From patchwork Tue Aug 1 12:49:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Marek_Beh=C3=BAn?= X-Patchwork-Id: 709436 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B0ABC001DF for ; Tue, 1 Aug 2023 12:49:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232278AbjHAMti (ORCPT ); Tue, 1 Aug 2023 08:49:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231697AbjHAMti (ORCPT ); Tue, 1 Aug 2023 08:49:38 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A18DE6 for ; Tue, 1 Aug 2023 05:49:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BC48F6158F for ; Tue, 1 Aug 2023 12:49:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02817C433C7; Tue, 1 Aug 2023 12:49:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690894176; bh=l5zgW34TeKaOMLTdsybU9+eKvfYnaA6X9dVN/rjINy4=; h=From:To:Cc:Subject:Date:From; b=hMhl0IGALsBspFe4VruESqnSfmFMna5MKmUBO/tLAvxR7XTp2uSvnWpVWate4vPhK sqP+v+JNBj3RZfvW/2+9H08fLk3UEvR0mFq+GpygHbNTH1QTLouT3BMFsTmJJNWNjc cfhp6wLzHtROISEpaJTqj9Kr/wHMzf3uVG0mlss2GdsZqvl+iFmwLovF+EtWc+c1DC aAe/watOaTQuEk3SIYzL4HAX5/uuscdGJ7jbHQrlmxWdZN0wv7RJzy7E3NjLocTokz 8C9Jeot2jmOJUo2hZcoUm3YIGfYPVV4zzTRzFelnyjiPrquqFoFDnRQ7xoOJNlCERu V3szf26AsZliw== From: =?utf-8?q?Marek_Beh=C3=BAn?= To: Pavel Machek , Lee Jones , linux-leds@vger.kernel.org, Dan Murphy Cc: =?utf-8?q?Marek_Beh=C3=BAn?= Subject: [PATCH] leds: multicolor: Use rounded division when calculating color components Date: Tue, 1 Aug 2023 14:49:31 +0200 Message-ID: <20230801124931.8661-1-kabel@kernel.org> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org 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 --- 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 e317408583df..ec62a4811613 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; }