[PATCH RFC] iio: dac: Fix build error when CONFIG_SPI_MASTER=y &&CONFIG_I2C=m

[Axel Lin]

This patch fixes below build error when CONFIG_SPI_MASTER=y && CONFIG_I2C=m:

drivers/built-in.o: In function `ad5064_i2c_write':
drivers/iio/dac/ad5064.c:608: undefined reference to `i2c_master_send'
drivers/built-in.o: In function `ad5064_i2c_register_driver':
drivers/iio/dac/ad5064.c:646: undefined reference to `i2c_register_driver'
drivers/built-in.o: In function `ad5064_i2c_unregister_driver':
drivers/iio/dac/ad5064.c:651: undefined reference to `i2c_del_driver'
make: *** [vmlinux] Error 1

Add config IIO_DAC_I2C_AND_SPI helper to handle such case:
When CONFIG_I2C=m, meaning we can't build the drivers in with I2C support.
Thus don't allow the drivers to be compiled as built-in.

Signed-off-by: Axel Lin <axel.lin@xxxxxxxxxx>
---
 drivers/iio/dac/Kconfig | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index f4a6f08..34bc1d7 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -1,11 +1,22 @@
 #
 # DAC drivers
 #
+
+# Helper to resolve issues with configs that have SPI enabled but I2C
+# modular, meaning we can't build the drivers in with I2C support.
+# We use an ordered list of conditional defaults to pick the appropriate
+# setting - SPI can't be modular so that case doesn't need to be covered.
+config IIO_DAC_I2C_AND_SPI
+	tristate
+	default m if I2C=m
+	default y if I2C=y
+	default y if SPI_MASTER=y
+
 menu "Digital to analog converters"
 
 config AD5064
 	tristate "Analog Devices AD5064 and similar multi-channel DAC driver"
-	depends on (SPI_MASTER || I2C)
+	depends on IIO_DAC_I2C_AND_SPI
 	help
 	  Say yes here to build support for Analog Devices AD5024, AD5025, AD5044,
 	  AD5045, AD5064, AD5064-1, AD5065, AD5628, AD5629R, AD5648, AD5666, AD5668,
@@ -27,7 +38,7 @@ config AD5360
 
 config AD5380
 	tristate "Analog Devices AD5380/81/82/83/84/90/91/92 DAC driver"
-	depends on (SPI_MASTER || I2C)
+	depends on IIO_DAC_I2C_AND_SPI
 	select REGMAP_I2C if I2C
 	select REGMAP_SPI if SPI_MASTER
 	help
@@ -57,7 +68,7 @@ config AD5624R_SPI
 
 config AD5446
 	tristate "Analog Devices AD5446 and similar single channel DACs driver"
-	depends on (SPI_MASTER || I2C)
+	depends on IIO_DAC_I2C_AND_SPI
 	help
 	  Say yes here to build support for Analog Devices AD5300, AD5301, AD5310,
 	  AD5311, AD5320, AD5321, AD5444, AD5446, AD5450, AD5451, AD5452, AD5453,
-- 
1.8.1.2



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