From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/iio/afe/iio-rescale.c | 611 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 611 insertions(+) create mode 100644 drivers/iio/afe/iio-rescale.c (limited to 'drivers/iio/afe/iio-rescale.c') diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c new file mode 100644 index 000000000..56e5913ab --- /dev/null +++ b/drivers/iio/afe/iio-rescale.c @@ -0,0 +1,611 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * IIO rescale driver + * + * Copyright (C) 2018 Axentia Technologies AB + * Copyright (C) 2022 Liam Beguin + * + * Author: Peter Rosin + */ + +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +int rescale_process_scale(struct rescale *rescale, int scale_type, + int *val, int *val2) +{ + s64 tmp; + int _val, _val2; + s32 rem, rem2; + u32 mult; + u32 neg; + + switch (scale_type) { + case IIO_VAL_INT: + *val *= rescale->numerator; + if (rescale->denominator == 1) + return scale_type; + *val2 = rescale->denominator; + return IIO_VAL_FRACTIONAL; + case IIO_VAL_FRACTIONAL: + /* + * When the product of both scales doesn't overflow, avoid + * potential accuracy loss (for in kernel consumers) by + * keeping a fractional representation. + */ + if (!check_mul_overflow(*val, rescale->numerator, &_val) && + !check_mul_overflow(*val2, rescale->denominator, &_val2)) { + *val = _val; + *val2 = _val2; + return IIO_VAL_FRACTIONAL; + } + fallthrough; + case IIO_VAL_FRACTIONAL_LOG2: + tmp = (s64)*val * 1000000000LL; + tmp = div_s64(tmp, rescale->denominator); + tmp *= rescale->numerator; + + tmp = div_s64_rem(tmp, 1000000000LL, &rem); + *val = tmp; + + if (!rem) + return scale_type; + + if (scale_type == IIO_VAL_FRACTIONAL) + tmp = *val2; + else + tmp = ULL(1) << *val2; + + rem2 = *val % (int)tmp; + *val = *val / (int)tmp; + + *val2 = rem / (int)tmp; + if (rem2) + *val2 += div_s64((s64)rem2 * 1000000000LL, tmp); + + 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 ? 1000000000L : 1000000L; + + /* + * For IIO_VAL_INT_PLUS_{MICRO,NANO} scale types if either *val + * OR *val2 is negative the schan scale is negative, i.e. + * *val = 1 and *val2 = -0.5 yields -1.5 not -0.5. + */ + neg = *val < 0 || *val2 < 0; + + tmp = (s64)abs(*val) * abs(rescale->numerator); + *val = div_s64_rem(tmp, abs(rescale->denominator), &rem); + + tmp = (s64)rem * mult + (s64)abs(*val2) * abs(rescale->numerator); + tmp = div_s64(tmp, abs(rescale->denominator)); + + *val += div_s64_rem(tmp, mult, val2); + + /* + * If only one of the rescaler elements or the schan scale is + * negative, the combined scale is negative. + */ + if (neg ^ ((rescale->numerator < 0) ^ (rescale->denominator < 0))) { + if (*val) + *val = -*val; + else + *val2 = -*val2; + } + + return scale_type; + default: + return -EOPNOTSUPP; + } +} +EXPORT_SYMBOL_NS_GPL(rescale_process_scale, IIO_RESCALE); + +int rescale_process_offset(struct rescale *rescale, int scale_type, + int scale, int scale2, int schan_off, + int *val, int *val2) +{ + s64 tmp, tmp2; + + switch (scale_type) { + case IIO_VAL_FRACTIONAL: + tmp = (s64)rescale->offset * scale2; + *val = div_s64(tmp, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT: + *val = div_s64(rescale->offset, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_FRACTIONAL_LOG2: + tmp = (s64)rescale->offset * (1 << scale2); + *val = div_s64(tmp, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT_PLUS_NANO: + 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 * 1000000LL; + tmp2 = ((s64)scale * 1000000LL) + scale2; + *val = div64_s64(tmp, tmp2) + schan_off; + return IIO_VAL_INT; + default: + return -EOPNOTSUPP; + } +} +EXPORT_SYMBOL_NS_GPL(rescale_process_offset, IIO_RESCALE); + +static int rescale_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct rescale *rescale = iio_priv(indio_dev); + int scale, scale2; + int schan_off = 0; + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (rescale->chan_processed) + /* + * When only processed channels are supported, we + * read the processed data and scale it by 1/1 + * augmented with whatever the rescaler has calculated. + */ + return iio_read_channel_processed(rescale->source, val); + else + return iio_read_channel_raw(rescale->source, val); + + case IIO_CHAN_INFO_SCALE: + if (rescale->chan_processed) { + /* + * Processed channels are scaled 1-to-1 + */ + *val = 1; + *val2 = 1; + ret = IIO_VAL_FRACTIONAL; + } else { + ret = iio_read_channel_scale(rescale->source, val, val2); + } + return rescale_process_scale(rescale, ret, val, val2); + case IIO_CHAN_INFO_OFFSET: + /* + * Processed channels are scaled 1-to-1 and source offset is + * already taken into account. + * + * In other cases, real world measurement are expressed as: + * + * schan_scale * (raw + schan_offset) + * + * Given that the rescaler parameters are applied recursively: + * + * rescaler_scale * (schan_scale * (raw + schan_offset) + + * rescaler_offset) + * + * Or, + * + * (rescaler_scale * schan_scale) * (raw + + * (schan_offset + rescaler_offset / schan_scale) + * + * Thus, reusing the original expression the parameters exposed + * to userspace are: + * + * scale = schan_scale * rescaler_scale + * offset = schan_offset + rescaler_offset / schan_scale + */ + if (rescale->chan_processed) { + *val = rescale->offset; + return IIO_VAL_INT; + } + + if (iio_channel_has_info(rescale->source->channel, + IIO_CHAN_INFO_OFFSET)) { + ret = iio_read_channel_offset(rescale->source, + &schan_off, NULL); + if (ret != IIO_VAL_INT) + return ret < 0 ? ret : -EOPNOTSUPP; + } + + if (iio_channel_has_info(rescale->source->channel, + IIO_CHAN_INFO_SCALE)) { + ret = iio_read_channel_scale(rescale->source, &scale, &scale2); + return rescale_process_offset(rescale, ret, scale, scale2, + schan_off, val, val2); + } + + /* + * If we get here we have no scale so scale 1:1 but apply + * rescaler and offset, if any. + */ + return rescale_process_offset(rescale, IIO_VAL_FRACTIONAL, 1, 1, + schan_off, val, val2); + default: + return -EINVAL; + } +} + +static int rescale_read_avail(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int **vals, int *type, int *length, + long mask) +{ + struct rescale *rescale = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + *type = IIO_VAL_INT; + return iio_read_avail_channel_raw(rescale->source, + vals, length); + default: + return -EINVAL; + } +} + +static const struct iio_info rescale_info = { + .read_raw = rescale_read_raw, + .read_avail = rescale_read_avail, +}; + +static ssize_t rescale_read_ext_info(struct iio_dev *indio_dev, + uintptr_t private, + struct iio_chan_spec const *chan, + char *buf) +{ + struct rescale *rescale = iio_priv(indio_dev); + + return iio_read_channel_ext_info(rescale->source, + rescale->ext_info[private].name, + buf); +} + +static ssize_t rescale_write_ext_info(struct iio_dev *indio_dev, + uintptr_t private, + struct iio_chan_spec const *chan, + const char *buf, size_t len) +{ + struct rescale *rescale = iio_priv(indio_dev); + + return iio_write_channel_ext_info(rescale->source, + rescale->ext_info[private].name, + buf, len); +} + +static int rescale_configure_channel(struct device *dev, + struct rescale *rescale) +{ + struct iio_chan_spec *chan = &rescale->chan; + struct iio_chan_spec const *schan = rescale->source->channel; + + chan->indexed = 1; + chan->output = schan->output; + chan->ext_info = rescale->ext_info; + chan->type = rescale->cfg->type; + + if (iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) && + (iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE) || + iio_channel_has_info(schan, IIO_CHAN_INFO_OFFSET))) { + dev_info(dev, "using raw+scale/offset source channel\n"); + } else if (iio_channel_has_info(schan, IIO_CHAN_INFO_PROCESSED)) { + dev_info(dev, "using processed