From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759562AbdJQIxE (ORCPT ); Tue, 17 Oct 2017 04:53:04 -0400 Received: from 3.mo2.mail-out.ovh.net ([46.105.58.226]:59763 "EHLO 3.mo2.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759549AbdJQIwh (ORCPT ); Tue, 17 Oct 2017 04:52:37 -0400 X-Greylist: delayed 2056 seconds by postgrey-1.27 at vger.kernel.org; Tue, 17 Oct 2017 04:52:37 EDT Subject: Re: about pca955x led driver gpio management To: Andrea Scian - DAVE Embedded Systems Cc: Bryan Wu , Richard Purdie , Jacek Anaszewski , linux-leds@vger.kernel.org, linux-kernel References: From: =?UTF-8?Q?C=c3=a9dric_Le_Goater?= Message-ID: <998d7654-f69a-1a99-d4e7-19abd0a54da0@kaod.org> Date: Tue, 17 Oct 2017 10:52:28 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=iso-8859-15 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Ovh-Tracer-Id: 14182679653306370839 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedttddrudeggddutdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfqggfjpdevjffgvefmvefgnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/17/2017 10:20 AM, Andrea Scian - DAVE Embedded Systems wrote: > > Il 17/10/2017 10:18, Cédric Le Goater ha scritto: >> On 10/17/2017 09:36 AM, Andrea Scian - DAVE Embedded Systems wrote: >>> Dear all, >>> >>> I'm working on an iMX6 based board with a PCA9555 which is used both to drive LEDs and manage some GPIOs. >> The PCA9555 chip and the PCA955[0-3] chips have different control >> registers. You need a different led driver for it. > > My typo sorry, as you can see in the device tree below, I'm using pca9551 ok. You might want to take a look at how we mixed gpios and leds on the witherspoon system using pca9552 chips. we added a gpio-leds binding. https://github.com/openbmc/linux/blob/dev-4.10/arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts Cheers, C. > >>> My current kernel is quite old (4.1.15) but I've found Cédric patches on mainline and backported to this old revision. >>> >>> I'm facing an issue with it, because it seems that it fails when it's used in a mixed (led/gpios) environment. >>> >>> E.g.: let's say that I have one led connected to LED0 output and one GPIO connected at LED1 output. >>> >>> I define it as >>> >>>                          pca9551: pca9551@60 { >>>                                  compatible = "nxp,pca9551"; >>>                                  reg = <0x60>; >>>                                  #address-cells = <1>; >>>                                  #size-cells = <0>; >>>                                  #gpio-cells = <1>; >>> >>>                                  led@0 { >>>                                          label = "led0"; >>>                                          reg = <0>; >>>                                          linux,default-trigger = "none"; >>>                                  }; >>>                                  gpio@1 { >>>                                          label = "gpio1"; >>>                                          reg = <1>; >>>                                          type = <2>; /* GPIO */ >>>                                  }; >>>                  }; >>> >>> At boot it's probed as >>> >>> root@sbc-lynx:~# dmesg | grep pca >>> [    5.315425] leds-pca955x 5-0060: leds-pca955x: Using pca9551 8-bit LED driver at slave address 0x60 >>> [    5.350349] leds-pca955x 5-0060: gpios 511...511 >>> >>> But I cannot access it: >>> >>> root@sbc-lynx:~# echo 511 > /sys/class/gpio/export >>> -sh: echo: write error: Device or resource busy >>> >>> Because for pca955x_gpio_request_pin() this is at offset 0 (in fact is the first gpio registered of this gpio_chip) but it's the index 1 inside pca955x->leds[] >>> >>> Am I missing something? (maybe I made a mistake in my backport and/or I'm missing some patches about the GPIO subsystems). >>> >>> If I'm right I think I can send a patch to fix this (I'm thinking about having an array of GPIO index to map offset -> pca955x->leds[] index or just register all pins as GPIOs and then just report the busy state) >>> >>> WDYT? >>> >>> Kind Regards, >>> >