From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753058Ab3A1JgP (ORCPT ); Mon, 28 Jan 2013 04:36:15 -0500 Received: from smtp0.epfl.ch ([128.178.224.218]:39323 "HELO smtp0.epfl.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750972Ab3A1JgN (ORCPT ); Mon, 28 Jan 2013 04:36:13 -0500 Message-ID: <51064687.5090605@epfl.ch> Date: Mon, 28 Jan 2013 10:36:07 +0100 From: Florian Vaussard Reply-To: florian.vaussard@epfl.ch User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Peter Ujfalusi CC: Thierry Reding , Bryan Wu , Richard Purdie , linux-leds@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/3] pwm: Add pwm_cansleep() as exported API to users References: <1359121471-21457-1-git-send-email-florian.vaussard@epfl.ch> <1359121471-21457-2-git-send-email-florian.vaussard@epfl.ch> <20130126054024.GB29243@avionic-0098.adnet.avionic-design.de> <51063AB5.2060108@ti.com> In-Reply-To: <51063AB5.2060108@ti.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Le 28/01/2013 09:45, Peter Ujfalusi a écrit : > hi Thierry, > > On 01/26/2013 06:40 AM, Thierry Reding wrote: >>> + * @pwm: PWM device >>> + * >>> + * It returns nonzero if accessing the PWM can sleep. >>> + */ >>> +int pwm_cansleep(struct pwm_device *pwm) >> >> I actually liked pwm_can_sleep() better. I find it to be more consistent >> with the naming of other function names. It would furthermore match the >> field name. > > I was looking at the GPIO API to suggest this name change, but you are right > we should be consistent with the PWM API here. > Sorry Florian. > No problem, I agree with the PWM API consistency. >> >>> +{ >>> + return pwm->chip->can_sleep; >>> +} >>> +EXPORT_SYMBOL_GPL(pwm_cansleep); >> >> Would it make sense to check for NULL pointers here? I guess that >> passing NULL into the function could be considered a programming error >> and an oops would be okay, but in that case there's no point in making >> the function return an int. Also see my next comment. > > While it is unlikely to happen it is better to be safe, something like this > will do: > > return pwm ? pwm->chip->can_sleep : 0; > Ok. And what about: BUG_ON(pwm == NULL); return pwm->chip->can_sleep; >> >>> + >>> #ifdef CONFIG_DEBUG_FS >>> static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s) >>> { >>> diff --git a/include/linux/pwm.h b/include/linux/pwm.h >>> index 70655a2..e2cb5c7 100644 >>> --- a/include/linux/pwm.h >>> +++ b/include/linux/pwm.h >>> @@ -146,6 +146,8 @@ struct pwm_ops { >>> * @base: number of first PWM controlled by this chip >>> * @npwm: number of PWMs controlled by this chip >>> * @pwms: array of PWM devices allocated by the framework >>> + * @can_sleep: flag must be set iff config()/enable()/disable() methods sleep, >>> + * as they must while accessing PWM chips over I2C or SPI >>> */ >>> struct pwm_chip { >>> struct device *dev; >>> @@ -159,6 +161,7 @@ struct pwm_chip { >>> struct pwm_device * (*of_xlate)(struct pwm_chip *pc, >>> const struct of_phandle_args *args); >>> unsigned int of_pwm_n_cells; >>> + unsigned int can_sleep:1; >> >> What's the reason for making this a bitfield? Couldn't we just use a >> bool instead? > > I have also overlooked this. In my version I had the can_sleep as bool also. > Ok for a bool. Thank you for your reviews. I will send a v3 sometimes today. Cheers, Florian