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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Tue, 25 Jan 2022 18:54:46 +0100
Message-ID: <CAJZ5v0gt+aDr_Te_mco_0CyRJAWgyeDKUb+dksfZz0mj91G0hw@mail.gmail.com>
Subject: Re: [PATCH v4 2/3] docs: firmware-guide: ACPI: Add named interrupt doc
To:     Akhil R <akhilrajeev@nvidia.com>
Cc:     =?UTF-8?Q?Uwe_Kleine=2DK=C3=B6nig?= 
        <u.kleine-koenig@pengutronix.de>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        Dmitry Osipenko <digetx@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jon Hunter <jonathanh@nvidia.com>,
        Laxman Dewangan <ldewangan@nvidia.com>,
        Len Brown <lenb@kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
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        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-tegra <linux-tegra@vger.kernel.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
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        Thierry Reding <thierry.reding@gmail.com>,
        Wolfram Sang <wsa@kernel.org>
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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
>