gpio: loongson: Use BIT() macros

This switches the Loongson driver over to using the bitops BIT()
macros and drops some local variables and make the code easier
to read (in my opinion).

Cc: Keguang Zhang <keguang.zhang@gmail.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: linux-mips@linux-mips.org
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-loongson.c

@@ -19,6 +19,7 @@
 #include <linux/err.h>
 #include <linux/gpio/driver.h>
 #include <linux/platform_device.h>
+#include <linux/bitops.h>
 #include <asm/types.h>
 #include <loongson.h>
 
@@ -31,6 +32,11 @@
 #define LOONGSON_N_GPIO	STLS2F_N_GPIO
 #endif
 
+/*
+ * Offset into the register where we read lines, we write them from offset 0.
+ * This offset is the only thing that stand between us and using
+ * GPIO_GENERIC.
+ */
 #define LOONGSON_GPIO_IN_OFFSET	16
 
 static DEFINE_SPINLOCK(gpio_lock);
@@ -38,30 +44,25 @@ static DEFINE_SPINLOCK(gpio_lock);
 static int loongson_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
 {
 	u32 val;
-	u32 mask;
 
-	mask = 1 << (gpio + LOONGSON_GPIO_IN_OFFSET);
 	spin_lock(&gpio_lock);
 	val = LOONGSON_GPIODATA;
 	spin_unlock(&gpio_lock);
 
-	return (val & mask) != 0;
+	return !!(val & BIT(gpio + LOONGSON_GPIO_IN_OFFSET));
 }
 
 static void loongson_gpio_set_value(struct gpio_chip *chip,
 		unsigned gpio, int value)
 {
 	u32 val;
-	u32 mask;
-
-	mask = 1 << gpio;
 
 	spin_lock(&gpio_lock);
 	val = LOONGSON_GPIODATA;
 	if (value)
-		val |= mask;
+		val |= BIT(gpio);
 	else
-		val &= (~mask);
+		val &= ~BIT(gpio);
 	LOONGSON_GPIODATA = val;
 	spin_unlock(&gpio_lock);
 }
@@ -69,12 +70,10 @@ static void loongson_gpio_set_value(struct gpio_chip *chip,
 static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
 {
 	u32 temp;
-	u32 mask;
 
 	spin_lock(&gpio_lock);
-	mask = 1 << gpio;
 	temp = LOONGSON_GPIOIE;
-	temp |= mask;
+	temp |= BIT(gpio);
 	LOONGSON_GPIOIE = temp;
 	spin_unlock(&gpio_lock);
 
@@ -85,13 +84,11 @@ static int loongson_gpio_direction_output(struct gpio_chip *chip,
 		unsigned gpio, int level)
 {
 	u32 temp;
-	u32 mask;
 
 	loongson_gpio_set_value(chip, gpio, level);
 	spin_lock(&gpio_lock);
-	mask = 1 << gpio;
 	temp = LOONGSON_GPIOIE;
-	temp &= (~mask);
+	temp &= ~BIT(gpio);
 	LOONGSON_GPIOIE = temp;
 	spin_unlock(&gpio_lock);