• Lan Tianyu's avatar
    I2C/ACPI: Add i2c ACPI operation region support · 5d98e61d
    Lan Tianyu authored
    ACPI 5.0 spec(5.5.2.4.5) defines GenericSerialBus(i2c, spi, uart) operation region.
    It allows ACPI aml code able to access such kind of devices to implement
    some ACPI standard method.
    
    ACPI Spec defines some access attribute to associate with i2c protocol.
    AttribQuick 	       	       		Read/Write Quick Protocol
    AttribSendReceive			Send/Receive Byte Protocol
    AttribByte 			 	Read/Write Byte Protocol
    AttribWord				Read/Write Word Protocol
    AttribBlock				Read/Write Block Protocol
    AttribBytes				Read/Write N-Bytes Protocol
    AttribProcessCall			Process Call Protocol
    AttribBlockProcessCall			Write Block-Read Block Process Call Protocol
    AttribRawBytes 				Raw Read/Write N-BytesProtocol
    AttribRawProcessBytes			Raw Process Call Protocol
    
    On the Asus T100TA, Bios use GenericSerialBus operation region to access
    i2c device to get battery info.
    
    Sample code From Asus T100TA
    
        Scope (_SB.I2C1)
        {
            Name (UMPC, ResourceTemplate ()
            {
                I2cSerialBus (0x0066, ControllerInitiated, 0x00061A80,
                    AddressingMode7Bit, "\\_SB.I2C1",
                    0x00, ResourceConsumer, ,
                    )
            })
    
    	...
    
            OperationRegion (DVUM, GenericSerialBus, Zero, 0x0100)
            Field (DVUM, BufferAcc, NoLock, Preserve)
            {
                Connection (UMPC),
                Offset (0x81),
                AccessAs (BufferAcc, AttribBytes (0x3E)),
                FGC0,   8
            }
    	...
         }
    
         Device (BATC)
         {
             Name (_HID, EisaId ("PNP0C0A"))  // _HID: Hardware ID
             Name (_UID, One)  // _UID: Unique ID
    	 ...
    
                Method (_BST, 0, NotSerialized)  // _BST: Battery Status
                {
                    If (LEqual (AVBL, One))
                    {
                        Store (FGC0, BFFG)
                        If (LNotEqual (STAT, One))
                        {
                            ShiftRight (CHST, 0x04, Local0)
                            And (Local0, 0x03, Local0)
                            If (LOr (LEqual (Local0, One), LEqual (Local0, 0x02)))
                            {
                                Store (0x02, Local1)
                            }
    	...
    
        }
    
    The i2c operation region is defined under I2C1 scope. _BST method under
    battery device BATC read battery status from the field "FCG0". The request
    would be sent to i2c operation region handler.
    
    This patch is to add i2c ACPI operation region support. Due to there are
    only "Byte" and "Bytes" protocol access on the Asus T100TA, other protocols
    have not been tested.
    
    About RawBytes and RawProcessBytes protocol, they needs specific drivers to interpret
    reference data from AML code according ACPI 5.0 SPEC(5.5.2.4.5.3.9 and 5.5.2.4.5.3.10).
    So far, not found such case and will add when find real case.
    Signed-off-by: default avatarLan Tianyu <tianyu.lan@intel.com>
    Reviewed-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
    Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
    5d98e61d
Makefile 458 Bytes