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=-5.3 required=3.0 tests=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 27C28C54E8D for ; Mon, 11 May 2020 14:20:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 034AB20736 for ; Mon, 11 May 2020 14:20:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="BCtdLU1i" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729540AbgEKOUV (ORCPT ); Mon, 11 May 2020 10:20:21 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:40966 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726173AbgEKOUU (ORCPT ); Mon, 11 May 2020 10:20:20 -0400 Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 04BEGcGs006570; Mon, 11 May 2020 16:19:52 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=STMicroelectronics; bh=S3ukbw9u6FBmyTso7iZC4fMons9sfi9Jz8USWlyYHr4=; b=BCtdLU1i1e1sY0kQKq6NHtKCA7Qa6KE+1bPXjU5tWMIsb8NrQePj6yz7jM1GBBs6Sfv7 ciiTqp7NHfJq0KlVTvGTpF73y4W7fywa7bfaHJgHL0lYQC4EleydGZzpaNbad+n2xdDI oYlMatPd4BpLa8J4IqZ/JeVh44pTggoKbITnKLNDkxPc2f6nBEYXc+J565BboL/+//f+ ZIiyg9kS0sFlKNh9jAPRtonqAYLsXrQr3ycz1Qfxee3MHT7bRSe/rfUbyZSr13RzeYCR hWXCayAH68a6IulyYJh+Kk6yB3QGJjUQT938jxvt2NyMxNX72fPUhsRfembY2W7cdgVU FQ== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 30wkdgtj4s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 11 May 2020 16:19:52 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 99626100034; Mon, 11 May 2020 16:19:50 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag6node2.st.com [10.75.127.17]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 7B24D2C38B2; Mon, 11 May 2020 16:19:50 +0200 (CEST) Received: from [10.211.5.64] (10.75.127.50) by SFHDAG6NODE2.st.com (10.75.127.17) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Mon, 11 May 2020 16:19:48 +0200 Subject: Re: [PATCH v4 10/10] mtd: rawnand: stm32_fmc2: get resources from parent node To: Miquel Raynal CC: , , , , , , , , , , References: <1588756279-17289-1-git-send-email-christophe.kerello@st.com> <1588756279-17289-11-git-send-email-christophe.kerello@st.com> <20200511111855.48216940@xps13> <3377adc6-3e5e-b9b7-12be-c7aa44bfac82@st.com> <20200511135926.3e5c622d@xps13> <0c704fea-f2a6-2cec-8741-d322acf6afd5@st.com> <20200511145855.35c6abfb@xps13> From: Christophe Kerello Message-ID: <6f822f79-18f1-5308-16cc-b31f0be80d5a@st.com> Date: Mon, 11 May 2020 16:19:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20200511145855.35c6abfb@xps13> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.50] X-ClientProxiedBy: SFHDAG8NODE3.st.com (10.75.127.24) To SFHDAG6NODE2.st.com (10.75.127.17) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.676 definitions=2020-05-11_06:2020-05-11,2020-05-11 signatures=0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Miquel, On 5/11/20 2:58 PM, Miquel Raynal wrote: > Hi Christophe, > > Christophe Kerello wrote on Mon, 11 May > 2020 14:47:09 +0200: > >> Hi Miquel, >> >> On 5/11/20 1:59 PM, Miquel Raynal wrote: >>> Hi Christophe, >>> >>> Christophe Kerello wrote on Mon, 11 May >>> 2020 12:21:03 +0200: >>> >>>> Hi Miquel, >>>> >>>> On 5/11/20 11:18 AM, Miquel Raynal wrote: >>>>> Hi Christophe, >>>>> >>>>> Christophe Kerello wrote on Wed, 6 May 2020 >>>>> 11:11:19 +0200: >>>>> >>>> FMC2 EBI support has been added. Common resources (registers base >>>>>> and clock) are now shared between the 2 drivers. It means that the >>>>>> common resources should now be found in the parent device when EBI >>>>>> node is available. >>>>>> >>>>>> Signed-off-by: Christophe Kerello >>>>>> --- >>>>> >>>>> [...] >>>>> >>>> + >>>>>> +static bool stm32_fmc2_nfc_check_for_parent(struct platform_device *pdev) >>>>>> +{ >>>>>> + u32 i; >>>>>> + int nb_resources = 0; >>>>>> + >>>>>> + /* Count the number of resources in reg property */ >>>>>> + for (i = 0; i < pdev->num_resources; i++) { >>>>>> + struct resource *res = &pdev->resource[i]; >>>>>> + >>>>>> + if (resource_type(res) == IORESOURCE_MEM) >>>>>> + nb_resources++; >>>>>> + } >>>>>> + >>>>>> + /* Each CS needs 3 resources defined (data, cmd and addr) */ >>>>>> + if (nb_resources % 3) >>>>>> + return false; >>>>>> + >>>>>> + return true; >>>>>> +} >>>>> >>>>> This function looks fragile. Why not just checking the compatible >>>>> string of the parent node? >>>>> >> >>>> Yes, it is another way to check that we have an EBI parent node. >>>> >>>> In this implementation, I was checking the number of reg tuples. >>>> In case we have 6, it means that the register base address is defined in the parent node (EBI node). >>>> In case we have 7, it means that the register base address is defined in the current node (NFC node). >>> >>> Yes, I understand what you are doing, but I kind of dislike the logic. >>> Relying on the number of reg tuples is something that can be done (I >>> used it myself one time), but I think this is more a hack that you do >>> when you have no other way to differentiate. I guess the proper way >>> would be to look at the parent's compatible. If it matches what you >>> expect, then you can store the dev->of_node->parent->dev somewhere in >>> your controller's structure and then use it to initialize the clock and >>> regmap. This way you don't have to move anything else in the probe path. >>> >> >> OK, I will check the compatible string of the parent device using of_device_is_compatible API in v5. >> In case of the parent is found, I will add it in the structure of the controller (dev_parent). >> I will rely on this field only to get the common resources (the register base address and the clock) in the NFC node or in the EBI node. > > I had something slightly different in mind: what about setting a > default value to this field as being the controller's device itself. > This way, once it is set to either the parent device or the device > itself, you can use it "blindly" in your devm_clk_get/regmap_init calls? > I will try to explain what I have in mind. I will add a new field in the structure of the controller (not called dev_parent but cdev) struct device *cdev; Then, at probe time, this field will be assigned: nfc->cdev = of_device_is_compatible(dev->parent->of_node, "bla bla") : dev->parent ? dev; For the clock, it will be nfc->clk = devm_clk_get(nfc->cdev, NULL); For the register base, I need to replace: res = platform_get_resource(pdev, IORESOURCE_MEM, 0); mmio = devm_ioremap_resource(dev, res); if (IS_ERR(mmio)) return PTR_ERR(mmio); nfc->regmap = devm_regmap_init_mmio(dev, mmio, &stm32_fmc2_regmap_cfg); if (IS_ERR(nfc->regmap)) return PTR_ERR(nfc->regmap); nfc->io_phys_addr = res->start; With: ret = of_address_to_resource(nfc->cdev->of_node, 0, &res); if (ret) return ret; nfc->io_phys_addr = res.start; nfc->regmap = device_node_to_regmap(nfc->cdev->of_node); if (IS_ERR(nfc->regmap)) return PTR_ERR(nfc->regmap); I expect that you were thinking about something like this proposal. Regards, Christophe Kerello.