From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758848AbcG0CL4 (ORCPT ); Tue, 26 Jul 2016 22:11:56 -0400 Received: from regular1.263xmail.com ([211.150.99.135]:41997 "EHLO regular1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756066AbcG0CLs (ORCPT ); Tue, 26 Jul 2016 22:11:48 -0400 X-263anti-spam: KSV:0; X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 X-RL-SENDER: wxt@rock-chips.com X-FST-TO: linux@roeck-us.net X-SENDER-IP: 103.29.142.67 X-LOGIN-NAME: wxt@rock-chips.com X-UNIQUE-TAG: <95ebd607e50b643b0432d406e2dab410> X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Message-ID: <57981852.1040006@rock-chips.com> Date: Wed, 27 Jul 2016 10:11:30 +0800 From: Caesar Wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Guenter Roeck CC: Caesar Wang , devicetree@vger.kernel.org, heiko@sntech.de, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, dianders@chromium.org, linux-rockchip@lists.infradead.org, robh+dt@kernel.org, john@metanate.com, jic23@kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 1/4] iio: adc: rockchip_saradc: reset saradc controller before programming it References: <1469535195-5227-1-git-send-email-wxt@rock-chips.com> <57976814.3040605@roeck-us.net> <579777F4.2090002@rock-chips.com> <20160726170023.GA6590@roeck-us.net> <57980362.3000406@rock-chips.com> <579815B2.5010205@roeck-us.net> In-Reply-To: <579815B2.5010205@roeck-us.net> 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 On 2016年07月27日 10:00, Guenter Roeck wrote: > On 07/26/2016 05:42 PM, Caesar Wang wrote: >> >> On 2016年07月27日 01:00, Guenter Roeck wrote: >>> On Tue, Jul 26, 2016 at 10:47:16PM +0800, Caesar Wang wrote: >>>> On 2016年07月26日 21:39, Guenter Roeck wrote: >>>>>> static int rockchip_saradc_probe(struct platform_device *pdev) >>>>>> { >>>>>> struct rockchip_saradc *info = NULL; >>>>>> @@ -218,6 +231,21 @@ static int rockchip_saradc_probe(struct >>>>>> platform_device *pdev) >>>>>> if (IS_ERR(info->regs)) >>>>>> return PTR_ERR(info->regs); >>>>>> >>>>>> + /* >>>>>> + * The reset should be an optional property, as it should work >>>>>> + * with old devicetrees as well >>>>>> + */ >>>>>> + info->reset = devm_reset_control_get_optional(&pdev->dev, >>>>>> + "saradc-apb"); >>>>> Does anyone know what the _optional API is for ? It seems to be >>>>> exactly >>>>> the same >>>>> as devm_reset_control_get(). >>>> “ >>>> As far as I see, the difference is WARN_ON(1) >>>> when is not defined. >>>> >>>> >>>> The _optional functions were introduced by the following commit: >>>> >>>> ----------------->8----------------- >>>> commit b424080a9e086e683ad5fdc624a7cf3c024e0c0f >>>> Author: Philipp Zabel >>>> Date: Fri Mar 7 15:18:47 2014 +0100 >>>> >>>> reset: Add optional resets and stubs >>>> >>>> This patch adds device_reset_optional and >>>> variants that drivers can use to indicate they can function without >>>> control >>>> over the reset line. For those functions, stubs are added so the >>>> drivers can >>>> be compiled with CONFIG_RESET_CONTROLLER disabled. >>>> Also, device_reset is annotated with __must_check. Drivers >>>> ignoring the return >>>> value should use device_reset_optional instead. >>>> >>> Is that really what we are looking for here ? CONFIG_RESET_CONTROLLER >>> is required for other functions of rk3399, isn't it ? >> >> Right, as the DRM and thermal are depend on the >> CONFIG_RESET_CONTROLLER ..... >> > > Since "optional" doesn't really mean "the reset property is optional" > but "CONFIG_RESET_CONTROLLER is optional", I would suggest to use > devm_reset_control_get(). Agree, free riding. Maybe the API (_optional) will be changed in later. As someone make a point present an idea on http://www.spinics.net/lists/kernel/msg2306677.html Okay, devm_reset_control_get() will be better, anyway the driver has been depend on the CONFIG_RESET_CONTROLLER. -- I will send a new patch for upstream if nobody object it on today. Sorry for noisy! > > Guenter > > > _______________________________________________ > Linux-rockchip mailing list > Linux-rockchip@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-rockchip -- caesar wang | software engineer | wxt@rock-chip.com