From mboxrd@z Thu Jan 1 00:00:00 1970 From: festevam@gmail.com (Fabio Estevam) Date: Fri, 1 Apr 2016 20:52:16 -0300 Subject: [PATCH v2 3/4] fsl-imx-sdma.txt: Document 'fsl, sdma-event-remap' property In-Reply-To: <1459554737-19684-1-git-send-email-festevam@gmail.com> References: <1459554737-19684-1-git-send-email-festevam@gmail.com> Message-ID: <1459554737-19684-3-git-send-email-festevam@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Fabio Estevam Document the 'fsl,sdma-event-remap' property and provide an example of its usage. Cc: Vinod Koul Signed-off-by: Fabio Estevam --- Changes since v1: - Newly introduced in this series .../devicetree/bindings/dma/fsl-imx-sdma.txt | 27 ++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt b/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt index dc8d3aa..175f0e4 100644 --- a/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt +++ b/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt @@ -58,6 +58,15 @@ The third cell specifies the transfer priority as below. 1 Medium 2 Low +Optional properties: + +- gpr : The phandle to the General Purpose Register (GPR) node. +- fsl,sdma-event-remap : Register bits of sdma event remap, the format is + . + reg is the GPR register offset. + shift is the bit position inside the GPR register. + val is the value of the bit (0 or 1). + Examples: sdma at 83fb0000 { @@ -83,3 +92,21 @@ ssi2: ssi at 70014000 { dma-names = "rx", "tx"; fsl,fifo-depth = <15>; }; + +Using the fsl,sdma-event-remap property: + +If we want to use SDMA on the SAI1 port on a MX6SX: + +&sdma { + gpr = <&gpr>; + /* SDMA events remap for SAI1_RX and SAI1_TX */ + fsl,sdma-event-remap = <0 15 1>, <0 16 1>; +}; + +The fsl,sdma-event-remap property in this case has two values: +- <0 15 1> means that the offset is 0, so GPR0 is the register of the +SDMA remap. Bit 15 of GPR0 selects between UART4_RX and SAI1_RX. +Setting bit 15 to 1 selects SAI1_RX. +- <0 16 1> means that the offset is 0, so GPR0 is the register of the +SDMA remap. Bit 16 of GPR0 selects between UART4_TX and SAI1_TX. +Setting bit 16 to 1 selects SAI1_TX. -- 1.9.1