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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 97602C433E0 for ; Tue, 30 Mar 2021 15:34:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66CE2619CE for ; Tue, 30 Mar 2021 15:34:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231622AbhC3Pdv (ORCPT ); Tue, 30 Mar 2021 11:33:51 -0400 Received: from gecko.sbs.de ([194.138.37.40]:57575 "EHLO gecko.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232335AbhC3Pde (ORCPT ); Tue, 30 Mar 2021 11:33:34 -0400 Received: from mail2.sbs.de (mail2.sbs.de [192.129.41.66]) by gecko.sbs.de (8.15.2/8.15.2) with ESMTPS id 12UFX7GU024983 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 30 Mar 2021 17:33:07 +0200 Received: from md1za8fc.ad001.siemens.net ([167.87.2.166]) by mail2.sbs.de (8.15.2/8.15.2) with ESMTP id 12UFN6KW024700; Tue, 30 Mar 2021 17:23:06 +0200 Date: Tue, 30 Mar 2021 17:23:05 +0200 From: Henning Schild To: Andy Shevchenko Cc: Linux Kernel Mailing List , Linux LED Subsystem , Platform Driver , linux-watchdog@vger.kernel.org, Srikanth Krishnakar , Jan Kiszka , Gerd Haeussler , Guenter Roeck , Wim Van Sebroeck , Mark Gross , Hans de Goede , Pavel Machek , Enrico Weigelt Subject: Re: [PATCH v3 2/4] leds: simatic-ipc-leds: add new driver for Siemens Industial PCs Message-ID: <20210330172305.67b6e050@md1za8fc.ad001.siemens.net> In-Reply-To: References: <20210329174928.18816-1-henning.schild@siemens.com> <20210329174928.18816-3-henning.schild@siemens.com> <20210330135808.373c3308@md1za8fc.ad001.siemens.net> <20210330143011.0e8ae4a0@md1za8fc.ad001.siemens.net> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Am Tue, 30 Mar 2021 15:41:53 +0300 schrieb Andy Shevchenko : > On Tue, Mar 30, 2021 at 3:35 PM Henning Schild > wrote: > > Am Tue, 30 Mar 2021 15:15:16 +0300 > > schrieb Andy Shevchenko : > > > On Tue, Mar 30, 2021 at 2:58 PM Henning Schild > > > wrote: > > > > Am Tue, 30 Mar 2021 14:04:35 +0300 > > > > schrieb Andy Shevchenko : > > > > > On Mon, Mar 29, 2021 at 8:59 PM Henning Schild > > > > > wrote: > > > > > > > +static struct simatic_ipc_led simatic_ipc_leds_mem[] = { > > > > > > + {0x500 + 0x1A0, "red:" LED_FUNCTION_STATUS "-1"}, > > > > > > + {0x500 + 0x1A8, "green:" LED_FUNCTION_STATUS "-1"}, > > > > > > + {0x500 + 0x1C8, "red:" LED_FUNCTION_STATUS "-2"}, > > > > > > + {0x500 + 0x1D0, "green:" LED_FUNCTION_STATUS "-2"}, > > > > > > + {0x500 + 0x1E0, "red:" LED_FUNCTION_STATUS "-3"}, > > > > > > + {0x500 + 0x198, "green:" LED_FUNCTION_STATUS "-3"}, > > > > > > + { } > > > > > > +}; > > > > > > > > > > It seems to me like poking GPIO controller registers directly. > > > > > This is not good. The question still remains: Can we simply > > > > > register a GPIO (pin control) driver and use an LED GPIO > > > > > driver with an additional board file that instantiates it? > > > > > > > > I wrote about that in reply to the cover letter. My view is > > > > still that it would be an abstraction with only one user, just > > > > causing work and likely not ending up as generic as it might > > > > eventually have to be. > > > > > > > > The region is reserved, not sure what the problem with the > > > > "poking" is. > > > > > > > > > > Maybe i do not understand all the benefits of such a split at > > > > this point in time. At the moment i only see work with hardly > > > > any benefit, not just work for me but also for maintainers. I > > > > sure do not mean to be ignorant. Maybe you go into details and > > > > convince me or we wait for other peoples opinions on how to > > > > proceed, maybe there is a second user that i am not aware of? > > > > Until i am convinced otherwise i will try to argue that a > > > > single-user-abstraction is needless work/code, and should be > > > > done only when actually needed. > > > > > > I have just read your messages (there is a cover letter and > > > additional email which was sent lately). > > > > > > I would like to know what the CPU model number on that board is. > > > Than we can continue to see what possibilities we have here. > > > > I guess we are talking about the one that uses memory mapped, that > > is called an "IPC127E" and seems to have either Intel Atom E3940 or > > E3930 which seems to be Apollo Lake. > > Yep. And now the question, in my patch series you should have got the > apollolake-pinctrl driver loaded (if not, we have to investigate why > it's not being instantiated). This will give you a read GPIO driver. Ok, so there is the existing driver i asked about several times. Thanks for pointing it out. > So, you may use regular LED GPIO on top of it > (https://elixir.bootlin.com/linux/latest/source/drivers/leds/leds-gpio.c). > I would like to understand why it can't be achieved. Will have a look. Unfortunately this one box is missing in my personal collection, but let us assume that one can be converted to that existing driver. I guess that will still mean the PIO-based part of the LED driver will have to stay as is. regards, Henning