From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from SHSQR01.spreadtrum.com (mx1.unisoc.com [222.66.158.135]) (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 E23B520DE0 for ; Mon, 22 Jan 2024 08:18:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=222.66.158.135 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705911507; cv=none; b=qJKSOexWzDA9NgUzU4Wt7URkd8M4bmJ9EX4k4LXQA7RdWOz0WKOneHvn63nqhl1EzepT7vjKFcUJyvp0qaqDCm7QWaF1riTkdf2kk/J4iv4CUjWQ1MsQCK8wY6SOdGYjI+lt9rVXrNq/3ITeOk+N0FxoS1fQ2e4DwfR2ecTOk+A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705911507; c=relaxed/simple; bh=r5yH1TaiCnUCBJprvitoDlf5mXdrpFFc3uvABTt2tEs=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=npuBSDWpZd74C65McHHdMJYZDbSH9+1zAhtE50Ep9TO6+V4njJcOcSescw2ogVWYytS36BSzNNln9EzxiBo4ZB7L/S4blNtFD0sy1/E5j6Eh2FjaHDXZqVuhFfjzIIf70uWK7ewRPcPhYCqH1sXwdXNruAVZSdCm9qZMkhCvpns= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=unisoc.com; spf=pass smtp.mailfrom=unisoc.com; arc=none smtp.client-ip=222.66.158.135 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=unisoc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=unisoc.com Received: from dlp.unisoc.com ([10.29.3.86]) by SHSQR01.spreadtrum.com with ESMTP id 40M8I5t6055439; Mon, 22 Jan 2024 16:18:05 +0800 (+08) (envelope-from Wenhua.Lin@unisoc.com) Received: from SHDLP.spreadtrum.com (shmbx06.spreadtrum.com [10.0.1.11]) by dlp.unisoc.com (SkyGuard) with ESMTPS id 4TJNFf5R23z2Rb68H; Mon, 22 Jan 2024 16:10:46 +0800 (CST) Received: from xm9614pcu.spreadtrum.com (10.13.2.29) by shmbx06.spreadtrum.com (10.0.1.11) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Mon, 22 Jan 2024 16:18:03 +0800 From: Wenhua Lin To: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= CC: Orson Zhai , Baolin Wang , Chunyan Zhang , , , wenhua lin , Wenhua Lin , Xiongpeng Wu , zhaochen su , Zhaochen Su , Xiaolong Wang Subject: [PATCH 3/6] pwm: sprd: Optimize the calculation method of duty Date: Mon, 22 Jan 2024 16:17:51 +0800 Message-ID: <20240122081754.17058-4-Wenhua.Lin@unisoc.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20240122081754.17058-1-Wenhua.Lin@unisoc.com> References: <20240122081754.17058-1-Wenhua.Lin@unisoc.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-ClientProxiedBy: SHCAS03.spreadtrum.com (10.0.1.207) To shmbx06.spreadtrum.com (10.0.1.11) X-MAIL:SHSQR01.spreadtrum.com 40M8I5t6055439 Use DIV_ROUND_CLOSEST_ULL to avoid overflow and improve accuracy when calculating duty. Signed-off-by: Wenhua Lin --- drivers/pwm/pwm-sprd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/pwm/pwm-sprd.c b/drivers/pwm/pwm-sprd.c index 411e91891c6d..22793e2b8707 100644 --- a/drivers/pwm/pwm-sprd.c +++ b/drivers/pwm/pwm-sprd.c @@ -156,7 +156,8 @@ static int sprd_pwm_config(struct sprd_pwm_chip *spc, struct pwm_device *pwm, * given settings (MOD and input clock). */ mod = spc->mod[pwm->hwpwm]; - duty = duty_ns * mod / period_ns; + tmp = (u64)duty_ns * mod; + duty = DIV_ROUND_CLOSEST_ULL(tmp, period_ns); tmp = (u64)chn->clk_rate * period_ns; do_div(tmp, NSEC_PER_SEC); -- 2.17.1