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 6731511710 for ; Mon, 11 Sep 2023 15:24:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE713C433C7; Mon, 11 Sep 2023 15:24:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694445889; bh=w68OcLwnBurfeqPdOmBRERQSn2eU9RFIjiahhGdWbkk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vl+OOIiZnQ0i1QtOl5XVMQtzO79SAvU5LLHPR0yfJ4QUf/LHyBtznHw5AiUR/s1NM 5bUyMVtROS1RGtD0IoB6eZAS9/maHtp4L0nAyNtvxyjug+L1bCJE3JxlUchveBdnd9 22c9a4JDgzMgTT6w4ku/GujFwTBOg9B7/PYIeOYo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Marek=20Beh=C3=BAn?= , Lee Jones , Sasha Levin Subject: [PATCH 6.1 507/600] leds: multicolor: Use rounded division when calculating color components Date: Mon, 11 Sep 2023 15:49:00 +0200 Message-ID: <20230911134648.584497371@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230911134633.619970489@linuxfoundation.org> References: <20230911134633.619970489@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marek Behún [ Upstream commit 065d099f1be58187e6629273c50b948a02b7e1bf ] Given channel intensity, LED brightness and max LED brightness, the multicolor LED framework helper led_mc_calc_color_components() computes the color channel brightness as chan_brightness = brightness * chan_intensity / max_brightness Consider the situation when (brightness, intensity, max_brightness) is for example (16, 15, 255), then chan_brightness is computed to 0 although the fractional divison would give 0.94, which should be rounded to 1. Use DIV_ROUND_CLOSEST here for the division to give more realistic component computation: chan_brightness = DIV_ROUND_CLOSEST(brightness * chan_intensity, max_brightness) Fixes: 55d5d3b46b08 ("leds: multicolor: Introduce a multicolor class definition") Signed-off-by: Marek Behún Link: https://lore.kernel.org/r/20230801124931.8661-1-kabel@kernel.org Signed-off-by: Lee Jones Signed-off-by: Sasha Levin --- drivers/leds/led-class-multicolor.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c index e317408583df9..ec62a48116135 100644 --- a/drivers/leds/led-class-multicolor.c +++ b/drivers/leds/led-class-multicolor.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -19,9 +20,10 @@ int led_mc_calc_color_components(struct led_classdev_mc *mcled_cdev, int i; for (i = 0; i < mcled_cdev->num_colors; i++) - mcled_cdev->subled_info[i].brightness = brightness * - mcled_cdev->subled_info[i].intensity / - led_cdev->max_brightness; + mcled_cdev->subled_info[i].brightness = + DIV_ROUND_CLOSEST(brightness * + mcled_cdev->subled_info[i].intensity, + led_cdev->max_brightness); return 0; } -- 2.40.1