serdev: Introduce new bus for serial attached devices

robherring · gregkh · commit cd6484e1830b · 2017-02-03T10:17:02.000+01:00
The serdev bus is designed for devices such as Bluetooth, WiFi, GPS
and NFC connected to UARTs on host processors. Tradionally these have
been handled with tty line disciplines, rfkill, and userspace glue such
as hciattach. This approach has many drawbacks since it doesn't fit
into the Linux driver model. Handling of sideband signals, power control
and firmware loading are the main issues.

This creates a serdev bus with controllers (i.e. host serial ports) and
attached devices. Typically, these are point to point connections, but
some devices have muxing protocols or a h/w mux is conceivable. Any
muxing is not yet supported with the serdev bus.

Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
Reviewed-By: Sebastian Reichel &lt;sre@kernel.org&gt;
Tested-By: Sebastian Reichel &lt;sre@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
diff --git a/MAINTAINERS b/MAINTAINERS
@@ -10831,6 +10831,14 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/serial/
 F:	drivers/tty/serial/
 
+SERIAL DEVICE BUS
+M:	Rob Herring <robh@kernel.org>
+L:	linux-serial@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/serial/slave-device.txt
+F:	drivers/tty/serdev/
+F:	include/linux/serdev.h
+
 SERIAL IR RECEIVER
 M:	Sean Young <sean@mess.org>
 L:	linux-media@vger.kernel.org
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
@@ -46,6 +46,7 @@ config SGI_MBCS
          say Y or M here, otherwise say N.
 
 source "drivers/tty/serial/Kconfig"
+source "drivers/tty/serdev/Kconfig"
 
 config TTY_PRINTK
 	tristate "TTY driver to output user messages via printk"
diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_R3964)		+= n_r3964.o
 obj-y				+= vt/
 obj-$(CONFIG_HVC_DRIVER)	+= hvc/
 obj-y				+= serial/
+obj-$(CONFIG_SERIAL_DEV_BUS)	+= serdev/
 
 # tty drivers
 obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o
diff --git a/drivers/tty/serdev/Kconfig b/drivers/tty/serdev/Kconfig
@@ -0,0 +1,8 @@
+#
+# Serial bus device driver configuration
+#
+menuconfig SERIAL_DEV_BUS
+	tristate "Serial device bus"
+	help
+	  Core support for devices connected via a serial port.
+
diff --git a/drivers/tty/serdev/Makefile b/drivers/tty/serdev/Makefile
@@ -0,0 +1,3 @@
+serdev-objs := core.o
+
+obj-$(CONFIG_SERIAL_DEV_BUS) += serdev.o
diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
diff --git a/include/linux/serdev.h b/include/linux/serdev.h

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+serdev-objs := core.o`
	`2`	`+`
	`3`	`+obj-$(CONFIG_SERIAL_DEV_BUS) += serdev.o`