From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754656Ab1KAMrQ (ORCPT ); Tue, 1 Nov 2011 08:47:16 -0400 Received: from mailhost.informatik.uni-hamburg.de ([134.100.9.70]:43789 "EHLO mailhost.informatik.uni-hamburg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754606Ab1KAMrN (ORCPT ); Tue, 1 Nov 2011 08:47:13 -0400 Message-ID: <4EAFEA3D.9030103@metafoo.de> Date: Tue, 01 Nov 2011 13:46:53 +0100 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20111004 Icedove/3.0.11 MIME-Version: 1.0 To: =?UTF-8?B?UGFsaSBSb2jDoXI=?= CC: linux-kernel@vger.kernel.org, Anton Vorontsov , syed rafiuddin , Rodolfo Giometti , David Woodhouse Subject: Re: [PATCH 8/9] bq27x00: Add miscdevice for each battery with ioctl for reading registers References: <1316531933-7159-1-git-send-email-pali.rohar@gmail.com> <1320108191-6647-1-git-send-email-pali.rohar@gmail.com> <1320108191-6647-8-git-send-email-pali.rohar@gmail.com> <4EAFE184.5010409@metafoo.de> In-Reply-To: X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/01/2011 01:23 PM, Pali Rohár wrote: > 2011/11/1 Lars-Peter Clausen : >> On 11/01/2011 01:43 AM, Pali Rohár wrote: >>> * When bq27x00_battery module is loaded it take control of bq27200 i2c battery chip and then it is not possible to use i2cget program from user space (returns -EBUSY) >>> * This patch adds new miscdevice for each battery which has ioctl BQ27X00_READ_REG for reading battery registers from user space >>> >>> * ioctl cmd: >>> #define BQ27X00_READ_REG _IO(MISC_MAJOR, 0) >>> >>> * ioctl arg: >>> struct bq27x00_reg_parms { >>> int reg; /* battery register (in) */ >>> int single; /* 1 - 8bit register, 0 - 16bit register (in) */ >>> int ret; /* register status, negative indicate error (out) */ >>> }; >>> >>> Signed-off-by: Pali Rohár >> >> I'm not sure if this is such a good idea. Why do you need to read the registers >> from userspace? Shouldn't all relevant information be available in a >> standardized format through the power_supply userspace API? If you want to use >> it for debugging it might be a better idea to provide a debugfs file. >> >> - Lars >> > > bq27200 chip has a lot of registers (for diagnostic) which is usefull > on Nokia N900. power_supply interface is not very abstract to handle > all of them. Which registers are we talking about here. And if this generally useful information does it make sense to add a new property to the power_supply interface? > Also on Nokia N900 is needed proprietary pogram BME for > battery charging which need to access to bq27200 registers. A simple > LD_PRELOAD library which wrap i2c-dev access to this device provided > by this patch is here: > https://code.launchpad.net/~pali/+junk/maemo_libbqioctl Yes, but that really is a hack to work around the closed source nature of the BME program. I don't think we should put such hacks into the kernel.