> -----Original Message----- > From: Jonathan Cameron [mailto:jic23@xxxxxxxxxx] > Sent: 01 January, 2015 12:30 > To: Tirdea, Irina; linux-iio@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx; Dogaru, Vlad; Baluta, Daniel; Hartmut Knaack; Lars-Peter Clausen; Peter Meerwald > Subject: Re: [PATCH 1/8] iio: core: Introduce CALORIES channel type > > On 29/12/14 14:42, Tirdea, Irina wrote: > > > > > >> -----Original Message----- > >> From: linux-iio-owner@xxxxxxxxxxxxxxx [mailto:linux-iio-owner@xxxxxxxxxxxxxxx] On Behalf Of Jonathan Cameron > >> Sent: 26 December, 2014 15:26 > >> To: Tirdea, Irina; linux-iio@xxxxxxxxxxxxxxx > >> Cc: linux-kernel@xxxxxxxxxxxxxxx; Dogaru, Vlad; Baluta, Daniel; Hartmut Knaack; Lars-Peter Clausen; Peter Meerwald > >> Subject: Re: [PATCH 1/8] iio: core: Introduce CALORIES channel type > >> > >> On 19/12/14 22:57, Irina Tirdea wrote: > >>> Some devices compute the number of calories that the user has > >>> burnt since the last reset. > >>> > >>> One of this devices is Freescale's MMA9553L > >>> (http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf) > >>> that computes the number of calories based on weight and step rate. > >>> > >>> Introduce a new channel type CALORIES to export these values. > >>> > >>> Signed-off-by: Irina Tirdea <irina.tirdea@xxxxxxxxx> > >> hmm.. Ideally we use SI units for everything, but in human energy usage > >> Calories are the most common unit by a long way. I'm having some trouble > >> even finding the conversion for this particular for of calorie. > >> > > > > Initially I wanted to use the calorie as unit, but it seemed a little bit confusing because there are 2 different units both called calorie: > > - The small calorie or gram calorie approximates the energy needed to increase the temperature of 1 gram of water by 1 C. > > - The kilogram calorie or "large calorie" is an obsolete term used for the kilocalorie, which is the calorie used to express the energy > content of foods. However, in practice, the prefix "kilo" is usually omitted. > > > oops. I didn't actually read the patch beyond seeing CALORIES as the type in the title ;) > > Instead of using cal (small calorie), kcal or Calorie (large calorie) as unit, I think it would be more clear to use Joule since that would > eliminate confusion and it is also a SI unit. > > > > According to the conversion table from here http://physics.nist.gov/Pubs/SP811/appenB9.html#ENERGY, we could convert > nutritional calories to Joules using the following formula: > > Energy (Joules) = 4 184 * calories_th_nutrition > > I used this formula in the implementation of the driver. > Joules is good, but then the type needs to be ENERGY rather than CALORIES. > (and in_energy_* etc). That sounds better. Will change the type to ENERGY. > > > >> Now clearly it doesn't matter if the only energy sensors we ever get > >> are for human activity. However, that's unlikely to be the case. We > >> already have devices doing instantaneous power and there are plenty > >> of smart meter chips out there (though of course, they will use the > >> option of kW Hours just to confuse matters). > >> > >> I'd definitely prefer joules if we can do it with out a large amount of > >> pain. > >> > >> Lars - any views on this? (Analog do make plenty of 'energy' measurement > >> devices after all!) > >>> --- > >>> Documentation/ABI/testing/sysfs-bus-iio | 9 +++++++++ > >>> drivers/iio/industrialio-core.c | 1 + > >>> include/linux/iio/types.h | 1 + > >>> 3 files changed, 11 insertions(+) > >>> > >>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio > >>> index df5e69e..bb9342b 100644 > >>> --- a/Documentation/ABI/testing/sysfs-bus-iio > >>> +++ b/Documentation/ABI/testing/sysfs-bus-iio > >>> @@ -282,6 +282,7 @@ What: /sys/bus/iio/devices/iio:deviceX/in_current_scale > >>> What: /sys/bus/iio/devices/iio:deviceX/in_accel_scale > >>> What: /sys/bus/iio/devices/iio:deviceX/in_accel_peak_scale > >>> What: /sys/bus/iio/devices/iio:deviceX/in_anglvel_scale > >>> +What: /sys/bus/iio/devices/iio:deviceX/in_calories_scale > >>> What: /sys/bus/iio/devices/iio:deviceX/in_magn_scale > >>> What: /sys/bus/iio/devices/iio:deviceX/in_magn_x_scale > >>> What: /sys/bus/iio/devices/iio:deviceX/in_magn_y_scale > >>> @@ -1049,6 +1050,14 @@ Description: > >>> For a list of available output power modes read > >>> in_accel_power_mode_available. > >>> > >>> +What: /sys/.../iio:deviceX/in_calories_input > >>> +What: /sys/.../iio:deviceX/in_calories_raw > >>> +KernelVersion: 3.17 > >>> +Contact: linux-iio@xxxxxxxxxxxxxxx > >>> +Description: > >>> + This attribute is used to read the number of calories burned since the last > >>> + reset. Units after application of scale are Joules. > >>> + > >>> What: /sys/bus/iio/devices/iio:deviceX/store_eeprom > >>> KernelVersion: 3.4.0 > >>> Contact: linux-iio@xxxxxxxxxxxxxxx > >>> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c > >>> index ee442ee..5d95e84 100644 > >>> --- a/drivers/iio/industrialio-core.c > >>> +++ b/drivers/iio/industrialio-core.c > >>> @@ -72,6 +72,7 @@ static const char * const iio_chan_type_name_spec[] = { > >>> [IIO_HUMIDITYRELATIVE] = "humidityrelative", > >>> [IIO_ACTIVITY] = "activity", > >>> [IIO_STEPS] = "steps", > >>> + [IIO_CALORIES] = "calories", > >>> }; > >>> > >>> static const char * const iio_modifier_names[] = { > >>> diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h > >>> index 904dcbb..d2fe930 100644 > >>> --- a/include/linux/iio/types.h > >>> +++ b/include/linux/iio/types.h > >>> @@ -32,6 +32,7 @@ enum iio_chan_type { > >>> IIO_HUMIDITYRELATIVE, > >>> IIO_ACTIVITY, > >>> IIO_STEPS, > >>> + IIO_CALORIES, > >>> }; > >>> > >>> enum iio_modifier { > >>> > >> > >> -- > >> 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 -- 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
