From mboxrd@z Thu Jan 1 00:00:00 1970 From: naidu.tellapati@gmail.com Subject: [PATCH RESEND v4 4/4] DT: pdm: Add binding document for IMG PDM DAC Date: Sat, 22 Nov 2014 07:23:32 +0530 Message-ID: <1416621212-11701-5-git-send-email-Naidu.Tellapati@gmail.com> References: <1416621212-11701-1-git-send-email-Naidu.Tellapati@gmail.com> Return-path: In-Reply-To: <1416621212-11701-1-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: linux-pwm@vger.kernel.org, devicetree@vger.kernel.org, Arul.Ramasamy@imgtec.com, Sai.Masarapu@imgtec.com, Naidu Tellapati List-Id: devicetree@vger.kernel.org From: Naidu Tellapati 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..730d38a --- /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: Must contain an entry for each entry in clock-names. + - clock-names: Must include the following entry: + Required elements: "pdm" + - 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