korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2025-01-08 23:04:35 +08:00
Code Issues Packages Projects Releases Wiki Activity

bindings: fsl-imx-sdma: Document 'fsl,sdma-event-remap' property

Browse Source 
Document the 'fsl,sdma-event-remap' property and provide an example of
its usage.

Cc: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This commit is contained in:
Fabio Estevam 2016-04-01 20:52:16 -03:00 committed by Shawn Guo
parent 88b53b9c1f
commit 3883dd74f0
1 changed files with 27 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt
View File

@ -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 shift val>.
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@83fb0000 {
@ -83,3 +92,21 @@ ssi2: ssi@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.