Re: [PATCH 2/4] spi: gpio: Fix reading for 3WIRE

[Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>]

> On Tue, Sep 04, 2018 at 11:49:49PM +0200, Linus Walleij wrote:
> 
> > So remains to add two new permutations:
> > bitbang_txrx_be_3wire_cpha[0|1]() and double the
> > code in spi-bitbang-txrx.h. Not good for maintenance.
> 
> > So damned if I do, damned if I don't.
> 
> > But I guess I go for the latter approach?
> 
> Yes, I think so - there's obviously a lot of overhead from bitbanging
> this stuff so it's worth it to try to minimize it.

Hi Linus and Mark,

maybe here we can move flags definition in spi_bitbang_bufs routine, e.g:

-	return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t, 0);
+
+	if (spi->master->flags & (SPI_MASTER_NO_TX | SPI_MASTER_NO_RX))
+		return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t,
+				     spi->master->flags);
+	else
+		return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t, 0);

in this way we can unify spi_gpio_txrx_word_mode{0-3}/spi_gpio_spec_txrx_word_mode{0-3} definitions
in spi-gpio.c and other drivers in the future can use this optimization. What
do you think? Are there any side affects with that approach?

Regards,
Lorenzo