On 09/03/15 10:27, Geert Uytterhoeven wrote:

Hi Arnd,

On Wed, Jan 28, 2015 at 2:58 PM, Arnd Bergmann [off-list ref] wrote:

quoted

ak8975 depends on I2C and GPIOLIB, so any symbols that selects
ak8975 must have the same dependency, or we get build errors:

drivers/iio/magnetometer/ak8975.c: In function 'ak8975_who_i_am':
drivers/iio/magnetometer/ak8975.c:393:2: error: implicit declaration of function 'i2c_smbus_read_i2c_block_data' [-Werror=implicit-function-declaration]
  ret = i2c_smbus_read_i2c_block_data(client, AK09912_REG_WIA1,
  ^
drivers/iio/magnetometer/ak8975.c: In function 'ak8975_set_mode':
drivers/iio/magnetometer/ak8975.c:431:2: error: implicit declaration of function 'i2c_smbus_write_byte_data' [-Werror=implicit-function-declaration]
  ret = i2c_smbus_write_byte_data(data->client,

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 57e73a423b1e85 ("iio: ak8975: add ak09911 and ak09912 support")
---
I found this recent regression doing ARM randconfig builds, please apply

diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
index 4c7a4c52dd06..a5d6de72c523 100644
--- a/drivers/iio/magnetometer/Kconfig
+++ b/drivers/iio/magnetometer/Kconfig

@@ -18,6 +18,8 @@ config AK8975

 config AK09911
        tristate "Asahi Kasei AK09911 3-axis Compass"
+       depends on I2C
+       depends on GPIOLIB
        select AK8975
        help
          Deprecated: AK09911 is now supported by AK8975 driver.

I just saw the AK8975/AK09911 config options disappear for a v4.0-rc3 m68k
allmodconfig kernel. Apparently it built fine with !GPIOLIB before, as many
gpiolib (consumer) functions have dummies for the !GPIOLIB case.

So I think the GPIOLIB dependency can be relaxed to "GPIOLIB || COMPILE_TEST".
The same may be true for many other GPIOLIB consumer drivers.
Will look into it and send patches...

Gr{oetje,eeting}s,

                        Geert

Sounds likely and would be great to increase build coverage on these if we can.

Jonathan