From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter =?iso-8859-1?q?H=FCwe?= Subject: i2c_transfer & dma Date: Tue, 23 Sep 2014 21:38:32 +0200 Message-ID: <201409232138.33067.PeterHuewe@gmx.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org Hi, I was wondering if the buffer in an i2c_msg, passed to i2c_transfer must be dma-able i.e. dynamically allocated, like for USB? The reason why I'm asking is because the e.g. the i2c_robotfuzz_osif usb-to- i2c adapter passes the incoming data directly to a usb_control_msg which of course expects the buffer to be dma-able. So the question is - does the user of i2c_transfer have to provide a dma-able buffer, or is the bus driver (like the robotfuzz one) expected to convert incoming buffer into a dma-able buffer? Thanks, Peter