From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [RFC PATCH] dma: at_xdmac: creation of the atmel eXtended DMA Controller driver Date: Tue, 10 Jun 2014 19:58:01 +0200 Message-ID: <11151546.Z6056AoQxM@wuerfel> References: <1401179736-8235-1-git-send-email-ludovic.desroches@atmel.com> <20140610154118.GA4254@lukather> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <20140610154118.GA4254@lukather> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Maxime Ripard Cc: Ludovic Desroches , dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, vinod.koul-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org, dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org List-Id: devicetree@vger.kernel.org On Tuesday 10 June 2014 17:41:18 Maxime Ripard wrote: > > +DMA clients connected to the Atmel XDMA controller must use the format > > +described in the dma.txt file, using a three-cell specifier for each channel: > > +a phandle plus two integer cells. > > +The three cells in order are: > > + > > +1. A phandle pointing to the DMA controller. > > +2. The memory interface (16 most significant bits), the peripheral interface > > +(16 less significant bits). > > Can you elaborate on this? What are they? The request IDs on both ends > of the transfers? > > > +3. Channel configuration register. Configurable fields are: > > + - bit 2-1: MBSIZE, memory burst size. > > + - bit 10-8: CSIZE, chunk size. > > + - bit 12-11: DWIDTH, data width. > > I'd rather see those as generic properties. Actually these are standard settings that a slave driver configures using dma_slave_config. They don't belong into DT at all, as they are slave driver specific. Arnd -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html