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 // SPDX-License-Identifier: GPL-2.0 /* * helpers to map values in a linear range to range index * * Original idea borrowed from regulator framework * * It might be useful if we could support also inversely proportional ranges? * Copyright 2020 ROHM Semiconductors */ #include #include #include #include #include /** * linear_range_values_in_range - return the amount of values in a range * @r: pointer to linear range where values are counted * * Compute the amount of values in range pointed by @r. Note, values can * be all equal - range with selectors 0,...,2 with step 0 still contains * 3 values even though they are all equal. * * Return: the amount of values in range pointed by @r */ unsigned int linear_range_values_in_range(const struct linear_range *r) { if (!r) return 0; return r->max_sel - r->min_sel + 1; } EXPORT_SYMBOL_GPL(linear_range_values_in_range); /** * linear_range_values_in_range_array - return the amount of values in ranges * @r: pointer to array of linear ranges where values are counted * @ranges: amount of ranges we include in computation. * * Compute the amount of values in ranges pointed by @r. Note, values can * be all equal - range with selectors 0,...,2 with step 0 still contains * 3 values even though they are all equal. * * Return: the amount of values in first @ranges ranges pointed by @r */ unsigned int linear_range_values_in_range_array(const struct linear_range *r, int ranges) { int i, values_in_range = 0; for (i = 0; i < ranges; i++) { int values; values = linear_range_values_in_range(&r[i]); if (!values) return values; values_in_range += values; } return values_in_range; } EXPORT_SYMBOL_GPL(linear_range_values_in_range_array); /** * linear_range_get_max_value - return the largest value in a range * @r: pointer to linear range where value is looked from * * Return: the largest value in the given range */ unsigned int linear_range_get_max_value(const struct linear_range *r) { return r->min + (r->max_sel - r->min_sel) * r->step; } EXPORT_SYMBOL_GPL(linear_range_get_max_value); /** * linear_range_get_value - fetch a value from given range * @r: pointer to linear range where value is looked from * @selector: selector for which the value is searched * @val: address where found value is updated * * Search given ranges for value which matches given selector. * * Return: 0 on success, -EINVAL given selector is not found from any of the * ranges. */ int linear_range_get_value(const struct linear_range *r, unsigned int selector, unsigned int *val) { if (r->min_sel > selector || r->max_sel < selector) return -EINVAL; *val = r->min + (selector - r->min_sel) * r->step; return 0; } EXPORT_SYMBOL_GPL(linear_range_get_value); /** * linear_range_get_value_array - fetch a value from array of ranges * @r: pointer to array of linear ranges where value is looked from * @ranges: amount of ranges in an array * @selector: selector for which the value is searched * @val: address where found value is updated * * Search through an array of ranges for value which matches given selector. * * Return: 0 on success, -EINVAL given selector is not found from any of the * ranges. */ int linear_range_get_value_array(const struct linear_range *r, int ranges, unsigned int selector, unsigned int *val) { int i; for (i = 0; i < ranges; i++) if (r[i].min_sel <= selector && r[i].max_sel >= selector) return linear_range_get_value(&r[i], selector, val); return -EINVAL; } EXPORT_SYMBOL_GPL(linear_range_get_value_array); /** * linear_range_get_selector_low - return linear range selector for value * @r: pointer to linear range where selector is looked from * @val: value for which the selector is searched * @selector: address where found selector value is updated * @found: flag to indicate that given value was in the range * * Return selector for which range value is closest match for given * input value. Value is matching if it is equal or smaller than given * value. If given value is in the range, then @found is set true. * * Return: 0 on success, -EINVAL if range is invalid or does not contain * value smaller or equal to given value */ int linear_range_get_selector_low(const struct linear_range *r, unsigned int val, unsigned int *selector, bool *found) { *found = false; if (r->min > val) return -EINVAL; if (linear_range_get_max_value(r) < val) { *selector = r->max_sel; return 0; } *found = true; if (r->step == 0) *selector = r->min_sel; else *selector = (val - r->min) / r->step + r->min_sel; return 0; } EXPORT_SYMBOL_GPL(linear_range_get_selector_low); /** * linear_range_get_selector_low_array - return linear range selector for value * @r: pointer to array of linear ranges where selector is looked from * @ranges: amount of ranges to scan from array * @val: value for which the selector is searched * @selector: address where found selector value is updated * @found: flag to indicate that given value was in the range * * Scan array of ranges for selector for which range value matches given * input value. Value is matching if it is equal or smaller than given * value. If given value is found to be in a range scanning is stopped and * @found is set true. If a range with values smaller than given value is found * but the range max is being smaller than given value, then the range's * biggest selector is updated to @selector but scanning ranges is continued * and @found is set to false. * * Return: 0 on success, -EINVAL if range array is invalid or does not contain * range with a value smaller or equal to given value */ int linear_range_get_selector_low_array(const struct linear_range *r, int ranges, unsigned int val, unsigned int *selector, bool *found) { int i; int ret = -EINVAL; for (i = 0; i < ranges; i++) { int tmpret; tmpret = linear_range_get_selector_low(&r[i], val, selector, found); if (!tmpret) ret = 0; if (*found) break; } return ret; } EXPORT_SYMBOL_GPL(linear_range_get_selector_low_array); /** * linear_range_get_selector_high - return linear range selector for value * @r: pointer to linear range where selector is looked from * @val: value for which the selector is searched * @selector: address where found selector value is updated * @found: flag to indicate that given value was in the range * * Return selector for which range value is closest match for given * input value. Value is matching if it is equal or higher than given * value. If given value is in the range, then @found is set true. * * Return: 0 on success, -EINVAL if range is invalid or does not contain * value greater or equal to given value */ int linear_range_get_selector_high(const struct linear_range *r, unsigned int val, unsigned int *selector, bool *found) { *found = false; if (linear_range_get_max_value(r) < val) return -EINVAL; if (r->min > val) { *selector = r->min_sel; return 0; } *found = true; if (r->step == 0) *selector = r->max_sel; else *selector = DIV_ROUND_UP(val - r->min, r->step) + r->min_sel; return 0; } EXPORT_SYMBOL_GPL(linear_range_get_selector_high); MODULE_DESCRIPTION("linear-ranges helper"); MODULE_LICENSE("GPL");