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From: Michal Wilczynski <michal.wilczynski@intel.com>
To: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	nvdimm@lists.linux.dev
Cc: rafael.j.wysocki@intel.com, andriy.shevchenko@intel.com,
	lenb@kernel.org, dan.j.williams@intel.com,
	vishal.l.verma@intel.com, ira.weiny@intel.com,
	rui.zhang@intel.com,
	Michal Wilczynski <michal.wilczynski@intel.com>,
	Elena Reshetova <elena.reshetova@intel.com>
Subject: [PATCH v1 2/9] docs: firmware-guide: ACPI: Clarify ACPI bus concepts
Date: Mon, 25 Sep 2023 17:48:35 +0300	[thread overview]
Message-ID: <20230925144842.586829-3-michal.wilczynski@intel.com> (raw)
In-Reply-To: <20230925144842.586829-1-michal.wilczynski@intel.com>

Some devices implement ACPI driver as a way to manage devices
enumerated by the ACPI. This might be confusing as a preferred way to
implement a driver for devices not connected to any bus is a platform
driver, as stated in the documentation. Clarify relationships between
ACPI device, platform device and ACPI entries.

Suggested-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
---
 Documentation/firmware-guide/acpi/enumeration.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/firmware-guide/acpi/enumeration.rst b/Documentation/firmware-guide/acpi/enumeration.rst
index 56d9913a3370..f56cc79a9e83 100644
--- a/Documentation/firmware-guide/acpi/enumeration.rst
+++ b/Documentation/firmware-guide/acpi/enumeration.rst
@@ -64,6 +64,19 @@ If the driver needs to perform more complex initialization like getting and
 configuring GPIOs it can get its ACPI handle and extract this information
 from ACPI tables.
 
+ACPI bus
+====================
+
+Historically some devices not connected to any bus were represented as ACPI
+devices, and had to implement ACPI driver. This is not a preferred way for new
+drivers. As explained above devices not connected to any bus should implement
+platform driver. ACPI device would be created during enumeration nonetheless,
+and would be accessible through ACPI_COMPANION() macro, and the ACPI handle would
+be accessible through ACPI_HANDLE() macro. ACPI device is meant to describe
+information related to ACPI entry e.g. handle of the ACPI entry. Think -
+ACPI device interfaces with the FW, and the platform device with the rest of
+the system.
+
 DMA support
 ===========
 
-- 
2.41.0


  parent reply	other threads:[~2023-09-25 14:49 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-25 14:48 [PATCH v1 0/9] Replace acpi_driver with platform_driver Michal Wilczynski
2023-09-25 14:48 ` [PATCH v1 1/9] ACPI: bus: Make notify wrappers more generic Michal Wilczynski
2023-10-04 19:09   ` Rafael J. Wysocki
2023-10-05  8:09     ` Wilczynski, Michal
2023-10-05 10:57       ` Rafael J. Wysocki
2023-10-05 12:05         ` Wilczynski, Michal
2023-10-05 15:30           ` Rafael J. Wysocki
2023-10-05 17:03             ` Rafael J. Wysocki
2023-10-05 18:27               ` Wilczynski, Michal
2023-10-05 18:29                 ` Rafael J. Wysocki
2023-09-25 14:48 ` Michal Wilczynski [this message]
2023-10-05 17:57   ` [PATCH v1 2/9] docs: firmware-guide: ACPI: Clarify ACPI bus concepts Rafael J. Wysocki
2023-10-05 18:28     ` Wilczynski, Michal
2023-10-05 18:58       ` Wilczynski, Michal
2023-10-06 15:36         ` Rafael J. Wysocki
2023-10-06 17:29           ` Wilczynski, Michal
2023-09-25 14:48 ` [PATCH v1 3/9] ACPI: AC: Remove unnecessary checks Michal Wilczynski
2023-09-25 14:48 ` [PATCH v1 4/9] ACPI: AC: Use string_choices API instead of ternary operator Michal Wilczynski
2023-09-25 14:48 ` [PATCH v1 5/9] ACPI: AC: Replace acpi_driver with platform_driver Michal Wilczynski
2023-09-25 14:48 ` [PATCH v1 6/9] ACPI: AC: Rename ACPI device from device to adev Michal Wilczynski
2023-09-25 14:48 ` [PATCH v1 7/9] ACPI: NFIT: Replace acpi_driver with platform_driver Michal Wilczynski
2023-09-25 14:48 ` [PATCH v1 8/9] ACPI: NFIT: Remove redundant call to to_acpi_dev() Michal Wilczynski
2023-09-25 14:48 ` [PATCH v1 9/9] ACPI: NFIT: Don't use KBUILD_MODNAME for driver name Michal Wilczynski
2023-09-25 15:47   ` Andy Shevchenko
2023-09-25 16:11     ` Dan Williams

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