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[93.144.20.233]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4873061ef41sm168098415e9.3.2026.03.30.01.15.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2026 01:15:37 -0700 (PDT) Date: Mon, 30 Mar 2026 10:15:35 +0200 From: Stefano Radaelli To: Frank Li Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, pierluigi.p@variscite.com, Stefano Radaelli , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam Subject: Re: [PATCH v1 1/1] arm64: dts: imx91-var-dart-sonata: add RGB select supply for PCA6408 Message-ID: References: <20260327163243.17334-1-stefano.r@variscite.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hi Frank, On Fri, Mar 27, 2026 at 02:41:21PM -0400, Frank Li wrote: > > Accroding to signal name, it is MUX chip select signal. Of couse it may > connect to a buffer's EN pin. I have not checked your schematic. > > If it connect to MUX chip or some select signal, it should use above method, > even though it is permanently asserted when access PCA6408. > > If it connect to EN pin of buffer, regualtor should be good. > Yes, it is exactly the second case! It's just an EN pin, that enables a buffer to route RGB signals used on the DART-MX91 som only. That's why I think regulator is the right way for this case. Best Regards, Stefano