21a097aedc
This adds a generic I2C driver that can be described in the devicetree
and used to generate ACPI objects in the SSDT based on the information
provided in the config registers.
The I2C bus can be configured and the device can provide an interrupt and
wake capability to the OS. A configuration option allows for a GPIO to
be provided that will be checked to determine if the device is preset on
the board before including it in the generated SSDT.
The driver is generic enough to be used for basic I2C devices that do
not have special configuration needs such as touchpads, touchscreens,
sensors, some audio codec/amplifiers, etc.
Sample usage for a touchpad device:
device pci 15.1 on
chip drivers/i2c/generic
register "hid" = ""ELAN0000""
register "desc" = "ELAN Touchpad"
register "irq" = "IRQ_EDGE_LOW(GPP_B3_IRQ)"
register "wake" = "GPE0_DW0_05"
device i2c 15.0 on end
end
end
Will result in the following code in the SSDT:
Scope (\_SB.PCI0.I2C1) {
Device (D015) {
Name (_HID, "ELAN0000")
Name (_UID, 0)
Name (_S0W, 4)
Name (_PRW, Package () { 5, 3 })
Method (_STA) { Return (0x0f) }
Name (_CRS, ResourceTemplate () {
I2cSerialBus (0x15, ControllerInitiated, 400000, AddressingMode7Bit,
"\\_S.PCI0.I2C1", 0, ResourceConsumer)
Interrupt (ResourceConsumer, Edge, ActiveLow) { 51 }
})
}
}
Change-Id: Ib32055720835b70e91ede5e4028ecd91894d70d5
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/15016
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
16 lines
524 B
C
16 lines
524 B
C
#include <arch/acpi_device.h>
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#include <device/i2c.h>
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struct drivers_i2c_generic_config {
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const char *hid; /* ACPI _HID (required) */
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const char *name; /* ACPI Device Name */
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const char *desc; /* Device Description */
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unsigned uid; /* ACPI _UID */
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enum i2c_speed speed; /* Bus speed in Hz, default is I2C_SPEED_FAST */
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unsigned wake; /* Wake GPE */
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struct acpi_irq irq; /* Interrupt */
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/* GPIO used to indicate if this device is present */
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unsigned device_present_gpio;
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unsigned device_present_gpio_invert;
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};
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