Re: [PATCH 02/14] ARM : SAMSUNG : Add RS485 support.
Paul Schilling <paul.s.schilling <at> gmail.com>
2011-11-01 19:22:59 GMT
Sorry for the formatting mess on the previous email. Lets try
I need an opinion on two issues before I resubmit the Samsung
First of all the driver works. I have tested it on a logic analyser
and I found that it switches from transmit to receive in token
mode exactly after 1 bit of idle time as long as interrupts are kept
enabled and nothing tries to wait or sleep inside of an interrupt.
I found 2 maybe 3 places where this occurs up to 22 milliseconds.
The opinion part... I needed a timer to switch from transmit to
receive after the FIFO was empty. I started by using the low
resolution timer using jiffies first. I found that wasn't high enough
resolution, so I switched to the Linux HRT. Currently I have both
versions that can be selected by conditional compile. Should I
just remove the low resolution timer completely or leave it in.
Second, I have a chunk of code that if it could be made to work
could off load the receiving to DMA up to the last couple of bytes
then switch back to interrupts for the token byte. Should I leave
that code in a #if 0 statement or should I just delete it.
> On Tue, Nov 1, 2011 at 9:57 AM, Paul Schilling
> <paul.s.schilling <at> gmail.com> wrote:
>> I am working on resubmitting this stuff right now. I have 14 patches