soc: bcm: bcm2835-power: Refactor ASB control

The functions to control the async AXI bridges are almost identical.
So define a general function to handle it and keep the original ones as
wrapper. This should make this driver easier to extend.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220625113619.15944-9-stefan.wahren@i2se.com

drivers/soc/bcm/bcm2835-power.c

@@ -148,7 +148,7 @@ struct bcm2835_power {
 	struct reset_controller_dev reset;
 };
 
-static int bcm2835_asb_enable(struct bcm2835_power *power, u32 reg)
+static int bcm2835_asb_control(struct bcm2835_power *power, u32 reg, bool enable)
 {
 	u64 start;
 
@@ -158,7 +158,12 @@ static int bcm2835_asb_enable(struct bcm2835_power *power, u32 reg)
 	start = ktime_get_ns();
 
 	/* Enable the module's async AXI bridges. */
-	ASB_WRITE(reg, ASB_READ(reg) & ~ASB_REQ_STOP);
+	if (enable) {
+		ASB_WRITE(reg, ASB_READ(reg) & ~ASB_REQ_STOP);
+	} else {
+		ASB_WRITE(reg, ASB_READ(reg) | ASB_REQ_STOP);
+	}
+
 	while (ASB_READ(reg) & ASB_ACK) {
 		cpu_relax();
 		if (ktime_get_ns() - start >= 1000)
@@ -168,24 +173,14 @@ static int bcm2835_asb_enable(struct bcm2835_power *power, u32 reg)
 	return 0;
 }
 
-static int bcm2835_asb_disable(struct bcm2835_power *power, u32 reg)
+static int bcm2835_asb_enable(struct bcm2835_power *power, u32 reg)
 {
-	u64 start;
-
-	if (!reg)
-		return 0;
-
-	start = ktime_get_ns();
-
-	/* Enable the module's async AXI bridges. */
-	ASB_WRITE(reg, ASB_READ(reg) | ASB_REQ_STOP);
-	while (!(ASB_READ(reg) & ASB_ACK)) {
-		cpu_relax();
-		if (ktime_get_ns() - start >= 1000)
-			return -ETIMEDOUT;
-	}
+	return bcm2835_asb_control(power, reg, true);
+}
 
-	return 0;
+static int bcm2835_asb_disable(struct bcm2835_power *power, u32 reg)
+{
+	return bcm2835_asb_control(power, reg, false);
 }
 
 static int bcm2835_power_power_off(struct bcm2835_power_domain *pd, u32 pm_reg)