Messages in this thread | | | Subject | Re: [PATCH v2 1/8] add header file for kelvin to/from Celsius conversion helpers | From | Daniel Lezcano <> | Date | Fri, 6 Dec 2019 17:49:18 +0100 |
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On 28/11/2019 15:54, Akinobu Mita wrote: > There are several helper macros to convert kelvin to/from Celsius in > <linux/thermal.h> for thermal drivers. These are useful for any other > drivers or subsystems, but it's odd to include <linux/thermal.h> just for > the helpers. > > This adds a new <linux/temperature.h> that provides the equivalent inline > functions for any drivers or subsystems. It is intended to replace the > helpers in <linux/thermal.h>. > > Cc: Sujith Thomas <sujith.thomas@intel.com> > Cc: Darren Hart <dvhart@infradead.org> > Cc: Andy Shevchenko <andy@infradead.org> > Cc: Zhang Rui <rui.zhang@intel.com> > Cc: Daniel Lezcano <daniel.lezcano@linaro.org> > Cc: Amit Kucheria <amit.kucheria@verdurent.com> > Cc: Jean Delvare <jdelvare@suse.com> > Cc: Guenter Roeck <linux@roeck-us.net> > Cc: Keith Busch <kbusch@kernel.org> > Cc: Jens Axboe <axboe@fb.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Sagi Grimberg <sagi@grimberg.me> > Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> > --- > * v2 > - add deci_kelvin_to_millicelsius_with_offset() in linux/temperature.h > - stop including linux/temperature.h from linux/thermal.h > > include/linux/temperature.h | 51 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 51 insertions(+) > create mode 100644 include/linux/temperature.h > > diff --git a/include/linux/temperature.h b/include/linux/temperature.h > new file mode 100644 > index 0000000..679e70a > --- /dev/null > +++ b/include/linux/temperature.h > @@ -0,0 +1,51 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _LINUX_TEMPERATURE_H > +#define _LINUX_TEMPERATURE_H
It sounds strange to create a temperature file just for a few conversion functions. Why not create an units.h file, so some more conversions could be added later (not necessarily related to temperature) ?
> +#include <linux/kernel.h> > + > +#define ABSOLUTE_ZERO_MILLICELSIUS -273150 > + > +static inline long kelvin_to_millicelsius(long t)
Why 'long' ?
> +{ > + return t * 1000 + ABSOLUTE_ZERO_MILLICELSIUS; > +} > + > +static inline long millicelsius_to_kelvin(long t) > +{ > + return DIV_ROUND_CLOSEST(t - ABSOLUTE_ZERO_MILLICELSIUS, 1000);
Please don't duplicate these operations, just do the conversion to the right unit and then call a single function.
Replace the constant by macros like what we find in time64.h.
eg. #define MILLICELSIUS_PER_CELCIUS 1000
So you can really do the cleanup in all the drivers, like removing:
drivers/iio/adc/qcom-vadc-common.h:#define KELVINMIL_CELSIUSMIL 273150 drivers/iio/pressure/st_pressure_core.c:#define MCELSIUS_PER_CELSIUS 1000 drivers/hwmon/xgene-hwmon.c:#define CELSIUS_TO_mCELSIUS(x) ((x) * 1000) drivers/net/wireless/intel/iwlegacy/common.h:#define KELVIN_TO_CELSIUS(x) ((x)-273) drivers/net/wireless/intel/iwlegacy/common.h:#define CELSIUS_TO_KELVIN(x) ((x)+273) drivers/net/wireless/intel/iwlwifi/dvm/dev.h:#define KELVIN_TO_CELSIUS(x) ((x)-273) drivers/net/wireless/intel/iwlwifi/dvm/dev.h:#define CELSIUS_TO_KELVIN(x) ((x)+273) drivers/power/supply/sbs-battery.c:#define TEMP_KELVIN_TO_CELSIUS 2731 drivers/thermal/armada_thermal.c:#define TO_MCELSIUS(c) ((c) * 1000) drivers/thermal/rcar_gen3_thermal.c:#define MCELSIUS(temp) ((temp) * 1000) drivers/thermal/rcar_thermal.c:#define MCELSIUS(temp) ((temp) * 1000) drivers/thermal/samsung/exynos_tmu.c:#define MCELSIUS 1000 drivers/thermal/samsung/exynos_tmu.c: temp /= MCELSIUS; drivers/thermal/samsung/exynos_tmu.c: hyst /= MCELSIUS; drivers/thermal/samsung/exynos_tmu.c: ref = trips[0].temperature / MCELSIUS; drivers/thermal/samsung/exynos_tmu.c: *temp = code_to_temp(data, value) * MCELSIUS; drivers/thermal/samsung/exynos_tmu.c: temp /= MCELSIUS;
> +} > + > +static inline long deci_kelvin_to_celsius(long t) > +{ > + return DIV_ROUND_CLOSEST(t * 100 + ABSOLUTE_ZERO_MILLICELSIUS, 1000); > +} > + > +static inline long celsius_to_deci_kelvin(long t) > +{ > + return t * 10 - DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, 100); > +} > + > +/** > + * deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius > + * @t: temperature value in decidegrees Kelvin > + * @offset: difference between Kelvin and Celsius in millidegrees > + * > + * Return: temperature value in millidegrees Celsius > + */ > +static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset) > +{ > + return t * 100 - offset; > +} > + > +static inline long deci_kelvin_to_millicelsius(long t) > +{ > + return t * 100 + ABSOLUTE_ZERO_MILLICELSIUS; > +} > + > +static inline long millicelsius_to_deci_kelvin(long t) > +{ > + return DIV_ROUND_CLOSEST(t - ABSOLUTE_ZERO_MILLICELSIUS, 100); > +} > + > +#endif /* _LINUX_TEMPERATURE_H */ >
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