| Message ID | 1398147855-9868-8-git-send-email-tianyu.lan@intel.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Tue, Apr 22, 2014 at 02:24:13PM +0800, Lan Tianyu wrote: > diff --git a/drivers/i2c/i2c-acpi.c b/drivers/i2c/i2c-acpi.c > new file mode 100644 > index 0000000..942abdf > --- /dev/null > +++ b/drivers/i2c/i2c-acpi.c > @@ -0,0 +1,282 @@ > +/* > + * I2C ACPI code > + * > + * Copyright (C) 2014 Intel Corp > + * > + * Author: Lan Tianyu <tianyu.lan@intel.com> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY > + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License > + * for more details. > + */ > +#define pr_fmt(fmt) "I2C/ACPI : " fmt > + > +#include <linux/kernel.h> > +#include <linux/errno.h> > +#include <linux/err.h> > +#include <linux/i2c.h> > +#include <linux/acpi.h> > + > +struct acpi_i2c_handler_data { > + struct acpi_connection_info info; > + struct i2c_adapter *adapter; > +} __packed; Why __packed? > + > +struct gsb_buffer { > + u8 status; > + u8 len; > + union { > + u16 wdata; > + u8 bdata; > + u8 data[0]; > + }; > +} __packed; > + > +static int acpi_gsb_i2c_read_bytes(struct i2c_client *client, > + u8 cmd, u8 *data, u8 data_len) > +{ > + > + struct i2c_msg msgs[2]; > + int ret; > + u8 *buffer; You seem to have two spaces here. > + > + buffer = kzalloc(data_len, GFP_KERNEL); > + if (!buffer) > + return AE_NO_MEMORY; > + > + msgs[0].addr = client->addr; > + msgs[0].flags = client->flags; > + msgs[0].len = 1; > + msgs[0].buf = &cmd; > + > + msgs[1].addr = client->addr; > + msgs[1].flags = client->flags | I2C_M_RD; > + msgs[1].len = data_len; > + msgs[1].buf = buffer; > + > + ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); > + if (ret < 0) > + pr_err("i2c read failed\n"); > + else > + memcpy(data, buffer, data_len); > + > + kfree(buffer); > + return ret; > +} > + > +static int acpi_gsb_i2c_write_bytes(struct i2c_client *client, > + u8 cmd, u8 *data, u8 data_len) > +{ > + > + struct i2c_msg msgs[1]; > + u8 *buffer; Ditto. > + int ret = AE_OK; > + > + buffer = kzalloc(data_len + 1, GFP_KERNEL); > + if (!buffer) > + return AE_NO_MEMORY; > + > + buffer[0] = cmd; > + memcpy(buffer + 1, data, data_len); > + > + msgs[0].addr = client->addr; > + msgs[0].flags = client->flags; > + msgs[0].len = data_len + 1; > + msgs[0].buf = buffer; > + > + ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); > + if (ret < 0) > + pr_err("i2c write failed\n"); Since you have pointer to the adapter, can't you use dev_err() instead? > + > + kfree(buffer); > + return ret; > +} > + > +static acpi_status > +acpi_i2c_space_handler(u32 function, acpi_physical_address command, > + u32 bits, u64 *value64, > + void *handler_context, void *region_context) > +{ > + struct gsb_buffer *gsb = (struct gsb_buffer *)value64; > + struct acpi_i2c_handler_data *data = handler_context; > + struct acpi_connection_info *info = &data->info; > + struct acpi_resource_i2c_serialbus *sb; > + struct i2c_adapter *adapter = data->adapter; > + struct i2c_client client; > + struct acpi_resource *ares; > + u32 accessor_type = function >> 16; > + u8 action = function & ACPI_IO_MASK; > + int status; > + > + acpi_buffer_to_resource(info->connection, info->length, &ares); > + if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) > + return AE_BAD_PARAMETER; > + > + sb = &ares->data.i2c_serial_bus; > + if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) > + return AE_BAD_PARAMETER; Do you leak the resource buffer here? > + > + client.adapter = adapter; > + client.addr = sb->slave_address; > + client.flags = 0; I'm not sure if this is the correct way to use struct i2c_client (allocating it from stack and passing forward to functions that might expect a real i2c_client structure). It has ->dev and all. I'm wondering if you can use i2c_transfer() and i2c_smbus_xfer() here instead, passing just the adapter pointer? > + > + if (sb->access_mode == ACPI_I2C_10BIT_MODE) > + client.flags |= I2C_CLIENT_TEN; > + > + switch (accessor_type) { > + case ACPI_GSB_ACCESS_ATTRIB_QUICK: > + if (action == ACPI_READ) > + status = i2c_smbus_quick_read(&client); > + else > + status = i2c_smbus_quick_write(&client); > + break; > + > + case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV: > + if (action == ACPI_READ) { > + status = i2c_smbus_read_byte(&client); > + if (status >= 0) { > + gsb->bdata = status; > + status = 0; > + } > + } else { > + status = i2c_smbus_write_byte(&client, gsb->bdata); > + } > + break; > + > + case ACPI_GSB_ACCESS_ATTRIB_BYTE: > + if (action == ACPI_READ) { > + status = i2c_smbus_read_byte_data(&client, command); > + if (status >= 0) { > + gsb->bdata = status; > + status = 0; > + } > + } else { > + status = i2c_smbus_write_byte_data(&client, command, > + gsb->bdata); > + } > + break; > + > + case ACPI_GSB_ACCESS_ATTRIB_WORD: > + if (action == ACPI_READ) { > + status = i2c_smbus_read_word_data(&client, command); > + if (status >= 0) { > + gsb->wdata = status; > + status = 0; > + } > + } else { > + status = i2c_smbus_write_word_data(&client, command, > + gsb->wdata); > + } > + break; > + > + case ACPI_GSB_ACCESS_ATTRIB_BLOCK: > + if (action == ACPI_READ) { > + status = i2c_smbus_read_block_data(&client, command, > + gsb->data); > + if (status >= 0) { > + gsb->len = status; > + status = 0; > + } > + } else { > + status = i2c_smbus_write_block_data(&client, command, > + gsb->len, gsb->data); > + } > + break; > + > + case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE: > + if (action == ACPI_READ) { > + status = acpi_gsb_i2c_read_bytes(&client, command, > + gsb->data, info->access_length); > + if (status > 0) > + status = 0; > + } else { > + status = acpi_gsb_i2c_write_bytes(&client, command, > + gsb->data, info->access_length); > + } > + break; > + > + case ACPI_GSB_ACCESS_ATTRIB_WORD_CALL: > + status = i2c_smbus_word_proc_call(&client, command, gsb->wdata); > + if (status >= 0) { > + gsb->wdata = status; > + status = 0; > + } > + break; > + > + case ACPI_GSB_ACCESS_ATTRIB_BLOCK_CALL: > + status = i2c_smbus_block_proc_call(&client, command, gsb->len, > + gsb->data); > + if (status > 0) { > + gsb->len = status; > + status = 0; > + } > + break; > + > + default: > + pr_info("protocl(0x%02x) is not supported.\n", accessor_type); protocl -> protocol > + return AE_BAD_PARAMETER; > + } > + > + gsb->status = status; > + return AE_OK; > +} -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Mika: Thanks a lot for your review. On 2014?04?22? 19:36, Mika Westerberg wrote: >> > + >> > + client.adapter = adapter; >> > + client.addr = sb->slave_address; >> > + client.flags = 0; > I'm not sure if this is the correct way to use struct i2c_client > (allocating it from stack and passing forward to functions that might > expect a real i2c_client structure). It has ->dev and all. I check all i2c_smbus_xxx helper functions and they are simple wrappers of i2c_smbus_xfer(). Only adapter, addr and flags of struct client are used in these functions. > > I'm wondering if you can use i2c_transfer() and i2c_smbus_xfer() here > instead, passing just the adapter pointer? > Yes, I can do that but this needs to copy all codes of i2c_smbus_xxx helper function in the i2c-core.c here. This seems duplicated?
