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 I²S 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 | _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
