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 BAE5BC433B4 for ; Thu, 1 Apr 2021 10:45:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9106160FED for ; Thu, 1 Apr 2021 10:45:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234035AbhDAKpC (ORCPT ); Thu, 1 Apr 2021 06:45:02 -0400 Received: from lizzard.sbs.de ([194.138.37.39]:34838 "EHLO lizzard.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232565AbhDAKo4 (ORCPT ); Thu, 1 Apr 2021 06:44:56 -0400 Received: from mail2.sbs.de (mail2.sbs.de [192.129.41.66]) by lizzard.sbs.de (8.15.2/8.15.2) with ESMTPS id 131AiIRf013128 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 1 Apr 2021 12:44:18 +0200 Received: from md1za8fc.ad001.siemens.net ([139.22.45.60]) by mail2.sbs.de (8.15.2/8.15.2) with ESMTP id 131AiG12019279; Thu, 1 Apr 2021 12:44:16 +0200 Date: Thu, 1 Apr 2021 12:44:15 +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: <20210401124415.3c9321c0@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> <20210330172305.67b6e050@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-leds@vger.kernel.org Am Wed, 31 Mar 2021 18:40:23 +0300 schrieb Andy Shevchenko : > On Tue, Mar 30, 2021 at 6:33 PM Henning Schild > wrote: > > 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. > > If you remember, I asked you about the chip twice :-) > I assumed that we were talking about Apollo Lake and that's why I > insisted that the driver is in the kernel source tree. Sorry, maybe i did not get the context of your question and which of the machines you asked about. Now it is clear i guess. > > > > 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. > > OK! > > > I guess that will still mean the PIO-based part of the LED driver > > will have to stay as is. > > Probably yes. I haven't looked into that part and I have no idea > what's going on on that platform(s). > Which i guess means the series can be reviewed as if the mmio bits for that apollo lake would not be in it, maybe i will even send a version without that one box. We have others in the "backlog" might as well delay that one if it helps sorting out a base-line. regards, Henning