linux/Documentation/devicetree/bindings/dma/st_fdma.txt
Peter Griffin 897f419add dmaengine: st_fdma: Add STMicroelectronics FDMA DT binding documentation
This patch adds the DT binding documentation for the FDMA constroller
found on STi based chipsets from STMicroelectronics.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2016-10-18 20:12:05 +05:30

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* STMicroelectronics Flexible Direct Memory Access Device Tree bindings
The FDMA is a general-purpose direct memory access controller capable of
supporting 16 independent DMA channels. It accepts up to 32 DMA requests.
The FDMA is based on a Slim processor which requires a firmware.
* FDMA Controller
Required properties:
- compatible : Should be one of
- st,stih407-fdma-mpe31-11, "st,slim-rproc";
- st,stih407-fdma-mpe31-12, "st,slim-rproc";
- st,stih407-fdma-mpe31-13, "st,slim-rproc";
- reg : Should contain an entry for each name in reg-names
- reg-names : Must contain "slimcore", "dmem", "peripherals", "imem" entries
- interrupts : Should contain one interrupt shared by all channels
- dma-channels : Number of channels supported by the controller
- #dma-cells : Must be <3>. See DMA client section below
- clocks : Must contain an entry for each clock
See: Documentation/devicetree/bindings/clock/clock-bindings.txt
Example:
fdma0: dma-controller@8e20000 {
compatible = "st,stih407-fdma-mpe31-11", "st,slim-rproc";
reg = <0x8e20000 0x8000>,
<0x8e30000 0x3000>,
<0x8e37000 0x1000>,
<0x8e38000 0x8000>;
reg-names = "slimcore", "dmem", "peripherals", "imem";
clocks = <&clk_s_c0_flexgen CLK_FDMA>,
<&clk_s_c0_flexgen CLK_EXT2F_A9>,
<&clk_s_c0_flexgen CLK_EXT2F_A9>,
<&clk_s_c0_flexgen CLK_EXT2F_A9>;
interrupts = <GIC_SPI 5 IRQ_TYPE_NONE>;
dma-channels = <16>;
#dma-cells = <3>;
};
* DMA client
Required properties:
- dmas: Comma separated list of dma channel requests
- dma-names: Names of the aforementioned requested channels
Each dmas request consists of 4 cells:
1. A phandle pointing to the FDMA controller
2. The request line number
3. A 32bit mask specifying (see include/linux/platform_data/dma-st-fdma.h)
-bit 2-0: Holdoff value, dreq will be masked for
0x0: 0-0.5us
0x1: 0.5-1us
0x2: 1-1.5us
-bit 17: data swap
0x0: disabled
0x1: enabled
-bit 21: Increment Address
0x0: no address increment between transfers
0x1: increment address between transfers
-bit 22: 2 STBus Initiator Coprocessor interface
0x0: high priority port
0x1: low priority port
4. transfers type
0 free running
1 paced
Example:
sti_uni_player2: sti-uni-player@2 {
compatible = "st,sti-uni-player";
status = "disabled";
#sound-dai-cells = <0>;
st,syscfg = <&syscfg_core>;
clocks = <&clk_s_d0_flexgen CLK_PCM_2>;
assigned-clocks = <&clk_s_d0_flexgen CLK_PCM_2>;
assigned-clock-parents = <&clk_s_d0_quadfs 2>;
assigned-clock-rates = <50000000>;
reg = <0x8D82000 0x158>;
interrupts = <GIC_SPI 86 IRQ_TYPE_NONE>;
dmas = <&fdma0 4 0 1>;
dai-name = "Uni Player #1 (DAC)";
dma-names = "tx";
st,uniperiph-id = <2>;
st,version = <5>;
st,mode = "PCM";
};