From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: Problem to init AD1938 on i.MX25 Date: Mon, 16 Aug 2010 09:30:40 +0200 Message-ID: <20100816073040.GH27749@pengutronix.de> References: <4C68C3C5.5030701@googlemail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: quoted-printable Return-path: Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [92.198.50.35]) by alsa0.perex.cz (Postfix) with ESMTP id B80FB1037F3 for ; Mon, 16 Aug 2010 09:30:40 +0200 (CEST) Content-Disposition: inline In-Reply-To: <4C68C3C5.5030701@googlemail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Sven Zeisberg Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org Hello Sven, On Mon, Aug 16, 2010 at 06:51:17AM +0200, Sven Zeisberg wrote: > Hello, > = > we're working on an ALSA driver for AD1938 for i.MX25 based system. > On the I=B2S the CODEC is Master. On the SPI, the MCU is Master. > = > SSI seems to work (when we set the CODEC as Master by Hardware). > = > We have problems to get the communication via SPI working. The CODEC = > requires 24Bit words and we can set SPI according to this in the = > board-file and verify this also with a logic analyzer. However, we can = > send only one word to the CODEC! This first word is transferred = > correctly, but all subsequent transfers show no activity on the SPI = > lines. We do not get any error messages from the SPI drivers! All SPI = > writes after the first word seem to be executed in software but show not = > effect in hardware. All reads return 0xff. This is probaly more a problem in the SPI driver than alsa related. The i.MX SPI unit comes in many different variants and there may well be a bug in the i.MX25 path. As a test you could configure the SPI pads in gpio mode and use the bitbang gpio spi driver (drivers/spi/spi_gpio.c). When this works you can hunt down the bug in the SPI driver. Sascha -- = Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |