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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 7DBB0C43142 for ; Thu, 2 Aug 2018 19:39:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0723021566 for ; Thu, 2 Aug 2018 19:39:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0723021566 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ravnborg.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727841AbeHBVbs (ORCPT ); Thu, 2 Aug 2018 17:31:48 -0400 Received: from asavdk4.altibox.net ([109.247.116.15]:41118 "EHLO asavdk4.altibox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726177AbeHBVbs (ORCPT ); Thu, 2 Aug 2018 17:31:48 -0400 Received: from ravnborg.org (unknown [158.248.196.126]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by asavdk4.altibox.net (Postfix) with ESMTPS id 0A48A804E4; Thu, 2 Aug 2018 21:39:10 +0200 (CEST) Date: Thu, 2 Aug 2018 21:39:09 +0200 From: Sam Ravnborg To: Noralf =?iso-8859-1?Q?Tr=F8nnes?= , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: Sam Ravnborg Subject: [RFC PATCH v1 0/5] Add pardata bus + tinydrm driver Message-ID: <20180802193909.GA11443@ravnborg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-CMAE-Score: 0 X-CMAE-Analysis: v=2.3 cv=UpRNyd4B c=1 sm=1 tr=0 a=ddpE2eP9Sid01c7MzoqXPA==:117 a=ddpE2eP9Sid01c7MzoqXPA==:17 a=kj9zAlcOel0A:10 a=85nIN3Etu3eYjTezwu4A:9 a=CjuIK1q_8ugA:10 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an RFC - to get some responses on the overall design. The code builds but has not yet been tested on any HW. Before investing more time into this I would like some feedback if this is the right way forward or a different design should be pursued. The problem to solve is that I have a propriatary ARM based board with a display that is connected using a parallel bus. The display is capable of showing graphics so it is more advanced than what is found in auxdisplay/ I know there are others using a display connected usign a parallel data bus, so this is not a unique problem for my board alone. But I do not expect many users as any modern design likely uses SPI or similar. The old (proprietary) approach was to implement a char driver and then let some 3rd party lib use the char driver to write to the display. The goal is to move to a more modern world where I expect to have a simple Qt based program running that can be used for a few simple things. (I do not expect any high performance and do not need it). Implementation: A pardata bus is implemented. It uses a platform_driver to hook into the DT. When probed the pardatabus driver creates pardata devices for all child nodes in the tree. Within tinydrm the pardata support is used to implement a driver for the display I have (Winstar wg160160). A library module is used to implement the more basic things allowing us to have a more simple driver, and thus making it simpler to add new drivers. The implmentation uses array support in gpiolib to try to have some performance on screen updates. TODO: - Test on HW - Add locking so there can be more than one user on the bus - Improve pardata.rst documentation - Add support for a sparkfun parallel data display (To verify that the library is generic) - I may add a class if I see the need - Likewise I may add sysfs attributes if there is a need for it Any comments appreciated! Sam Sam Ravnborg (5): dt-bindings: add parallel data bus (pardata) pardata: new bus for parallel data access tinydrm: add support for parallel data displays dt-bindings: add winstar,wg160160 display bindings tinydrm: add winstar wg160160 driver .../bindings/display/winstar,wg160160.txt | 53 +++ .../bindings/pardata/parallel-data-bus.txt | 60 +++ Documentation/driver-api/index.rst | 1 + Documentation/driver-api/pardata.rst | 60 +++ MAINTAINERS | 14 + drivers/Kconfig | 2 + drivers/Makefile | 1 + drivers/gpu/drm/tinydrm/Kconfig | 13 + drivers/gpu/drm/tinydrm/Makefile | 2 + drivers/gpu/drm/tinydrm/pardata-dbi.c | 417 +++++++++++++++++++++ drivers/gpu/drm/tinydrm/wg160160.c | 298 +++++++++++++++ drivers/pardata/Kconfig | 17 + drivers/pardata/Makefile | 5 + drivers/pardata/pardata.c | 282 ++++++++++++++ include/drm/tinydrm/pardata-dbi.h | 257 +++++++++++++ include/linux/pardata.h | 138 +++++++ 16 files changed, 1620 insertions(+)