[PATCH 2/2] iio: dac: Fix dependencies of AD9739A

[Alexey Makhalov]

0-DAY CI Kernel Test automation reported an issue:

   ld: drivers/base/regmap/regmap-spi.o: in function `regmap_spi_read':
   regmap-spi.c:(.text+0xf): undefined reference to `spi_write_then_read'
   ld: drivers/base/regmap/regmap-spi.o: in function `regmap_spi_gather_write':
   regmap-spi.c:(.text+0x2b4): undefined reference to `spi_sync'
   ld: drivers/base/regmap/regmap-spi.o: in function `spi_sync_transfer.constprop.0':
   regmap-spi.c:(.text+0x337): undefined reference to `spi_sync'
   ld: drivers/base/regmap/regmap-spi.o: in function `regmap_spi_async_write':
   regmap-spi.c:(.text+0x445): undefined reference to `spi_async'
   ld: drivers/iio/dac/ad9739a.o: in function `ad9739a_driver_init':
   ad9739a.c:(.init.text+0x10): undefined reference to `__spi_register_driver'

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for REGMAP_SPI
   Depends on [n]: SPI [=n]
   Selected by [y]:
   - AD9739A [=y] && IIO [=y] && (SPI [=n] || COMPILE_TEST [=y])

The issue is caused by CONFIG_AD9739A=y when CONFIG_SPI is not set.

Add explicit dependency on SPI and conditional selection of REGMAP_SPI.

Fixes: e77603d5468b ("iio: dac: support the ad9739a RF DAC")
Reported-by: kernel test robot <lkp at intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202406152104.FxakP1MB-lkp@intel.com/
Signed-off-by: Alexey Makhalov <alexey.makhalov at broadcom.com>
---
 drivers/iio/dac/Kconfig | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index 3c2bf620f00f..d095f4d26e49 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -133,8 +133,8 @@ config AD5624R_SPI
 
 config AD9739A
 	tristate "Analog Devices AD9739A RF DAC spi driver"
-	depends on SPI || COMPILE_TEST
-	select REGMAP_SPI
+	depends on SPI
+	select REGMAP_SPI if SPI_MASTER
 	select IIO_BACKEND
 	help
 	  Say yes here to build support for Analog Devices AD9739A Digital-to
-- 
2.39.4