From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9039C382F2D; Sun, 10 May 2026 12:42:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778416954; cv=none; b=iLmb+Yn22Sqb/TkDdUELCXtOCCei/Ewd5G8CdFQAKJBDMCISQGCaXbG7ma0Br6hYVFYtSQLCxu9brTIPtROyYjt8mpEqRsFVS7pFbG1TUtAXSvqUomkQ+BvvOkmDhXEeRw9pYzMHjmqIYnqKgBl76sIYH3q202CF40Si5gUvUgY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778416954; c=relaxed/simple; bh=JYMvvV9kEoUo4ixyGxEEOStHDHETRyXjQhoHsXlYHWw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=lPaDIq9g/z08Om1Ho/qhQ1v3FlqG3mCigM6xfDXRYF1s8z8WnisW9YUBAjvFJfaGeN5tJVz+h/vHSa7ovxgpuKD4qX/uiAfxotLqRBRsyasPNEJ1DvwJu0nWbShPRSmgrZ4/q2EMdZbYeDVGcvXMibhl50mZnxCFlpAQaKAyGME= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TCtJjDI5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TCtJjDI5" Received: by smtp.kernel.org (Postfix) with ESMTPS id 5B476C2BCB8; Sun, 10 May 2026 12:42:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778416954; bh=JYMvvV9kEoUo4ixyGxEEOStHDHETRyXjQhoHsXlYHWw=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=TCtJjDI5rqthsJIAoGovouY1siGWTJEbvNfE80ZYtVxaeQu54lO+AxqoN0winYYx8 OTMiOhU4+ZHpzEHtnTucoVQL55wv61o17DivflfVlJ1X7MC3ssFIKp/urOu9Yzvr5n ZHDYcImxvvKsmgY6FRZd2rbM7alxeQCU9hf62tI2JCWkTxyqqUXRl/+FSXYxHoIzsh 0NaEP3Vp7Ak0qdpDal8McduMdPW5X6mcG/YjFOnMRX9hs384Qj+/ddbW8+suUc7S5M p30w+9OD8oxdCeS4wsjv/UJlU5BjPz9IRc1NukPfdmsEQG9+1Y//0DKwWuU2eOMY7u 0G6wucCRzWF0w== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 471F3CD37BA; Sun, 10 May 2026 12:42:34 +0000 (UTC) From: Rodrigo Alencar via B4 Relay Date: Sun, 10 May 2026 13:42:20 +0100 Subject: [PATCH v12 02/11] lib: kstrtox: add kstrtoudec64() and kstrtodec64() Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260510-adf41513-iio-driver-v12-2-34af2ed2779f@analog.com> References: <20260510-adf41513-iio-driver-v12-0-34af2ed2779f@analog.com> In-Reply-To: <20260510-adf41513-iio-driver-v12-0-34af2ed2779f@analog.com> To: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-doc@vger.kernel.org Cc: Jonathan Cameron , David Lechner , Andy Shevchenko , Lars-Peter Clausen , Michael Hennerich , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jonathan Corbet , Andrew Morton , Petr Mladek , Steven Rostedt , Andy Shevchenko , Rasmus Villemoes , Sergey Senozhatsky , Shuah Khan , Rodrigo Alencar X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1778416952; l=5013; i=rodrigo.alencar@analog.com; s=default; h=from:subject:message-id; bh=bfxEiBTybcnSmFHQsPmGvhUNRsDbjiLCPlXgEF2s4Ig=; b=QcDCQboWkgn9txE6S3gg5cKg42R9opLiUERDeDWYEj3UJ7FVydYvzJZNlYhXQMbSI53u6yrHk PJJK6nIle1/CWDwI9LuKkE3xLEgTJbJ7+4jXXI/Vam3TfjZ31IpTOt/ X-Developer-Key: i=rodrigo.alencar@analog.com; a=ed25519; pk=ULeHbgU/OYh/PG/4anHDfLgldFItQHAhOktYRVLMFRo= X-Endpoint-Received: by B4 Relay for rodrigo.alencar@analog.com/default with auth_id=561 X-Original-From: Rodrigo Alencar Reply-To: rodrigo.alencar@analog.com From: Rodrigo Alencar Add helpers that parses decimal numbers into 64-bit number, i.e., decimal point numbers with pre-defined scale are parsed into a 64-bit value (fixed precision). After the decimal point, digits beyond the specified scale are ignored. Signed-off-by: Rodrigo Alencar --- include/linux/kstrtox.h | 3 ++ lib/kstrtox.