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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B8C1C54EE9 for ; Fri, 16 Sep 2022 08:51:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230221AbiIPIvH (ORCPT ); Fri, 16 Sep 2022 04:51:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57856 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230486AbiIPIu4 (ORCPT ); Fri, 16 Sep 2022 04:50:56 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9B69A831C; Fri, 16 Sep 2022 01:50:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 91C09B8236E; Fri, 16 Sep 2022 08:50:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C53B7C433C1; Fri, 16 Sep 2022 08:50:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663318246; bh=r3bkzNMOCn2xHdYiUy9dIp4wjERKZqka5pJYVf/I0rE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=mFsfWg59Jflzdl04r8/e8bgPyQp/zW8a6jH+HWVMGCVLFH7109JOaKXxd3IcmmWD1 7thXhgZ372v2aGadCyXjih8SJ7VYhw4OKBv6EIex7DEeefYQrHbuH8MtOf0T57sTGd syTXxJm5+Zj4CM+7dxh7W314VNk5TrIlLibezAJFjKwtYO+Gh+Psfbfpsfuks8ycOU sHjSJ6bO3AVZ++YVxFhRNeBIWDlJht9Nij5cmSWLUxFtW8FQbeHLOGBN+o1eaUERlC W8zNCap7AuXAVRLgZrH5VDJt80/de5RZYUkwbK8uI3N5l6cL8CpBjQM3lbAxmlo1Qr KzK9l/ZD0LSfg== Message-ID: <6c8f1bfd-2aab-c9e3-4fe8-2e555b969e3a@kernel.org> Date: Fri, 16 Sep 2022 11:50:42 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v4 1/3] memory: omap-gpmc: allow shared wait pins Content-Language: en-US To: "B. Niedermayr" , linux-omap@vger.kernel.org, devicetree@vger.kernel.org Cc: tony@atomide.com, krzysztof.kozlowski@linaro.org, robh+dt@kernel.org References: <20220915091333.2425306-1-benedikt.niedermayr@siemens.com> <20220915091333.2425306-2-benedikt.niedermayr@siemens.com> From: Roger Quadros In-Reply-To: <20220915091333.2425306-2-benedikt.niedermayr@siemens.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi, On 15/09/2022 12:13, B. Niedermayr wrote: > From: Benedikt Niedermayr > > Newer kernels refuse to probe when using the same wait pin for > different chipselect regions. > > But this may be a usecase when connecting for example FPGA or ASIC > modules to the gpmc, which only got one wait pin installed. > > Signed-off-by: Benedikt Niedermayr > --- > drivers/memory/omap-gpmc.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c > index d9bf1c2ac319..e3674a15b934 100644 > --- a/drivers/memory/omap-gpmc.c > +++ b/drivers/memory/omap-gpmc.c > @@ -2221,9 +2221,13 @@ static int gpmc_probe_generic_child(struct platform_device *pdev, > GPIO_ACTIVE_HIGH, > GPIOD_IN); > if (IS_ERR(waitpin_desc)) { > - dev_err(&pdev->dev, "invalid wait-pin: %d\n", wait_pin); > ret = PTR_ERR(waitpin_desc); > - goto err; > + if (ret == -EBUSY) { > + dev_info(&pdev->dev, "shared wait-pin: %d\n", wait_pin); What if this GPI was taken by someone other than us for wait-pin usage? e.g. some other device driver for GPI usage? In that case that GPIO functionality will break if we now start using it for wait-pin usage. Right? One solution could be keep track if we reserved that pin for wait-pin usage and if so sharing the wait-pin for wait-pin usage is fine. > + } else { > + dev_err(&pdev->dev, "invalid wait-pin: %d\n", wait_pin); > + goto err; > + } > } > } > cheers, -roger