Jonathan Cameron wrote on 2010-10-05: > On 10/05/10 12:52, Hennerich, Michael wrote: >> Jonathan Cameron wrote on 2010-10-05: >>> On 10/05/10 12:24, Hennerich, Michael wrote: >>>> /** >>>> * IIO_CONST_ATTR_SCAN_EL_TYPE - attr to specify the data format >>>> of a scan el * @name: the scan el name (may be more general and >>>> cover a set of scan elements * @_sign: either s or u for signed >>>> or unsigned * >>>> @_bits: number of actual bits occuplied by the value * >>>> @_storagebits: number of bits _bits is padded to when read out of >>>> buffer **/ >>>> #define IIO_CONST_ATTR_SCAN_EL_TYPE(_name, _sign, _bits, >>>> _storagebits) \ >>>> IIO_CONST_ATTR(_name##_type, >>>> #_sign#_bits"/"#_storagebits); There are cases where bits < >>>> storagebits and the result is not alligned to the LSB. Lets say we >>>> have an 10-bit ADC. The output is stored in a 16-bit word, with >>>> four leading zeros, then the 10-bit datum, followed by 2 don't care bits. >>>> >>>> So it would be good to provide an additional shift value? >>>> Or how shall we handle these cases? >>> This was discussed in the original debate and we simply proposed >>> leaving it until we had a user. So the question is how to describe >>> the shift. >>> >>> So taking your example, how about: >>> >>> u10/16>>2 >>> >>> Where the shift is optional. >>> >>> Other suggestions welcome given I made that up with 2 seconds > thought. >> >> I think this is sufficient. I can only think about right shifts being >> useful. This notation would consistently allow both, that's why I like >> it. It would be decidedly odd for right shift to make sense. >> >> A bit off topic - some common defines for signed/unsigned types might >> also be useful. >> >> #define IIO_SCAN_EL_TYPE_SIGNED 's' #define >> IIO_SCAN_EL_TYPE_UNSIGNED 'u' Fine with me. Shall we add the shift option to the existing macro? Or shall we create a new one? How would you name it? Greetings, Michael Analog Devices GmbH Wilhelm-Wagenfeld-Str. 6 80807 Muenchen Sitz der Gesellschaft Muenchen, Registergericht Muenchen HRB 4036 Geschaeftsfuehrer Thomas Wessel, William A. Martin, Margaret Seif -- 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
