gpio: pca953x (i2c) handles max7310 too

The pca953x driver can handle another 8-bit I/O expander, the max7310.
This patch adds that chip to the list of supported IDs in that driver, and
expands the Kconfig helptext accordingly.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/gpio/Kconfig

@@ -28,12 +28,18 @@ config DEBUG_GPIO
 comment "I2C GPIO expanders:"
 
 config GPIO_PCA953X
-	tristate "PCA953x I/O ports"
+	tristate "PCA953x, PCA955x, and MAX7310 I/O ports"
 	depends on I2C
 	help
-	  Say yes here to support the PCA9534 (8-bit), PCA9535 (16-bit),
-	  PCA9536 (4-bit), PCA9537 (4-bit), PCA9538 (8-bit), and PCA9539
-	  (16-bit) I/O ports. These parts are made by NXP and TI.
+	  Say yes here to provide access to several register-oriented
+	  SMBus I/O expanders, made mostly by NXP or TI.  Compatible
+	  models include:
+
+	  4 bits:	pca9536, pca9537
+
+	  8 bits:	max7310, pca9534, pca9538, pca9554, pca9557
+
+	  16 bits:	pca9535, pca9539, pca9555
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called pca953x.

drivers/gpio/pca953x.c

@@ -33,7 +33,7 @@ static const struct i2c_device_id pca953x_id[] = {
 	{ "pca9554", 8, },
 	{ "pca9555", 16, },
 	{ "pca9557", 8, },
-	/* REVISIT several pca955x parts should work here too */
+	{ "max7310", 8, },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, pca953x_id);