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(modemcable055.92-163-184.mc.videotron.ca. [184.163.92.55]) by smtp.gmail.com with ESMTPSA id y15sm14551106qkp.22.2022.02.12.18.57.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 12 Feb 2022 18:57:43 -0800 (PST) From: Liam Beguin To: liambeguin@gmail.com, peda@axentia.se, jic23@kernel.org, andy.shevchenko@gmail.com, lars@metafoo.de Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org Subject: [PATCH v15 00/10] iio: afe: add temperature rescaling support Date: Sat, 12 Feb 2022 21:57:29 -0500 Message-Id: <20220213025739.2561834-1-liambeguin@gmail.com> X-Mailer: git-send-email 2.35.1.4.g5d01301f2b86 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Jonathan, Peter, Andy, This series focuses on adding temperature rescaling support to the IIO Analog Front End (AFE) driver. The main changes to the AFE driver include an initial Kunit test suite, support for IIO_VAL_INT_PLUS_{NANO,MICRO} scales, and support for RTDs and temperature transducer sensors. Thanks for your time, Liam Changes since v14: - Revert units.h changes in favor of "raw" values Changes since v13: - fix SI prefix in rescale_temp_sense_rtd_props() - add comment explaining SI prefixes are sometimes used as mathematical multipliers with no particular physical meaning associated. Changes since v12: - rebase on latest testing branch - fix copyright holder in newly created header file - add myself as a copyright holder of the iio-rescale.c driver at Peter's suggestion - fix undefined behavior on left-shift operation Changes since v11: - update commits with my personal email since all this work was done on my own time - apply Peter's Reviewed-by to my local tree - fix use of units.h - make use of units.h more consistently in iio-rescale.c and in the tests - fix #include ordering - treat 04/16 as a fix. Move it, and add a Fixes: tag - fix undefined behavior on left-shift operation - add comment about fract_mult with iio_str_to_fixpoint() - reword commit message for 14/16, based on Andy's comments Changes since v10: - apply Andy's suggestion for offset calculations - make use of units.h more consistently Changes since v9: - make use of linux/units.h - reorder commits, fix fract_log2 before merging fract - keep fractional representation when not overflowing Changes since v8: - reword comment - fix erroneous 64-bit division - optimize and use 32-bit divisions when values are know to not overflow - keep IIO_VAL_FRACTIONAL scale when possible, if not default to fixed point - add test cases - use nano precision in test cases - simplify offset calculation in rtd_props() Changes since v7: - drop gcd() logic in rescale_process_scale() - use div_s64() instead of do_div() for signed 64-bit divisions - combine IIO_VAL_FRACTIONAL and IIO_VAL_FRACTIONAL_LOG2 scale cases - switch to INT_PLUS_NANO when accuracy is lost with FRACTIONAL scales - rework test logic to allow for small relative error - rename test variables to align error output messages Changes since v6: - rework IIO_VAL_INT_PLUS_{NANO,MICRO} based on Peter's suggestion - combine IIO_VAL_INT_PLUS_{NANO,MICRO} cases - add test cases for negative IIO_VAL_INT_PLUS_{NANO,MICRO} corner cases - force use of positive integers with gcd() - reduce risk of integer overflow in IIO_VAL_FRACTIONAL_LOG2 - fix duplicate symbol build error - apply Reviewed-by Changes since v5: - add include/linux/iio/afe/rescale.h - expose functions use to process scale and offset - add basic iio-rescale kunit test cases - fix integer overflow case - improve precision for IIO_VAL_FRACTIONAL_LOG2 Changes since v4: - only use gcd() when necessary in overflow mitigation - fix INT_PLUS_{MICRO,NANO} support - apply Reviewed-by - fix temperature-transducer bindings Changes since v3: - drop unnecessary fallthrough statements - drop redundant local variables in some calculations - fix s64 divisions on 32bit platforms by using do_div - add comment describing iio-rescaler offset calculation - drop unnecessary MAINTAINERS entry Changes since v2: - don't break implicit offset truncations - make a best effort to get a valid value for fractional types - drop return value change in iio_convert_raw_to_processed_unlocked() - don't rely on processed value for offset calculation - add INT_PLUS_{MICRO,NANO} support in iio-rescale - revert generic implementation in favor of temperature-sense-rtd and temperature-transducer - add separate section to MAINTAINERS file Changes since v1: - rebase on latest iio `testing` branch - also apply consumer scale on integer channel scale types - don't break implicit truncation in processed channel offset calculation - drop temperature AFE flavors in favor of a simpler generic implementation Liam Beguin (10): iio: afe: rescale: expose scale processing function iio: afe: rescale: add INT_PLUS_{MICRO,NANO} support iio: afe: rescale: add offset support iio: afe: rescale: