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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 D0E3CC2D0DB for ; Mon, 20 Jan 2020 10:10:51 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id ACFB620684 for ; Mon, 20 Jan 2020 10:10:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ACFB620684 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-m68k.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 332796E898; Mon, 20 Jan 2020 10:10:51 +0000 (UTC) Received: from mail-oi1-f194.google.com (mail-oi1-f194.google.com [209.85.167.194]) by gabe.freedesktop.org (Postfix) with ESMTPS id B7C206E898 for ; Mon, 20 Jan 2020 10:10:49 +0000 (UTC) Received: by mail-oi1-f194.google.com with SMTP id d62so27999367oia.11 for ; Mon, 20 Jan 2020 02:10:49 -0800 (PST) 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; bh=8+qrvwPOgPvxahwyd5KQ9RV4ePgSqOg74nqe3gTMzKQ=; b=nwlsN13b2bNHLVkrln7ql06u5+kWzo6b/k3FYpyIOthPLZYRQf1UyOAHP3Rgs45zQq 3fZuVkYJz77wTJWa/6hOmX2y64lIUxL7bmpJdiWRJjJ5u1ZB/8vs5gYe0Yj7qmk3VFwC zIfR4X/9f65MMz4YclWAIusrBO5H+3nyiQj49z7reeS/UDmjSj+QaLY4J2RVsvcI5kpT IXfRbvDZsr0WrEqHc1Jf0pZGX6+SfNUl5aEEdh3269HX5NbBCRyK0IbrGEwf6CLxA4Fg 9rv/vc/O4Tf3p2bbnwg1SZPn5EiQIXTNGYWMSA5y//8bkpdJOf0DCpJuna0WowD7GhNX U8sw== X-Gm-Message-State: APjAAAXUIl0TaUcnoF+KLzjBJqPCMJg3Fc9X4IURvzoGjCtaJdVeFs7K CaB8qCAB8HSHQbe1ypNQfo+EJ9y/8t2Bv0n0a98= X-Google-Smtp-Source: APXvYqxBD1lgBtsNPuNMqT1o27W7Ir+ePtVv464K7y/05wcGh/xr4/6RJVBUe/4BzfIfkFWOB49rWDJJVkncf5LeRX0= X-Received: by 2002:aca:5905:: with SMTP id n5mr12459471oib.54.1579515048959; Mon, 20 Jan 2020 02:10:48 -0800 (PST) MIME-Version: 1.0 References: <20180802193909.GA11443@ravnborg.org> <20180802194536.10820-2-sam@ravnborg.org> In-Reply-To: <20180802194536.10820-2-sam@ravnborg.org> From: Geert Uytterhoeven Date: Mon, 20 Jan 2020 11:10:37 +0100 Message-ID: Subject: Re: [PATCH v1 2/5] pardata: new bus for parallel data access To: Sam Ravnborg X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Greg Kroah-Hartman , Linux Kernel Mailing List , DRI Development Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Sam, (stumbled on this accidentally) On Thu, Aug 2, 2018 at 9:46 PM Sam Ravnborg wrote: > The pardata supports implement a simple bus for devices > that are connected using a parallel bus driven by GPIOs. > The is often used in combination with simple displays > that is often seen in older embedded designs. > There is a demand for this support also in the linux > kernel for HW designs that uses these kind of displays. > > The pardata bus uses a platfrom_driver that when probed > creates devices for all child nodes in the DT, > which are then supposed to be handled by pardata_drivers. > > Signed-off-by: Sam Ravnborg > --- /dev/null > +++ b/Documentation/driver-api/pardata.rst > @@ -0,0 +1,60 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +========================= > +Parallel Data Bus/Drivers > +========================= > + > +Displays may be connected using a simple parallel bus. > +This is often seen in embedded systems with a simple MCU, but is also > +used in Linux based systems to a small extent. > + > +The bus looks like this: > + > +.. code-block:: none > + > + ----+ > + | DB0-DB7 or DB4-DB7 +---- > + ===/======================== > + | E - enable | D > + ---------------------------- I > + C | Reset | S > + P ---------------------------- P > + U | Read/Write (one or two) | L > + ---------------------------- A > + | RS - instruction/data | Y > + ---------------------------- > + | +---- > + ----+ Oh, cool! Looks like this can be used by the hd44780 driver. Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt drivers/auxdisplay/hd44780.c Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel