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authorAkhil R <akhilrajeev@nvidia.com>2022-01-28 14:44:26 +0300
committerWolfram Sang <wsa@kernel.org>2022-01-28 23:56:09 +0300
commit20e8ef5c7ffaa4c1d5f65727c536ffaf37078d5f (patch)
tree9d97e4fef78351d2e8118045e97329b4e5088f46 /Documentation/firmware-guide
parentca0acb511c21738b32386ce0f85c284b351d919e (diff)
downloadlinux-20e8ef5c7ffaa4c1d5f65727c536ffaf37078d5f.tar.xz
docs: firmware-guide: ACPI: Add named interrupt doc
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>
Diffstat (limited to 'Documentation/firmware-guide')
-rw-r--r--Documentation/firmware-guide/acpi/enumeration.rst39
1 files changed, 39 insertions, 0 deletions
diff --git a/Documentation/firmware-guide/acpi/enumeration.rst b/Documentation/firmware-guide/acpi/enumeration.rst
index 74b830b2fd59..d0022567c022 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
======================