firmware-guide/acpi/enumeration.rst

1 .. SPDX-License-Identifier: GPL-2.0
13 that are accessed through memory-mapped registers.
15 In order to support this and re-use the existing drivers as much as
18   - Devices that have no bus connector resource are represented as
21   - Devices behind real busses where there is a connector resource
34 This means that when ACPI_HANDLE(dev) returns non-NULL the device was
36 device-specific configuration. There is an example of this below.
43 for the device and add supported ACPI IDs. If this same IP-block is used on
44 some other non-ACPI platform, the driver might work out of the box or needs
151 The interrupt name can be listed in _DSD as 'interrupt-names'. The names
168             ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
170                 Package () { "interrupt-names", Package () { "default", "alert" } },
180 The driver can call the function - fwnode_irq_get_byname() with the fwnode
233 			ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
238 				Package () { "address-width", 16 },
244 APIs during ->probe() phase like::
254 	err = device_property_read_u32(dev, "address-width", &addr_width);
299             ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
301                 Package () { "compatible", Package () { "pwm-leds" } },
302                 Package () { "label", "alarm-led" },
316 In the above example the PWM-based LED driver references to the PWM channel 0
351 			ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
354 				Package () { "power-gpios", Package () { ^DEV, 0, 0, 0 } },
355 				Package () { "irq-gpios", Package () { ^DEV, 1, 0, 0 } },
366 Documentation/admin-guide/gpio/.
389 See Documentation/firmware-guide/acpi/gpio-properties.rst for more information
392 RS-485 support
395 ACPI _DSD (Device Specific Data) can be used to describe RS-485 capability
404 		// ACPI 5.1 _DSD used for RS-485 capabilities
407 			ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
410 				Package () {"rs485-rts-active-low", Zero},
411 				Package () {"rs485-rx-active-high", Zero},
412 				Package () {"rs485-rx-during-tx", Zero},
425   - The children share the parent ACPI handle.
426   - The MFD cell can specify the ACPI id of the device.
469 6.0).  For non-enumerable bus types that object must be _HID and its value must
473 existing DT-compatible device identification in ACPI and to satisfy the above
496 For example, the following ACPI sample might be used to enumerate an lm75-type
504 			ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
535 Refer to Documentation/firmware-guide/acpi/DSD-properties-rules.rst for more
545 in a fixed position (ethernet, Wi-Fi, serial ports, etc.). In this conditions it
555 16 GPIOs and we want to add the property ``gpio-line-names`` [1] to these pins.
574 	07:00.0 Serial controller: Exar Corp. XR17V3521 Dual PCIe UART (rev 03) <-- Exar
579 	-[0000:00]-+-00.0
581 	           +-13.0-[01]----00.0
582 	           +-13.1-[02]----00.0
583 	           +-13.2-[03]--
584 	           +-14.0-[04]----00.0
585 	           +-14.1-[05-09]----00.0-[06-09]--+-01.0-[07]----00.0 <-- Exar
586 	           |                               +-02.0-[08]----00.0
587 	           |                               \-03.0-[09]--
589 	           \-1f.1
594 	Bus: 0 - Device: 14 - Function: 1
602 	acpixtract -a acpidump
603 	iasl -e ssdt?.* -d dsdt.dat
649 						ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
654 								"gpio-line-names",
684 [1] Documentation/firmware-guide/acpi/gpio-properties.rst
686 [2] Documentation/admin-guide/acpi/initrd_table_override.rst
688 [3] ACPI Specifications, Version 6.3 - Paragraph 6.1.1 _ADR Address)
690     referenced 2020-11-18