From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755212AbcC3Wwv (ORCPT ); Wed, 30 Mar 2016 18:52:51 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:38587 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753395AbcC3Wwr (ORCPT ); Wed, 30 Mar 2016 18:52:47 -0400 Date: Wed, 30 Mar 2016 15:52:44 -0700 From: Guenter Roeck To: Boris Brezillon Cc: Thierry Reding , linux-pwm@vger.kernel.org, Mike Turquette , Stephen Boyd , linux-clk@vger.kernel.org, Mark Brown , Liam Girdwood , Kamil Debski , lm-sensors@lm-sensors.org, Jean Delvare , Dmitry Torokhov , linux-input@vger.kernel.org, Bryan Wu , Richard Purdie , Jacek Anaszewski , linux-leds@vger.kernel.org, Maxime Ripard , Chen-Yu Tsai , linux-sunxi@googlegroups.com, Joachim Eastwood , Thomas Petazzoni , Heiko Stuebner , linux-rockchip@lists.infradead.org, Jingoo Han , Lee Jones , linux-fbdev@vger.kernel.org, Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Robert Jarzmik , Alexandre Belloni , Kukjin Kim , Krzysztof Kozlowski , linux-samsung-soc@vger.kernel.org, intel-gfx@lists.freedesktop.org, Daniel Vetter , Jani Nikula , Jonathan Corbet , linux-doc@vger.kernel.org, David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Hartley Sweeten , Ryan Mallon , Alexander Shiyan , Milo Kim Subject: Re: [PATCH v5 08/46] hwmon: pwm-fan: use pwm_get_args() where appropriate Message-ID: <20160330225244.GA24044@roeck-us.net> References: <1459368249-13241-1-git-send-email-boris.brezillon@free-electrons.com> <1459368249-13241-9-git-send-email-boris.brezillon@free-electrons.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1459368249-13241-9-git-send-email-boris.brezillon@free-electrons.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=0.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 30, 2016 at 10:03:31PM +0200, Boris Brezillon wrote: > The PWM framework has clarified the concept of reference PWM config > (the platform dependent config retrieved from the DT or the PWM > lookup table) and real PWM state. > > Use pwm_get_args() when the PWM user wants to retrieve this reference > config and not the current state. > > This is part of the rework allowing the PWM framework to support > hardware readout and expose real PWM state even when the PWM has > just been requested (before the user calls pwm_config/enable/disable()). > > Signed-off-by: Boris Brezillon > --- > drivers/hwmon/pwm-fan.c | 19 +++++++++++++------ > 1 file changed, 13 insertions(+), 6 deletions(-) > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > index 3e23003..82c5656 100644 > --- a/drivers/hwmon/pwm-fan.c > +++ b/drivers/hwmon/pwm-fan.c > @@ -40,15 +40,18 @@ struct pwm_fan_ctx { > > static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) > { > + struct pwm_args pargs = { }; Hi Boris, I guess I am missing some context; sorry for that. Unfortunately, I did not easily find an explanation, so please bear with me. Two questions: Why do we need a local copy of struct pwm_args instead of a pointer to it ? If it can change while being used, isn't it inconsistent anyway ? Also, assuming the local copy is necessary, why initialize pargs ? After all, pwm_get_args() just overwrites it. Thanks, Guenter > unsigned long duty; > int ret = 0; > > + pwm_get_args(ctx->pwm, &pargs); > + > mutex_lock(&ctx->lock); > if (ctx->pwm_value == pwm) > goto exit_set_pwm_err; > > - duty = DIV_ROUND_UP(pwm * (ctx->pwm->period - 1), MAX_PWM); > - ret = pwm_config(ctx->pwm, duty, ctx->pwm->period); > + duty = DIV_ROUND_UP(pwm * (pargs.period - 1), MAX_PWM); > + ret = pwm_config(ctx->pwm, duty, pargs.period); > if (ret) > goto exit_set_pwm_err; > > @@ -214,6 +217,7 @@ static int pwm_fan_of_get_cooling_data(struct device *dev, > static int pwm_fan_probe(struct platform_device *pdev) > { > struct thermal_cooling_device *cdev; > + struct pwm_args pargs = { }; > struct pwm_fan_ctx *ctx; > struct device *hwmon; > int duty_cycle; > @@ -234,10 +238,11 @@ static int pwm_fan_probe(struct platform_device *pdev) > platform_set_drvdata(pdev, ctx); > > /* Set duty cycle to maximum allowed */ > - duty_cycle = ctx->pwm->period - 1; > + pwm_get_args(ctx->pwm, &pargs); > + duty_cycle = pargs.period - 1; > ctx->pwm_value = MAX_PWM; > > - ret = pwm_config(ctx->pwm, duty_cycle, ctx->pwm->period); > + ret = pwm_config(ctx->pwm, duty_cycle, pargs.period); > if (ret) { > dev_err(&pdev->dev, "Failed to configure PWM\n"); > return ret; > @@ -303,14 +308,16 @@ static int pwm_fan_suspend(struct device *dev) > static int pwm_fan_resume(struct device *dev) > { > struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); > + struct pwm_args pargs = { }; > unsigned long duty; > int ret; > > if (ctx->pwm_value == 0) > return 0; > > - duty = DIV_ROUND_UP(ctx->pwm_value * (ctx->pwm->period - 1), MAX_PWM); > - ret = pwm_config(ctx->pwm, duty, ctx->pwm->period); > + pwm_get_args(ctx->pwm, &pargs); > + duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM); > + ret = pwm_config(ctx->pwm, duty, pargs.period); > if (ret) > return ret; > return pwm_enable(ctx->pwm); > -- > 2.5.0 >