Re: [PATCH 1/2 (v2)] leds-bcm6328: Reuse bcm6328_led_set() instead of copying its functionality

From: Jacek Anaszewski
Date: Tue Nov 17 2015 - 03:15:15 EST

On 11/17/2015 09:06 AM, Jacek Anaszewski wrote:
Hi Alvaro, Simon,

On 11/17/2015 08:42 AM, Simon Arlott wrote:
On 16/11/15 21:33, Ãlvaro FernÃndez Rojas wrote:
Still wrong, you are setting the led value after unlocking the spinlock.

I have to unlock it because bcm6328_led_set() locks that spinlock.

Commit message from the first version of the patch justified that
properly. It should be preserved in the final patch:

As bcm6328_led_set() expects to acquire the spinlock, narrow the locking
to only cover reading of the current state. There is no need to hold the
spinlock between reading the current value and setting it again because
the LED device has not yet been registered.

Hmm, if so, then spin_lock in bcm6328_led isn't needed at all, as it
is guaranteed that no concurrent process will be executing this

El 16/11/2015 a las 21:24, Simon Arlott escribiÃ:
When ensuring a consistent initial LED state in bcm6328_led (as they
be blinking instead of on/off), the LED register is set using an
copy of bcm6328_led_set(). To avoid further errors relating to
active low
handling, call this function directly instead.

As bcm6328_led_set() acquires the same spinlock again when updating the
register, it is called after unlocking.

Signed-off-by: Simon Arlott <simon@xxxxxxxxxxx>
drivers/leds/leds-bcm6328.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/leds/leds-bcm6328.c b/drivers/leds/leds-bcm6328.c
index c7ea5c6..95d0cf9 100644
--- a/drivers/leds/leds-bcm6328.c
+++ b/drivers/leds/leds-bcm6328.c
@@ -314,14 +314,10 @@ static int bcm6328_led(struct device *dev,
struct device_node *nc, u32 reg,
} else {
led->cdev.brightness = LED_OFF;
- if ((led->active_low && led->cdev.brightness == LED_FULL) ||
- (!led->active_low && led->cdev.brightness == LED_OFF))
- bcm6328_led_mode(led, BCM6328_LED_MODE_ON);
- else
- bcm6328_led_mode(led, BCM6328_LED_MODE_OFF);
spin_unlock_irqrestore(lock, flags);

+ bcm6328_led_set(&led->cdev, led->cdev.brightness);
led->cdev.brightness_set = bcm6328_led_set;
led->cdev.blink_set = bcm6328_blink_set;

Best Regards,
Jacek Anaszewski
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