From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Forcing PIO mode instead of DMA via DT property Date: Sun, 22 Jul 2012 23:28:26 +0200 Message-ID: <201207222328.27008.marex@denx.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Cc: pavel-ynQEQJNshbs@public.gmane.org, Wolfgang Denk List-Id: devicetree@vger.kernel.org Hi guys, I'm trying to implement a driver that can do both DMA and PIO, and it would be nice if the user was able to select the mode (on a per-bus basis) using the DT. The PIO mode can reduce the overhead in some cases and therefore be better choice than the DMA (for example when most transfers move only very few data, or when board-specific hardware properties kick in). I was thinking about using some "manf,use-pio" DT property, but I haven't found any such example yet, so I wonder if this is a good idea. What is your suggestion how I shoud address such a problem? Thanks in advance! Best regards, Marek Vasut