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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 61FBAC433ED for ; Mon, 22 Mar 2021 12:53:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 484E4619F1 for ; Mon, 22 Mar 2021 12:53:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232519AbhCVMw1 (ORCPT ); Mon, 22 Mar 2021 08:52:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:34646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232429AbhCVMmg (ORCPT ); Mon, 22 Mar 2021 08:42:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3F36161998; Mon, 22 Mar 2021 12:40:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1616416827; bh=J0Y3sIMV2n/Y1OuK3iAET8+O3YG9ezdpmXSxTGcPkOQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yzesrRCN1WCQ5SVz+rfcoCXf/oyvzB3c7Jc4BJEC6ser/BrTS9JyR/P4e+b5RRVk3 /bxjk0HiW6DgDdkjYsUaXK+MH+EmQOJ3FvnGiP6bPZ2NacFLMef7H4CDMedPS0NKjH IWqKYALMBG51vsqrK3fY1fNRP5EXnqPIJeUY+B2M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, William Breathitt Gray , Fabrice Gasnier , Stable@vger.kernel.org, Jonathan Cameron Subject: [PATCH 5.10 136/157] counter: stm32-timer-cnt: fix ceiling miss-alignment with reload register Date: Mon, 22 Mar 2021 13:28:13 +0100 Message-Id: <20210322121938.068069851@linuxfoundation.org> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20210322121933.746237845@linuxfoundation.org> References: <20210322121933.746237845@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Fabrice Gasnier commit b14d72ac731753708a7c1a6b3657b9312b6f0042 upstream. Ceiling value may be miss-aligned with what's actually configured into the ARR register. This is seen after probe as currently the ARR value is zero, whereas ceiling value is set to the maximum. So: - reading ceiling reports zero - in case the counter gets enabled without any prior configuration, it won't count. - in case the function gets set by the user 1st, (priv->ceiling) is used. Fix it by getting rid of the cached "priv->ceiling" variable. Rather use the ARR register value directly by using regmap read or write when needed. There should be no drawback on performance as priv->ceiling isn't used in performance critical path. There's also no point in writing ARR while setting function (sms), so it can be safely removed. Fixes: ad29937e206f ("counter: Add STM32 Timer quadrature encoder") Suggested-by: William Breathitt Gray Signed-off-by: Fabrice Gasnier Acked-by: William Breathitt Gray Cc: Link: https://lore.kernel.org/r/1614793789-10346-1-git-send-email-fabrice.gasnier@foss.st.com Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/counter/stm32-timer-cnt.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) --- a/drivers/counter/stm32-timer-cnt.c +++ b/drivers/counter/stm32-timer-cnt.c @@ -31,7 +31,6 @@ struct stm32_timer_cnt { struct counter_device counter; struct regmap *regmap; struct clk *clk; - u32 ceiling; u32 max_arr; bool enabled; struct stm32_timer_regs bak; @@ -75,8 +74,10 @@ static int stm32_count_write(struct coun const unsigned long val) { struct stm32_timer_cnt *const priv = counter->priv; + u32 ceiling; - if (val > priv->ceiling) + regmap_read(priv->regmap, TIM_ARR, &ceiling); + if (val > ceiling) return -EINVAL; return regmap_write(priv->regmap, TIM_CNT, val); @@ -138,10 +139,6 @@ static int stm32_count_function_set(stru regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0); - /* TIMx_ARR register shouldn't be buffered (ARPE=0) */ - regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0); - regmap_write(priv->regmap, TIM_ARR, priv->ceiling); - regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms); /* Make sure that registers are updated */ @@ -199,7 +196,6 @@ static ssize_t stm32_count_ceiling_write regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0); regmap_write(priv->regmap, TIM_ARR, ceiling); - priv->ceiling = ceiling; return len; } @@ -374,7 +370,6 @@ static int stm32_timer_cnt_probe(struct priv->regmap = ddata->regmap; priv->clk = ddata->clk; - priv->ceiling = ddata->max_arr; priv->max_arr = ddata->max_arr; priv->counter.name = dev_name(dev);