gpio: mxs: add name_to_gpio() function

Override the default name_to_gpio() function with one that
accepts strings of the form bank:pin.  If a colon is present
in the provided name, it behaves like the default version.

This lets the "gpio" command work with sane names rather than
requiring the user to enter the bank/pin composite in decimal.

Signed-off-by: Mans Rullgard <mans@mansr.com>
Reviewed-by: Stefano Babic <sbabic@denx.de>
diff --git a/drivers/gpio/mxs_gpio.c b/drivers/gpio/mxs_gpio.c
index da0199b..b54a10b 100644
--- a/drivers/gpio/mxs_gpio.c
+++ b/drivers/gpio/mxs_gpio.c
@@ -114,3 +114,18 @@
 {
 	return 0;
 }
+
+int name_to_gpio(const char *name)
+{
+	unsigned bank, pin;
+	char *end;
+
+	bank = simple_strtoul(name, &end, 10);
+
+	if (!*end || *end != ':')
+		return bank;
+
+	pin = simple_strtoul(end + 1, NULL, 10);
+
+	return (bank << MXS_PAD_BANK_SHIFT) | (pin << MXS_PAD_PIN_SHIFT);
+}