On Tue, May 20, 2014 at 08:59:23PM +0800, Lan Tianyu wrote:
> 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: Lan Tianyu <tianyu.lan@xxxxxxxxx>
Added Mika's review tag and applied to for-next, thanks!
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