gpio: pcf857x: add lock and handle more chips

Two small updates to the pcf857x driver: (a) the max732[89] chips are
also second sources for the pcf8574/a, and (b) add a mutex to prevent
trashing the cached state.  Adding the lock is effectively a bugfix,
although it seems unlikely that anyone would have run into the issue it
protects against.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 9e0c4fbfc51a..fced1909cbba 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -45,7 +45,7 @@ config GPIO_PCA953X
           will be called pca953x.
 
 config GPIO_PCF857X
-        tristate "PCF857x, PCA857x, and PCA967x I2C GPIO expanders"
+        tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders"
         depends on I2C
         help
           Say yes here to provide access to most "quasi-bidirectional" I2C
@@ -54,7 +54,8 @@ config GPIO_PCF857X
           some of them.  Compatible models include:
 
           8 bits:   pcf8574, pcf8574a, pca8574, pca8574a,
-                    pca9670, pca9672, pca9674, pca9674a
+                    pca9670, pca9672, pca9674, pca9674a,
+                    max7328, max7329
 
           16 bits:  pcf8575, pcf8575c, pca8575,
                     pca9671, pca9673, pca9675