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([178.197.219.137]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4247d0be9fasm141769465e9.16.2024.06.23.06.46.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 23 Jun 2024 06:46:08 -0700 (PDT) From: Krzysztof Kozlowski To: Lee Jones , Rob Herring , Krzysztof Kozlowski , Conor Dooley , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Krzysztof Kozlowski , Linus Walleij , Arnd Bergmann , Conor Dooley Subject: [PATCH v2] dt-bindings: mfd: Explain lack of child dependency in simple-mfd Date: Sun, 23 Jun 2024 15:46:00 +0200 Message-ID: <20240623134600.115098-1-krzysztof.kozlowski@linaro.org> X-Mailer: git-send-email 2.43.0 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="utf-8" Content-Transfer-Encoding: quoted-printable Common mistake of usage of 'simple-mfd' compatible is a dependency of children on resources acquired and managed by the parent, e.g. clocks. Extend the simple-mfd documentation to cover this case. Cc: Linus Walleij Cc: Arnd Bergmann Reviewed-by: Conor Dooley Signed-off-by: Krzysztof Kozlowski Reviewed-by: Rob Herring (Arm) --- Changes in v2: 1. Rephrase the paragraph, as discussed with Lee. 2. Add Rb=C2=A0tag. --- Documentation/devicetree/bindings/mfd/mfd.txt | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/Documentation/devicetree/bindings/mfd/mfd.txt b/Documentation/= devicetree/bindings/mfd/mfd.txt index 336c0495c8a3..b938fa26d2ce 100644 --- a/Documentation/devicetree/bindings/mfd/mfd.txt +++ b/Documentation/devicetree/bindings/mfd/mfd.txt @@ -17,13 +17,14 @@ A typical MFD can be: =20 Optional properties: =20 -- compatible : "simple-mfd" - this signifies that the operating system sho= uld - consider all subnodes of the MFD device as separate devices akin to how - "simple-bus" indicates when to see subnodes as children for a simple - memory-mapped bus. For more complex devices, when the nexus driver has to - probe registers to figure out what child devices exist etc, this should = not - be used. In the latter case the child devices will be determined by the - operating system. +- compatible : "simple-mfd" - this signifies that the operating system + should consider all subnodes of the MFD device as separate and independe= nt + devices, so not needing any resources to be provided by the parent devic= e. + Similarly to how "simple-bus" indicates when to see subnodes as children= for + a simple memory-mapped bus. + For more complex devices, when the nexus driver has to probe registers to + figure out what child devices exist etc, this should not be used. In the + latter case the child devices will be determined by the operating system. =20 - ranges: Describes the address mapping relationship to the parent. Should= set the child's base address to 0, the physical address within parent's addr= ess --=20 2.43.0