gpio: add driver for MAX7300 I2C GPIO extender

Add the MAX7300-I2C variant of the MAX7301-SPI version.  Both chips share
the same core logic, so the generic part of the in-kernel SPI-driver is
refactored into a generic part.  The I2C and SPI specific funtions are
then wrapped into seperate drivers picking up the generic part.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Juergen Beisert <j.beisert@pengutronix.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 1f1d88ae68d6..f3549b8779d8 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -65,6 +65,9 @@ config GPIO_SYSFS
 
 # put expanders in the right section, in alphabetical order
 
+config GPIO_MAX730X
+        tristate
+
 comment "Memory mapped GPIO expanders:"
 
 config GPIO_PL061
@@ -87,6 +90,13 @@ config GPIO_VR41XX
 
 comment "I2C GPIO expanders:"
 
+config GPIO_MAX7300
+        tristate "Maxim MAX7300 GPIO expander"
+        depends on I2C
+        select GPIO_MAX730X
+        help
+          GPIO driver for Maxim MAX7301 I2C-based GPIO expander.
+
 config GPIO_MAX732X
         tristate "MAX7319, MAX7320-7327 I2C Port Expanders"
         depends on I2C
@@ -226,8 +236,9 @@ comment "SPI GPIO expanders:"
 config GPIO_MAX7301
         tristate "Maxim MAX7301 GPIO expander"
         depends on SPI_MASTER
+        select GPIO_MAX730X
         help
-          gpio driver for Maxim MAX7301 SPI GPIO expander.
+          GPIO driver for Maxim MAX7301 SPI-based GPIO expander.
 
 config GPIO_MCP23S08
         tristate "Microchip MCP23S08 I/O expander"