From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753492Ab3LSI4R (ORCPT ); Thu, 19 Dec 2013 03:56:17 -0500 Received: from mail-we0-f175.google.com ([74.125.82.175]:53662 "EHLO mail-we0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752757Ab3LSI4N (ORCPT ); Thu, 19 Dec 2013 03:56:13 -0500 Date: Thu, 19 Dec 2013 08:56:07 +0000 From: Lee Jones To: Sebastian Andrzej Siewior Cc: Jonathan Cameron , Dmitry Torokhov , Samuel Ortiz , Zubair Lutfullah , Felipe Balbi , linux-iio@vger.kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/5] mfd: ti_am335x_tscadc: don't read back REG_SE Message-ID: <20131219085607.GG2621@lee--X1> References: <1387385577-24447-1-git-send-email-bigeasy@linutronix.de> <1387385577-24447-4-git-send-email-bigeasy@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1387385577-24447-4-git-send-email-bigeasy@linutronix.de> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 18 Dec 2013, Sebastian Andrzej Siewior wrote: > The purpose of reg_se_cache has been defeated. It should avoid the > read-back of the register to avoid the latency and the fact that the > bits are reset to 0 after the individual conversation took place. > > The reason why this is required like this to work, is that read-back of > the register removes the bits of the ADC so they do not start another > conversation after the register is re-written from the TSC side for the > update. > To avoid the unrequired read-back I introduce a "set adc" variant which > does not update the cache mask. After the conversation completes, the > register bit is removed from the SE reister anyway and we don't plan a > new conversation "any time soon". > This is a small preparation for a larger sync-rework. > > Signed-off-by: Sebastian Andrzej Siewior > --- > drivers/iio/adc/ti_am335x_adc.c | 2 +- > drivers/mfd/ti_am335x_tscadc.c | 12 ++++++++++-- > include/linux/mfd/ti_am335x_tscadc.h | 1 + > 3 files changed, 12 insertions(+), 3 deletions(-) Looks about right: Acked-by: Lee Jones -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog