[PATCH v5] leds-bcm6328: support second hw blinking interval

["Álvaro Fernández Rojas" <noltari@gmail.com>]

Right now the driver uses only 3 LED modes:
0: On
1: HW Blinking (Interval 1)
3: Off

However, the controller supports a second HW blinking interval, which results
in 4 possible LED modes:
0: On
1: HW Blinking (Interval 1)
2: HW Blinking (Interval 2)
3: Off

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 v5: add commit description including LED modes clarification
 v4: improve code documentation and use blink instead of intervals, which
     should make the code much more clear to understand
 v3: add code documentation
 v2: remove LED from the other blinking interval

 drivers/leds/leds-bcm6328.c | 97 ++++++++++++++++++++++++++++---------
 1 file changed, 75 insertions(+), 22 deletions(-)

diff --git a/drivers/leds/leds-bcm6328.c b/drivers/leds/leds-bcm6328.c
index 42e1b7598c3a..bad7efb75112 100644
--- a/drivers/leds/leds-bcm6328.c
+++ b/drivers/leds/leds-bcm6328.c
@@ -24,12 +24,17 @@
 
 #define BCM6328_LED_MAX_COUNT		24
 #define BCM6328_LED_DEF_DELAY		500
-#define BCM6328_LED_INTERVAL_MS		20
 
-#define BCM6328_LED_INTV_MASK		0x3f
-#define BCM6328_LED_FAST_INTV_SHIFT	6
-#define BCM6328_LED_FAST_INTV_MASK	(BCM6328_LED_INTV_MASK << \
-					 BCM6328_LED_FAST_INTV_SHIFT)
+#define BCM6328_LED_BLINK_DELAYS	2
+#define BCM6328_LED_BLINK_MS		20
+
+#define BCM6328_LED_BLINK_MASK		0x3f
+#define BCM6328_LED_BLINK1_SHIFT	0
+#define BCM6328_LED_BLINK1_MASK		(BCM6328_LED_BLINK_MASK << \
+					 BCM6328_LED_BLINK1_SHIFT)
+#define BCM6328_LED_BLINK2_SHIFT	6
+#define BCM6328_LED_BLINK2_MASK		(BCM6328_LED_BLINK_MASK << \
+					 BCM6328_LED_BLINK2_SHIFT)
 #define BCM6328_SERIAL_LED_EN		BIT(12)
 #define BCM6328_SERIAL_LED_MUX		BIT(13)
 #define BCM6328_SERIAL_LED_CLK_NPOL	BIT(14)
@@ -45,8 +50,8 @@
 
 #define BCM6328_LED_MODE_MASK		3
 #define BCM6328_LED_MODE_ON		0
-#define BCM6328_LED_MODE_FAST		1
-#define BCM6328_LED_MODE_BLINK		2
+#define BCM6328_LED_MODE_BLINK1		1
+#define BCM6328_LED_MODE_BLINK2		2
 #define BCM6328_LED_MODE_OFF		3
 #define BCM6328_LED_SHIFT(X)		((X) << 1)
 
@@ -127,12 +132,18 @@ static void bcm6328_led_set(struct led_classdev *led_cdev,
 	unsigned long flags;
 
 	spin_lock_irqsave(led->lock, flags);
-	*(led->blink_leds) &= ~BIT(led->pin);
+
+	/* Remove LED from cached HW blinking intervals */
+	led->blink_leds[0] &= ~BIT(led->pin);
+	led->blink_leds[1] &= ~BIT(led->pin);
+
+	/* Set LED on/off */
 	if ((led->active_low && value == LED_OFF) ||
 	    (!led->active_low && value != LED_OFF))
 		bcm6328_led_mode(led, BCM6328_LED_MODE_ON);
 	else
 		bcm6328_led_mode(led, BCM6328_LED_MODE_OFF);
+
 	spin_unlock_irqrestore(led->lock, flags);
 }
 
@@ -140,8 +151,8 @@ static unsigned long bcm6328_blink_delay(unsigned long delay)
 {
 	unsigned long bcm6328_delay;
 
-	bcm6328_delay = delay + BCM6328_LED_INTERVAL_MS / 2;
-	bcm6328_delay = bcm6328_delay / BCM6328_LED_INTERVAL_MS;
+	bcm6328_delay = delay + BCM6328_LED_BLINK_MS / 2;
+	bcm6328_delay = bcm6328_delay / BCM6328_LED_BLINK_MS;
 	if (bcm6328_delay == 0)
 		bcm6328_delay = 1;
 
@@ -168,28 +179,68 @@ static int bcm6328_blink_set(struct led_classdev *led_cdev,
 		return -EINVAL;
 	}
 
-	if (delay > BCM6328_LED_INTV_MASK) {
+	if (delay > BCM6328_LED_BLINK_MASK) {
 		dev_dbg(led_cdev->dev,
 			"fallback to soft blinking (delay > %ums)\n",
-			BCM6328_LED_INTV_MASK * BCM6328_LED_INTERVAL_MS);
+			BCM6328_LED_BLINK_MASK * BCM6328_LED_BLINK_MS);
 		return -EINVAL;
 	}
 
 	spin_lock_irqsave(led->lock, flags);
-	if (*(led->blink_leds) == 0 ||
-	    *(led->blink_leds) == BIT(led->pin) ||
-	    *(led->blink_delay) == delay) {
+	/*
+	 * Check if any of the two configurable HW blinking intervals is
+	 * available:
+	 *   1. No LEDs assigned to the HW blinking interval.
+	 *   2. Only this LED is assigned to the HW blinking interval.
+	 *   3. LEDs with the same delay assigned.
+	 */
+	if (led->blink_leds[0] == 0 ||
+	    led->blink_leds[0] == BIT(led->pin) ||
+	    led->blink_delay[0] == delay) {
 		unsigned long val;
 
-		*(led->blink_leds) |= BIT(led->pin);
-		*(led->blink_delay) = delay;
+		/* Add LED to the first HW blinking interval cache */
+		led->blink_leds[0] |= BIT(led->pin);
+
+		/* Remove LED from the second HW blinking interval cache */
+		led->blink_leds[1] &= ~BIT(led->pin);
 
+		/* Cache first HW blinking interval delay */
+		led->blink_delay[0] = delay;
+
+		/* Update the delay for the first HW blinking interval */
 		val = bcm6328_led_read(led->mem + BCM6328_REG_INIT);
-		val &= ~BCM6328_LED_FAST_INTV_MASK;
-		val |= (delay << BCM6328_LED_FAST_INTV_SHIFT);
+		val &= ~BCM6328_LED_BLINK1_MASK;
+		val |= (delay << BCM6328_LED_BLINK1_SHIFT);
 		bcm6328_led_write(led->mem + BCM6328_REG_INIT, val);
 
-		bcm6328_led_mode(led, BCM6328_LED_MODE_BLINK);
+		/* Set the LED to first HW blinking interval */
+		bcm6328_led_mode(led, BCM6328_LED_MODE_BLINK1);
+
+		rc = 0;
+	} else if (led->blink_leds[1] == 0 ||
+		   led->blink_leds[1] == BIT(led->pin) ||
+		   led->blink_delay[1] == delay) {
+		unsigned long val;
+
+		/* Remove LED from the first HW blinking interval */
+		led->blink_leds[0] &= ~BIT(led->pin);
+
+		/* Add LED to the second HW blinking interval */
+		led->blink_leds[1] |= BIT(led->pin);
+
+		/* Cache second HW blinking interval delay */
+		led->blink_delay[1] = delay;
+
+		/* Update the delay for the second HW blinking interval */
+		val = bcm6328_led_read(led->mem + BCM6328_REG_INIT);
+		val &= ~BCM6328_LED_BLINK2_MASK;
+		val |= (delay << BCM6328_LED_BLINK2_SHIFT);
+		bcm6328_led_write(led->mem + BCM6328_REG_INIT, val);
+
+		/* Set the LED to second HW blinking interval */
+		bcm6328_led_mode(led, BCM6328_LED_MODE_BLINK2);
+
 		rc = 0;
 	} else {
 		dev_dbg(led_cdev->dev,
@@ -358,11 +409,13 @@ static int bcm6328_leds_probe(struct platform_device *pdev)
 	if (!lock)
 		return -ENOMEM;
 
-	blink_leds = devm_kzalloc(dev, sizeof(*blink_leds), GFP_KERNEL);
+	blink_leds = devm_kcalloc(dev, BCM6328_LED_BLINK_DELAYS,
+				  sizeof(*blink_leds), GFP_KERNEL);
 	if (!blink_leds)
 		return -ENOMEM;
 
-	blink_delay = devm_kzalloc(dev, sizeof(*blink_delay), GFP_KERNEL);
+	blink_delay = devm_kcalloc(dev, BCM6328_LED_BLINK_DELAYS,
+				   sizeof(*blink_delay), GFP_KERNEL);
 	if (!blink_delay)
 		return -ENOMEM;
 
-- 
2.26.2