Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751839AbaLCPLZ (ORCPT ); Wed, 3 Dec 2014 10:11:25 -0500 Received: from mail-lb0-f179.google.com ([209.85.217.179]:33102 "EHLO mail-lb0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751262AbaLCPLX convert rfc822-to-8bit (ORCPT ); Wed, 3 Dec 2014 10:11:23 -0500 From: Alexander Kochetkov Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Subject: Question about patch "i2c: omap: resize fifos before each message" Date: Wed, 3 Dec 2014 18:11:18 +0300 Message-Id: Cc: Kevin Hilman , Tony Lindgren , Wolfram Sang , linux-omap , linux-i2c@vger.kernel.org, LKML To: Felipe Balbi Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) X-Mailer: Apple Mail (2.1878.6) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Felipe, Question about the patch[1]. I want to change the code in a way to not touch fifo thresholds for each message. Because: 1. dev->threshold is valid only with checking of transfer direction. So, if last transfer was transmission and ISR get RRDY interrupt from slave receiver, then dev->threshold is invalid. We must read threshold value from BUF register, to process correctly. 2. I want to avoid changing fifos before message submission, because IP can start receiving message in a slave mode (race). 3. dev->threshold is changed in range 1-fifo_size/2. So instead of RDR we get RRDY and for messages larger then fifo_size/2 we still get RRDY and RDR. Felipe, do you have in mind why do you want to avoid RDR and XDR events? Something about errata? [1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/i2c/busses/i2c-omap.c?id=dd74548ddece4b9d68e5528287a272fa552c81d0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/