Re: [PATCH v4 2/3] docs: firmware-guide: ACPI: Add named interrupt doc

Rafael J. Wysocki
2022-01-25T17:57:12Z

On Sat, Jan 22, 2022 at 12:33 PM Akhil R <akhilrajeev@nvidia.com> wrote:
>
> Add a detailed example of the named interrupts in the ACPI table.
>
> Signed-off-by: Akhil R <akhilrajeev@nvidia.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> ---
> Documentation/firmware-guide/acpi/enumeration.rst | 39 +++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/Documentation/firmware-guide/acpi/enumeration.rst b/Documentation/firmware-guide/acpi/enumeration.rst
> index 74b830b2..d002256 100644
> --- a/Documentation/firmware-guide/acpi/enumeration.rst
> +++ b/Documentation/firmware-guide/acpi/enumeration.rst
> @@ -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
> ======================
>
> --
> 2.7.4
>