From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934391AbdJQIUW (ORCPT ); Tue, 17 Oct 2017 04:20:22 -0400 Received: from mx.dave-tech.it ([2.229.21.40]:46971 "EHLO mx.dave-tech.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934291AbdJQIUT (ORCPT ); Tue, 17 Oct 2017 04:20:19 -0400 Subject: Re: about pca955x led driver gpio management To: =?UTF-8?Q?C=c3=a9dric_Le_Goater?= References: Cc: Bryan Wu , Richard Purdie , Jacek Anaszewski , linux-leds@vger.kernel.org, linux-kernel From: Andrea Scian - DAVE Embedded Systems Organization: DAVE Embedded Systems Message-ID: Date: Tue, 17 Oct 2017 10:20:17 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 8bit Content-Language: it-IT X-Antivirus: avast! (VPS 171016-6, 16/10/2017), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >> 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, >>