From: Peter Robinson pbrobinson@gmail.com
[ Upstream commit 1d99f92f71b6b4b2eee776562c991428490f71ef ]
The BRCMSTB and BRCMSTB_RESCAL reset drivers are also used in the BCM2712, AKA the RPi5. The RPi platforms have typically used the ARCH_BCM2835, and the PCIe support for this SoC can use this config which depends on these drivers so enable building them when just that arch option is enabled to ensure the platform works as expected.
Signed-off-by: Peter Robinson pbrobinson@gmail.com Acked-by: Florian Fainelli florian.fainelli@broadcom.com Link: https://lore.kernel.org/r/20250630175301.846082-1-pbrobinson@gmail.com Signed-off-by: Philipp Zabel p.zabel@pengutronix.de Signed-off-by: Sasha Levin sashal@kernel.org ---
LLM Generated explanations, may be completely bogus:
**Backport Status: YES**
This commit should be backported to stable kernel trees. Here's my extensive analysis:
## Analysis of the Commit
### 1. **Nature of the Change** The commit makes a simple Kconfig dependency update to enable two existing reset controller drivers (`RESET_BRCMSTB` and `RESET_BRCMSTB_RESCAL`) for the `ARCH_BCM2835` platform. The changes are: - Lines 54-55: Adds `ARCH_BCM2835` to the depends and default lines for `RESET_BRCMSTB` - Lines 63-64: Adds `ARCH_BCM2835` to the depends and default lines for `RESET_BRCMSTB_RESCAL` - Line 67: Updates the help text to mention BCM2712 alongside BCM7216
### 2. **This is a Bug Fix** This commit fixes a configuration bug where the Raspberry Pi 5 (BCM2712) platform, which uses `ARCH_BCM2835`, cannot properly enable critical reset controllers needed for PCIe functionality. Without this fix, users building kernels for RPi5 with just `ARCH_BCM2835` enabled would have non-functional PCIe support.
### 3. **Minimal and Contained Change** The commit is extremely minimal - it only modifies 6 lines in a single Kconfig file. It doesn't touch any C code, doesn't change any logic, and only updates build configuration dependencies. This is the ideal type of change for stable backporting.
### 4. **No Side Effects** The change has no negative side effects: - It only enables building existing drivers for an additional platform - The drivers themselves are already tested and working (used by BRCMSTB platforms) - The change is additive - it doesn't remove or modify existing functionality - No API/ABI changes
### 5. **Platform-Specific Fix** While the change is platform-specific (Raspberry Pi 5/BCM2712), it's important because: - RPi platforms are widely used - PCIe support is critical functionality - The fix enables existing, tested code to be built for a platform that needs it
### 6. **Clear Hardware Support Issue** From the commit message, this addresses a real hardware support issue where the BCM2712 (RPi5) SoC reuses the same reset controller IP blocks as other Broadcom STB SoCs but couldn't enable them due to missing Kconfig dependencies.
### 7. **Low Risk** The risk of regression is essentially zero because: - Only affects kernel builds that explicitly enable `ARCH_BCM2835` - Doesn't change behavior for existing platforms - The drivers being enabled are mature and already in use
### 8. **Follows Stable Rules** This perfectly fits the stable kernel criteria: - Fixes a real bug (missing hardware support) - Obviously correct (just adding platform to existing dependency) - Small change (6 lines) - Already tested (has Acked-by from Broadcom maintainer)
The commit enables essential functionality (PCIe support via reset controllers) for a popular platform (Raspberry Pi 5) through a minimal, risk-free configuration change. This is exactly the type of fix that should be backported to ensure stable kernels properly support current hardware.
drivers/reset/Kconfig | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig index 2a52c990d4fe..c561a93af655 100644 --- a/drivers/reset/Kconfig +++ b/drivers/reset/Kconfig @@ -51,8 +51,8 @@ config RESET_BERLIN
config RESET_BRCMSTB tristate "Broadcom STB reset controller" - depends on ARCH_BRCMSTB || COMPILE_TEST - default ARCH_BRCMSTB + depends on ARCH_BRCMSTB || ARCH_BCM2835 || COMPILE_TEST + default ARCH_BRCMSTB || ARCH_BCM2835 help This enables the reset controller driver for Broadcom STB SoCs using a SUN_TOP_CTRL_SW_INIT style controller. @@ -60,11 +60,11 @@ config RESET_BRCMSTB config RESET_BRCMSTB_RESCAL tristate "Broadcom STB RESCAL reset controller" depends on HAS_IOMEM - depends on ARCH_BRCMSTB || COMPILE_TEST - default ARCH_BRCMSTB + depends on ARCH_BRCMSTB || ARCH_BCM2835 || COMPILE_TEST + default ARCH_BRCMSTB || ARCH_BCM2835 help This enables the RESCAL reset controller for SATA, PCIe0, or PCIe1 on - BCM7216. + BCM7216 or the BCM2712.
config RESET_HSDK bool "Synopsys HSDK Reset Driver"