On Thu, Dec 15, 2022 at 04:13:03PM +0000, Russell King (Oracle) wrote:

Hi Christian,

Thanks for the patch.

I think Andrew's email is offline at the moment.

Notice by gmail spamming me "I CAN'T SEND IT AHHHHH"
Holidy times I guess?

On Thu, Dec 15, 2022 at 12:54:28AM +0100, Christian Marangi wrote:

quoted

+static bool led_trigger_is_supported(struct led_classdev *led_cdev,
+				     struct led_trigger *trigger)
+{
+	switch (led_cdev->blink_mode) {
+	case SOFTWARE_CONTROLLED:
+		if (trigger->supported_blink_modes == HARDWARE_ONLY)
+			return 0;
+		break;
+	case HARDWARE_CONTROLLED:
+		if (trigger->supported_blink_modes == SOFTWARE_ONLY)
+			return 0;
+		break;
+	case SOFTWARE_HARDWARE_CONTROLLED:
+		break;
+	default:
+		return 0;
+	}
+
+	return 1;

Should be returning true/false. I'm not sure I'm a fan of the style of
this though - wouldn't the following be easier to read?

	switch (led_cdev->blink_mode) {
	case SOFTWARE_CONTROLLED:
		return trigger->supported_blink_modes != HARDWARE_ONLY;

	case HARDWARE_CONTROLLED:
		return trigger->supported_blink_modes != SOFTWARE_ONLY;

	case SOFTWARE_HARDWARE_CONTROLLED:
		return true;
	}
?

Much better!

Also, does it really need a default case - without it, when the
led_blink_modes enum is expanded and the switch statement isn't
updated, we'll get a compiler warning which will prompt this to be
updated - whereas, with a default case, it won't.

I added the default just to mute some compiler warning. But guess if
every enum is handled the warning should not be reported.

quoted

@@ -188,6 +213,10 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
 		led_set_brightness(led_cdev, LED_OFF);
 	}
 	if (trig) {
+		/* Make sure the trigger support the LED blink mode */
+		if (!led_trigger_is_supported(led_cdev, trig))
+			return -EINVAL;

Shouldn't validation happen before we start taking any actions? In other
words, before we remove the previous trigger?

trigger_set first remove any trigger and set the led off. Then apply the
new trigger. So the validation is done only when a trigger is actually
applied. Think we should understand the best case here.

quoted

@@ -350,12 +381,26 @@ static inline bool led_sysfs_is_disabled(struct led_classdev *led_cdev)
 
 #define TRIG_NAME_MAX 50
 
+enum led_trigger_blink_supported_modes {
+	SOFTWARE_ONLY = SOFTWARE_CONTROLLED,
+	HARDWARE_ONLY = HARDWARE_CONTROLLED,
+	SOFTWARE_HARDWARE = SOFTWARE_HARDWARE_CONTROLLED,

I suspect all these generic names are asking for eventual namespace
clashes. Maybe prefix them with LED_ ?

Agree they are pretty generic so I can see why... My only concern was
making them too long... Maybe reduce them to SW or HW? LEDS_SW_ONLY...
LEDS_SW_CONTROLLED?

Thanks.

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