Selecting only REGMAP_I2C can leave REGMAP unset, causing build errors,
so also select REGMAP to prevent the build errors.

../drivers/misc/eeprom/at24.c:540:42: warning: 'struct regmap_config' declared inside parameter list will not be visible outside of this definition or declaration
  540 |                                   struct regmap_config *regmap_config)
../drivers/misc/eeprom/at24.c: In function 'at24_make_dummy_client':
../drivers/misc/eeprom/at24.c:552:18: error: implicit declaration of function 'devm_regmap_init_i2c' [-Werror=implicit-function-declaration]
  552 |         regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
../drivers/misc/eeprom/at24.c:552:16: warning: assignment to 'struct regmap *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
  552 |         regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
../drivers/misc/eeprom/at24.c: In function 'at24_probe':
../drivers/misc/eeprom/at24.c:586:16: error: variable 'regmap_config' has initializer but incomplete type
  586 |         struct regmap_config regmap_config = { };
../drivers/misc/eeprom/at24.c:586:30: error: storage size of 'regmap_config' isn't known
  586 |         struct regmap_config regmap_config = { };
../drivers/misc/eeprom/at24.c:586:30: warning: unused variable 'regmap_config' [-Wunused-variable]

Fixes: 5c015258478e ("eeprom: at24: add basic regmap_i2c support")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: linux-i2c@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Mark Brown <broonie@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
---
 drivers/misc/eeprom/Kconfig |    1 +
 1 file changed, 1 insertion(+)

diff -- a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig
--- a/drivers/misc/eeprom/Kconfig
+++ b/drivers/misc/eeprom/Kconfig
@@ -6,6 +6,7 @@ config EEPROM_AT24
 	depends on I2C && SYSFS
 	select NVMEM
 	select NVMEM_SYSFS
+	select REGMAP
 	select REGMAP_I2C
 	help
 	  Enable this driver to get read/write support to most I2C EEPROMs

On Thu, Jun 8, 2023 at 4:54 AM Randy Dunlap <rdunlap@infradead.org> wrote:
>
> Selecting only REGMAP_I2C can leave REGMAP unset, causing build errors,
> so also select REGMAP to prevent the build errors.
>
> ../drivers/misc/eeprom/at24.c:540:42: warning: 'struct regmap_config' declared inside parameter list will not be visible outside of this definition or declaration
>   540 |                                   struct regmap_config *regmap_config)
> ../drivers/misc/eeprom/at24.c: In function 'at24_make_dummy_client':
> ../drivers/misc/eeprom/at24.c:552:18: error: implicit declaration of function 'devm_regmap_init_i2c' [-Werror=implicit-function-declaration]
>   552 |         regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
> ../drivers/misc/eeprom/at24.c:552:16: warning: assignment to 'struct regmap *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
>   552 |         regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
> ../drivers/misc/eeprom/at24.c: In function 'at24_probe':
> ../drivers/misc/eeprom/at24.c:586:16: error: variable 'regmap_config' has initializer but incomplete type
>   586 |         struct regmap_config regmap_config = { };
> ../drivers/misc/eeprom/at24.c:586:30: error: storage size of 'regmap_config' isn't known
>   586 |         struct regmap_config regmap_config = { };
> ../drivers/misc/eeprom/at24.c:586:30: warning: unused variable 'regmap_config' [-Wunused-variable]
>
> Fixes: 5c015258478e ("eeprom: at24: add basic regmap_i2c support")
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: Heiner Kallweit <hkallweit1@gmail.com>
> Cc: Bartosz Golaszewski <brgl@bgdev.pl>
> Cc: linux-i2c@vger.kernel.org
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> ---
>  drivers/misc/eeprom/Kconfig |    1 +
>  1 file changed, 1 insertion(+)
>
> diff -- a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig
> --- a/drivers/misc/eeprom/Kconfig
> +++ b/drivers/misc/eeprom/Kconfig
> @@ -6,6 +6,7 @@ config EEPROM_AT24
>         depends on I2C && SYSFS
>         select NVMEM
>         select NVMEM_SYSFS
> +       select REGMAP
>         select REGMAP_I2C
>         help
>           Enable this driver to get read/write support to most I2C EEPROMs

Applied, thanks!

Bart