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i2c: core: Add new i2c_acpi_new_device helper function 

By default the i2c subsys creates an i2c-client for the first I2cSerialBus
resource of an acpi_device, but some acpi_devices have multiple
I2cSerialBus resources and we may want to instantiate i2c-clients for
the others.

This commit adds a new i2c_acpi_new_device function which can be used to
create an i2c-client for any I2cSerialBus resource of an acpi_device.

Note that the other resources may even be on a different i2c bus, so just
retrieving the client address is not enough.

Here is an example DSDT excerpt from such a device:

Device (WIDR)
{
    Name (_HID, "INT33FE" /* XPOWER Battery Device */)
    Name (_CID, "INT33FE" /* XPOWER Battery Device */)
    Name (_DDN, "WC PMIC Battery Device")
<snip>
    Name (RBUF, ResourceTemplate ()
    {
        I2cSerialBusV2 (0x005E, ControllerInitiated, 0x000186A0,
            AddressingMode7Bit, "\\_SB.PCI0.I2C7",
            0x00, ResourceConsumer, , Exclusive,
            )
        I2cSerialBusV2 (0x0036, ControllerInitiated, 0x000186A0,
            AddressingMode7Bit, "\\_SB.PCI0.I2C1",
            0x00, ResourceConsumer, , Exclusive,
            )
        I2cSerialBusV2 (0x0022, ControllerInitiated, 0x00061A80,
            AddressingMode7Bit, "\\_SB.PCI0.I2C1",
            0x00, ResourceConsumer, , Exclusive,
            )
        I2cSerialBusV2 (0x0054, ControllerInitiated, 0x00061A80,
            AddressingMode7Bit, "\\_SB.PCI0.I2C1",
            0x00, ResourceConsumer, , Exclusive,
            )
        GpioInt (Level, ActiveLow, Exclusive, PullNone, 0x0000,
            "\\_SB.PCI0.I2C7.PMI5", 0x00, ResourceConsumer, ,
            )
            {   // Pin list
        0x0012
            }
        GpioInt (Edge, ActiveLow, ExclusiveAndWake, PullNone, 0x0000,
            "\\_SB.GPO1", 0x00, ResourceConsumer, ,
            )
            {   // Pin list
        0x0005
            }
        GpioInt (Level, ActiveLow, Exclusive, PullNone, 0x0000,
            "\\_SB.PCI0.I2C7.PMI5", 0x00, ResourceConsumer, ,
            )
            {   // Pin list
        0x0013
            }
    })
    Method (_CRS, 0, NotSerialized)  // _CRS: Current Resource Settings
    {
        Return (RBUF) /* \_SB_.PCI0.I2C7.WIDR.RBUF */
    }
<snip>
}

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Hans de Goede 2017-04-05 00:03:33 +02:00 committed by Wolfram Sang
parent 417f784379
commit 605f8fc224
2 changed files with 56 additions and 0 deletions
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49
drivers/i2c/i2c-core.c
View File

@ -421,6 +421,55 @@ static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
static struct notifier_block i2c_acpi_notifier = {
.notifier_call = i2c_acpi_notify,
};
/**
* i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
* @dev: Device owning the ACPI resources to get the client from
* @index: Index of ACPI resource to get
* @info: describes the I2C device; note this is modified (addr gets set)
* Context: can sleep
*
* By default the i2c subsys creates an i2c-client for the first I2cSerialBus
* resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
* resources, in that case this function can be used to create an i2c-client
* for other I2cSerialBus resources in the Current Resource Settings table.
*
* Also see i2c_new_device, which this function calls to create the i2c-client.
*
* Returns a pointer to the new i2c-client, or NULL if the adapter is not found.
*/
struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
struct i2c_board_info *info)
{
struct i2c_acpi_lookup lookup;
struct i2c_adapter *adapter;
struct acpi_device *adev;
LIST_HEAD(resource_list);
int ret;
adev = ACPI_COMPANION(dev);
if (!adev)
return NULL;
memset(&lookup, 0, sizeof(lookup));
lookup.info = info;
lookup.device_handle = acpi_device_handle(adev);
lookup.index = index;
ret = acpi_dev_get_resources(adev, &resource_list,
i2c_acpi_fill_info, &lookup);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0 || !info->addr)
return NULL;
adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
if (!adapter)
return NULL;
return i2c_new_device(adapter, info);
}
EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
#else /* CONFIG_ACPI */
static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
extern struct notifier_block i2c_acpi_notifier;

7
include/linux/i2c.h
View File

@ -824,11 +824,18 @@ static inline const struct of_device_id
#if IS_ENABLED(CONFIG_ACPI)
u32 i2c_acpi_find_bus_speed(struct device *dev);
struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
struct i2c_board_info *info);
#else
static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
{
return 0;
}
static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
int index, struct i2c_board_info *info)
{
return NULL;
}
#endif /* CONFIG_ACPI */
#endif /* _LINUX_I2C_H */