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Diffstat (limited to 'Documentation/devicetree/bindings/spi/spi-sprd-adi.txt')
-rw-r--r-- | Documentation/devicetree/bindings/spi/spi-sprd-adi.txt | 63 |
1 files changed, 0 insertions, 63 deletions
diff --git a/Documentation/devicetree/bindings/spi/spi-sprd-adi.txt b/Documentation/devicetree/bindings/spi/spi-sprd-adi.txt deleted file mode 100644 index 2567c829e2dc..000000000000 --- a/Documentation/devicetree/bindings/spi/spi-sprd-adi.txt +++ /dev/null @@ -1,63 +0,0 @@ -Spreadtrum ADI controller - -ADI is the abbreviation of Anolog-Digital interface, which is used to access -analog chip (such as PMIC) from digital chip. ADI controller follows the SPI -framework for its hardware implementation is alike to SPI bus and its timing -is compatile to SPI timing. - -ADI controller has 50 channels including 2 software read/write channels and -48 hardware channels to access analog chip. For 2 software read/write channels, -users should set ADI registers to access analog chip. For hardware channels, -we can configure them to allow other hardware components to use it independently, -which means we can just link one analog chip address to one hardware channel, -then users can access the mapped analog chip address by this hardware channel -triggered by hardware components instead of ADI software channels. - -Thus we introduce one property named "sprd,hw-channels" to configure hardware -channels, the first value specifies the hardware channel id which is used to -transfer data triggered by hardware automatically, and the second value specifies -the analog chip address where user want to access by hardware components. - -Since we have multi-subsystems will use unique ADI to access analog chip, when -one system is reading/writing data by ADI software channels, that should be under -one hardware spinlock protection to prevent other systems from reading/writing -data by ADI software channels at the same time, or two parallel routine of setting -ADI registers will make ADI controller registers chaos to lead incorrect results. -Then we need one hardware spinlock to synchronize between the multiple subsystems. - -The new version ADI controller supplies multiple master channels for different -subsystem accessing, that means no need to add hardware spinlock to synchronize, -thus change the hardware spinlock support to be optional to keep backward -compatibility. - -Required properties: -- compatible: Should be "sprd,sc9860-adi". -- reg: Offset and length of ADI-SPI controller register space. -- #address-cells: Number of cells required to define a chip select address - on the ADI-SPI bus. Should be set to 1. -- #size-cells: Size of cells required to define a chip select address size - on the ADI-SPI bus. Should be set to 0. - -Optional properties: -- hwlocks: Reference to a phandle of a hwlock provider node. -- hwlock-names: Reference to hwlock name strings defined in the same order - as the hwlocks, should be "adi". -- sprd,hw-channels: This is an array of channel values up to 49 channels. - The first value specifies the hardware channel id which is used to - transfer data triggered by hardware automatically, and the second - value specifies the analog chip address where user want to access - by hardware components. - -SPI slave nodes must be children of the SPI controller node and can contain -properties described in Documentation/devicetree/bindings/spi/spi-bus.txt. - -Example: - adi_bus: spi@40030000 { - compatible = "sprd,sc9860-adi"; - reg = <0 0x40030000 0 0x10000>; - hwlocks = <&hwlock1 0>; - hwlock-names = "adi"; - #address-cells = <1>; - #size-cells = <0>; - sprd,hw-channels = <30 0x8c20>; - }; |