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[86.177.159.74]) by mx.google.com with ESMTPSA id ch6sm61135254wjc.3.2015.02.24.09.34.34 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 24 Feb 2015 09:34:35 -0800 (PST) From: Lee Jones To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: lee.jones@linaro.org, kernel@stlinux.com, mturquette@linaro.org, sboyd@codeaurora.org, devicetree@vger.kernel.org Subject: [PATCH v3 4/4] clk: dt: Introduce always-on clock domain documentation Date: Tue, 24 Feb 2015 17:33:42 +0000 Message-Id: <1424799222-9301-5-git-send-email-lee.jones@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1424799222-9301-1-git-send-email-lee.jones@linaro.org> References: <1424799222-9301-1-git-send-email-lee.jones@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: list List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: lee.jones@linaro.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.217.172 as permitted sender) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , Signed-off-by: Lee Jones --- .../devicetree/bindings/clock/clk-always-on.txt | 35 ++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/clk-always-on.txt diff --git a/Documentation/devicetree/bindings/clock/clk-always-on.txt b/Documentation/devicetree/bindings/clock/clk-always-on.txt new file mode 100644 index 0000000..d61eaca --- /dev/null +++ b/Documentation/devicetree/bindings/clock/clk-always-on.txt @@ -0,0 +1,35 @@ +Always-on Clock Domain + +Some hardware contains bunches of clocks which must never be turned +off. If drivers a) fail to obtain a reference to any of these or b) +give up a previously obtained reference during suspend, the common clk +framework will attempt to disable them and the hardware can fail +irrecoverably. Usually the only way to recover from these failures is +to restart. + +To avoid either of these two scenarios from catastrophically disabling +an otherwise perfectly healthy running system, an always-on clock +domain has been provided. In this implementation clocks are consumed +and references are taken, thus preventing them from being shut down by +the framework. + +This binding is not to be abused. It is only to be used to protect +platforms from being crippled by gated clocks, not as a convenience +function to avoid using clk_disable_unused. + +We use the generic clock bindings found in: + Documentation/devicetree/bindings/clock/clock-bindings.txt + +Required properties: +- compatible : Must be "clk-always-on" + +Example: + +icn { + compatible = "clk-always-on"; + clocks = <&clk_s_c0_flexgen CLK_ICN_SBC>, + <&clk_s_c0_flexgen CLK_ICN_LMI>, + <&clk_s_c0_flexgen CLK_ICN_CPU>, + <&clk_s_c0_flexgen CLK_TX_ICN_DMU>, + <&clk_s_a0_flexgen CLK_IC_LMI0>, +};