From patchwork Tue Jan 19 16:12:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Simon South X-Patchwork-Id: 1428728 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-pwm-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4DKv0M0M2Hz9sVk for ; Wed, 20 Jan 2021 03:16:03 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392147AbhASQO5 (ORCPT ); Tue, 19 Jan 2021 11:14:57 -0500 Received: from mailout.easymail.ca ([64.68.200.34]:52118 "EHLO mailout.easymail.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392132AbhASQOu (ORCPT ); Tue, 19 Jan 2021 11:14:50 -0500 Received: from localhost (localhost [127.0.0.1]) by mailout.easymail.ca (Postfix) with ESMTP id 707412508A; Tue, 19 Jan 2021 16:14:07 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at emo06-pco.easydns.vpn Received: from mailout.easymail.ca ([127.0.0.1]) by localhost (emo06-pco.easydns.vpn [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XzNuQnkCdiqe; Tue, 19 Jan 2021 16:14:07 +0000 (UTC) Received: from localhost.localdomain (unknown [108.162.141.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mailout.easymail.ca (Postfix) with ESMTPSA id 4D8CD25085; Tue, 19 Jan 2021 16:13:48 +0000 (UTC) From: Simon South To: tpiepho@gmail.com, thierry.reding@gmail.com, u.kleine-koenig@pengutronix.de, robin.murphy@arm.com, lee.jones@linaro.org, heiko@sntech.de, bbrezillon@kernel.org, david.wu@rock-chips.com, steven.liu@rock-chips.com, linux-pwm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Cc: simon@simonsouth.net Subject: [PATCH v4 5/5] pwm: rockchip: Enable clock before calling clk_get_rate() Date: Tue, 19 Jan 2021 11:12:09 -0500 Message-Id: <4924f18fea9b028cab92ad4e79d957f5cb336b9c.1610976129.git.simon@simonsouth.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org The documentation for clk_get_rate() in include/linux/clk.h states the function's result is valid only for a clock source that has been enabled. However, the Rockchip PWM driver uses this function in two places to query the rate of a clock without first ensuring it is enabled. Fix this by modifying rockchip_pwm_get_state() and rockchip_pwm_apply() so they enable a device's PWM clock before querying its rate (in the latter case, the querying is actually done in rockchip_pwm_config()) and disable the clock again before returning. Reported-by: Uwe Kleine-König Signed-off-by: Simon South Reviewed-by: Uwe Kleine-König --- drivers/pwm/pwm-rockchip.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c index 228147e9bc6e..6ad7d0a50aed 100644 --- a/drivers/pwm/pwm-rockchip.c +++ b/drivers/pwm/pwm-rockchip.c @@ -72,6 +72,10 @@ static void rockchip_pwm_get_state(struct pwm_chip *chip, if (ret) return; + ret = clk_enable(pc->clk); + if (ret) + return; + clk_rate = clk_get_rate(pc->clk); tmp = readl_relaxed(pc->base + pc->data->regs.period); @@ -90,6 +94,7 @@ static void rockchip_pwm_get_state(struct pwm_chip *chip, else state->polarity = PWM_POLARITY_NORMAL; + clk_disable(pc->clk); clk_disable(pc->pclk); } @@ -189,6 +194,10 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, if (ret) return ret; + ret = clk_enable(pc->clk); + if (ret) + return ret; + pwm_get_state(pwm, &curstate); enabled = curstate.enabled; @@ -208,6 +217,7 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, } out: + clk_disable(pc->clk); clk_disable(pc->pclk); return ret;