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 08:42:10 +0800 Message-ID: <57980362.3000406@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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20160726170023.GA6590-0h96xk9xTtrk1uMJSBkQmQ@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, dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, john-HooS5bfzL4hWk0Htik3J/w@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org List-Id: devicetree@vger.kernel.org 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 exa= ctly >>> the same >>> as devm_reset_control_get(). >> =E2=80=9C >> As far as I see, the difference is WARN_ON(1) >> when CONFIG_RESET_CONTROLLER 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 (devm_)reset_control_get_o= ptional >> variants that drivers can use to indicate they can function without = control >> over the reset line. For those functions, stubs are added so the dri= vers 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= =20 =2E.... > > Guenter > >> Signed-off-by: Philipp Zabel >> ------------------8<----------------------------- >> =E2=80=9D >> >> for more information on http://www.spinics.net/lists/kernel/msg23066= 77.html >> :-) >> >>> Guenter >>> >>>> + if (IS_ERR(info->reset)) { >>>> + ret =3D PTR_ERR(info->reset); >>>> + if (ret !=3D -ENOENT) >>>> + return ret; >>>> + >>>> + dev_dbg(&pdev->dev, "no reset control found\n"); >>>> + info->reset =3D NULL; >>>> + } >>>> + >>>> init_completion(&info->completion); >>>> >>>> irq =3D platform_get_irq(pdev, 0); >>>> @@ -252,6 +280,9 @@ static int rockchip_saradc_probe(struct >>>> platform_device *pdev) >>>> return PTR_ERR(info->vref); >>>> } >>>> >>>> + if (info->reset) >>>> + rockchip_saradc_reset_controller(info->reset); >>>> + >>>> /* >>>> * Use a default value for the converter clock. >>>> * This may become user-configurable in the future. >>>> >>> >>> _______________________________________________ >>> 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 >> >> > _______________________________________________ > 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