From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 118C4C2D0DB for ; Mon, 20 Jan 2020 12:09:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD3B520882 for ; Mon, 20 Jan 2020 12:09:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="QT4LLwOD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728587AbgATMJg (ORCPT ); Mon, 20 Jan 2020 07:09:36 -0500 Received: from fllv0015.ext.ti.com ([198.47.19.141]:60544 "EHLO fllv0015.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726775AbgATMJg (ORCPT ); Mon, 20 Jan 2020 07:09:36 -0500 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 00KC9VZk063374; Mon, 20 Jan 2020 06:09:31 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1579522171; bh=9/SDI0K0Pj+c3i7x4wk45t+LI01ZuMhyaKeap/VbCWo=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=QT4LLwOD3Z1W8fBcs1CWsdHPnF8xtpfpUpuITcUti+eIwNN+ZNC/n0qfFDihxiq5V xgKQXzhFR9apiDRM9ms1czgf1en6Sp8oSJk/dxx0bboMMAp0z2taO4dMFjofgxd5Vz 2TGCCQlDMk29HFUrg6mQzarAkws7TDHcwYfkUTw8= Received: from DLEE108.ent.ti.com (dlee108.ent.ti.com [157.170.170.38]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 00KC9Vfj071771 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 20 Jan 2020 06:09:31 -0600 Received: from DLEE106.ent.ti.com (157.170.170.36) by DLEE108.ent.ti.com (157.170.170.38) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3; Mon, 20 Jan 2020 06:09:30 -0600 Received: from lelv0327.itg.ti.com (10.180.67.183) by DLEE106.ent.ti.com (157.170.170.36) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3 via Frontend Transport; Mon, 20 Jan 2020 06:09:30 -0600 Received: from [192.168.2.6] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 00KC9Siu099356; Mon, 20 Jan 2020 06:09:29 -0600 Subject: Re: [PATCH] media: rcar_drif: Use dma_request_chan() instead dma_request_slave_channel() To: Geert Uytterhoeven CC: Mauro Carvalho Chehab , Ramesh Shanmugasundaram , Vinod , Linux Media Mailing List , Linux Kernel Mailing List , Linux-Renesas References: <20191217104025.23318-1-peter.ujfalusi@ti.com> From: Peter Ujfalusi Message-ID: Date: Mon, 20 Jan 2020 14:10:08 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Geert, On 20/01/2020 14.05, Geert Uytterhoeven wrote: > On Tue, Dec 17, 2019 at 11:41 AM Peter Ujfalusi wrote: >> dma_request_slave_channel() is a wrapper on top of dma_request_chan() >> eating up the error code. >> >> By using dma_request_chan() directly the driver can support deferred >> probing against DMA. >> >> Signed-off-by: Peter Ujfalusi > > Reviewed-by: Geert Uytterhoeven > > One comment below. > >> --- a/drivers/media/platform/rcar_drif.c >> +++ b/drivers/media/platform/rcar_drif.c >> @@ -275,10 +275,10 @@ static int rcar_drif_alloc_dmachannels(struct rcar_drif_sdr *sdr) >> for_each_rcar_drif_channel(i, &sdr->cur_ch_mask) { >> struct rcar_drif *ch = sdr->ch[i]; >> >> - ch->dmach = dma_request_slave_channel(&ch->pdev->dev, "rx"); >> - if (!ch->dmach) { >> + ch->dmach = dma_request_chan(&ch->pdev->dev, "rx"); >> + if (IS_ERR(ch->dmach)) { >> rdrif_err(sdr, "ch%u: dma channel req failed\n", i); > > Now there is an error code, you might (1) want to print it, and (2) only > do so when it is not due to probe deferral: > > if (PTR_ERR(ch->dmach) != -EPROBE_DEFER) > rdrif_err(sdr, "ch%u: dma channel req failed %pe\n", > i, ch->dmach); Yes, this is true. > >> - ret = -ENODEV; >> + ret = PTR_ERR(ch->dmach); if (ret != -EPROBE_DEFER) rdrif_err(sdr, "ch%u: dma channel req failed (%d)\n", i, ret); might be simpler. >> goto dmach_error; >> } > > Gr{oetje,eeting}s, > > Geert > - Péter Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki