tty: Added a CONFIG_TTY option to allow removal of TTY

The option allows you to remove TTY and compile without errors. This
saves space on systems that won't support TTY interfaces anyway.
bloat-o-meter output is below.

The bulk of this patch consists of Kconfig changes adding "depends on
TTY" to various serial devices and similar drivers that require the TTY
layer.  Ideally, these dependencies would occur on a common intermediate
symbol such as SERIO, but most drivers "select SERIO" rather than
"depends on SERIO", and "select" does not respect dependencies.

bloat-o-meter output comparing our previous minimal to new minimal by
removing TTY.  The list is filtered to not show removed entries with awk
'$3 != "-"' as the list was very long.

add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350)
function                                     old     new   delta
chr_dev_init                                 166     170      +4
allow_signal                                  80      82      +2
static.__warned                              143     142      -1
disallow_signal                               63      62      -1
__set_special_pids                            95      94      -1
unregister_console                           126     121      -5
start_kernel                                 546     541      -5
register_console                             593     588      -5
copy_from_user                                45      40      -5
sys_setsid                                   128     120      -8
sys_vhangup                                   32      19     -13
do_exit                                     1543    1526     -17
bitmap_zero                                   60      40     -20
arch_local_irq_save                          137     117     -20
release_task                                 674     652     -22
static.spin_unlock_irqrestore                308     260     -48

Signed-off-by: Joe Millenbach <jmillenbach@gmail.com>
Reviewed-by: Jamey Sharp <jamey@minilop.net>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 515cfe790543..3d6f548dd3d4 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -192,6 +192,8 @@ config TOUCHSCREEN_DA9052
 	  To compile this driver as a module, choose M here: the
 	  module will be called da9052_tsi.
 
+if TTY
+
 config TOUCHSCREEN_DYNAPRO
 	tristate "Dynapro serial touchscreen"
 	select SERIO
@@ -216,6 +218,8 @@ config TOUCHSCREEN_HAMPSHIRE
 	  To compile this driver as a module, choose M here: the
 	  module will be called hampshire.
 
+endif # TTY
+
 config TOUCHSCREEN_EETI
 	tristate "EETI touchscreen panel support"
 	depends on I2C
@@ -237,6 +241,7 @@ config TOUCHSCREEN_EGALAX
 
 config TOUCHSCREEN_FUJITSU
 	tristate "Fujitsu serial touchscreen"
+	depends on TTY
 	select SERIO
 	help
 	  Say Y here if you have the Fujitsu touchscreen (such as one
@@ -275,6 +280,8 @@ config TOUCHSCREEN_S3C2410
 	  To compile this driver as a module, choose M here: the
 	  module will be called s3c2410_ts.
 
+if TTY
+
 config TOUCHSCREEN_GUNZE
 	tristate "Gunze AHL-51S touchscreen"
 	select SERIO
@@ -311,6 +318,8 @@ config TOUCHSCREEN_WACOM_W8001
 	  To compile this driver as a module, choose M here: the
 	  module will be called wacom_w8001.
 
+endif # TTY
+
 config TOUCHSCREEN_WACOM_I2C
 	tristate "Wacom Tablet support (I2C)"
 	depends on I2C
@@ -369,6 +378,8 @@ config TOUCHSCREEN_MMS114
 	  To compile this driver as a module, choose M here: the
 	  module will be called mms114.
 
+if TTY
+
 config TOUCHSCREEN_MTOUCH
 	tristate "MicroTouch serial touchscreens"
 	select SERIO
@@ -393,6 +404,8 @@ config TOUCHSCREEN_INEXIO
 	  To compile this driver as a module, choose M here: the
 	  module will be called inexio.
 
+endif # TTY
+
 config TOUCHSCREEN_INTEL_MID
 	tristate "Intel MID platform resistive touchscreen"
 	depends on INTEL_SCU_IPC
@@ -450,6 +463,7 @@ config TOUCHSCREEN_HTCPEN
 
 config TOUCHSCREEN_PENMOUNT
 	tristate "Penmount serial touchscreen"
+	depends on TTY
 	select SERIO
 	help
 	  Say Y here if you have a Penmount serial touchscreen connected to
@@ -493,6 +507,8 @@ config TOUCHSCREEN_TNETV107X
 	  To compile this driver as a module, choose M here: the
 	  module will be called tnetv107x-ts.
 
+if TTY
+
 config TOUCHSCREEN_TOUCHRIGHT
 	tristate "Touchright serial touchscreen"
 	select SERIO
@@ -517,6 +533,8 @@ config TOUCHSCREEN_TOUCHWIN
 	  To compile this driver as a module, choose M here: the
 	  module will be called touchwin.
 
+endif # TTY
+
 config TOUCHSCREEN_TI_AM335X_TSC
 	tristate "TI Touchscreen Interface"
 	depends on MFD_TI_AM335X_TSCADC
@@ -790,6 +808,8 @@ config TOUCHSCREEN_USB_EASYTOUCH
 	  Say Y here if you have an EasyTouch USB Touch controller.
 	  If unsure, say N.
 
+if TTY
+
 config TOUCHSCREEN_TOUCHIT213
 	tristate "Sahara TouchIT-213 touchscreen"
 	select SERIO
@@ -813,6 +833,8 @@ config TOUCHSCREEN_TSC_SERIO
 	  To compile this driver as a module, choose M here: the
 	  module will be called tsc40.
 
+endif # TTY
+
 config TOUCHSCREEN_TSC2005
         tristate "TSC2005 based touchscreens"
         depends on SPI_MASTER && GENERIC_HARDIRQS