On 2014?04?23? 15:28, Mika Westerberg wrote: > On Wed, Apr 23, 2014 at 09:53:21AM +0800, Lan Tianyu wrote: >> Hi Mika: >> Thanks a lot for your review. >> >> On 2014?04?22? 19:36, Mika Westerberg wrote: >>>>> + >>>>> + client.adapter = adapter; >>>>> + client.addr = sb->slave_address; >>>>> + client.flags = 0; >>> I'm not sure if this is the correct way to use struct i2c_client >>> (allocating it from stack and passing forward to functions that might >>> expect a real i2c_client structure). It has ->dev and all. >> >> I check all i2c_smbus_xxx helper functions and they are simple wrappers >> of i2c_smbus_xfer(). Only adapter, addr and flags of struct client are >> used in these functions. > > In that case I suppose it is OK to (ab)use the client structure like this. > > I think you still want to initialize the whole structure (unused fields > with zero) before passing it to the wrappers. > Ok. I will do that.
On Wed, Apr 23, 2014 at 09:53:21AM +0800, Lan Tianyu wrote: > Hi Mika: > Thanks a lot for your review. > > On 2014?04?22? 19:36, Mika Westerberg wrote: > >> > + > >> > + client.adapter = adapter; > >> > + client.addr = sb->slave_address; > >> > + client.flags = 0; > > I'm not sure if this is the correct way to use struct i2c_client > > (allocating it from stack and passing forward to functions that might > > expect a real i2c_client structure). It has ->dev and all. > > I check all i2c_smbus_xxx helper functions and they are simple wrappers > of i2c_smbus_xfer(). Only adapter, addr and flags of struct client are > used in these functions. In that case I suppose it is OK to (ab)use the client structure like this. I think you still want to initialize the whole structure (unused fields with zero) before passing it to the wrappers. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index 1722f50..80db307 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -2,8 +2,11 @@ # Makefile for the i2c core. # +i2ccore-y := i2c-core.o +i2ccore-$(CONFIG_ACPI) += i2c-acpi.o + obj-$(CONFIG_I2C_BOARDINFO) += i2c-boardinfo.o -obj-$(CONFIG_I2C) += i2c-core.o +obj-$(CONFIG_I2C) += i2ccore.o obj-$(CONFIG_I2C_SMBUS) += i2c-smbus.o obj-$(CONFIG_I2C_CHARDEV) += i2c-dev.o obj-$(CONFIG_I2C_MUX) += i2c-mux.o diff --git a/drivers/i2c/i2c-acpi.c b/drivers/i2c/i2c-acpi.c new file mode 100644 index 0000000..942abdf --- /dev/null +++ b/drivers/i2c/i2c-acpi.c @@ -0,0 +1,282 @@ +/* + * I2C ACPI code + * + * Copyright (C) 2014 Intel Corp + * + * Author: Lan Tianyu <tianyu.lan@intel.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + */ +#define pr_fmt(fmt) "I2C/ACPI : " fmt + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/acpi.h> + +struct acpi_i2c_handler_data { + struct acpi_connection_info info; + struct i2c_adapter *adapter; +} __packed; + +struct gsb_buffer { + u8 status; + u8 len; + union { + u16 wdata; + u8 bdata; + u8 data[0]; + }; +} __packed; + +static int acpi_gsb_i2c_read_bytes(struct i2c_client *client, + u8 cmd, u8 *data, u8 data_len) +{ + + struct i2c_msg msgs[2]; + int ret; + u8 *buffer; + + buffer = kzalloc(data_len, GFP_KERNEL); + if (!buffer) + return AE_NO_MEMORY; + + msgs[0].addr = client->addr; + msgs[0].flags = client->flags; + msgs[0].len = 1; + msgs[0].buf = &cmd; + + msgs[1].addr = client->addr; + msgs[1].flags = client->flags | I2C_M_RD; + msgs[1].len = data_len; + msgs[1].buf = buffer; + + ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); + if (ret < 0) + pr_err("i2c read failed\n"); + else + memcpy(data, buffer, data_len); + + kfree(buffer); + return ret; +} + +static int acpi_gsb_i2c_write_bytes(struct i2c_client *client, + u8 cmd, u8 *data, u8 data_len) +{ + + struct i2c_msg msgs[1]; + u8 *buffer; + int ret = AE_OK; + + buffer = kzalloc(data_len + 1, GFP_KERNEL); + if (!buffer) + return AE_NO_MEMORY; + + buffer[0] = cmd; + memcpy(buffer + 1, data, data_len); + + msgs[0].addr = client->addr; + msgs[0].flags = client->flags; + msgs[0].len = data_len + 1; + msgs[0].buf = buffer; + + ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); + if (ret < 0) + pr_err("i2c write failed\n"); + + kfree(buffer); + return ret; +} + +static acpi_status +acpi_i2c_space_handler(u32 function, acpi_physical_address command, + u32 bits, u64 *value64, + void *handler_context, void *region_context) +{ + struct gsb_buffer *gsb = (struct gsb_buffer *)value64; + struct acpi_i2c_handler_data *data = handler_context; + struct acpi_connection_info *info = &data->info; + struct acpi_resource_i2c_serialbus *sb; + struct i2c_adapter *adapter = data->adapter; + struct i2c_client client; + struct acpi_resource *ares; + u32 accessor_type = function >> 16; + u8 action = function & ACPI_IO_MASK; + int status; + + acpi_buffer_to_resource(info->connection, info->length, &ares); + if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) + return AE_BAD_PARAMETER; + + sb = &ares->data.i2c_serial_bus; + if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) + return AE_BAD_PARAMETER; + + client.adapter = adapter; + client.addr = sb->slave_address; + client.flags = 0; + + if (sb->access_mode == ACPI_I2C_10BIT_MODE) + client.flags |= I2C_CLIENT_TEN; + + switch (accessor_type) { + case ACPI_GSB_ACCESS_ATTRIB_QUICK: + if (action == ACPI_READ) + status = i2c_smbus_quick_read(&client); + else + status = i2c_smbus_quick_write(&client); + break; + + case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV: + if (action == ACPI_READ) { + status = i2c_smbus_read_byte(&client); + if (status >= 0) { + gsb->bdata = status; + status = 0; + } + } else { + status = i2c_smbus_write_byte(&client, gsb->bdata); + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_BYTE: + if (action == ACPI_READ) { + status = i2c_smbus_read_byte_data(&client, command); + if (status >= 0) { + gsb->bdata = status; + status = 0; + } + } else { + status = i2c_smbus_write_byte_data(&client, command, + gsb->bdata); + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_WORD: + if (action == ACPI_READ) { + status = i2c_smbus_read_word_data(&client, command); + if (status >= 0) { + gsb->wdata = status; + status = 0; + } + } else { + status = i2c_smbus_write_word_data(&client, command, + gsb->wdata); + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_BLOCK: + if (action == ACPI_READ) { + status = i2c_smbus_read_block_data(&client, command, + gsb->data); + if (status >= 0) { + gsb->len = status; + status = 0; + } + } else { + status = i2c_smbus_write_block_data(&client, command, + gsb->len, gsb->data); + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE: + if (action == ACPI_READ) { + status = acpi_gsb_i2c_read_bytes(&client, command, + gsb->data, info->access_length); + if (status > 0) + status = 0; + } else { + status = acpi_gsb_i2c_write_bytes(&client, command, + gsb->data, info->access_length); + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_WORD_CALL: + status = i2c_smbus_word_proc_call(&client, command, gsb->wdata); + if (status >= 0) { + gsb->wdata = status; + status = 0; + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_BLOCK_CALL: + status = i2c_smbus_block_proc_call(&client, command, gsb->len, + gsb->data); + if (status > 0) { + gsb->len = status; + status = 0; + } + break; + + default: + pr_info("protocl(0x%02x) is not supported.