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 D51FAC46467 for ; Mon, 16 Jan 2023 09:26:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232439AbjAPJ0y (ORCPT ); Mon, 16 Jan 2023 04:26:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232345AbjAPJ0q (ORCPT ); Mon, 16 Jan 2023 04:26:46 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA9E4166C1 for ; Mon, 16 Jan 2023 01:26:45 -0800 (PST) Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1pHLlG-0007IW-CX; Mon, 16 Jan 2023 10:26:38 +0100 Message-ID: Date: Mon, 16 Jan 2023 10:26:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 From: Ahmad Fatoum Subject: Re: [PATCH 2/2] ARM: dts: imx6qdl: support child mfd cells for the reset controller To: Krzysztof Kozlowski , Bastian Krause , Philipp Zabel , Rob Herring , Krzysztof Kozlowski , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20230113-syscon-child-mfd-v1-0-0dd31b7de373@pengutronix.de> <20230113-syscon-child-mfd-v1-2-0dd31b7de373@pengutronix.de> <392f6e9d-b7c2-37df-2067-f7d967a20f10@linaro.org> <12080bf5-2cc4-e215-555e-5438ed1bd851@pengutronix.de> <1b5613ad-6d0d-0979-ddd0-4677ade7beb9@linaro.org> Content-Language: en-US In-Reply-To: <1b5613ad-6d0d-0979-ddd0-4677ade7beb9@linaro.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 2a0a:edc0:0:900:1d::77 X-SA-Exim-Mail-From: a.fatoum@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 16.01.23 10:14, Krzysztof Kozlowski wrote: > On 16/01/2023 09:27, Ahmad Fatoum wrote: >> Hello Krzysztof, >> >> On 16.01.23 09:20, Krzysztof Kozlowski wrote: >>> On 13/01/2023 18:32, Bastian Krause wrote: >>>> The actual syscon-reboot-mode child node can be added by a board >>>> device-tree or fixed up by the bootloader. For the child node to be >>>> probed, the compatible needs to include simple-mfd. The binding now >>>> specifies this, so have the SoC dtsi adhere to it. >>>> >>>> Suggested-by: Ahmad Fatoum >>>> Signed-off-by: Bastian Krause >>>> --- >>>> arch/arm/boot/dts/imx6qdl.dtsi | 3 ++- >>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi >>>> index ff1e0173b39be..b16be39458aa6 100644 >>>> --- a/arch/arm/boot/dts/imx6qdl.dtsi >>>> +++ b/arch/arm/boot/dts/imx6qdl.dtsi >>>> @@ -865,7 +865,8 @@ epit2: epit@20d4000 { /* EPIT2 */ >>>> }; >>>> >>>> src: reset-controller@20d8000 { >>>> - compatible = "fsl,imx6q-src", "fsl,imx51-src"; >>>> + compatible = "fsl,imx6q-src", "fsl,imx51-src", >>>> + "syscon", "simple-mfd"; >>> >>> You need children here. Otherwise simple-mfd does not make sense. If you >>> expect something else to add children (I don't understand why, usually >>> reboot capability is fixed per SoC and only sometimes extended with some >>> other means), then this "else" will also change compatible. >> >> It's about syscon-reboot-mode, not syscon-reboot. Such modes are board- >> not soc-specific. > > syscon-reboot-mode is also mostly SoC specific. What exactly would > differ on different boards? Register offsets of SoC component? Register > values used by SoC power management unit? The modes supported. Let's say you want a bootloader mode that drops the board's bootloader into a fastboot gadget mode. You'd add a syscon-reboot-mode pointing at one of the non-volatile registers and you would define a magic value to indicate fastboot, both in the bootloader and Linux. In theory, the reboot mode could also talk to the bootrom[1] to change the bootsource. This is also not board-agnostic, because it may not make sense to have a spinor reboot mode if your board doesn't have one. We have this scheme for STM32MP1 already and that's why I suggested Bastian to do it likewise for i.MX as he needs this functionality: https://lore.kernel.org/all/20201021102855.18026-1-a.fatoum@pengutronix.de/ https://elixir.bootlin.com/barebox/latest/source/arch/arm/dts/stm32mp151.dtsi#L44 Here's the barebox documentation for reboot modes btw: https://www.barebox.org/doc/latest/user/reboot-mode.html [1]: The i.MX bootrom samples two registers to determine boot mode override. The upstream syscon-reboot-mode binding supports only one 32-bit value and thus can be used as-is only for communicating with the "user" bootloader. > Anyway, the binding is then not correct - it does not allow > syscon-reboot-mode child. I'll comment there. > > > Best regards, > Krzysztof > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |