Re: [PATCH 12/14] mfd: remove unused mcp-sa11x0/ucb1x00 driver

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] The commit deletes headers `<linux/platform_data/mfd-mcp-sa11x0.h>` and `<linux/mfd/ucb1x00.h>`, but the SA1100 platform still exists and relies on them, causing build errors.
- [Medium] Referencing a removed Kconfig symbol `MCP_UCB1200` leaves the `collie_battery` driver as orphaned dead code.
--

commit 3e512215b27ee60439f00d2cbf7fccc06602c45a
Author: Arnd Bergmann <arnd@arndb.de>
Subject: mfd: remove unused mcp-sa11x0/ucb1x00 driver

This commit removes the MCP and UCB1x00 MFD drivers, along with their associated platform data headers and Kconfig entries. The removal is based on the premise that the sa1100 platform has been removed and these drivers are no longer used anywhere.

> mfd: remove unused mcp-sa11x0/ucb1x00 driver
>
> The sa1100 platform has been removed, so these drivers are no longer
> used anywhere.

[Severity: High]
Is the sa1100 platform fully removed in this series? Looking at the tree,
arch/arm/mach-sa1100/assabet.c and arch/arm/mach-sa1100/collie.c still
exist and unconditionally include the headers deleted by this patch.

For example, arch/arm/mach-sa1100/assabet.c includes the headers and
instantiates the platform data:

#include <linux/platform_data/mfd-mcp-sa11x0.h>
...
static struct mcp_plat_data assabet_mcp_data = {
...

Since this commit deletes include/linux/mfd/ucb1x00.h and
include/linux/platform_data/mfd-mcp-sa11x0.h, does this cause a build
failure when compiling the assabet or collie boards?

[ ... ]

> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 8a3bbb6286933..0395af7270f9e 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -2258,30 +2258,6 @@ config MFD_QCOM_PM8008
>  	  under it in the device tree. Additional drivers must be enabled in
>  	  order to use the functionality of the device.
>  
> -menu "Multimedia Capabilities Port drivers"
> -	depends on ARCH_SA1100
> -
> -config MCP
> -	tristate
> -
> -# Interface drivers
> -config MCP_SA11X0
> -	tristate "Support SA11x0 MCP interface"
> -	depends on ARCH_SA1100
> -	select MCP
> -
> -# Chip drivers
> -config MCP_UCB1200
> -	tristate "Support for UCB1200 / UCB1300"
> -	depends on MCP_SA11X0
> -	select MCP
> -
> -config MCP_UCB1200_TS
> -	tristate "Touchscreen interface support"
> -	depends on MCP_UCB1200 && INPUT
> -
> -endmenu
> -
>  config MFD_VEXPRESS_SYSREG
>  	tristate "Versatile Express System Registers"
>  	depends on VEXPRESS_CONFIG && GPIOLIB

[Severity: Medium]
Does removing the MCP_UCB1200 config symbol leave the collie_battery
driver as orphaned dead code?

Looking at drivers/power/supply/Kconfig, BATTERY_COLLIE depends on
SA1100_COLLIE && MCP_UCB1200. Furthermore,
drivers/power/supply/collie_battery.c still includes the now-deleted
include/linux/mfd/ucb1x00.h header.

If this Kconfig symbol is removed without cleaning up the power supply
subsystem, it causes an unmet dependency warning and leaves the battery
driver unselectable.

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260909132153.1596191-1-arnd@kernel.org?part=12