From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ppsw-50.csi.cam.ac.uk ([131.111.8.150]:47856 "EHLO ppsw-50.csi.cam.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752675Ab1CXPQ3 (ORCPT ); Thu, 24 Mar 2011 11:16:29 -0400 Message-ID: <4D8B609A.5070603@cam.ac.uk> Date: Thu, 24 Mar 2011 15:17:46 +0000 From: Jonathan Cameron MIME-Version: 1.0 To: "Hennerich, Michael" CC: "linux-iio@vger.kernel.org" , Drivers , "device-drivers-devel@blackfin.uclinux.org" Subject: Re: [PATCH] IIO: ADC: New driver for the AD7880 / AD7781 24-bit Sigma-Delta ADC References: <1300975814-14423-1-git-send-email-michael.hennerich@analog.com> <4D8B5D86.8010503@cam.ac.uk> <544AC56F16B56944AEC3BD4E3D59177137545394A3@LIMKCMBX1.ad.analog.com> In-Reply-To: <544AC56F16B56944AEC3BD4E3D59177137545394A3@LIMKCMBX1.ad.analog.com> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 03/24/11 15:12, Hennerich, Michael wrote: > Jonathan Cameron wrote on 2011-03-24: >> On 03/24/11 14:10, michael.hennerich@analog.com wrote: >>> From: Michael Hennerich >> >> Hi Michael, >> >> Some slightly inconsistent handling of the absence of pdata. >> Is it possible to use this device without pdrst being connected? > > Yes and no. > You could but then the AD7780 asserts SDO/RDY whenever a new sample is available. > No way to stop it, without utilizing PDRST. > I therefore use spi bus locking and keep the part in reset/power down whenever is should be quiet. > The part also lacks a dedicated spi chip select. So we definitely want to use PDRST. Fair enough. That's an 'interesting' bit of hardware! > >> If not, then check for pdata early in probe and fail if not present. > > Yes - I typically do this, however it slipped this time. > >> The datardy on the data out line is a delightful big of hardware >> design and I guess what you have here is the only way to handle it. > > Unfortunately that's the case. > >> Having said that, perhaps some explanatory comments, maybe in the >> header, would be useful. Do you have that irq pin dual wired to the >> spi data out? > > Yes > > Thanks for the review. > You are most welcome.