leds: bcm6328: improve blink support

BCM6328 controller has a margin of 20ms per blink step, which means that
we can only set it to 20, 40, 60 ... 1260 ms (0x3f * 20ms).
However, when checking if delay_on == delay_off, we were not considering
the case when the user had set delay_on=20 and delay_off=21, since this
will cause the driver to fallback to software blinking.
This update fixes this issue and improves blink steps by rounding them
in a more sensible way. Now 30-49ms is rounded to 40 ms, and previous
behaviour implied 40-59ms being rounded to 40 ms.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/drivers/leds/leds-bcm6328.c b/drivers/leds/leds-bcm6328.c
index 47f7c9f310be..1548259297c1 100644
--- a/drivers/leds/leds-bcm6328.c
+++ b/drivers/leds/leds-bcm6328.c
@@ -140,6 +140,18 @@ static void bcm6328_led_set(struct led_classdev *led_cdev,
         spin_unlock_irqrestore(led->lock, flags);
 }
 
+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;
+        if (bcm6328_delay == 0)
+                bcm6328_delay = 1;
+
+        return bcm6328_delay;
+}
+
 static int bcm6328_blink_set(struct led_classdev *led_cdev,
                              unsigned long *delay_on, unsigned long *delay_off)
 {
@@ -153,16 +165,14 @@ static int bcm6328_blink_set(struct led_classdev *led_cdev,
         if (!*delay_off)
                 *delay_off = BCM6328_LED_DEF_DELAY;
 
-        if (*delay_on != *delay_off) {
+        delay = bcm6328_blink_delay(*delay_on);
+        if (delay != bcm6328_blink_delay(*delay_off)) {
                 dev_dbg(led_cdev->dev,
                         "fallback to soft blinking (delay_on != delay_off)\n");
                 return -EINVAL;
         }
 
-        delay = *delay_on / BCM6328_LED_INTERVAL_MS;
-        if (delay == 0) {
-                delay = 1;
-        } else if (delay > BCM6328_LED_INTV_MASK) {
+        if (delay > BCM6328_LED_INTV_MASK) {
                 dev_dbg(led_cdev->dev,
                         "fallback to soft blinking (delay > %ums)\n",
                         BCM6328_LED_INTV_MASK * BCM6328_LED_INTERVAL_MS);