| Message ID | e2cd1349-5cfb-4456-a1f5-74e7affff085@BN1AFFO11FD006.protection.gbl (mailing list archive) |
|---|---|
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Hello, > I recently found that you developed a driver for XADC and I thought I > enable it (see patch below). But it seems something is not working > correctly. The values I tested don't seem to be right and also fixed. > I.e. they don't change over time or across boards: > > # cat in_temp0_scale > 123.040771484 > # cat in_voltage0_vccint_scale > 0.732421875 > # cat in_voltage0_vccint_raw > 1384 > # cat in_voltage1_vccaux_s[ 1203.660637] random: nonblocking pool is initialized > # cat in_voltage1_vccaux_scale > 0.732421875 > # cat in_voltage3_vccpint_scale > 0.732421875 the _scale values are supposed to be constant; their purpose is to scale a measurement so that the result is in a given unit e.g. in_temp0_scale scales in_temp0_raw so that the result (in_temp0_raw * in_temp0_scale) in milli Celsius in_voltage0_vccint_raw * in_voltage0_vccint_scale is supposed to give milli Volts so in_voltage0_vccint_raw should vary accross time / boards (and voltage hopefully :), but not the _scales regards, p.
On 06/04/2014 08:47 AM, Peter Meerwald wrote: > Hello, > >> I recently found that you developed a driver for XADC and I thought I >> enable it (see patch below). But it seems something is not working >> correctly. The values I tested don't seem to be right and also fixed. >> I.e. they don't change over time or across boards: >> >> # cat in_temp0_scale >> 123.040771484 >> # cat in_voltage0_vccint_scale >> 0.732421875 >> # cat in_voltage0_vccint_raw >> 1384 >> # cat in_voltage1_vccaux_s[ 1203.660637] random: nonblocking pool is initialized >> # cat in_voltage1_vccaux_scale >> 0.732421875 >> # cat in_voltage3_vccpint_scale >> 0.732421875 > > the _scale values are supposed to be constant; their purpose is to scale a > measurement so that the result is in a given unit > > e.g. in_temp0_scale scales in_temp0_raw so that the result > (in_temp0_raw * in_temp0_scale) in milli Celsius > > in_voltage0_vccint_raw * in_voltage0_vccint_scale is supposed to give > milli Volts > > so in_voltage0_vccint_raw should vary accross time / boards (and voltage > hopefully :), but not the _scales Yep, as Peter said scale and offset will be constant, raw should change though, e.g. both voltage and temperature should a slight jitter if you repeatedly read them. If not something is broken. We had the driver in our images for Zynq board for a while now and so far it worked fine. I think Mrinal and Radhey from Xilinx also tested the driver. - Lars
Hi Lars, Peter, On Wed, 2014-06-04 at 09:27AM +0200, Lars-Peter Clausen wrote: > On 06/04/2014 08:47 AM, Peter Meerwald wrote: > >Hello, > > > >>I recently found that you developed a driver for XADC and I thought I > >>enable it (see patch below). But it seems something is not working > >>correctly. The values I tested don't seem to be right and also fixed. > >>I.e. they don't change over time or across boards: > >> > >> # cat in_temp0_scale > >> 123.040771484 > >> # cat in_voltage0_vccint_scale > >> 0.732421875 > >> # cat in_voltage0_vccint_raw > >> 1384 > >> # cat in_voltage1_vccaux_s[ 1203.660637] random: nonblocking pool is initialized > >> # cat in_voltage1_vccaux_scale > >> 0.732421875 > >> # cat in_voltage3_vccpint_scale > >> 0.732421875 > > > >the _scale values are supposed to be constant; their purpose is to scale a > >measurement so that the result is in a given unit > > > >e.g. in_temp0_scale scales in_temp0_raw so that the result > >(in_temp0_raw * in_temp0_scale) in milli Celsius > > > >in_voltage0_vccint_raw * in_voltage0_vccint_scale is supposed to give > >milli Volts > > > >so in_voltage0_vccint_raw should vary accross time / boards (and voltage > >hopefully :), but not the _scales > > Yep, as Peter said scale and offset will be constant, raw should > change though, e.g. both voltage and temperature should a slight > jitter if you repeatedly read them. If not something is broken. We > had the