From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ludwig Schwardt Subject: Writing a mini ALSA driver from scratch Date: Wed, 25 Aug 2004 22:09:02 +0200 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <412CF1DE.1060203@sun.ac.za> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org Hi, A student of mine is working on an audio capture driver for an ARM Linux system. The ARM (AT91RM9200) processor talks via SSC and I2S to a set of audio ADCs that capture 6 channels of 24-bit 192 kHz audio (no playback involved). The application is real-time sound logging (latency not important). I figured it might save the application developers some hassles by presenting this capture device as a soundcard to Linux. That way it may simplify realtime processing by using standard callback interfaces such as JACK (less apps to write!). My questions to the ALSA gurus are: 1) Is this a sound approach? (sorry, that slipped out) 2) Is it possible to write a bare-bones ALSA driver with only capturing functionality (no playback/mixer)? What are the bare essentials that make up an ALSA driver? (I'm worried about overkill) 3) Are there any existing drivers that could serve as a good template for a minimalist driver (I'm ignoring issues such as ISA/PCI etc.), to see how viable this option is? I was thinking maybe Gravis Ultrasound or such... 4) Is an ALSA driver even possible on ARM (dunno much about mmap and the like)? Thanks in advance for any tips. I was thinking of ploughing back any generic stuff along the way (like the AT91 SSC support). Ludwig Schwardt ------------------------------------------------------- SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media 100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33 Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift. http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285