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 110 insertions(+) diff --git a/include/linux/kstrtox.h b/include/linux/kstrtox.h index 6ea897222af1..bec2fc17bde0 100644 --- a/include/linux/kstrtox.h +++ b/include/linux/kstrtox.h @@ -97,6 +97,9 @@ int __must_check kstrtou8(const char *s, unsigned int base, u8 *res); int __must_check kstrtos8(const char *s, unsigned int base, s8 *res); int __must_check kstrtobool(const char *s, bool *res); +int __must_check kstrtoudec64(const char *s, unsigned int scale, u64 *res); +int __must_check kstrtodec64(const char *s, unsigned int scale, s64 *res); + int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res); int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res); int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res); diff --git a/lib/kstrtox.c b/lib/kstrtox.c index 97be2a39f537..da7b5f83a3c5 100644 --- a/lib/kstrtox.c +++ b/lib/kstrtox.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -392,6 +393,112 @@ int kstrtobool(const char *s, bool *res) } EXPORT_SYMBOL(kstrtobool); +static int _kstrtoudec64(const char *s, unsigned int scale, u64 *res) +{ + u64 _res = 0, _frac = 0; + unsigned int rv; + + if (scale > 19) /* log10(2^64) = 19.26 */ + return -EINVAL; + + if (*s != '.') { + rv = _parse_integer(s, 10, &_res); + if (rv & KSTRTOX_OVERFLOW) + return -ERANGE; + if (rv == 0) + return -EINVAL; + s += rv; + } + + if (*s == '.' && scale) { + s++; /* skip decimal point */ + rv = _parse_integer_limit(s, 10, &_frac, scale); + if (rv & KSTRTOX_OVERFLOW) + return -ERANGE; + if (rv == 0) + return -EINVAL; + s += rv; + if (rv < scale) + _frac *= int_pow(10, scale - rv); + while (isdigit(*s)) /* truncate */ + s++; + } + + if (*s == '\n') + s++; + if (*s) + return -EINVAL; + + if (check_mul_overflow(_res, int_pow(10, scale), &_res) || + check_add_overflow(_res, _frac, &_res)) + return -ERANGE; + + *res = _res; + return 0; +} + +/** + * kstrtoudec64() - Convert a string to an unsigned 64-bit value that represents + * a scaled decimal number. + * @s: The start of the string. The string must be null-terminated, and may also + * include a single newline before its terminating null. The first character + * may also be a plus sign, but not a minus sign. Digits beyond the specified + * scale are ignored. + * @scale: The number of digits to the right of the decimal point. For example, + * a scale of 2 would mean the number is represented with two decimal places, + * so "123.45" would be represented as 12345. + * @res: Where to write the result of the conversion on success. + * + * Return: 0 on success, -ERANGE on overflow and -EINVAL on parsing error. + */ +noinline +int kstrtoudec64(const char *s, unsigned int scale, u64 *res) +{ + if (s[0] == '+') + s++; + return _kstrtoudec64(s, scale, res); +} +EXPORT_SYMBOL(kstrtoudec64); + +/** + * kstrtodec64() - Convert a string to a signed 64-bit value that represents a + * scaled decimal number. + * @s: The start of the string. The string must be null-terminated, and may also + * include a single newline before its terminating null. The first character + * may also be a plus sign or a minus sign. Digits beyond the specified + * scale are ignored. + * @scale: The number of digits to the right of the decimal point. For example, + * a scale of 5 would mean the number is represented with five decimal places, + * so "-3.141592" would be represented as -314159. + * @res: Where to write the result of the conversion on success. + * + * Return: 0 on success, -ERANGE on overflow and -EINVAL on parsing error. + */ +noinline +int kstrtodec64(const char *s, unsigned int scale, s64 *res) +{ + u64 tmp; + int rv; + + if (s[0] == '-') { + rv = _kstrtoudec64(s + 1, scale, &tmp); + if (rv < 0) + return rv; + if ((s64)-tmp > 0) + return -ERANGE; + *res = -tmp; + } else { + rv = kstrtoudec64(s, scale, &tmp); + if (rv < 0) + return rv; + if ((s64)tmp < 0) + return -ERANGE; + *res = tmp; + } + return 0; +} +EXPORT_SYMBOL(kstrtodec64); + /* * Since "base" would be a nonsense argument, this open-codes the * _from_user helper instead of using the helper macro below. -- 2.43.0