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docs: firmware-guide: ACPI: Add named interrupt doc

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Add a detailed example of the named interrupts in the ACPI table.

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
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Akhil R 2022-01-28 17:14:26 +05:30 committed by Wolfram Sang
parent ca0acb511c
commit 20e8ef5c7f
1 changed files with 39 additions and 0 deletions
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39
Documentation/firmware-guide/acpi/enumeration.rst
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@ -143,6 +143,45 @@ In robust cases the client unfortunately needs to call
acpi_dma_request_slave_chan_by_index() directly and therefore choose the
specific FixedDMA resource by its index.
Named Interrupts
================
Drivers enumerated via ACPI can have names to interrupts in the ACPI table
which can be used to get the IRQ number in the driver.
The interrupt name can be listed in _DSD as 'interrupt-names'. The names
should be listed as an array of strings which will map to the Interrupt()
resource in the ACPI table corresponding to its index.
The table below shows an example of its usage::
Device (DEV0) {
...
Name (_CRS, ResourceTemplate() {
...
Interrupt (ResourceConsumer, Level, ActiveHigh, Exclusive) {
0x20,
0x24
}
})
Name (_DSD, Package () {
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package () {
Package () {"interrupt-names",
Package (2) {"default", "alert"}},
}
...
})
}
The interrupt name 'default' will correspond to 0x20 in Interrupt()
resource and 'alert' to 0x24. Note that only the Interrupt() resource
is mapped and not GpioInt() or similar.
The driver can call the function - fwnode_irq_get_byname() with the fwnode
and interrupt name as arguments to get the corresponding IRQ number.
SPI serial bus support
======================