Re: [PATCH v8 3/5] iio: dac: mcp47feb02: refactor MCP47FEB02 I2C driver into two modules

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] kconfig: silent loss of driver during oldconfig upgrade due to prompt removal
--

commit 18f0a50c0487bf003f9efe902b8ee1569bb70adb
Author: Ariana Lazar <ariana.lazar@microchip.com>

iio: dac: mcp47feb02: refactor MCP47FEB02 I2C driver into two modules

This commit refactors the MCP47FEB02 I2C driver into a core module and an
I2C-specific module to prepare for future SPI support.

> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index b6c8873c68c54..8121a71945f63 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -611,9 +611,13 @@ config MCP47A1
>  	  will be called mcp47a1.
>  
>  config MCP47FEB02
> -	tristate "MCP47F(E/V)B01/02/04/08/11/12/14/18/21/22/24/28 DAC driver"
> +	tristate

[Severity: Medium]
Will this cause a silent loss of the driver for existing users upgrading
their kernel?

Because the original user-visible Kconfig symbol CONFIG_MCP47FEB02 had its
prompt removed here, the build system (e.g., when running make oldconfig)
will see it has no prompt and reset it to 'n'.

> +
> +config MCP47FEB02_I2C
> +	tristate "MCP47F(E/V)B01/02/04/08/11/12/14/18/21/22/24/28 I2C DAC driver"
>  	depends on I2C
>  	select REGMAP_I2C
> +	select MCP47FEB02

At the same time, the newly introduced CONFIG_MCP47FEB02_I2C defaults to 'n'.
This results in existing configurations losing the DAC driver entirely upon
upgrade.

Would it be better to keep the original CONFIG_MCP47FEB02 symbol as the
user-visible driver to preserve backwards compatibility, and instead introduce
a new hidden symbol like CONFIG_MCP47FEB02_CORE for the shared code?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260924-mcp47feb02_refactor-v8-0-17dc2ce3485e@microchip.com?part=3