Thread (58 messages) 58 messages, 7 authors, 2020-02-26

Re: [RFC 04/25] spi: gpio: Implement LSB First bitbang support

From: Andreas Färber <afaerber@suse.de>
Date: 2019-12-12 21:08:28
Also in: linux-leds, linux-spi, lkml

Am 12.12.19 um 18:19 schrieb Mark Brown:
On Thu, Dec 12, 2019 at 04:14:59PM +0100, Andreas Färber wrote:
quoted
Am 12.12.19 um 09:40 schrieb Geert Uytterhoeven:
quoted
On Thu, Dec 12, 2019 at 4:41 AM Andreas Färber [off-list ref] wrote:
quoted
Add support for slave DT property spi-lsb-first, i.e., SPI_LSB_FIRST mode.
quoted
quoted
quoted
Duplicate the inline helpers bitbang_txrx_be_cpha{0,1} as LE versions.
Make checkpatch.pl happy by changing "unsigned" to "unsigned int".
Separate patch for this?
For the checkpatch cleanup? Or helpers preparation vs. spi-gpio.c usage?
quoted
So from that angle I don't see a better way than either duplicating the
functions or using some macro magic to #include the header twice. If we
wanted to go down that path, we could probably de-duplicate the existing
two functions, too, but I was trying to err on the cautious side, since
I don't have setups to test all four code paths myself (and a ton of
more relevant but less fun patches to flush out ;)).
Yeah, I don't think there's any great options here with the potential
performance issues - probably the nicest thing would be to autogenerate
lots of variants but I think that's far more trouble than it's worth.
Maybe add another code comment to revisit that idea later then?

Thanks,
Andreas

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