Messages in this thread | | | Date | Fri, 28 Sep 2018 09:18:33 +0200 | From | Boris Brezillon <> | Subject | Re: [PATCH 1/2] spi: spi-mem: Add the spi_set_xfer_bpw function |
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On Fri, 28 Sep 2018 06:59:58 +0000 Chuanhua Han <chuanhua.han@nxp.com> wrote:
> > > > It's still unclear why you need to specify a bits_per_word value, > > but if this is needed, it's probably something you want to add to > > spi.c, when a message is queued. > To specify a specific bits_per_word to be able to use the xspi > (32bit) mode of the fsl_dspi module to transfer data, you can look at > my PATCH 2/2. Do not add a value in spis.c that takes into account > that the value assigned to bits_per_word is decided before the > transfer. Thanks for your check and reply!
I might be wrong, but that's not my understanding of ->bits_per_word. To me, it's something that you can use when your *device* (not controller) expects non-byte aligned words [1]. The spi-mem protocol is definitely designed to work with 1byte large words, so, as I said, I suspect you're abusing xfer->bits_per_word to address a controller driver issue.
[1]https://elixir.bootlin.com/linux/latest/source/include/linux/spi/spi.h#L114
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