From mboxrd@z Thu Jan 1 00:00:00 1970 From: Naidu Tellapati Subject: [PATCH v6 4/4] DT: pdm: Add binding document for IMG PDM DAC Date: Fri, 28 Nov 2014 23:42:25 +0530 Message-ID: <1417198345-19633-5-git-send-email-Naidu.Tellapati@gmail.com> References: <1417198345-19633-1-git-send-email-Naidu.Tellapati@gmail.com> Return-path: In-Reply-To: <1417198345-19633-1-git-send-email-Naidu.Tellapati@gmail.com> Sender: linux-pwm-owner@vger.kernel.org To: thierry.reding@gmail.com, abrestic@chromium.org, gregkh@linuxfoundation.org, arnd@arndb.de, James.Hartley@imgtec.com, Ezequiel.Garcia@imgtec.com Cc: devicetree@vger.kernel.org, linux-pwm@vger.kernel.org, Arul.Ramasamy@imgtec.com, Sai.Masarapu@imgtec.com, Naidu Tellapati , Naidu Tellapati List-Id: devicetree@vger.kernel.org Add binding document for the Pulse Density Modulator (PDM) DAC present on the Pistachio SOC. Signed-off-by: Naidu Tellapati Signed-off-by: Arul Ramasamy --- Documentation/devicetree/bindings/misc/img-pdm.txt | 54 ++++++++++++++++++++ 1 files changed, 54 insertions(+), 0 deletions(-) create mode 100644 Documentation/devicetree/bindings/misc/img-pdm.txt diff --git a/Documentation/devicetree/bindings/misc/img-pdm.txt b/Documentation/devicetree/bindings/misc/img-pdm.txt new file mode 100644 index 0000000..a530f4b --- /dev/null +++ b/Documentation/devicetree/bindings/misc/img-pdm.txt @@ -0,0 +1,54 @@ +*Imagination Technologies Pulse Density Modulator (PDM) DAC. + +Required properties: +- compatible: Must be "img,pistachio-pdm" +- clocks: phandle to input PDM clock +- clock-names: Must include the following entry: + - pdm: input clock to pdm block. +- img,cr-periph: Must contain a phandle to the peripheral control + syscon node which contains PDM control registers. +- #pdm-cells: Must be 2. +- The first cell is the PDM channel number (valid values: 0, 1, 2, 3) +- The second cell is 12-bit pulse-in value + +Specifying PDM information for devices +====================================== + +1. PDM User nodes + +PDM properties should be named "pdms". The exact meaning of each pdms property +is described above. + + pdm-specifier : array of #pdm-cells specifying the given PDM + (controller specific) + +The following example could be used to describe a PDM-based backlight device: + + pdm: pdm { + #pdm-cells = <2>; + }; + + [...] + + bl: backlight { + pdms = <&pdm 2 0>; + }; + +pdm-specifier typically encodes the chip-relative PDM channel number and the +12-bit pulse-in value. + +2. PDM Controller nodes + +PDM controller nodes must specify the number of cells used for the specifier +using the '#pdm-cells' property. + +An example PDM controller might look like this: + +Example: + pdm: pdm@18148000 { + compatible = "img,pistachio-pdm"; + clocks = <&pdm_clk>; + clk-names = "pdm"; + img,cr-periph = <&cr_periph>; + #pdm-cells = <2>; + }; -- 1.7.0.4