: The temperature steps for the reading ADC + value in millicelsius. +- temperature-lookup-table: The ADC reading value on each step of the + temperature starting from lower temperature + to upper temperature. + When ADC is read, the value is looked up on the + table to get the equivalent temperature. +- #thermal-sensor-cells: Should be 1. See ./thermal.txt for a description + of this property. + +Example : +#include <dt-bindings/thermal/thermal.h> + +i2c@7000c400 { + ads1015: ads1015@4a { + reg = <0x4a>; + compatible = "ads1015"; + sampling-frequency = <3300>; + #io-channel-cells = <1>; + }; +}; + +thermal-sensor@1 { + compatible = "generic-adc-thermal"; + #thermal-sensor-cells = <0>; + io-channels = <&ads1015 1>; + io-channel-names = "sensor-channel"; + lower-temperature = <(-40000)>; + upper-temperature = <125000>; + step-temperature = <1000>; + temperature-lookup-table = <2578 2577 2576 2575 2574 + 2573 2572 2571 2569 2568 + 2567 2565 2563 2561 2559 + :::::::::: + 254 247 240 233 226 220 + 214 208>; +}; + +dummy_cool_dev: dummy-cool-dev { + compatible = "dummy-cooling-dev"; + #cooling-cells = <2>; /* min followed by max */ +}; + +thermal-zones { + Tboard { + polling-delay = <15000>; /* milliseconds */ + polling-delay-passive = <0>; /* milliseconds */ + thermal-sensors = <&tboard_thermistor>; + + trips { + therm_est_trip: therm_est_trip { + temperature = <40000>; + type = "active"; + hysteresis = <1000>; + writable; + }; + }; + + cooling-maps { + map0 { + trip = <&therm_est_trip>; + cooling-device = <&dummy_cool_dev THERMAL_NO_LIMIT THERMAL_NO_LIMIT>; + contribution = <100>; + cdev-type = "therm_est_activ"; + }; + }; + + }; +};
Sometimes, thermal sensors like NCT thermistors are connected to the ADC channel. The temperature is read by reading the voltage across the sensor resistance via ADC and referring the lookup table for ADC value to temperature. The ADC interface is provided through the IIO framework. Add DT binding doc for the adc based thermal sensor driver to detail the DT property and provide the example for how to use it. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> --- .../bindings/thermal/thermal-generic-adc.txt | 86 ++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt