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-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>;
- };