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From: Robert Richter <rrichter@amd.com>
To: Masahiro Yamada <masahiroy@kernel.org>,
	Michal Marek <michal.lkml@markovi.net>,
	Jonathan Corbet <corbet@lwn.net>
Cc: Robert Richter <rrichter@amd.com>,
	linux-kbuild@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v3] Documentation/kbuild: Document the kconfig choice default value
Date: Mon, 19 Jul 2021 22:28:44 +0200	[thread overview]
Message-ID: <20210719202844.18281-1-rrichter@amd.com> (raw)
In-Reply-To: <YPXeqUV+22sxXS9y@rric.localdomain>

Document how choice defaults are determined:

Default of a choice is its first visible choice element unless it is
explicitly set by the 'default' property [1]. Choice elements do not
support default attributes. [2]

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/kconfig/symbol.c?h=v5.14-rc1#n245
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/kconfig/menu.c?h=v5.14-rc1#n494

Signed-off-by: Robert Richter <rrichter@amd.com>
---
v3: Fix base of v2 (rebased onto v5.14-rc2)
v2: clarification on 'default' attribute of a choice
    added example
---
 Documentation/kbuild/kconfig-language.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst
index 98c24183d8c3..d919dde0bcbf 100644
--- a/Documentation/kbuild/kconfig-language.rst
+++ b/Documentation/kbuild/kconfig-language.rst
@@ -417,6 +417,21 @@ definitions of that choice. If a [symbol] is associated to the choice,
 then you may define the same choice (i.e. with the same entries) in another
 place.
 
+The default value of a choice is set to the first visible choice
+element unless it is explicitly set by the 'default' property.
+
+Note:
+	Choice options do not support the 'default' attribute.
+
+E.g.::
+
+  choice
+	default C1
+  config C0
+  config C1
+	# no default attribute here
+  endchoice
+
 comment::
 
 	"comment" <prompt>
-- 
2.29.2


  reply	other threads:[~2021-07-19 20:59 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-15  9:26 [PATCH] ACPI: Kconfig: Fix table override from built-in initrd Robert Richter
2021-07-15  9:26 ` [PATCH] Documentation: Fix intiramfs script name Robert Richter
2021-07-18 13:58   ` Masahiro Yamada
2021-07-15  9:26 ` [PATCH] Documentation/kbuild: Document the kconfig choice default value Robert Richter
2021-07-18  9:36   ` Masahiro Yamada
2021-07-19  9:16     ` [PATCH v2] " Robert Richter
2021-07-19 20:20       ` Robert Richter
2021-07-19 20:28         ` Robert Richter [this message]
2021-08-05 12:47           ` [PATCH v3] " Masahiro Yamada
2021-07-16 17:29 ` [PATCH] ACPI: Kconfig: Fix table override from built-in initrd Rafael J. Wysocki

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