acpi_device: Add support for writing ACPI I2C descriptors

Hardware / Coreboot - Duncan Laurie [chromium.org] - 27 May 2016 20:47 UTC

Add required definitions to describe an ACPI I2C bus and a method to write the I2cSerialBus() descriptor to the SSDT.

This will be used by device drivers to describe their I2C resources to the OS. The devicetree i2c device can supply the address and 7 or 10 bit mode as well as indicate the GPIO controller device, and the bus speed can be fixed or configured by the driver.

chip.h: struct drivers_i2c_generic_config { enum i2c_speed bus_speed; };

generic.c:
void acpi_fill_ssdt_generator(struct device *dev) { struct drivers_i2c_generic_config *config = dev->chip_info; struct acpi_i2c i2c = { .address = dev->path->i2c.device, .mode_10bit = dev->path.i2c.mode_10bit, .speed = config->bus_speed ? : I2C_SPEED_FAST, .resource = acpi_device_path(dev->bus->dev) };

acpi_device_write_i2c(&i2c);

}

devicetree.cb: device pci 15.0 on chip drivers/i2c/generic device i2c 10.0 on end end end

SSDT.dsl: I2cSerialBus (0x10, ControllerInitiated, 400000, AddressingMode7Bit, "\\_SB.PCI0.I2C0", 0, ResourceConsumer)

Change-Id: I598401ac81a92c72f19da0271af1e218580a6c49

1010b4a acpi_device: Add support for writing ACPI I2C descriptors
src/arch/x86/acpi_device.c | 58 +++++++++++++++++++++++++++++++
src/arch/x86/include/arch/acpi_device.h | 27 ++++++++++++++
src/include/device/i2c.h | 13 +++++++
3 files changed, 98 insertions(+)

Upstream: review.coreboot.org

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