Messages in this thread | | | Subject | Re: [PATCH] sh: maple: add support for Maple controller as a joystick | From | Adrian McMenamin <> | Date | Sat, 20 Dec 2008 20:47:00 +0000 |
| |
On Sat, 2008-12-20 at 12:19 -0800, Dmitry Torokhov wrote: > On Saturday 20 December 2008 08:07:27 Adrian McMenamin wrote: > > On Sat, 2008-12-20 at 15:16 +0000, Matt Fleming wrote: > > > On Fri, Dec 19, 2008 at 11:15:42PM +0000, Adrian McMenamin wrote: > > > > Add support for the SEGA Dreamcast Maple controller as a joystick > > > > > > [snip] > > > > > > > + struct dc_pad *pad = maple_get_drvdata(mapledev); > > > > + struct input_dev *dev = pad->dev; > > > > + unsigned char *res = mq->recvbuf; > > > > + > > > > + buttons = ~cpu_to_le16(*(unsigned short *)(res + 8)); > > > > + > > > > > > I may be wrong but shouldn't this use the I/O accessor functions? > > > > It's not iomemory, so I don't think so. The maple bus writes to a buffer > > in the physical RAM. > > > > Hmm, but why we are going _from_ cpu order to le16??? I'd expect we > wanted to do conversion the other way around. I pulled it out of 'next' > for now. > The data is transmitted here by the bus in 32 bit little endian blocks but makes sense in le16 bit lumps. Off is 1 and on is 0 - hence the ~
The first 16 bits are the button data the next 16 bits are the (start of) the axis data. Both cpu and bus data (in this case - it can vary) are little endian.
| |