From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753749AbaE1NaZ (ORCPT ); Wed, 28 May 2014 09:30:25 -0400 Received: from mail.active-venture.com ([67.228.131.205]:63279 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752287AbaE1NaA (ORCPT ); Wed, 28 May 2014 09:30:00 -0400 X-Originating-IP: 108.223.40.66 Message-ID: <5385E4C9.2010204@roeck-us.net> Date: Wed, 28 May 2014 06:29:45 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Andreas Werner , Lee Jones CC: Johannes Thumshirn , linux-kernel@vger.kernel.org, sameo@linux.intel.com, wim@iguana.be, linux-watchdog@vger.kernel.org, cooloney@gmail.com, rpurdie@rpsys.net, linux-leds@vger.kernel.org Subject: Re: [PATCH v2 1/3] drivers/mfd/menf21bmc: introduce MEN 14F021P00 BMC MFD Core driver References: <20140527150547.GA4227@lee--X1> <20140528070222.GA24101@jtlinux> <20140528082404.GA10803@lee--X1> <20140528115159.GA2090@awelinux> In-Reply-To: <20140528115159.GA2090@awelinux> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/28/2014 04:51 AM, Andreas Werner wrote: > aOn Wed, May 28, 2014 at 09:24:05AM +0100, Lee Jones wrote: >>>>> The MEN 14F021P00 Board Management Controller provides an >>>>> I2C interface to the host to access the feature implemented in the BMC. >>>>> The BMC is a PIC Microntroller assembled on CPCI Card from MEN Mikroelektronik >>>>> and on a few Box/Display Computer. >>>>> >>>>> Added MFD Core driver, supporting the I2C communication to the device. >>>>> >>>>> The MFD driver currently supports the following features: >>>>> - Watchdog >>>>> - LEDs >>>>> >>>>> Signed-off-by: Andreas Werner >>>>> --- >>>>> drivers/mfd/Kconfig | 12 +++ >>>>> drivers/mfd/Makefile | 1 + >>>>> drivers/mfd/menf21bmc.c | 220 ++++++++++++++++++++++++++++++++++++++++++ >>>>> include/linux/mfd/menf21bmc.h | 31 ++++++ >>>>> 4 files changed, 264 insertions(+) >>>>> create mode 100644 drivers/mfd/menf21bmc.c >>>>> create mode 100644 include/linux/mfd/menf21bmc.h >> >> [...] >> >>>>> +static int menf21bmc_write_byte(struct i2c_client *client, u8 val) >>>>> +{ >>>>> + int ret; >>>>> + struct menf21bmc *data = i2c_get_clientdata(client); >>>>> + >>>>> + mutex_lock(&data->lock); >>>>> + ret = i2c_smbus_write_byte(client, val); >>>>> + mutex_unlock(&data->lock); >>>>> + >>>>> + return ret; >>>>> +} >>>> >>>> Didn't we ask you to remove these? Just make the i2c_smbus_* calls >>>> from within the driver. The I2C subsystem conducts its own locking. >>>> I'm really starting to frown on aggregation for the sake of >>>> aggregation. It's just overhead. >>>> >>> >>> Correct me if I'm wrong but as far as I remember Guenther asked to retain the >>> original API, not the remove the "abstraction layer". Once we build a board with >>> one of these BMCs attached via e.g. SPI we would have to reintroduce it anyways, >>> in order to re-use these drivers. >> >> If there are two or more possible interfaces then I agree, these >> aggregations would be the best approach. However, as it stands, that's >> not currently the case. >> >> Genuine question; are Men on the verge of building such a board, or >> are we talking about 'ifs' and 'maybes'? >> > > I think it was a missunderstanding. I also thought that i just > have to adapt the wrapper to the original API, that is what I did in the patch, > and not to delete the functions completly. > > Anayway, we currently have another project which use a STM32 MCR connected to USB. > A nice feature of this STM is to update the firmware using the USB interface. > This is easy to implement and fast. > > We want to use such a functionality in all of our MCRs to easily update the firmware > at the customer if we found a bug. > > We also plan to have a BMC connected to USB. Then we have i2c and USB. > Even more likely that you would have to change the API in that case to be less I2C centric. Guenter