From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amit Virdi Subject: Re: [PATCH 2/3] can: c_can: Provide generic interface to configure c-can message objects Date: Wed, 16 Jan 2013 14:41:39 +0530 Message-ID: <50F66ECB.8070203@st.com> References: <50D31ADE.1050308@pengutronix.de> <50D37154.9020107@grandegger.com> <50F65A86.3060307@st.com> <50F66CE3.8070302@grandegger.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from eu1sys200aog119.obsmtp.com ([207.126.144.147]:45835 "EHLO eu1sys200aog119.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932119Ab3APJLu (ORCPT ); Wed, 16 Jan 2013 04:11:50 -0500 In-Reply-To: <50F66CE3.8070302@grandegger.com> Sender: linux-can-owner@vger.kernel.org List-ID: To: Wolfgang Grandegger Cc: Marc Kleine-Budde , "linux-can@vger.kernel.org" , Bhupesh SHARMA , "anilkumar@ti.com" , spear-devel On 1/16/2013 2:33 PM, Wolfgang Grandegger wrote: > On 01/16/2013 08:45 AM, Amit Virdi wrote: >> On 12/21/2012 1:43 AM, Wolfgang Grandegger wrote: >>> On 12/20/2012 03:04 PM, Marc Kleine-Budde wrote: >>>> On 12/20/2012 11:05 AM, Amit Virdi wrote: >>>>> Depending on the underlying platform, the configuration of the c-can >>>>> message objects can change. For e.g. in some systems, it makes more >>>>> sense to receive many message objects and transmit very few. In any >>>>> case, providing flexibility in configuring the message objects is >>>>> highly >>>>> desirable. >>>>> >>>>> The total number of message objects for C_CAN controller is fixed at >>>>> 32. >>>>> The receive message objects are assigned higher priority so they begin >>>>> with message object#1. So, in order to configure the message object the >>>>> driver just needs two parameters - rx_split (for differentiating >>>>> between >>>>> lower bucket and higher bucket) and tx_num. >>>>> >>>>> However, if the user doesn't specify these parameters, then the message >>>>> objects are configured with default parameters with equal distribution >>>>> of receive and transmit message objects (16 each). >>>> >>>> As Wolfgang pointed out, the DT should only describe the hardware. In >>>> the ethernet world I think there is ethtool to configure the hardware. >>>> Maybe we need something similar for CAN (or add CAN support to ethtool). >>> >>> Yeah, a simple tool using simple ioctl request would be nice, indeed. >>> Well, as a per device setting seems overkill a simple module parameter >>> would just do it. >>> >> >> So, you're saying to drop the device configuration from the DT and use >> some tool to do that. This would be nice if there are enough devices, >> apart from the Bosch C-CAN controller, which require this sort of >> configuration. > > No, I said: "a simple module parameter would just do it". > Ok, now I understood! Regards Amit Virdi