fix accuracy for small fractional scales iio: afe: rescale: reduce risk of integer overflow iio: test: add basic tests for the iio-rescale driver iio: afe: rescale: add RTD temperature sensor support iio: afe: rescale: add temperature transducers dt-bindings: iio: afe: add bindings for temperature-sense-rtd dt-bindings: iio: afe: add bindings for temperature transducers .../iio/afe/temperature-sense-rtd.yaml | 101 +++ .../iio/afe/temperature-transducer.yaml | 114 +++ drivers/iio/afe/iio-rescale.c | 283 ++++++- drivers/iio/test/Kconfig | 10 + drivers/iio/test/Makefile | 1 + drivers/iio/test/iio-test-rescale.c | 710 ++++++++++++++++++ include/linux/iio/afe/rescale.h | 36 + 7 files changed, 1220 insertions(+), 35 deletions(-) create mode 100644 Documentation/devicetree/bindings/iio/afe/temperature-sense-rtd.yaml create mode 100644 Documentation/devicetree/bindings/iio/afe/temperature-transducer.yaml create mode 100644 drivers/iio/test/iio-test-rescale.c create mode 100644 include/linux/iio/afe/rescale.h Range-diff against v14: -: ------------ > 1: ee26b0eeac65 iio: afe: rescale: expose scale processing function 1: a510097c83f1 ! 2: 78f9d37575a5 iio: afe: rescale: add INT_PLUS_{MICRO,NANO} support @@ Commit message Reviewed-by: Peter Rosin ## drivers/iio/afe/iio-rescale.c ## -@@ - #include - #include - #include -+#include - - #include - #include @@ drivers/iio/afe/iio-rescale.c: int rescale_process_scale(struct rescale *rescale, int scale_type, int *val, int *val2) { @@ drivers/iio/afe/iio-rescale.c: int rescale_process_scale(struct rescale *rescale + return scale_type; + case IIO_VAL_INT_PLUS_NANO: + case IIO_VAL_INT_PLUS_MICRO: -+ mult = scale_type == IIO_VAL_INT_PLUS_NANO ? GIGA : MEGA; ++ mult = scale_type == IIO_VAL_INT_PLUS_NANO ? 1000000000L : 1000000L; + + /* + * For IIO_VAL_INT_PLUS_{MICRO,NANO} scale types if either *val 2: 8f2f2699a9b4 ! 3: 5be82bd72453 iio: afe: rescale: add offset support @@ drivers/iio/afe/iio-rescale.c: int rescale_process_scale(struct rescale *rescale + *val = div_s64(tmp, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT_PLUS_NANO: -+ tmp = (s64)rescale->offset * GIGA; -+ tmp2 = ((s64)scale * GIGA) + scale2; ++ tmp = (s64)rescale->offset * 1000000000LL; ++ tmp2 = ((s64)scale * 1000000000LL) + scale2; + *val = div64_s64(tmp, tmp2) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT_PLUS_MICRO: -+ tmp = (s64)rescale->offset * MEGA; -+ tmp2 = ((s64)scale * MEGA) + scale2; ++ tmp = (s64)rescale->offset * 1000000LL; ++ tmp2 = ((s64)scale * 1000000LL) + scale2; + *val = div64_s64(tmp, tmp2) + schan_off; + return IIO_VAL_INT; + default: 3: 2efa970bad26 ! 4: 95ec184759f6 iio: afe: rescale: fix accuracy for small fractional scales @@ drivers/iio/afe/iio-rescale.c: int rescale_process_scale(struct rescale *rescale + return IIO_VAL_INT_PLUS_NANO; case IIO_VAL_INT_PLUS_NANO: case IIO_VAL_INT_PLUS_MICRO: - mult = scale_type == IIO_VAL_INT_PLUS_NANO ? GIGA : MEGA; + mult = scale_type == IIO_VAL_INT_PLUS_NANO ? 1000000000L : 1000000L; 4: 201037c0ead8 = 5: 2e1d41ef69d9 iio: afe: rescale: reduce risk of integer overflow 5: a0037cc3ee90 < -: ------------ iio: afe: rescale: make use of units.h 6: f8d47728f482 ! 6: 0b6c029dea1d iio: test: add basic tests for the iio-rescale driver @@ drivers/iio/test/iio-test-rescale.c (new) + +#include +#include -+#include + +#include +#include @@ drivers/iio/test/iio-test-rescale.c (new) + if (tmp < 0) + tmp2 *= -1; + -+ *nano = (s64)tmp * GIGA + tmp2; ++ *nano = (s64)tmp * 1000000000UL + tmp2; + + return ret; +} @@ drivers/iio/test/iio-test-rescale.c (new) + return -EINVAL; + } + -+ err = MEGA * abs(exp - real); ++ err = 1000000UL * abs(exp - real); + + return (int)div64_u64(err, abs(exp)); +} 7: a04685586340 ! 7: 951ea44d0f5c iio: afe: rescale: add RTD temperature sensor support @@ drivers/iio/afe/iio-rescale.c: static int rescale_voltage_divider_props(struct d + return ret; + } + -+ tmp = r0 * iexc * alpha / MEGA; -+ factor = gcd(tmp, MEGA); -+ rescale->numerator = MEGA / factor; ++ tmp = r0 * iexc * alpha / 1000000; ++ factor = gcd(tmp, 1000000); ++ rescale->numerator = 1000000 / factor; + rescale->denominator = tmp / factor; + -+ rescale->offset = -1 * ((r0 * iexc) / KILO); ++ rescale->offset = -1 * ((r0 * iexc) / 1000); + + return 0; +} 8: e3b716aaee50 ! 8: 56516fdc67bf iio: afe: rescale: add temperature transducers @@ drivers/iio/afe/iio-rescale.c: static int rescale_temp_sense_rtd_props(struct de + return ret; + } + -+ rescale->numerator = MEGA; ++ rescale->numerator = 1000000; + rescale->denominator = alpha * sense; + + rescale->offset = div_s64((s64)offset * rescale->denominator, 9: 22ae1458eb8b = 9: 8c409050990b dt-bindings: iio: afe: add bindings for temperature-sense-rtd 10: 33825ad452d6 = 10: bb39296590f3 dt-bindings: iio: afe: add bindings for temperature transducers base-commit: cd717ac6f69db4953ca701c6220c7cb58e17f35a Reviewed-by: Andy Shevchenko