driver in our images for Zynq board for a while now and so > far it worked fine. I think Mrinal and Radhey from Xilinx also > tested the driver. Okay, thanks for the answers. Since the _scale value was the only one close to a Celsius or Fahrenheit value I thought that would be the final temperature. Anyway, the raw values do show some jitter. So far, so good, but the math doesn't add up I think: # cat in_temp0_raw in_temp0_scale 2559 123.040771484 multiplying those values gives 2559 * 123.040771484 = 304156.787108 Even if that is mC, that would mean my chip is at 304 degrees C. I'm pretty sure my chip's not on fire :) (I have the feeling I just did another beginner's mistake here though). A 10x error might be in there somewhere. 30 degrees sounds realistic. I didn't test all voltages, but those look better. Also, is there a way to directly obtain a reading in a reasonable scale? This approach needs to read two sysfs files, one of those even giving a float. Sören
On 06/04/2014 04:27 PM, Sören Brinkmann wrote: > Hi Lars, Peter, > > On Wed, 2014-06-04 at 09:27AM +0200, Lars-Peter Clausen wrote: >> On 06/04/2014 08:47 AM, Peter Meerwald wrote: >>> Hello, >>> >>>> I recently found that you developed a driver for XADC and I thought I >>>> enable it (see patch below). But it seems something is not working >>>> correctly. The values I tested don't seem to be right and also fixed. >>>> I.e. they don't change over time or across boards: >>>> >>>> # cat in_temp0_scale >>>> 123.040771484 >>>> # cat in_voltage0_vccint_scale >>>> 0.732421875 >>>> # cat in_voltage0_vccint_raw >>>> 1384 >>>> # cat in_voltage1_vccaux_s[ 1203.660637] random: nonblocking pool is initialized >>>> # cat in_voltage1_vccaux_scale >>>> 0.732421875 >>>> # cat in_voltage3_vccpint_scale >>>> 0.732421875 >>> >>> the _scale values are supposed to be constant; their purpose is to scale a >>> measurement so that the result is in a given unit >>> >>> e.g. in_temp0_scale scales in_temp0_raw so that the result >>> (in_temp0_raw * in_temp0_scale) in milli Celsius >>> >>> in_voltage0_vccint_raw * in_voltage0_vccint_scale is supposed to give >>> milli Volts >>> >>> so in_voltage0_vccint_raw should vary accross time / boards (and voltage >>> hopefully :), but not the _scales >> >> Yep, as Peter said scale and offset will be constant, raw should >> change though, e.g. both voltage and temperature should a slight >> jitter if you repeatedly read them. If not something is broken. We >> had the driver in our images for Zynq board for a while now and so >> far it worked fine. I think Mrinal and Radhey from Xilinx also >> tested the driver. > > Okay, thanks for the answers. Since the _scale value was the only one > close to a Celsius or Fahrenheit value I thought that would be the > final temperature. Anyway, the raw values do show some jitter. So far, > so good, but the math doesn't add up I think: > > # cat in_temp0_raw in_temp0_scale > 2559 > 123.040771484 > > multiplying those values gives > 2559 * 123.040771484 = 304156.787108 > > Even if that is mC, that would mean my chip is at 304 degrees C. I'm pretty > sure my chip's not on fire :) > (I have the feeling I just did another beginner's mistake here though). > A 10x error might be in there somewhere. 30 degrees sounds realistic. There is also a in_temp0_offset attribute which needs to be added to in_temp0_raw temperature = (in_temp0_raw + in_temp0_offset) * in_temp0_scale. In your case that is: (2559 - 2219) * 123.040771484 = 41833.86 > > I didn't test all voltages, but those look better. > > Also, is there a way to directly obtain a reading in a reasonable scale? > This approach needs to read two sysfs files, one of those even giving a > float. No. - Lars
