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 B0DAFC433F5 for ; Mon, 28 Mar 2022 07:12:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236695AbiC1HOB (ORCPT ); Mon, 28 Mar 2022 03:14:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229457AbiC1HOB (ORCPT ); Mon, 28 Mar 2022 03:14:01 -0400 Received: from router.aksignal.cz (router.aksignal.cz [62.44.4.214]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 190B452B1E for ; Mon, 28 Mar 2022 00:12:20 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by router.aksignal.cz (Postfix) with ESMTP id 6275C453DD; Mon, 28 Mar 2022 09:12:17 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at router.aksignal.cz Received: from router.aksignal.cz ([127.0.0.1]) by localhost (router.aksignal.cz [127.0.0.1]) (amavisd-new, port 10026) with LMTP id N0uakXN2AbiN; Mon, 28 Mar 2022 09:12:16 +0200 (CEST) Received: from [172.25.161.48] (unknown [83.240.30.185]) (Authenticated sender: jiri.prchal@aksignal.cz) by router.aksignal.cz (Postfix) with ESMTPSA id 8D25F453DA; Mon, 28 Mar 2022 09:12:16 +0200 (CEST) Message-ID: <1d43c967-e3c9-21a8-3040-2db54ba85bdf@aksignal.cz> Date: Mon, 28 Mar 2022 09:12:16 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [libgpiod] bug: pull-up does not work Content-Language: en-US To: Kent Gibson Cc: linux-gpio@vger.kernel.org, brgl@bgdev.pl, andy.shevchenko@gmail.com References: <62b30818-92fa-e44c-c9dd-fd8cc49a6e6a@aksignal.cz> <20220325145742.GA46960@sol> <48129be0-f29d-96ae-cec3-2b4a2ee10aa8@aksignal.cz> <20220325160146.GA49114@sol> From: =?UTF-8?B?SmnFmcOtIFByY2hhbA==?= In-Reply-To: <20220325160146.GA49114@sol> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On 25. 03. 22 17:01, Kent Gibson wrote: > On Fri, Mar 25, 2022 at 04:13:11PM +0100, Jiří Prchal wrote: >> >> >> On 25. 03. 22 15:57, Kent Gibson wrote: >>> On Fri, Mar 25, 2022 at 11:02:07AM +0100, Jiří Prchal wrote: >>>> Hi, >>>> since in debian is 1.6.2 and pull-up doesn't work so I cloned git, branch >>>> next/libgpiod-2.0 and compiled libgpiod and tools, but no luck, same result. >>>> >>> >>> You mean it doesn't work for you on your platform. >>> >>> The libgpiod-2.0 branch is a work in progress and should not be considered >>> the place to go to find solutions to problems with v1.6. >>> Not that I'm saying that the v2 branch doesn't work, I'm actually pretty >>> sure it does, but its purpose is to switch to the latest kernel uAPI, not >>> to provide fixes, should they be needed, for v1.6. >> Just thought api v1 doesn't support pull-ups so tried v2. > > v1 does support bias since Linux v5.5, and libgpiod added support in v1.5. > >>> >>>> ~# uname -r >>>> 5.17.0-rc7_cpm9g25 >>>> >>>> floating pins should go with pull-up/down >>>> ~# gpioget -B pull-up 3 6 8 10 12 14 16 18 20 >>>> 0 0 0 0 0 0 0 0 >>>> ~# gpioget -B pull-up 3 6 8 10 12 14 16 18 20 >>>> 1 1 0 0 0 0 0 0 >>>> ~# gpioget -B pull-up 3 6 8 10 12 14 16 18 20 >>>> 0 1 0 1 0 0 0 0 >>>> >>>> ~# gpioget -v >>>> gpioget (libgpiod) v2.0-devel >>>> >>>> Whats wrong with it? >>> >>> You forgot to mention which of those pins are floating. >> All of them. >>> Or what gpiochip3 is and whether it supports biasing. >> AT91SAM9G25, hw supports pull-ups. >>> >>> So does your chip support pull-up/down? >>> The kernel can only enable it if the hardware and pinctrl driver supports it. >> Is there possibility that pinctrl doesn't support it? I think other gpios >> used in kernel are with pull-up. >> Example: >> pinctrl@fffff400 { >> 1wire { >> pinctrl_1wire: 1wire-0 { >> atmel,pins = ; /* PC0 >> PIO, pull-up */ >> }; >> }; >> }; >> > > Pinctrl and device tree are outside my area, but my understanding is > that setting via DT is a separate interface, so while it may be > supported by DT it may not be via the gpiolib interface. > But I will defer to anyone else on that. > (CCing in Andy since I'm pretty sure he would know) > > Not sure which pinctrl is relevant for your case. > pinctrl-at91 doesn't appear to support setting the pull-up via the gpiolib > interface, but pinctrl-at91-pio4 does, so my guess would be you are using > the pinctrl-at91. pinctrl-at91-pio4 didn't help, syminfo says "for Atmel PIO4 controller available on sama5d2 SoC" but my is sam9g25. How can I find out if it supports gpiolib? > > But again, this is outside my area so you would need to confirm that > yourself or get feedback from someone else. > If you determine that you are using a pinctrl that supports setting > bias via gpiolib then we'll have to do some more digging. > > Cheers, > Kent. > Thanks Jiri