Documentation/process/maintainer-soc.rst

1 .. SPDX-License-Identifier: GPL-2.0
8 --------
10 The SoC subsystem is a place of aggregation for SoC-specific code.
13 * devicetrees for 32- & 64-bit ARM and RISC-V
14 * 32-bit ARM board files (arch/arm/mach*)
15 * 32- & 64-bit ARM defconfigs
16 * SoC-specific drivers across architectures, in particular for 32- & 64-bit
17   ARM, RISC-V and Loongarch
19 These "SoC-specific drivers" do not include clock, GPIO etc drivers that have
20 other top-level maintainers. The drivers/soc/ directory is generally meant
21 for kernel-internal drivers that are used by other drivers to provide SoC-
30 The main SoC tree is housed on git.kernel.org:
31   https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git/
47 alias soc@kernel.org if there is no platform-specific maintainer, or if they
50 What the SoC tree is not, however, is a location for architecture-specific code
55 ------------------------------------
61 Devicetree ABI Stability
64 Perhaps one of the most important things to highlight is that dt-bindings
65 document the ABI between the devicetree and the kernel.
66 Please read Documentation/devicetree/bindings/ABI.rst.
68 If changes are being made to a devicetree that are incompatible with old
69 kernels, the devicetree patch should not be applied until the driver is, or an
78 A common problem is synchronizing changes between device drivers and devicetree
83 corresponding change to the devicetree binding description, to ensure they are
84 in fact compatible.  This means that the devicetree branch can end up causing
85 warnings in the "make dtbs_check" step.  If a devicetree change depends on
86 missing additions to a header file in include/dt-bindings/, it will fail the
91 * Avoid defining custom macros in include/dt-bindings/ for hardware constants
92   that can be derived from a datasheet -- binding macros in header files should
95 * Use literal values in the devicetree file in place of macros even when a
99 * Defer the devicetree changes to a release after the binding and driver have
103   both the driver change and the devicetree changes
105 * Add duplicate defines in the devicetree file guarded by an #ifndef section,
108 Devicetree Naming Convention
111 The general naming scheme for devicetree files is as follows.  The aspects of a
114 from board to board, are described in $soc-$board.dts.  An example of this is
115 jh7100-beaglev-starlight.dts.  Often many boards are variations on a theme, and
116 frequently there are intermediate files, such as jh7100-common.dtsi, which sit
117 between the $soc.dtsi and $soc-$board.dts files, containing the descriptions of
121 integrated into several different boards. For these platforms, $soc-$som.dtsi
122 and $soc-$som-$board.dts are typical.
127 Validating Devicetree Files
130 ``make dtbs_check`` can be used to validate that devicetree files are compliant
131 with the dt-bindings that describe the ABI.  Please read the section
132 "Running checks" of Documentation/devicetree/bindings/writing-schema.rst for
136 add any new warnings.  For RISC-V and Samsung SoC, ``make dtbs_check W=1`` is
138 If in any doubt about a devicetree change, reach out to the devicetree
145 submaintainers will do the same. Driver, defconfig and devicetree changes should
150 Small sets of patches can also be sent as separate emails to soc@kernel.org,
154 top-level branches, e.g. for a treewide rework, or the addition of new SoC
159 SoC tree.  An example here would be one branch for devicetree warning fixes, one
167 While there is no cut-off time for late pull requests, it helps to only send
177 requests, please see Documentation/maintainer/pull-requests.rst.