From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756669AbcGZOrg (ORCPT ); Tue, 26 Jul 2016 10:47:36 -0400 Received: from regular1.263xmail.com ([211.150.99.130]:42452 "EHLO regular1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754402AbcGZOre (ORCPT ); Tue, 26 Jul 2016 10:47:34 -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: <6ee1227cace986992954081f3199b4ea> X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Message-ID: <579777F4.2090002@rock-chips.com> Date: Tue, 26 Jul 2016 22:47:16 +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 , heiko@sntech.de CC: Caesar Wang , jic23@kernel.org, devicetree@vger.kernel.org, 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, 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> In-Reply-To: <57976814.3040605@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 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_optional 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. Signed-off-by: Philipp Zabel ------------------8<----------------------------- ” for more information on http://www.spinics.net/lists/kernel/msg2306677.html :-) > > Guenter > >> + if (IS_ERR(info->reset)) { >> + ret = PTR_ERR(info->reset); >> + if (ret != -ENOENT) >> + return ret; >> + >> + dev_dbg(&pdev->dev, "no reset control found\n"); >> + info->reset = NULL; >> + } >> + >> init_completion(&info->completion); >> >> irq = 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@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-rockchip -- caesar wang | software engineer | wxt@rock-chip.com