From mboxrd@z Thu Jan 1 00:00:00 1970 From: ryan@bluewatersys.com (Ryan Mallon) Date: Fri, 15 Oct 2010 10:57:47 +1300 Subject: [PATCH v3 2/3] ARM: ep93xx: add AC97 platform support In-Reply-To: <0D753D10438DA54287A00B02708426976450C42B0E@AUSP01VMBX24.collaborationhost.net> References: <14a8c7ea0482375fa32a022ea7e318ea4feae6f1.1287066937.git.mika.westerberg@iki.fi> <0D753D10438DA54287A00B02708426976450C42B0E@AUSP01VMBX24.collaborationhost.net> Message-ID: <4CB77CDB.6050908@bluewatersys.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10/15/2010 10:46 AM, H Hartley Sweeten wrote: > On Thursday, October 14, 2010 7:49 AM, Mika Westerberg wrote: >> +void __init ep93xx_register_ac97(void) >> +{ >> + /* >> + * Make sure that the AC97 pins are not used by I2S. >> + */ >> + ep93xx_devcfg_clear_bits(EP93XX_SYSCON_DEVCFG_I2SONAC97); > > This is fine for now. > > Eventually some thought should go into a proper iomux to prevent > loading drivers with conflicting pin requirements. Currently, depending > on the configuration, this could break if a user should try to use the > ac97 and i2s audio at the same time (I2SONAC97 mode). But, the same > problem already exists if a user tries using spi and i2s audio (I2SONSSP > mode). I initially suggested this also, since we have acquire/release functions for some other drivers, but I now think this is fine as is. It's highly unlikely that a board is going to have both I2S and AC97 audio. We can change this later if such a board shows up, no need to make the code more complicated for hypothetical boards :-). ~Ryan -- Bluewater Systems Ltd - ARM Technology Solution Centre Ryan Mallon 5 Amuri Park, 404 Barbadoes St ryan at bluewatersys.com PO Box 13 889, Christchurch 8013 http://www.bluewatersys.com New Zealand Phone: +64 3 3779127 Freecall: Australia 1800 148 751 Fax: +64 3 3779135 USA 1800 261 2934