From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757363AbcGZRAj (ORCPT ); Tue, 26 Jul 2016 13:00:39 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:57491 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757203AbcGZRAh (ORCPT ); Tue, 26 Jul 2016 13:00:37 -0400 Date: Tue, 26 Jul 2016 10:00:24 -0700 From: Guenter Roeck To: Caesar Wang Cc: heiko@sntech.de, 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 Message-ID: <20160726170023.GA6590@roeck-us.net> References: <1469535195-5227-1-git-send-email-wxt@rock-chips.com> <57976814.3040605@roeck-us.net> <579777F4.2090002@rock-chips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <579777F4.2090002@rock-chips.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 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. > Is that really what we are looking for here ? CONFIG_RESET_CONTROLLER is required for other functions of rk3399, isn't it ? Guenter > 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 > >