Re: [PATCH] spi: tegra114: initialize native chip selects inactive

Jon Hunter <[email protected]> Tue, 28 Jul 2026 10:34:52 +0100
Newsgroups org.kernel.vger.linux-tegra,org.kernel.vger.linux-kernel,org.kernel.vger.linux-spi
Message-ID <[email protected]>

On 28/07/2026 03:53, Abraham Zukor wrote:
> On 27/07/2026 13:07, Jon Hunter wrote:
>> What about the case where the SPI devices CS is active high or a
>> mixture of the two?
> 
> An all-active-high bus is the case the window gets right today: probe
> writes zero to the field, so an active-high CS idles deasserted and an
> active-low one sits asserted. This patch inverts that. No single
> constant covers a mixed board - one polarity or the other is asserted
> until tegra_spi_setup() runs for that device - so the question is
> which default is the right one, and active low is what the SPI core
> assumes when a device says nothing.

Exactly. That's my point. Which is the right one? The answer is probably 
neither, but whatever is present on the bus.

-- 
nvpublic