channel\n"); + rescale->chan_processed = true; + } else { + dev_err(dev, "source channel is not supported\n"); + return -EINVAL; + } + + chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE); + + if (rescale->offset) + chan->info_mask_separate |= BIT(IIO_CHAN_INFO_OFFSET); + + /* + * Using .read_avail() is fringe to begin with and makes no sense + * whatsoever for processed channels, so we make sure that this cannot + * be called on a processed channel. + */ + if (iio_channel_has_available(schan, IIO_CHAN_INFO_RAW) && + !rescale->chan_processed) + chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW); + + return 0; +} + +static int rescale_current_sense_amplifier_props(struct device *dev, + struct rescale *rescale) +{ + u32 sense; + u32 gain_mult = 1; + u32 gain_div = 1; + u32 factor; + int ret; + + ret = device_property_read_u32(dev, "sense-resistor-micro-ohms", + &sense); + if (ret) { + dev_err(dev, "failed to read the sense resistance: %d\n", ret); + return ret; + } + + device_property_read_u32(dev, "sense-gain-mult", &gain_mult); + device_property_read_u32(dev, "sense-gain-div", &gain_div); + + /* + * Calculate the scaling factor, 1 / (gain * sense), or + * gain_div / (gain_mult * sense), while trying to keep the + * numerator/denominator from overflowing. + */ + factor = gcd(sense, 1000000); + rescale->numerator = 1000000 / factor; + rescale->denominator = sense / factor; + + factor = gcd(rescale->numerator, gain_mult); + rescale->numerator /= factor; + rescale->denominator *= gain_mult / factor; + + factor = gcd(rescale->denominator, gain_div); + rescale->numerator *= gain_div / factor; + rescale->denominator /= factor; + + return 0; +} + +static int rescale_current_sense_shunt_props(struct device *dev, + struct rescale *rescale) +{ + u32 shunt; + u32 factor; + int ret; + + ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms", + &shunt); + if (ret) { + dev_err(dev, "failed to read the shunt resistance: %d\n", ret); + return ret; + } + + factor = gcd(shunt, 1000000); + rescale->numerator = 1000000 / factor; + rescale->denominator = shunt / factor; + + return 0; +} + +static int rescale_voltage_divider_props(struct device *dev, + struct rescale *rescale) +{ + int ret; + u32 factor; + + ret = device_property_read_u32(dev, "output-ohms", + &rescale->denominator); + if (ret) { + dev_err(dev, "failed to read output-ohms: %d\n", ret); + return ret; + } + + ret = device_property_read_u32(dev, "full-ohms", + &rescale->numerator); + if (ret) { + dev_err(dev, "failed to read full-ohms: %d\n", ret); + return ret; + } + + factor = gcd(rescale->numerator, rescale->denominator); + rescale->numerator /= factor; + rescale->denominator /= factor; + + return 0; +} + +static int rescale_temp_sense_rtd_props(struct device *dev, + struct rescale *rescale) +{ + u32 factor; + u32 alpha; + u32 iexc; + u32 tmp; + int ret; + u32 r0; + + ret = device_property_read_u32(dev, "excitation-current-microamp", + &iexc); + if (ret) { + dev_err(dev, "failed to read excitation-current-microamp: %d\n", + ret); + return ret; + } + + ret = device_property_read_u32(dev, "alpha-ppm-per-celsius", &alpha); + if (ret) { + dev_err(dev, "failed to read alpha-ppm-per-celsius: %d\n", + ret); + return ret; + } + + ret = device_property_read_u32(dev, "r-naught-ohms", &r0); + if (ret) { + dev_err(dev, "failed to read r-naught-ohms: %d\n", ret); + return ret; + } + + tmp = r0 * iexc * alpha / 1000000; + factor = gcd(tmp, 1000000); + rescale->numerator = 1000000 / factor; + rescale->denominator = tmp / factor; + + rescale->offset = -1 * ((r0 * iexc) / 1000); + + return 0; +} + +static int rescale_temp_transducer_props(struct device *dev, + struct rescale *rescale) +{ + s32 offset = 0; + s32 sense = 1; + s32 alpha; + int ret; + + device_property_read_u32(dev, "sense-offset-millicelsius", &offset); + device_property_read_u32(dev, "sense-resistor-ohms", &sense); + ret = device_property_read_u32(dev, "alpha-ppm-per-celsius", &alpha); + if (ret) { + dev_err(dev, "failed to read alpha-ppm-per-celsius: %d\n", ret); + return ret; + } + + rescale->numerator = 1000000; + rescale->denominator = alpha * sense; + + rescale->offset = div_s64((s64)offset * rescale->denominator, + rescale->numerator); + + return 0; +} + +enum rescale_variant { + CURRENT_SENSE_AMPLIFIER, + CURRENT_SENSE_SHUNT, + VOLTAGE_DIVIDER, + TEMP_SENSE_RTD, + TEMP_TRANSDUCER, +}; + +static const struct rescale_cfg rescale_cfg[] = { + [CURRENT_SENSE_AMPLIFIER] = { + .type = IIO_CURRENT, + .props = rescale_current_sense_amplifier_props, + }, + [CURRENT_SENSE_SHUNT] = { + .type = IIO_CURRENT, + .props = rescale_current_sense_shunt_props, + }, + [VOLTAGE_DIVIDER] = { + .type = IIO_VOLTAGE, + .props = rescale_voltage_divider_props, + }, + [TEMP_SENSE_RTD] = { + .type = IIO_TEMP, + .props = rescale_temp_sense_rtd_props, + }, + [TEMP_TRANSDUCER] = { + .type = IIO_TEMP, + .props = rescale_temp_transducer_props, + }, +}; + +static const struct of_device_id rescale_match[] = { + { .compatible = "current-sense-amplifier", + .data = &rescale_cfg[CURRENT_SENSE_AMPLIFIER], }, + { .compatible = "current-sense-shunt", + .data = &rescale_cfg[CURRENT_SENSE_SHUNT], }, + { .compatible = "voltage-divider", + .data = &rescale_cfg[VOLTAGE_DIVIDER], }, + { .compatible = "temperature-sense-rtd", + .data = &rescale_cfg[TEMP_SENSE_RTD], }, + { .compatible = "temperature-transducer", + .data = &rescale_cfg[TEMP_TRANSDUCER], }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, rescale_match); + +static int rescale_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct iio_dev *indio_dev; + struct iio_channel *source; + struct rescale *rescale; + int sizeof_ext_info; + int sizeof_priv; + int i; + int ret; + + source = devm_iio_channel_get(dev, NULL); + if (IS_ERR(source)) + return dev_err_probe(dev, PTR_ERR(source), + "failed to get source channel\n"); + + sizeof_ext_info = iio_get_channel_ext_info_count(source); + if (sizeof_ext_info) { + sizeof_ext_info += 1; /* one extra entry for the sentinel */ + sizeof_ext_info *= sizeof(*rescale->ext_info); + } + + sizeof_priv = sizeof(*rescale) + sizeof_ext_info; + + indio_dev = devm_iio_device_alloc(dev, sizeof_priv); + if (!indio_dev) + return -ENOMEM; + + rescale = iio_priv(indio_dev); + + rescale->cfg = device_get_match_data(dev); + rescale->numerator = 1; + rescale->denominator = 1; + rescale->offset = 0; + + ret = rescale->cfg->props(dev, rescale); + if (ret) + return ret; + + if (!rescale->numerator || !rescale->denominator) { + dev_err(dev, "invalid scaling factor.\n"); + return -EINVAL; + } + + platform_set_drvdata(pdev, indio_dev); + + rescale->source = source; + + indio_dev->name = dev_name(dev); + indio_dev->info = &rescale_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = &rescale->chan; + indio_dev->num_channels = 1; + if (sizeof_ext_info) { + rescale->ext_info = devm_kmemdup(dev, + source->channel->ext_info, + sizeof_ext_info, GFP_KERNEL); + if (!rescale->ext_info) + return -ENOMEM; + + for (i = 0; rescale->ext_info[i].name; ++i) { + struct iio_chan_spec_ext_info *ext_info = + &rescale->ext_info[i]; + + if (source->channel->ext_info[i].read) + ext_info->read = rescale_read_ext_info; + if (source->channel->ext_info[i].write) + ext_info->write = rescale_write_ext_info; + ext_info->private = i; + } + } + + ret = rescale_configure_channel(dev, rescale); + if (ret) + return ret; + + return devm_iio_device_register(dev, indio_dev); +} + +static struct platform_driver rescale_driver = { + .probe = rescale_probe, + .driver = { + .name = "iio-rescale", + .of_match_table = rescale_match, + }, +}; +module_platform_driver(rescale_driver); + +MODULE_DESCRIPTION("IIO rescale driver"); +MODULE_AUTHOR("Peter Rosin "); +MODULE_LICENSE("GPL v2"); -- cgit v1.2.3