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=-11.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 73117C4360C for ; Tue, 8 Oct 2019 23:30:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3990B2070B for ; Tue, 8 Oct 2019 23:30:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=bgdev-pl.20150623.gappssmtp.com header.i=@bgdev-pl.20150623.gappssmtp.com header.b="EMll1R7r" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726822AbfJHXaa (ORCPT ); Tue, 8 Oct 2019 19:30:30 -0400 Received: from mail-io1-f65.google.com ([209.85.166.65]:46281 "EHLO mail-io1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726068AbfJHXaa (ORCPT ); Tue, 8 Oct 2019 19:30:30 -0400 Received: by mail-io1-f65.google.com with SMTP id c6so722904ioo.13 for ; Tue, 08 Oct 2019 16:30:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=Wpg6ZUwaXoBQyOBNxI7uuEthX854/7IBZjGhrLVTWqg=; b=EMll1R7r/p3m4y+iIzy/wY7RudZ0lftv5HHWM7OtnSvjjJfRGDinp7oJUHdyERoTUg 07HeroDdms282GkF2+QTGa/GjqUq1uHNVzJU5iTHgoY+eNzV1okyRNRZez3iTsBIz6jF fsiQ1TXt/KLGIFSLeA+mPsVx8P9KBkbkQOgeZhAMzKNXqGfQkvZEn51IWEknNub40mw7 oOQk3QZU29Rtayy0CwX5DOFQu1adRfNIaAXdIwhArSb/y81utaDNxmtgpTDzmdkQ4Yjc lIWD/70fL/A2nFV6DUmaf1cK4+gvgSxsgsRbYAgBdSHBT0Ma2Gp23pSQc6IWeNQfruxG HfXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=Wpg6ZUwaXoBQyOBNxI7uuEthX854/7IBZjGhrLVTWqg=; b=KSEEM+fm1FgWBr3awz+3TwIzw952ars+loNkARHdjMqhWEjxAbvD5rwg3+dlqrGSEl DS4+EV0lGM4oOpATB7tzt7rXPxmDGz/yjI/GuamMC2sLYJy798DPBX5t04iVDv3H91ky AosvZ8kh1/agE3u4Tf30EGeYVCCxQxbzPIDDDKb4CDQLz8e5HgE1duON+eb1f7w2N6jc itpfphz+QIijfB2kPsGQFtNFpQIIVFyGxV33S6YQP+0jJdE7x61P3R7BfPWgm1Comji/ CI9obek95Bj/v/L10ZHbh+ckrdMufjQIgQtIRe3141nJ9OhdN/5+xzB2l1DYZ977CT+7 BkLg== X-Gm-Message-State: APjAAAU+Hb9WyTp4Z4eMbu7ylE38DYbs6TxWSFZlzhoKwfs6WGXVC7gz bM4bjFJw+fACzhFCDYzu6IbZESioo3BAT1y1d/dJVbZ2Oks= X-Google-Smtp-Source: APXvYqz5QQLDG3oxmDXxTFHZOu97QBEKnBIY9Q1hmYOudk3cipi0/1LMfUMzuvmNalwJMEfoUEMNyN6rl3ckFhqVbD0= X-Received: by 2002:a5d:8543:: with SMTP id b3mr739505ios.220.1570577429384; Tue, 08 Oct 2019 16:30:29 -0700 (PDT) MIME-Version: 1.0 References: <20190921102522.8970-1-drew@pdp7.com> <20191008061512.GA19956@sol> <20191008232120.GA9225@sol> In-Reply-To: <20191008232120.GA9225@sol> From: Bartosz Golaszewski Date: Wed, 9 Oct 2019 01:30:18 +0200 Message-ID: Subject: Re: [RFC] gpio: expose pull-up/pull-down line flags to userspace To: Kent Gibson Cc: Drew Fustini , "open list:GPIO SUBSYSTEM" , Linus Walleij , Thomas Petazzoni Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org =C5=9Br., 9 pa=C5=BA 2019 o 01:21 Kent Gibson napisa= =C5=82(a): > > On Tue, Oct 08, 2019 at 10:56:18PM +0200, Bartosz Golaszewski wrote: > > wt., 8 pa=C5=BA 2019 o 08:15 Kent Gibson napisa= =C5=82(a): > > > > > > On Sat, Sep 21, 2019 at 12:25:23PM +0200, Drew Fustini wrote: > > > > Add pull-up/pull-down flags to the gpio line get and > > > > set ioctl() calls. Use cases include a push button > > > > that does not have an external resistor. > > > > > > > > Addition use cases described by Limor Fried (ladyada) of > > > > Adafruit in this PR for Adafruit_Blinka Python lib: > > > > https://github.com/adafruit/Adafruit_Blinka/pull/59 > > > > > > > > Signed-off-by: Drew Fustini > > > > --- > > > > drivers/gpio/gpiolib.c | 12 ++++++++++++ > > > > include/uapi/linux/gpio.h | 4 ++++ > > > > 2 files changed, 16 insertions(+) > > > > > > > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > > > > index d9074191edef..9da1093cc7f5 100644 > > > > --- a/drivers/gpio/gpiolib.c > > > > +++ b/drivers/gpio/gpiolib.c > > > > @@ -427,6 +427,8 @@ struct linehandle_state { > > > > (GPIOHANDLE_REQUEST_INPUT | \ > > > > GPIOHANDLE_REQUEST_OUTPUT | \ > > > > GPIOHANDLE_REQUEST_ACTIVE_LOW | \ > > > > + GPIOHANDLE_REQUEST_PULL_UP | \ > > > > + GPIOHANDLE_REQUEST_PULL_DOWN | \ > > > > GPIOHANDLE_REQUEST_OPEN_DRAIN | \ > > > > GPIOHANDLE_REQUEST_OPEN_SOURCE) > > > > > > > > @@ -598,6 +600,10 @@ static int linehandle_create(struct gpio_devic= e *gdev, void __user *ip) > > > > set_bit(FLAG_OPEN_DRAIN, &desc->flags); > > > > if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE) > > > > set_bit(FLAG_OPEN_SOURCE, &desc->flags); > > > > + if (lflags & GPIOHANDLE_REQUEST_PULL_DOWN) > > > > + set_bit(FLAG_PULL_DOWN, &desc->flags); > > > > + if (lflags & GPIOHANDLE_REQUEST_PULL_UP) > > > > + set_bit(FLAG_PULL_UP, &desc->flags); > > > > > > > > ret =3D gpiod_set_transitory(desc, false); > > > > if (ret < 0) > > > > @@ -1102,6 +1108,10 @@ static long gpio_ioctl(struct file *filp, un= signed int cmd, unsigned long arg) > > > > if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) > > > > lineinfo.flags |=3D (GPIOLINE_FLAG_OPEN_SOURC= E | > > > > GPIOLINE_FLAG_IS_OUT); > > > > + if (test_bit(FLAG_PULL_DOWN, &desc->flags)) > > > > + lineinfo.flags |=3D GPIOLINE_FLAG_PULL_DOWN; > > > > + if (test_bit(FLAG_PULL_UP, &desc->flags)) > > > > + lineinfo.flags |=3D GPIOLINE_FLAG_PULL_UP; > > > > > > > > if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) > > > > return -EFAULT; > > > > @@ -2475,6 +2485,8 @@ static bool gpiod_free_commit(struct gpio_des= c *desc) > > > > clear_bit(FLAG_REQUESTED, &desc->flags); > > > > clear_bit(FLAG_OPEN_DRAIN, &desc->flags); > > > > clear_bit(FLAG_OPEN_SOURCE, &desc->flags); > > > > + clear_bit(FLAG_PULL_UP, &desc->flags); > > > > + clear_bit(FLAG_PULL_DOWN, &desc->flags); > > > > clear_bit(FLAG_IS_HOGGED, &desc->flags); > > > > ret =3D true; > > > > } > > > > diff --git a/include/uapi/linux/gpio.h b/include/uapi/linux/gpio.h > > > > index 4ebfe0ac6c5b..c2d1f7d908d6 100644 > > > > --- a/include/uapi/linux/gpio.h > > > > +++ b/include/uapi/linux/gpio.h > > > > @@ -33,6 +33,8 @@ struct gpiochip_info { > > > > #define GPIOLINE_FLAG_ACTIVE_LOW (1UL << 2) > > > > #define GPIOLINE_FLAG_OPEN_DRAIN (1UL << 3) > > > > #define GPIOLINE_FLAG_OPEN_SOURCE (1UL << 4) > > > > +#define GPIOLINE_FLAG_PULL_UP (1UL << 5) > > > > +#define GPIOLINE_FLAG_PULL_DOWN (1UL << 6) > > > > > > > > /** > > > > * struct gpioline_info - Information about a certain GPIO line > > > > @@ -62,6 +64,8 @@ struct gpioline_info { > > > > #define GPIOHANDLE_REQUEST_ACTIVE_LOW (1UL << 2) > > > > #define GPIOHANDLE_REQUEST_OPEN_DRAIN (1UL << 3) > > > > #define GPIOHANDLE_REQUEST_OPEN_SOURCE (1UL << 4) > > > > +#define GPIOHANDLE_REQUEST_PULL_UP (1UL << 5) > > > > +#define GPIOHANDLE_REQUEST_PULL_DOWN (1UL << 6) > > > > > > > > /** > > > > * struct gpiohandle_request - Information about a GPIO handle req= uest > > > > -- > > > > 2.20.1 > > > > > > > Sorry for the late feedback, but I'm still not sure whether this patc= h > > > is on track to be applied or not. I had thought not, at least not ye= t, > > > but just in case... > > > > > > > It still needs some fixes, but Linus seems to be fine with the general = idea. > > > > > You have added the flags to linehandle_create, but not lineevent_crea= te. > > > Given that your primary use case is push buttons, isn't the event req= uest > > > at least as important as the handle request? Even ignoring your use > > > case, I'd add them to lineevent_create just to maintain symmetry. > > > > > > Also, is it valid to set PULL_UP and PULL_DOWN simulaneously? > > > I would think not, but I could be wrong. > > > If not then that combination should be rejected with EINVAL. > > > > > > > Yes, some validity checks of the flags must be added. I even did it in > > my local branch[1]. > > > Your changes for linehandle_create look ok, but for lineevent_create > you explicitly disabled PULL_UP and PULL_DOWN, and in a block labelled > "This is just wrong: we don't look for events on output lines" at that. > Yeah, feel free to change it. > > Re: direction and configuration changes on requested lines: I think > > it's quite useful to add in the form of a new ioctl(): > > GPIOHANDLE_SET_CONFIG_IOCTL or something. I started hacking on this > > but eventually got more busy this week than I anticipated. I'm still > > planning on sending an RFC by the end of the week though. > > > I have the reverse problem - bored and looking for something to do, so > more than willing to help out - if you want it. > Sure, in that case let's just wait for your patches. You can just extend what I started, if you wish. > And while we're talking, does the gpio-mockup support pull up/down > being set from the kernel side? > No, but feel free to add it. Bart > Cheers, > Kent. > > > > [1] https://github.com/brgl/linux/commit/82fc38f6ab599ee03f7a8ed078de8a= bb41e6e611 > > > > > Cheers, > > > Kent.