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Tue, 28 Jul 2026 13:03:17 -0700 (PDT) From: Abraham Zukor To: Jon Hunter , Mark Brown , Laxman Dewangan Cc: Thierry Reding , linux-spi@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] spi: tegra114: initialize native chip selects inactive Date: Tue, 28 Jul 2026 13:03:12 -0700 Message-ID: <20260728200316.1363536-1-abe@maticrobots.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <9c196ab1-1945-49fc-a89a-5588d1e50046@nvidia.com> References: <20260725042944.1204409-1-abe@maticrobots.com> <20260728025503.162543-1-abe@maticrobots.com> <9c196ab1-1945-49fc-a89a-5588d1e50046@nvidia.com> Precedence: bulk X-Mailing-List: linux-tegra@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7bit On 28/07/2026 10:34, Jon Hunter wrote: > Exactly. That's my point. Which is the right one? The answer is > probably neither, but whatever is present on the bus. I think that defaulting to active-low is correct. The Tegra234 SPI controller hardware defaults to active-low (all bits in CS_POL_INACTIVE are set) so an active-high device is already asserted before this driver initializes. I checked the controller drivers under drivers/spi/; they either default to active-low or preserve the hardware default. A more complex option is to scan the device tree children, check each item for whether it uses native chip select (as opposed to GPIO CS) and check for spi-cs-high. I found no other spi drivers that do this at probe time, and I don't think it's worth the complexity, but I can send it as a v2 if needed. Thanks, Abe