From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751234AbeAWJUg (ORCPT ); Tue, 23 Jan 2018 04:20:36 -0500 Received: from mail-wr0-f194.google.com ([209.85.128.194]:45765 "EHLO mail-wr0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751156AbeAWJUd (ORCPT ); Tue, 23 Jan 2018 04:20:33 -0500 X-Google-Smtp-Source: AH8x2262FX2PbvLp2np4+L+FxN3i9ifheZM++H0onfN2lVg4KIv6rRrdbvqp7mxl5iX6Y+sFnTMSGQ== Subject: Re: [PATCH 1/4] dmaengine: qcom: bam_dma: make bam clk optional To: Vinod Koul Cc: Andy Gross , dmaengine@vger.kernel.org, Rob Herring , Mark Rutland , David Brown , Dan Williams , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, yanhe@quicinc.com, ramkri@qti.qualcomm.com, sdharia@quicinc.com References: <20180116190236.14558-1-srinivas.kandagatla@linaro.org> <20180116190236.14558-2-srinivas.kandagatla@linaro.org> <20180119055221.GV18649@localhost> <8dfa8ba1-6e98-a8e4-614c-592861cef571@linaro.org> <20180123091905.GY18649@localhost> From: Srinivas Kandagatla Message-ID: <86774341-19e6-5653-49ae-cb7614490d1b@linaro.org> Date: Tue, 23 Jan 2018 09:20:30 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20180123091905.GY18649@localhost> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/01/18 09:19, Vinod Koul wrote: > On Mon, Jan 22, 2018 at 09:55:01AM +0000, Srinivas Kandagatla wrote: > >>>> @@ -1180,13 +1180,14 @@ static int bam_dma_probe(struct platform_device *pdev) >>>> "qcom,controlled-remotely"); >>>> bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk"); >>> >>> but you still do clk_get unconditionally? >> >> Only reason to do this way is to not break existing users in the mainline. >> >> remotely controlled BAM is already supported in upstream driver, there are >> users of this who pass clk from device tree, If I make this conditional then >> subsequent reads to the BAM registers for those instances might crash the >> system. > > But these instances are remote controlled, so if we stop representing them > in Linux, why would we read them? Plan is that we would transition those users once we get these bindings/changes in. Currently I don't have access to any of those devices so I made the changes safe, such that it does not break devices on mainline. --srini >