On 15/01/17 14:41, jacopo mondi wrote: > Hi Jonathan, > > On 15/01/2017 15:31, Jonathan Cameron wrote: >> On 15/01/17 14:13, jacopo mondi wrote: >>> Hi Jonathan, >>> thanks for review, >>> >>> On 13/01/2017 10:50, Jacopo Mondi wrote: >>>> Hello, >>>> sending out v4 splitting device tree bindings documentation and actual ADC >>>> driver. >>>> No changes in driver code since v3. >>>> >>>> Same question for iio maintainers here: >>>> I would like to have clarified the measure unit returned by read_raw(). >>>> Currently (value_raw * value_scale) return the ADC input value in mV. >> Good. >>>> While testing the patch I've been questioned if that should not actually >>>> be in uV. This is easily achievable making _scale return a value in uV. >>>> I have found no mention of this in the ABI documentation as it speaks of >>>> generic voltage. Can we have a final word on this? >>> >>> I see you have reviewed the driver without complaining for the >>> read_raw() measure unit, so I assume this replies to the above >>> question as well... >>> >> The units are specified in Documentation/ABI/testing/sysfs-bus-iio. >> >>> What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_raw >>> What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_supply_raw >>> What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_i_raw >>> What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_q_raw >>> KernelVersion: 2.6.35 >>> Contact: linux-iio@xxxxxxxxxxxxxxx >>> Description: >>> Raw (unscaled no bias removal etc.) voltage measurement from >>> channel Y. In special cases where the channel does not >>> correspond to externally available input one of the named >>> versions may be used. The number must always be specified and >>> unique to allow association with event codes. Units after >>> application of scale and offset are millivolts. >> >> So millivolts. This comes from a, perhaps ill judged, decision to match >> hwmon units were we could. >> > > Thank you! The "generic voltage" I said is mentioned in the ABI > documentation is in _scale attributes description. I assume then the > measure unit of the value returned by _scale is not relevant as long > as the _raw one with scale applied returns millivolts. Yes. Scale is inherently a ratio really rather than a quantity with units at all. It just happens to correspond to the voltage represented by 1LSB. > > Thanks, as soon as I have feedbacks on DTS binding docs, I'll send v5 > and we can hopefully close this one ;) Cool. Got a while in this cycle yet, but I know it's always nice to get patches out of your personal queue! Jonathan > > Thanks j > > > >> Jonathan >> >>> Thanks j >>> >>>> >>>> Thanks Marek for having tested this. >>>> >>>> v1 -> v2: >>>> - incorporated pmeerw's review comments >>>> - retrieve vref from dts and use that to convert read_raw result >>>> to mV >>>> - add device tree bindings documentation >>>> >>>> v2 -> v3: >>>> - add _SCALE bit of read_raw function and change _RAW bit accordingly >>>> - call regulator_get_voltage when accessing the _SCALE part of read_raw >>>> and not during probe >>>> - add back remove function as regulator has to be disabled when detaching >>>> the module. Do not use devm_ version of iio_register/unregister functions >>>> anymore but do unregister in the remove. >>>> - remove mutex as access to SPI bus is protected by SPI core. Thanks marex >>>> >>>> v3 -> v4: >>>> - split device tree binding documentation and actual ADC driver >>>> - add "reg" to the list of required properties and use a better >>>> namimg for the adc device node in bindings documentation as suggested >>>> by Geert. >>>> >>>> Jacopo Mondi (2): >>>> iio: adc: Add Maxim MAX11100 driver >>>> dt-bindings: iio: document MAX11100 ADC >>>> >>>> .../devicetree/bindings/iio/adc/max11100.txt | 19 +++ >>>> drivers/iio/adc/Kconfig | 9 + >>>> drivers/iio/adc/Makefile | 1 + >>>> drivers/iio/adc/max11100.c | 187 +++++++++++++++++++++ >>>> 4 files changed, 216 insertions(+) >>>> create mode 100644 Documentation/devicetree/bindings/iio/adc/max11100.txt >>>> create mode 100644 drivers/iio/adc/max11100.c >>>> >>> >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html
