[RFC PATCH] dma: at_xdmac: creation of the atmel eXtended DMA Controller driver
arnd at arndb.de
Tue Jun 10 10:58:01 PDT 2014
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.
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