From mboxrd@z Thu Jan 1 00:00:00 1970 From: swarren@wwwdotorg.org (Stephen Warren) Date: Mon, 16 Sep 2013 10:34:28 -0600 Subject: [PATCH] clk: si570: Add a driver for SI570 oscillators In-Reply-To: <1379033737-30015-2-git-send-email-soren.brinkmann@xilinx.com> References: <1379033737-30015-1-git-send-email-soren.brinkmann@xilinx.com> <1379033737-30015-2-git-send-email-soren.brinkmann@xilinx.com> Message-ID: <52373314.5070806@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 09/12/2013 06:55 PM, Soren Brinkmann wrote: > Add a driver for SILabs 570, 571, 598, 599 programmable oscillators. > The devices generate low-jitter clock signals and are reprogrammable via > an I2C interface. > diff --git a/Documentation/devicetree/bindings/clock/silabs,si570.txt b/Documentation/devicetree/bindings/clock/silabs,si570.txt > +Required properties: > + - compatible: Shall be one of "silabs,si57x", "silabs,si59x". > + - reg: I2C device address. > + - #clock-cells: From common clock bindings: Shall be 0. > + - factory-fout: Factory set default frequency So, there's no way to query this from the device at all? Looking at the data-sheet, all the frequency generation parameters are in registers, and the device supports I2C read commands. As such, I'm not convinced this property is necessary. > +Optional properties: > + - initial-fout: Initial output frequency to set during probe "probe" is a Linux-specific concept. This property should be removed. If the driver is asked to set a specific frequency, it should do so, but I don't think it should program something pro-actively just because it starts up. If this property is acceptable, it'd be better to describe it more along the lines of the following: initial-fout: The frequency at which the system requires the clock to operate. > + - temperature-stability-7ppm: Indicate a device with a temperature stability > + of 7ppm > + > +Example: > + si570: clock-generator at 5d { > + #clock-cells = <0>; > + compatible = "silabs,si570"; > + reg = <0x5d>; > + factory-fout = <156250000>; > + }; From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH] clk: si570: Add a driver for SI570 oscillators Date: Mon, 16 Sep 2013 10:34:28 -0600 Message-ID: <52373314.5070806@wwwdotorg.org> References: <1379033737-30015-1-git-send-email-soren.brinkmann@xilinx.com> <1379033737-30015-2-git-send-email-soren.brinkmann@xilinx.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1379033737-30015-2-git-send-email-soren.brinkmann@xilinx.com> Sender: linux-doc-owner@vger.kernel.org To: Soren Brinkmann Cc: Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Rob Landley , Mike Turquette , Grant Likely , Guenter Roeck , devicetree@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Hyun Kwon List-Id: devicetree@vger.kernel.org On 09/12/2013 06:55 PM, Soren Brinkmann wrote: > Add a driver for SILabs 570, 571, 598, 599 programmable oscillators. > The devices generate low-jitter clock signals and are reprogrammable via > an I2C interface. > diff --git a/Documentation/devicetree/bindings/clock/silabs,si570.txt b/Documentation/devicetree/bindings/clock/silabs,si570.txt > +Required properties: > + - compatible: Shall be one of "silabs,si57x", "silabs,si59x". > + - reg: I2C device address. > + - #clock-cells: From common clock bindings: Shall be 0. > + - factory-fout: Factory set default frequency So, there's no way to query this from the device at all? Looking at the data-sheet, all the frequency generation parameters are in registers, and the device supports I2C read commands. As such, I'm not convinced this property is necessary. > +Optional properties: > + - initial-fout: Initial output frequency to set during probe "probe" is a Linux-specific concept. This property should be removed. If the driver is asked to set a specific frequency, it should do so, but I don't think it should program something pro-actively just because it starts up. If this property is acceptable, it'd be better to describe it more along the lines of the following: initial-fout: The frequency at which the system requires the clock to operate. > + - temperature-stability-7ppm: Indicate a device with a temperature stability > + of 7ppm > + > +Example: > + si570: clock-generator@5d { > + #clock-cells = <0>; > + compatible = "silabs,si570"; > + reg = <0x5d>; > + factory-fout = <156250000>; > + };