Re: [PATCH] Add Dallas DS1390 RTC chip

From: David Brownell
Date: Fri Oct 17 2008 - 11:29:36 EST

On Friday 17 October 2008, Mark Jackson wrote:
> >> +    /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
> >> +    xfer.tx_buf = chip->tx_buf;
> >> +    xfer.rx_buf = chip->rx_buf;
> >
> >  you use the same buffer a few functions below. either
> >  one way or the other. please investigate with the spi subsystem maintainer.
> David,
> Just to double check (as per Alessandro's suggestion), is this okay use of the
> spi buffers ?

Yes. That comment deserves to be updated.

SPI does bi-directional I/O, and the underlying controller
should be able to just replace the contents of a buffer
with a spi_transfer that uses the same rx and tx buffers.

- Dave
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