On Thu, 2014-06-05 at 10:26AM +0200, Lars-Peter Clausen wrote: > On 06/04/2014 04:27 PM, Sören Brinkmann wrote: > >Hi Lars, Peter, > > > >On Wed, 2014-06-04 at 09:27AM +0200, Lars-Peter Clausen wrote: > >>On 06/04/2014 08:47 AM, Peter Meerwald wrote: > >>>Hello, > >>> > >>>>I recently found that you developed a driver for XADC and I thought I > >>>>enable it (see patch below). But it seems something is not working > >>>>correctly. The values I tested don't seem to be right and also fixed. > >>>>I.e. they don't change over time or across boards: > >>>> > >>>> # cat in_temp0_scale > >>>> 123.040771484 > >>>> # cat in_voltage0_vccint_scale > >>>> 0.732421875 > >>>> # cat in_voltage0_vccint_raw > >>>> 1384 > >>>> # cat in_voltage1_vccaux_s[ 1203.660637] random: nonblocking pool is initialized > >>>> # cat in_voltage1_vccaux_scale > >>>> 0.732421875 > >>>> # cat in_voltage3_vccpint_scale > >>>> 0.732421875 > >>> > >>>the _scale values are supposed to be constant; their purpose is to scale a > >>>measurement so that the result is in a given unit > >>> > >>>e.g. in_temp0_scale scales in_temp0_raw so that the result > >>>(in_temp0_raw * in_temp0_scale) in milli Celsius > >>> > >>>in_voltage0_vccint_raw * in_voltage0_vccint_scale is supposed to give > >>>milli Volts > >>> > >>>so in_voltage0_vccint_raw should vary accross time / boards (and voltage > >>>hopefully :), but not the _scales > >> > >>Yep, as Peter said scale and offset will be constant, raw should > >>change though, e.g. both voltage and temperature should a slight > >>jitter if you repeatedly read them. If not something is broken. We > >>had the driver in our images for Zynq board for a while now and so > >>far it worked fine. I think Mrinal and Radhey from Xilinx also > >>tested the driver. > > > >Okay, thanks for the answers. Since the _scale value was the only one > >close to a Celsius or Fahrenheit value I thought that would be the > >final temperature. Anyway, the raw values do show some jitter. So far, > >so good, but the math doesn't add up I think: > > > > # cat in_temp0_raw in_temp0_scale > > 2559 > > 123.040771484 > > > >multiplying those values gives > >2559 * 123.040771484 = 304156.787108 > > > >Even if that is mC, that would mean my chip is at 304 degrees C. I'm pretty > >sure my chip's not on fire :) > >(I have the feeling I just did another beginner's mistake here though). > >A 10x error might be in there somewhere. 30 degrees sounds realistic. > > There is also a in_temp0_offset attribute which needs to be added to > in_temp0_raw > > temperature = (in_temp0_raw + in_temp0_offset) * in_temp0_scale. > > In your case that is: (2559 - 2219) * 123.040771484 = 41833.86 > > > > >I didn't test all voltages, but those look better. > > > >Also, is there a way to directly obtain a reading in a reasonable scale? > >This approach needs to read two sysfs files, one of those even giving a > >float. > > No. That explains things. Thanks a lot. Sören
diff --git a/arch/arm/boot/dts/zynq-7000.dtsi b/arch/arm/boot/dts/zynq-7000.dtsi index 760bbc463c5b..c5854286a95a 100644 --- a/arch/arm/boot/dts/zynq-7000.dtsi +++ b/arch/arm/boot/dts/zynq-7000.dtsi @@ -65,6 +65,14 @@ interrupt-parent = <&intc>; ranges; + adc@f8007100 { + compatible = "xlnx,zynq-xadc-1.00.a"; + reg = <0xf8007100 0x20>; + interrupts = <0 7 4>; + interrupt-parent = <&intc>; + clocks = <&clkc 12>; + }; + i2c0: i2c@e0004000 { compatible = "cdns,i2c-r1p10"; status = "disabled";
Hi Lars, I recently found that you developed a driver for XADC and I thought I enable it (see patch below). But it seems something is not working correctly. The values I tested don't seem to be right and also fixed. I.e. they don't change over time or across boards: # cat in_temp0_scale 123.040771484 # cat in_voltage0_vccint_scale 0.732421875 # cat in_voltage0_vccint_raw 1384 # cat in_voltage1_vccaux_s[ 1203.660637] random: nonblocking pool is initialized # cat in_voltage1_vccaux_scale 0.732421875 # cat in_voltage3_vccpint_scale 0.732421875 Do you have an idea what I'm missing? Thanks, Sören ----------------8<-----------------8<-----------------8<--------------8<-------- Date: Tue, 3 Jun 2014 15:11:26 -0700 Subject: [PATCH] ARM: zynq: DT: Add XADC node Add node for the Xilinx A/D Converter. Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> --- arch/arm/boot/dts/zynq-7000.dtsi | 8 ++++++++ 1 file changed, 8 insertions(+)