Hi, On Mon, Dec 10, 2012 at 01:23:09PM +0000, Jack Mitchell wrote: > Hi, > > I am currently having issues with the SPI driver on the beaglebone > using the 3.7-rc8 kernel[1]. I have probed the SPI pins and I have > found that writing works however reading doesn't. When using DMA the > program seems to lock hard and no data is sent on the bus. I am > testing the bus using spidev and the spidev_test[2] application, > however I first came across spi issues with a custom spi driver which > stopped working when I transitioned from 3.2-psp to 3.7-rc8. > > The current output I am seeing from the spidev_test program is just a > series of 0x00 data, which looks to me like no data is getting in at > all. The spidev_test program is not using DMA as the buffer size is > too low, so I forced the dma on when buffer size is > 1 and the > program hangs hard with the system still responding to other > commands.I have briged the pins 18 and 21 on the BeagleBone P9 > header. > > Has anyone seen issues like this, or if not if someone could please > test the latest 3.7-rc8 from [1] and let me know if it works for them > and the issue is at my end. > > To get spidev working with devicetree I applied the patch from [3] > and changed the dtb as in the patch pasted below. > > [1] https://github.com/beagleboard/kernel/tree/3.7 > [2] http://lxr.linux.no/#linux+v3.6.9/Documentation/spi/spidev_test.c > [3] http://www.mail-archive.com/spi-devel-general@xxxxxxxxxxxxxxxxxxxxx/msg09958.html do you have any debugging output from that driver ? It would be cool to see if DMA is at least being kicked properly for small transfers. It would also be nice to have a clear picture of what "custom spi driver" you're talking about. cheers -- balbi
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