From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [PATCH v2 1/3] drivers/mfd/menf21bmc: introduce MEN 14F021P00 BMC MFD Core driver Date: Wed, 28 May 2014 06:52:56 -0700 Message-ID: <5385EA38.9090200@roeck-us.net> References: <20140527150547.GA4227@lee--X1> <20140528070222.GA24101@jtlinux> <20140528082404.GA10803@lee--X1> <20140528115159.GA2090@awelinux> <5385E4C9.2010204@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.active-venture.com ([67.228.131.205]:51375 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752995AbaE1NxN (ORCPT ); Wed, 28 May 2014 09:53:13 -0400 In-Reply-To: <5385E4C9.2010204@roeck-us.net> Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org 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 On 05/28/2014 06:29 AM, Guenter Roeck wrote: > 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. > ... especially since you have "struct i2c_client *client" in your API function. Guenter