From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pf0-x242.google.com ([2607:f8b0:400e:c00::242]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1dDJB7-0006cp-NN for barebox@lists.infradead.org; Tue, 23 May 2017 23:25:27 +0000 Received: by mail-pf0-x242.google.com with SMTP id n23so30476833pfb.3 for ; Tue, 23 May 2017 16:25:04 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <46762e56-b2a0-4afd-6967-99b36af1e6fb@cogentembedded.com> References: <20170522152420.14443-1-andrew.smirnov@gmail.com> <20170522152420.14443-3-andrew.smirnov@gmail.com> <46762e56-b2a0-4afd-6967-99b36af1e6fb@cogentembedded.com> From: Andrey Smirnov Date: Tue, 23 May 2017 16:25:03 -0700 Message-ID: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH 3/4] gpiolib: Add support for GPIO "hog" nodes To: Nikita Yushchenko , Sascha Hauer Cc: "barebox@lists.infradead.org" , Chris Healy On Mon, May 22, 2017 at 11:52 PM, Nikita Yushchenko wrote: >> + ret = of_property_read_u32(chip_np, "#gpio-cells", &gpio_cells); >> + if (ret) >> + return ret; >> + >> + if (WARN_ON(gpio_cells != 2)) >> + return -ENOTSUPP; >> + >> + ret = of_property_read_u32_index(np, "gpios", idx * gpio_cells, >> + &gpio_num); >> + if (ret) >> + return ret; >> + >> + ret = of_property_read_u32_index(np, "gpios", idx * gpio_cells + 1, >> + &gpio_flags); >> + if (ret) >> + return ret; > > Doesn't this hardcode interpretation of device tree words in gpio > specification - while this is intended to be gpio-provider specific and > that's why #gpio-cells exist? > It does and yes that's my understanding of the purpose of #gpio-cells as well. The reason I did in such a primitive way was because Barebox's GPIO subsystem doesn't have any translation plumbing to be able to handle anything more than a simple one dimensional offset. Given the fact that of_get_named_gpio_flags() make similar assumption I thought that there are no real consumers of that functionality and left proper implementation as a future improvement that can be made once the need arises. > >> +static int of_gpiochip_scan_gpios(struct gpio_chip *chip) > > Not best choice of name for routine that scans hogs? > > (although I understand that it comes from linux counterpart) > Eh, I don't have any strong opinion on this one, I am more than happy to rename it if you think there are better alternatives. >> - return 0; >> + return of_gpiochip_scan_gpios(chip); > > Should we fail gpiochip registration on failure to claim hogs? > I don't know. I couldn't think of a use-case where it wasn't basically all or nothing: either I get everything working or I need to go back and fix my DT. Sascha, do you have an opinion on this one? Thanks, Andrey Smirnov _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox