[PATCH 3/5] ASoC: rockchip_pdm: select REGMAP_MMIO

[Jude Gyimah]

rockchip_pdm calls __devm_regmap_init_mmio_clk, which
drivers/base/regmap/regmap-mmio.c provides under REGMAP_MMIO.

  rockchip_pdm.c:(.text+0xef4): undefined reference to
    `__devm_regmap_init_mmio_clk'

The driver can be built into vmlinux while REGMAP_MMIO is a module, in
which case the symbol is not there at link time.

Select rather than depend on: REGMAP_MMIO has no prompt of its own and is
only ever enabled by a select, so a depends on would leave
SND_SOC_ROCKCHIP_PDM unselectable.

Reproduced on v7.3, x86_64, with CONFIG_SND_SOC_ROCKCHIP_PDM=y and
CONFIG_REGMAP_MMIO=m.

Found with kreach, a static check that compares what Kconfig allows
against the symbols the compiled objects actually reference.

Fixes: fc05a5b22253 ("ASoC: rockchip: add support for pdm controller")
Signed-off-by: Jude Gyimah <jude.gyimah87 at gmail.com>
---
 sound/soc/rockchip/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sound/soc/rockchip/Kconfig b/sound/soc/rockchip/Kconfig
index 0f8ef6868356..e0ded1fa4da5 100644
--- a/sound/soc/rockchip/Kconfig
+++ b/sound/soc/rockchip/Kconfig
@@ -25,6 +25,7 @@ config SND_SOC_ROCKCHIP_I2S_TDM
 
 config SND_SOC_ROCKCHIP_PDM
 	tristate "Rockchip PDM Controller Driver"
+	select REGMAP_MMIO
 	select SND_SOC_GENERIC_DMAENGINE_PCM
 	select RATIONAL
 	help
-- 
2.43.0