From mboxrd@z Thu Jan 1 00:00:00 1970 From: Caesar Wang Subject: Re: [PATCH v2 1/4] iio: adc: rockchip_saradc: reset saradc controller before programming it Date: Wed, 27 Jul 2016 10:11:30 +0800 Message-ID: <57981852.1040006@rock-chips.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <579815B2.5010205-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org> Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Guenter Roeck Cc: Caesar Wang , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org, linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, john-HooS5bfzL4hWk0Htik3J/w@public.gmane.org, jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-rockchip.vger.kernel.org On 2016=E5=B9=B407=E6=9C=8827=E6=97=A5 10:00, Guenter Roeck wrote: > On 07/26/2016 05:42 PM, Caesar Wang wrote: >> >> On 2016=E5=B9=B407=E6=9C=8827=E6=97=A5 01:00, Guenter Roeck wrote: >>> On Tue, Jul 26, 2016 at 10:47:16PM +0800, Caesar Wang wrote: >>>> On 2016=E5=B9=B407=E6=9C=8826=E6=97=A5 21:39, Guenter Roeck wrote: >>>>>> static int rockchip_saradc_probe(struct platform_device *pdev) >>>>>> { >>>>>> struct rockchip_saradc *info =3D 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 =3D devm_reset_control_get_optional(&pdev->dev, >>>>>> + "saradc-apb"); >>>>> Does anyone know what the _optional API is for ? It seems to be=20 >>>>> exactly >>>>> the same >>>>> as devm_reset_control_get(). >>>> =E2=80=9C >>>> 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 withou= t=20 >>>> control >>>> over the reset line. For those functions, stubs are added so the=20 >>>> 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_CONTROLL= ER >>> is required for other functions of rk3399, isn't it ? >> >> Right, as the DRM and thermal are depend on the=20 >> 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=20 http://www.spinics.net/lists/kernel/msg2306677.html Okay, devm_reset_control_get() will be better, anyway the driver has=20 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-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org > http://lists.infradead.org/mailman/listinfo/linux-rockchip --=20 caesar wang | software engineer | wxt-TNX95d0MmH73oGB3hsPCZA@public.gmane.org