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: Tue, 26 Jul 2016 22:47:16 +0800 Message-ID: <579777F4.2090002@rock-chips.com> References: <1469535195-5227-1-git-send-email-wxt@rock-chips.com> <57976814.3040605@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: <57976814.3040605-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org> Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Guenter Roeck , heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org Cc: Caesar Wang , jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@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, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-rockchip.vger.kernel.org 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=20 >> 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 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_opti= onal variants that drivers can use to indicate they can function without con= trol over the reset line. For those functions, stubs are added so the driver= s=20 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. Signed-off-by: Philipp Zabel ------------------8<----------------------------- =E2=80=9D for more information on=20 http://www.spinics.net/lists/kernel/msg2306677.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=20 >> 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