[PATCH v2 0/2] Enable sysfs module symlink for more built-in drivers

[Shashank Balaji]

struct device_driver's mod_name is not set by a number of bus' driver registration
functions. Without that, built-in drivers don't have the module symlink in sysfs.
We want this to go from unbound driver name -> module name -> kernel config name.
This is useful on embedded platforms to minimize kernel config, reduce kernel size,
and reduce boot time.

In order to achieve this, mod_name has to be set to KBUILD_MODNAME, and this has
to be done for all buses which don't yet do this.

Here are some treewide stats:
- 110 registration functions across all bus types
- 20 of them set mod_name
- Remaining 90 do not set mod_name:
    1. 36 functions under pattern 1:
        They have a __register function + register macro. KBUILD_MODNAME needs to
        be passed and the function needs to take mod_name as input.
    2. 42 functions under pattern 2:
        These have no macro wrapper. They need a double-underscore rename + macro
        wrapper to make them similar to pattern 1.
    3. Remaining 12 do not have such a clean registration interface. More analysis
       is required.

We plan to start with pattern 1, since it's the easiest category of changes.
Within that, for now we're only sending the platform patch. If we get the go-ahead
on that, we'll send the remaining ones.

Patch 2 depends on patch 1, without which arm64 defconfig fails to boot with
patch 2.

Co-developed-by: Rahul Bukte <rahul.bukte at sony.com>
Signed-off-by: Rahul Bukte <rahul.bukte at sony.com>
Signed-off-by: Shashank Balaji <shashank.mahadasyam at sony.com>
---
Changes in v2:
- Drop acpi patch, send platform instead (Rafael)
- Link to v1: https://patch.msgid.link/20260416-acpi_mod_name-v1-0-1a4d96fd86c9@sony.com

To: Kay Sievers <kay.sievers at vrfy.org>
To: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
To: "Rafael J. Wysocki" <rafael at kernel.org>
To: Danilo Krummrich <dakr at kernel.org>
To: Suzuki K Poulose <suzuki.poulose at arm.com>
To: Mike Leach <mike.leach at linaro.org>
To: James Clark <james.clark at linaro.org>
To: Alexander Shishkin <alexander.shishkin at linux.intel.com>
To: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
To: Alexandre Torgue <alexandre.torgue at foss.st.com>
To: Miguel Ojeda <ojeda at kernel.org>
To: Boqun Feng <boqun at kernel.org>
To: Gary Guo <gary at garyguo.net>
To: Björn Roy Baron <bjorn3_gh at protonmail.com>
To: Benno Lossin <lossin at kernel.org>
To: Andreas Hindborg <a.hindborg at kernel.org>
To: Alice Ryhl <aliceryhl at google.com>
To: Trevor Gross <tmgross at umich.edu>
To: Richard Cochran <richardcochran at gmail.com>
To: Jonathan Corbet <corbet at lwn.net>
To: Shuah Khan <skhan at linuxfoundation.org>
Cc: linux-kernel at vger.kernel.org
Cc: driver-core at lists.linux.dev
Cc: coresight at lists.linaro.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: rust-for-linux at vger.kernel.org
Cc: linux-doc at vger.kernel.org

---
Shashank Balaji (2):
      kernel: param: handle NULL module_kset in lookup_or_create_module_kobject()
      driver core: platform: set mod_name in driver registration

 Documentation/driver-api/driver-model/platform.rst |  3 ++-
 drivers/base/platform.c                            | 21 ++++++++++++++-------
 drivers/hwtracing/coresight/coresight-catu.c       |  3 ++-
 drivers/hwtracing/coresight/coresight-core.c       |  5 +++--
 drivers/hwtracing/coresight/coresight-cpu-debug.c  |  2 +-
 drivers/hwtracing/coresight/coresight-funnel.c     |  2 +-
 drivers/hwtracing/coresight/coresight-replicator.c |  2 +-
 drivers/hwtracing/coresight/coresight-stm.c        |  3 ++-
 drivers/hwtracing/coresight/coresight-tmc-core.c   |  3 ++-
 drivers/hwtracing/coresight/coresight-tnoc.c       |  3 ++-
 drivers/hwtracing/coresight/coresight-tpdm.c       |  2 +-
 drivers/hwtracing/coresight/coresight-tpiu.c       |  3 ++-
 include/linux/coresight.h                          |  3 ++-
 include/linux/platform_device.h                    | 17 +++++++++--------
 kernel/params.c                                    |  3 +++
 rust/kernel/platform.rs                            |  4 +++-
 16 files changed, 50 insertions(+), 29 deletions(-)
---
base-commit: b4e07588e743c989499ca24d49e752c074924a9a
change-id: 20260416-acpi_mod_name-f645a76e337b

Best regards,
--  
Shashank Balaji <shashank.mahadasyam at sony.com>