[PATCH] ASoC: codecs: wcd938x: fix wcd module dependency

[Arnd Bergmann <arnd@kernel.org>]

From: Arnd Bergmann <arnd@arndb.de>

With SND_SOC_ALL_CODECS=y and SND_SOC_WCD938X_SDW=m, there is a link
error from a reverse dependency, since the built-in codec driver calls
into the modular soundwire back-end:

x86_64-linux-ld: sound/soc/codecs/wcd938x.o: in function `wcd938x_codec_free':
wcd938x.c:(.text+0x2c0): undefined reference to `wcd938x_sdw_free'
x86_64-linux-ld: sound/soc/codecs/wcd938x.o: in function `wcd938x_codec_hw_params':
wcd938x.c:(.text+0x2f6): undefined reference to `wcd938x_sdw_hw_params'
x86_64-linux-ld: sound/soc/codecs/wcd938x.o: in function `wcd938x_codec_set_sdw_stream':
wcd938x.c:(.text+0x332): undefined reference to `wcd938x_sdw_set_sdw_stream'
x86_64-linux-ld: sound/soc/codecs/wcd938x.o: in function `wcd938x_tx_swr_ctrl':
wcd938x.c:(.text+0x23de): undefined reference to `wcd938x_swr_get_current_bank'
x86_64-linux-ld: sound/soc/codecs/wcd938x.o: in function `wcd938x_bind':
wcd938x.c:(.text+0x2579): undefined reference to `wcd938x_sdw_device_get'
x86_64-linux-ld: wcd938x.c:(.text+0x25a1): undefined reference to `wcd938x_sdw_device_get'
x86_64-linux-ld: wcd938x.c:(.text+0x262a): undefined reference to `__devm_regmap_init_sdw'

Work around this using two small hacks: An added Kconfig dependency
prevents the main driver from being built-in when soundwire support
itself is a loadable module to allow calling devm_regmap_init_sdw(),
and a Makefile trick links the wcd938x-sdw backend as built-in
if needed to solve the dependency between the two modules.

Fixes: 045442228868 ("ASoC: codecs: wcd938x: add audio routing and Kconfig")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
I saw this on -rc2, please ignore if this is already fixed
---
 sound/soc/codecs/Kconfig  | 1 +
 sound/soc/codecs/Makefile | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index 7ebae3f09435..459deba31485 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -1558,6 +1558,7 @@ config SND_SOC_WCD934X
 
 config SND_SOC_WCD938X
 	tristate
+	depends on SOUNDWIRE || !SOUNDWIRE
 
 config SND_SOC_WCD938X_SDW
 	tristate "WCD9380/WCD9385 Codec - SDW"
diff --git a/sound/soc/codecs/Makefile b/sound/soc/codecs/Makefile
index de8b83dd2c76..7bb38c370842 100644
--- a/sound/soc/codecs/Makefile
+++ b/sound/soc/codecs/Makefile
@@ -583,7 +583,10 @@ obj-$(CONFIG_SND_SOC_WCD_MBHC)	+= snd-soc-wcd-mbhc.o
 obj-$(CONFIG_SND_SOC_WCD9335)	+= snd-soc-wcd9335.o
 obj-$(CONFIG_SND_SOC_WCD934X)	+= snd-soc-wcd934x.o
 obj-$(CONFIG_SND_SOC_WCD938X)	+= snd-soc-wcd938x.o
-obj-$(CONFIG_SND_SOC_WCD938X_SDW) += snd-soc-wcd938x-sdw.o
+ifdef CONFIG_SND_SOC_WCD938X_SDW
+# avoid link failure by forcing sdw code built-in when needed
+obj-$(CONFIG_SND_SOC_WCD938X) += snd-soc-wcd938x-sdw.o
+endif
 obj-$(CONFIG_SND_SOC_WL1273)	+= snd-soc-wl1273.o
 obj-$(CONFIG_SND_SOC_WM0010)	+= snd-soc-wm0010.o
 obj-$(CONFIG_SND_SOC_WM1250_EV1) += snd-soc-wm1250-ev1.o
-- 
2.29.2