On 21/03/17 18:05, Uwe Kleine-König wrote:
On Tue, Mar 21, 2017 at 12:05:20PM +1000, Greg Ungerer wrote:
On 20/03/17 23:22, Vladimir Zapolskiy wrote:
For that type of bindings locally I have a hackish spi-imx driver change,
which supports this option, but I'm unsure if it is universal enough.
Do you mean supporting no cs-gpios tag?
That would be nice, but it would seem not many users of this are
using native chip selects.
The reason for this is that the native chip selects are less flexible
than gpios because you cannot control when they deassert. IIRC they do
it too much for some chips. So the only reason to stick to them is that
on some SoCs not all pins have a GPIO function. Not sure if transfer
speed is another reason, but I would expect that the gain isn't that
big.
For the particular SPI device I am using, a Silicon Labs 32260,
it actually wants the assertion and de-assertion of the chip-select
between each byte. So it is the only way it can work for me.
Regards
Greg
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