From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 042D3C43331 for ; Fri, 3 Apr 2020 09:37:44 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C912320737 for ; Fri, 3 Apr 2020 09:37:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ChGFihTP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C912320737 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=6cYvLLMNrEYAbCnNOlG0kT1l4Lbpk/3OMVeI0I0eAcE=; b=ChGFihTP0k/teX CXCtf5g8pRZxdR6XuOk+S6VrXs3D1ZUe07aBEJm2DzIYRr53wGYdG+fcd6VAkn5lH0BOtki3nBd1x nb64zK0HoqoAA0n2Y1i+vDEcv+MG5gTXd+B4BF2nUZQa9MSFC2QyZWouHJEyB/CvB7bpu8wtl83Ro RFcBtZ8YZtAIlk+aWm7E1QXa1kguqTMpXVBoeR/TFLkD8lpGe9/EyDvk5uGTbkfFy/8ALu/EobmkC 51yGDq6d2LZ5wTV1YTkQfQwiQ4B+5yIoodRcnC6iI8/KKDcp3HxPZu1ZTts0oqiesBcGpgSS8ywF8 35gJOHALoUyQZMaPRgcw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jKIlY-0005UN-J4; Fri, 03 Apr 2020 09:37:32 +0000 Received: from mga04.intel.com ([192.55.52.120]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jKIlQ-0005NP-L0; Fri, 03 Apr 2020 09:37:26 +0000 IronPort-SDR: Gsz53hmx6OmP2ZtW/ml8uKuXJK3qBwEAhbDil+tpBZpwim0SUmTB+d1GDph3xtPCjGGVsuKR1p 6297m1vl8aOw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Apr 2020 02:37:22 -0700 IronPort-SDR: 6ctsVTIkuOJW1zsi+6r+x5UJTRL261u9mGQ5257+l2jFXHqbvL/nMwpdqWjssQBbG2Gr5Ta/+y EYpqfJALPpNw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,339,1580803200"; d="scan'208";a="423470479" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by orsmga005.jf.intel.com with ESMTP; 03 Apr 2020 02:37:10 -0700 Received: from andy by smile with local (Exim 4.93) (envelope-from ) id 1jKIlD-00FOaL-Li; Fri, 03 Apr 2020 12:37:11 +0300 Date: Fri, 3 Apr 2020 12:37:11 +0300 From: Andy Shevchenko To: Matti Vaittinen Subject: Re: [PATCH v8 03/10] lib: add linear ranges helpers Message-ID: <20200403093711.GJ1922688@smile.fi.intel.com> References: <05ef7d49f1e2a895ac6688bfdd444d2cbba53e6e.1585902279.git.matti.vaittinen@fi.rohmeurope.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <05ef7d49f1e2a895ac6688bfdd444d2cbba53e6e.1585902279.git.matti.vaittinen@fi.rohmeurope.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200403_023724_710813_D1CF286D X-CRM114-Status: GOOD ( 37.01 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Andrei Stefanescu , Heiko Stuebner , "Rafael J. Wysocki" , Tony Lindgren , Linus Walleij , Brendan Higgins , Liam Girdwood , Andreas Kemnade , "Angelo G. Del Regno" , Hsin-Hsiung Wang , linux-samsung-soc@vger.kernel.org, linux-omap@vger.kernel.org, Axel Lin , Gregory CLEMENT , Bartlomiej Zolnierkiewicz , Krzysztof Kozlowski , Markus Reichl , Bartosz Golaszewski , Chen-Yu Tsai , Andy Gross , markus.laine@fi.rohmeurope.com, Adam Thomson , devicetree@vger.kernel.org, Charles Keepax , mazziesaccount@gmail.com, linux-arm-msm@vger.kernel.org, Richard Fitzgerald , Mark Brown , linux-mediatek@lists.infradead.org, Matthias Brugger , Thomas Gleixner , Bjorn Andersson , linux-arm-kernel@lists.infradead.org, Support Opensource , Baolin Wang , Sangbeom Kim , Greg Kroah-Hartman , linux-pm@vger.kernel.org, Randy Dunlap , Sebastian Reichel , linux-kernel@vger.kernel.org, mikko.mutanen@fi.rohmeurope.com, Vinod Koul , Rob Herring , patches@opensource.cirrus.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Fri, Apr 03, 2020 at 11:45:47AM +0300, Matti Vaittinen wrote: > Many devices have control registers which control some measurable > property. Often a register contains control field so that change in > this field causes linear change in the controlled property. It is not > a rare case that user wants to give 'meaningful' control values and > driver needs to convert them to register field values. Even more > often user wants to 'see' the currently set value - again in > meaningful units - and driver needs to convert the values it reads > from register to these meaningful units. Examples of this include: > > - regulators, voltage/current configurations > - power, voltage/current configurations > - clk(?) NCOs > > and maybe others I can't think of right now. > > Provide a linear_range helper which can do conversion from user value > to register value 'selector'. > > The idea here is stolen from regulator framework and patches refactoring > the regulator helpers to use this are following. > > Current implementation does not support inversely proportional ranges > but it might be useful if we could support also inversely proportional > ranges? > FWIW, Reviewed-by: Andy Shevchenko > Signed-off-by: Matti Vaittinen > Reviewed-by: Mark Brown > Reviewed-by: Linus Walleij > --- > > Changes since v7: > - Cleanups suggested by Andy, no functional changes > > include/linux/linear_range.h | 48 +++++++ > lib/Kconfig | 3 + > lib/Makefile | 1 + > lib/linear_ranges.c | 241 +++++++++++++++++++++++++++++++++++ > 4 files changed, 293 insertions(+) > create mode 100644 include/linux/linear_range.h > create mode 100644 lib/linear_ranges.c > > diff --git a/include/linux/linear_range.h b/include/linux/linear_range.h > new file mode 100644 > index 000000000000..17b5943727d5 > --- /dev/null > +++ b/include/linux/linear_range.h > @@ -0,0 +1,48 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* Copyright (C) 2020 ROHM Semiconductors */ > + > +#ifndef LINEAR_RANGE_H > +#define LINEAR_RANGE_H > + > +#include > + > +/** > + * struct linear_range - table of selector - value pairs > + * > + * Define a lookup-table for range of values. Intended to help when looking > + * for a register value matching certaing physical measure (like voltage). > + * Usable when increment of one in register always results a constant increment > + * of the physical measure (like voltage). > + * > + * @min: Lowest value in range > + * @min_sel: Lowest selector for range > + * @max_sel: Highest selector for range > + * @step: Value step size > + */ > +struct linear_range { > + unsigned int min; > + unsigned int min_sel; > + unsigned int max_sel; > + unsigned int step; > +}; > + > +unsigned int linear_range_values_in_range(const struct linear_range *r); > +unsigned int linear_range_values_in_range_array(const struct linear_range *r, > + int ranges); > +unsigned int linear_range_get_max_value(const struct linear_range *r); > + > +int linear_range_get_value(const struct linear_range *r, unsigned int selector, > + unsigned int *val); > +int linear_range_get_value_array(const struct linear_range *r, int ranges, > + unsigned int selector, unsigned int *val); > +int linear_range_get_selector_low(const struct linear_range *r, > + unsigned int val, unsigned int *selector, > + bool *found); > +int linear_range_get_selector_high(const struct linear_range *r, > + unsigned int val, unsigned int *selector, > + bool *found); > +int linear_range_get_selector_low_array(const struct linear_range *r, > + int ranges, unsigned int val, > + unsigned int *selector, bool *found); > + > +#endif > diff --git a/lib/Kconfig b/lib/Kconfig > index bc7e56370129..411ab2d2d800 100644 > --- a/lib/Kconfig > +++ b/lib/Kconfig > @@ -19,6 +19,9 @@ config RAID6_PQ_BENCHMARK > Benchmark all available RAID6 PQ functions on init and choose the > fastest one. > > +config LINEAR_RANGES > + tristate > + > config PACKING > bool "Generic bitfield packing and unpacking" > default n > diff --git a/lib/Makefile b/lib/Makefile > index 611872c06926..18c3d313872e 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -122,6 +122,7 @@ obj-$(CONFIG_DEBUG_LIST) += list_debug.o > obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o > > obj-$(CONFIG_BITREVERSE) += bitrev.o > +obj-$(CONFIG_LINEAR_RANGES) += linear_ranges.o > obj-$(CONFIG_PACKING) += packing.o > obj-$(CONFIG_CRC_CCITT) += crc-ccitt.o > obj-$(CONFIG_CRC16) += crc16.o > diff --git a/lib/linear_ranges.c b/lib/linear_ranges.c > new file mode 100644 > index 000000000000..d1336c75ccd7 > --- /dev/null > +++ b/lib/linear_ranges.c > @@ -0,0 +1,241 @@ > +// 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 > + > +/** > + * 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 which 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 which 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 ranges > + * 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 which 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); > -- > 2.21.0 > > > -- > Matti Vaittinen, Linux device drivers > ROHM Semiconductors, Finland SWDC > Kiviharjunlenkki 1E > 90220 OULU > FINLAND > > ~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~ > Simon says - in Latin please. > ~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~ > Thanks to Simon Glass for the translation =] -- With Best Regards, Andy Shevchenko _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek