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Thu, 6 Aug 2026 13:31:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786023077; bh=Y0AD+yfRRB8kFuS3umG0hhMkgfqhZmRwgX2ATJd2Akg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=hJTV5ehoIEF8y7Kgco+X0NK8DYm3FHIb5dwVRUwRJ+mDkIY67nsnTkvehjQzkyyOE +lU0FGL1ltpTL5CrMMW5U/tDWHoyh6M2NA48HP662X36/fOLJ4+d5+Q4aq3USy6AxH jr/gGrVQkNanDlcErJfMkiKmeNFK0mBr4gAbfG2WrInh7LbSdlW8JhZtT4oAZGVHPv SmNcAUbJTJ/7JUHNGXIIhiPOzEkoGNYMl0YB+1AFQREPucGLLpdar0eSPnma2ZuwdJ txnNntcMTSk6DP5HprY8bQtNAHroh8k6MbILqDlN8MN6TBWGUpLBWQkQ4RRVsA/sb1 rildWmczV4maA== Date: Thu, 6 Aug 2026 14:31:11 +0100 From: Lee Jones To: Yu-Che Hsieh Cc: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Joel Stanley , Andrew Jeffery , Chia-Wei Wang , Corey Minyard , Andrew Jeffery , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org, openipmi-developer@lists.sourceforge.net Subject: Re: [PATCH RFC 1/2] dt-bindings: mfd: aspeed-lpc: Document lpcN alias for multi-instance SoCs Message-ID: <20260806133111.GF2869284@google.com> References: <20260723-upstream_kcs_multiple_lpc-v1-0-d918b5270b86@aspeedtech.com> <20260723-upstream_kcs_multiple_lpc-v1-1-d918b5270b86@aspeedtech.com> X-Mailing-List: linux-aspeed@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260723-upstream_kcs_multiple_lpc-v1-1-d918b5270b86@aspeedtech.com> On Thu, 23 Jul 2026, Yu-Che Hsieh wrote: > Some SoCs (e.g. AST2700) expose more than one physical LPC controller > instance. Downstream devices such as KCS channels need a stable, > globally-unique index derived from which LPC controller instance they > belong to, so document the "lpcN" alias convention on the LPC > controller node that lets DT authors assign a fixed index per > instance, mirroring the existing alias-based numbering convention used > by mmc/i2c/spi/serial. > > Signed-off-by: Yu-Che Hsieh Why is this RFC? What's stopping me from applying this now? > --- > Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml b/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml > index cbc3a2485a2f..81c12e0fb312 100644 > --- a/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml > +++ b/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml > @@ -35,6 +35,13 @@ description: > configuration, therefore the host portion of the controller is exposed as a > syscon as a means to arbitrate access. > > + On SoCs that expose more than one LPC controller instance, it is possible to > + assign a fixed index to a given instance (and thus to downstream devices > + such as KCS channels that must be uniquely identified system-wide) by > + defining an "lpcN" alias for it in the /aliases device tree node. If no such > + alias is present, the SoC is treated as having a single LPC controller > + instance. > + > properties: > compatible: > items: > > -- > 2.34.1 > -- Lee Jones