From 5d98e61d337c181f199a6cb864569cc4e116ef4c Mon Sep 17 00:00:00 2001 From: Lan Tianyu Date: Tue, 20 May 2014 20:59:23 +0800 Subject: I2C/ACPI: Add i2c ACPI operation region support 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 Reviewed-by: Mika Westerberg Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux/i2c.h') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index b556e0ab946f..f7a939a2cb56 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -577,4 +577,14 @@ static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node } #endif /* CONFIG_OF */ +#ifdef CONFIG_ACPI +int acpi_i2c_install_space_handler(struct i2c_adapter *adapter); +void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter); +#else +static inline void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter) +{ } +static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter) +{ return 0; } +#endif + #endif /* _LINUX_I2C_H */ -- cgit v1.2.3