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* iio: afe: rescale: add temperature transducersLiam Beguin2022-02-281-0/+32
| | | | | | | | | | | | | | A temperature transducer is a device that converts a thermal quantity into any other physical quantity. This patch adds support for temperature to voltage (like the LTC2997) and temperature to current (like the AD590) linear transducers. In both cases these are assumed to be connected to a voltage ADC. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Reviewed-by: Peter Rosin <peda@axentia.se> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220213025739.2561834-9-liambeguin@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: rescale: add RTD temperature sensor supportLiam Beguin2022-02-281-0/+48
| | | | | | | | | | | | | An RTD (Resistance Temperature Detector) is a kind of temperature sensor used to get a linear voltage to temperature reading within a give range (usually 0 to 100 degrees Celsius). Common types of RTDs include PT100, PT500, and PT1000. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Reviewed-by: Peter Rosin <peda@axentia.se> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220213025739.2561834-8-liambeguin@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: rescale: reduce risk of integer overflowLiam Beguin2022-02-271-5/+18
| | | | | | | | | | | | Reduce the risk of integer overflow by doing the scale calculation on a 64-bit integer. Since the rescaling is only performed on *val, reuse the IIO_VAL_FRACTIONAL_LOG2 case. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Reviewed-by: Peter Rosin <peda@axentia.se> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220213025739.2561834-6-liambeguin@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: rescale: fix accuracy for small fractional scalesLiam Beguin2022-02-271-3/+17
| | | | | | | | | | | | | The approximation caused by integer divisions can be costly on smaller scale values since the decimal part is significant compared to the integer part. Switch to an IIO_VAL_INT_PLUS_NANO scale type in such cases to maintain accuracy. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Reviewed-by: Peter Rosin <peda@axentia.se> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220213025739.2561834-5-liambeguin@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: rescale: add offset supportLiam Beguin2022-02-271-0/+81
| | | | | | | | | | | This is a preparatory change required for the addition of temperature sensing front ends. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Reviewed-by: Peter Rosin <peda@axentia.se> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220213025739.2561834-4-liambeguin@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: rescale: add INT_PLUS_{MICRO,NANO} supportLiam Beguin2022-02-271-0/+34
| | | | | | | | | | | Some ADCs use IIO_VAL_INT_PLUS_{NANO,MICRO} scale types. Add support for these to allow using the iio-rescaler with them. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Reviewed-by: Peter Rosin <peda@axentia.se> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220213025739.2561834-3-liambeguin@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: rescale: expose scale processing functionLiam Beguin2022-02-271-37/+28
| | | | | | | | | | | In preparation for the addition of kunit tests, expose the logic responsible for combining channel scales. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Reviewed-by: Peter Rosin <peda@axentia.se> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220213025739.2561834-2-liambeguin@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: rescale: reorder includesLiam Beguin2022-01-301-2/+3
| | | | | | | | | | | Includes should be ordered alphabetically which is already the case, but follow what is done in other drivers by separation IIO specific headers with a blank line. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220108205319.2046348-6-liambeguin@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: rescale: use s64 for temporary scale calculationsLiam Beguin2022-01-301-4/+4
| | | | | | | | | | | | | | All four scaling coefficients can take signed values. Make tmp a signed 64-bit integer and switch to div_s64() to preserve signs during 64-bit divisions. Fixes: 8b74816b5a9a ("iio: afe: rescale: new driver") Signed-off-by: Liam Beguin <liambeguin@gmail.com> Reviewed-by: Peter Rosin <peda@axentia.se> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20220108205319.2046348-5-liambeguin@gmail.com Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: iio-rescale: Support processed channelsLinus Walleij2021-06-031-6/+35
| | | | | | | | | | | | | | | | | | It happens that an ADC will only provide raw or processed voltage conversion channels. (adc/ab8500-gpadc.c). On the Samsung GT-I9070 this is used for a light sensor and current sense amplifier so we need to think of something. The idea is to allow processed channels and scale them with 1/1 and then the rescaler can modify the result on top. Link: https://lore.kernel.org/linux-iio/20201101232211.1194304-1-linus.walleij@linaro.org/ Cc: Peter Rosin <peda@axentia.se> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Peter Rosin <peda@axentia.se> Link: https://lore.kernel.org/r/20210518092741.403080-1-linus.walleij@linaro.org Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: afe: iio-rescale: Simplify with dev_err_probe()Krzysztof Kozlowski2020-09-031-5/+3
| | | | | | | | | | | Common pattern of handling deferred probe can be simplified with dev_err_probe(). Less code and also it prints the error value. Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Acked-by: Peter Rosin <peda@axentia.se> Link: https://lore.kernel.org/r/20200829064726.26268-9-krzk@kernel.org Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* iio: remove explicit IIO device parent assignmentAlexandru Ardelean2020-06-141-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch applies the semantic patch: @@ expression I, P, SP; @@ I = devm_iio_device_alloc(P, SP); ... - I->dev.parent = P; It updates 302 files and does 307 deletions. This semantic patch also removes some comments like '/* Establish that the iio_dev is a child of the i2c device */' But this is is only done in case where the block is left empty. The patch does not seem to cover all cases. It looks like in some cases a different variable is used in some cases to assign the parent, but it points to the same reference. In other cases, the block covered by ... may be just too big to be covered by the semantic patch. However, this looks pretty good as well, as it does cover a big bulk of the drivers that should remove the parent assignment. Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2019-05-212-0/+2
| | | | | | | | | | | | | | Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* iio: afe: rescale: new driverPeter Rosin2018-04-283-0/+384
If an ADC channel measures the midpoint of a voltage divider, the interesting voltage is often the voltage over the full resistance. E.g. if the full voltage is too big for the ADC to handle. Likewise, if an ADC channel measures the voltage across a shunt resistor, with or without amplification, the interesting value is often the current through the resistor. This driver solves these problems by allowing to linearly scale a channel and/or by allowing changes to the type of the channel. Signed-off-by: Peter Rosin <peda@axentia.se> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>