\n", accessor_type); + return AE_BAD_PARAMETER; + } + + gsb->status = status; + return AE_OK; +} + + +int acpi_i2c_install_space_handler(struct i2c_adapter *adapter) +{ + acpi_handle handle = ACPI_HANDLE(adapter->dev.parent); + struct acpi_i2c_handler_data *data; + acpi_status status; + + if (!handle) + return -ENODEV; + + data = kzalloc(sizeof(struct acpi_i2c_handler_data), + GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->adapter = adapter; + status = acpi_bus_attach_private_data(handle, (void *)data); + if (ACPI_FAILURE(status)) { + kfree(data); + return -ENOMEM; + } + + status = acpi_install_address_space_handler(handle, + ACPI_ADR_SPACE_GSBUS, + &acpi_i2c_space_handler, + NULL, + data); + if (ACPI_FAILURE(status)) { + pr_err("Error installing i2c space handler\n"); + acpi_bus_attach_private_data(handle, NULL); + kfree(data); + return -ENOMEM; + } + + return 0; +} + +void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter) +{ + acpi_handle handle = ACPI_HANDLE(adapter->dev.parent); + struct acpi_i2c_handler_data *data; + acpi_status status; + + if (!handle) + return; + + acpi_remove_address_space_handler(handle, + ACPI_ADR_SPACE_GSBUS, + &acpi_i2c_space_handler); + + status = acpi_bus_get_private_data(handle, (void **)&data); + if (ACPI_SUCCESS(status)) + kfree(data); +} diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 638befd..bb9dc56 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1293,6 +1293,7 @@ exit_recovery: /* create pre-declared device nodes */ of_i2c_register_devices(adap); acpi_i2c_register_devices(adap); + acpi_i2c_install_space_handler(adap); if (adap->nr < __i2c_first_dynamic_bus_num) i2c_scan_static_board_info(adap); @@ -1466,6 +1467,7 @@ void i2c_del_adapter(struct i2c_adapter *adap) return; } + acpi_i2c_remove_space_handler(adap); /* Tell drivers about this removal */ mutex_lock(&core_lock); bus_for_each_drv(&i2c_bus_type, NULL, adap, diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 7a8f2cd..ea53b9b 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -361,6 +361,17 @@ extern bool osc_sb_apei_support_acked; #define OSC_PCI_EXPRESS_CAPABILITY_CONTROL 0x00000010 #define OSC_PCI_CONTROL_MASKS 0x0000001f +#define ACPI_GSB_ACCESS_ATTRIB_QUICK 0x00000002 +#define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV 0x00000004 +#define ACPI_GSB_ACCESS_ATTRIB_BYTE 0x00000006 +#define ACPI_GSB_ACCESS_ATTRIB_WORD 0x00000008 +#define ACPI_GSB_ACCESS_ATTRIB_BLOCK 0x0000000A +#define ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE 0x0000000B +#define ACPI_GSB_ACCESS_ATTRIB_WORD_CALL 0x0000000C +#define ACPI_GSB_ACCESS_ATTRIB_BLOCK_CALL 0x0000000D +#define ACPI_GSB_ACCESS_ATTRIB_RAW_BYTES 0x0000000E +#define ACPI_GSB_ACCESS_ATTRIB_RAW_PROCESS 0x0000000F + extern acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 724440a..681e689 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -583,4 +583,14 @@ 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 */
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@intel.com> --- drivers/i2c/Makefile | 5 +- drivers/i2c/i2c-acpi.c | 282 +++++++++++++++++++++++++++++++++++++++++++++++++ drivers/i2c/i2c-core.c | 2 + include/linux/acpi.h | 11 ++ include/linux/i2c.h | 10 ++ 5 files changed, 309 insertions(+), 1 deletion(-) create mode 100644 drivers/i2c/i2c-acpi.c