From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pascal Huerst Subject: Re: ASoC: cs4271: init/timing problem Date: Wed, 01 Apr 2015 11:57:22 +0200 Message-ID: <551BC102.6010403@gmail.com> References: <551A5FC9.4010109@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wi0-f169.google.com (mail-wi0-f169.google.com [209.85.212.169]) by alsa0.perex.cz (Postfix) with ESMTP id 2CC50260434 for ; Wed, 1 Apr 2015 11:57:24 +0200 (CEST) Received: by wixo5 with SMTP id o5so43136906wix.1 for ; Wed, 01 Apr 2015 02:57:23 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Brian Austin Cc: alsa-devel@alsa-project.org, Mark Brown , Paul.Handrigan@cirrus.com List-Id: alsa-devel@alsa-project.org Hey Brian, On 31.03.2015 23:01, Brian Austin wrote: > On Tue, 31 Mar 2015, Pascal Huerst wrote: > >> Hey all, >> >> We have a custom built hw, based on am335x and from time to time we need >> to rmmod/modprobe the ASoC machine driver. Depending on the hw, the >> first call to regmap_update_bits(..) in cs4271_codec_probe(..) fails >> with -EREMOTEIO. >> >> The error is originated in: >> >> drivers/i2c/busses/i2c-omap.c >> >> and happens if no i2c package acknowledge is received by the host. >> >> I think this is a timing issue and on some devices, the codec is just >> not ready yet, for communication. >> >> What is the right way to fix that? My attempt would be something like this: > > The error you are referring to is a NACK from a device (CODEC). That is > usually seen when you dont have it hooked up correctly. Could also be that > the I2C bus is too fast. How fast are you running the bus? clock-frequency is set to 100000, hence 100 kHz, which should be ok, according to the datasheet.