usb: typec: mux: add Qualcomm WCD939X USB SubSystem Altmode Mux driver

Qualcomm WCD9390/WCD9395 is a standalone Hi-Fi audio codec IC with a
functionally separate USB SubSystem for Altmode/Analog Audio Switch
accessible over an I2C interface.

It provides switching USB-C USB2.0 lines between USB and Audio Headphones
speaker lines, and the USB-C SBU lines between DisplayPort AUX and Audio
Headphones Microphone/Ground.

The Audio Headphone and Microphone data path between the Codec and the
USB-C Mux subsystems are external to the IC, thus requiring DT
port-endpoint graph description to handle USB-C altmode & orientation
switching for Audio Accessory Mode.
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231212-topic-sm8650-upstream-wcd939x-usbss-v2-2-38961fea5867@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/mux/Kconfig

@@ -56,4 +56,14 @@ config TYPEC_MUX_PTN36502
 	  Say Y or M if your system has a NXP PTN36502 Type-C redriver chip
 	  found on some devices with a Type-C port.
 
+config TYPEC_MUX_WCD939X_USBSS
+	tristate "Qualcomm WCD939x USBSS Analog Audio Switch driver"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Driver for the Qualcomm WCD939x Audio Codec USBSS domain which
+	  provides support for muxing analog audio and sideband signals on a
+	  common USB Type-C connector.
+	  If compiled as a module, the module will be named wcd939x-usbss.
+
 endmenu

drivers/usb/typec/mux/Makefile

@@ -6,3 +6,4 @@ obj-$(CONFIG_TYPEC_MUX_PI3USB30532)	+= pi3usb30532.o
 obj-$(CONFIG_TYPEC_MUX_INTEL_PMC)	+= intel_pmc_mux.o
 obj-$(CONFIG_TYPEC_MUX_NB7VPQ904M)	+= nb7vpq904m.o
 obj-$(CONFIG_TYPEC_MUX_PTN36502)	+= ptn36502.o
+obj-$(CONFIG_TYPEC_MUX_WCD939X_USBSS)	+= wcd939x-usbss.o