[PATCH] Enable HW LED blinking for hid-nintendo controllers

[Noa <coolreader18@gmail.com>]

This is my first patch, so hopefully I'm doing this right. I noticed
when trying to use `ledtrig-timer` on the Joycon LEDS that it at times
would hang for a while (I assume the firmware isn't a fan of frequent
LED subcommands, or something), and I've tested with this patch and it
blinks consistently with carefree abandon.

Separately, I was also thinking about exposing the LEDs as evdev codes,
but it doesn't seem like there's any good options of the `LED_*`
constants to represent them.

Signed-off-by: Noa <coolreader18@gmail.com>
---
 drivers/hid/hid-nintendo.c | 45 ++++++++++++++++++++++++++++++++------
 1 file changed, 38 insertions(+), 7 deletions(-)

diff --git a/drivers/hid/hid-nintendo.c b/drivers/hid/hid-nintendo.c
index 11ac246176ae..83dff0c4f7e1 100644
--- a/drivers/hid/hid-nintendo.c
+++ b/drivers/hid/hid-nintendo.c
@@ -2183,14 +2183,13 @@ static int joycon_input_create(struct joycon_ctlr *ctlr)
 	return 0;
 }
 
-/* Because the subcommand sets all the leds at once, the brightness argument is ignored */
-static int joycon_player_led_brightness_set(struct led_classdev *led,
-					    enum led_brightness brightness)
+/* Update the on/flash status of the leds according to their led_classdev fields */
+static int joycon_update_player_leds(struct device *dev)
 {
-	struct device *dev = led->dev->parent;
 	struct hid_device *hdev = to_hid_device(dev);
 	struct joycon_ctlr *ctlr;
 	int val = 0;
+	int flash = 0;
 	int i;
 	int ret;
 
@@ -2200,16 +2199,47 @@ static int joycon_player_led_brightness_set(struct led_classdev *led,
 		return -ENODEV;
 	}
 
-	for (i = 0; i < JC_NUM_LEDS; i++)
-		val |= ctlr->leds[i].brightness << i;
+	for (i = 0; i < JC_NUM_LEDS; i++) {
+		if (ctlr->leds[i].blink_delay_on || ctlr->leds[i].blink_delay_off)
+			flash |= 1 << i;
+		else if (ctlr->leds[i].brightness)
+			val |= 1 << i;
+	}
 
 	mutex_lock(&ctlr->output_mutex);
-	ret = joycon_set_player_leds(ctlr, 0, val);
+	ret = joycon_set_player_leds(ctlr, flash, val);
 	mutex_unlock(&ctlr->output_mutex);
 
 	return ret;
 }
 
+static int joycon_player_led_brightness_set(struct led_classdev *led,
+					    enum led_brightness brightness)
+{
+	led->brightness = brightness;
+
+	if (!brightness)
+		led->blink_delay_on = led->blink_delay_off = 0;
+
+	return joycon_update_player_leds(led->dev->parent);
+}
+
+/* the blink period of the leds can't be changed, and is always these values */
+static const JC_LED_BLINK_DELAY_ON = 500;
+static const JC_LED_BLINK_DELAY_OFF = 200;
+/* the different leds on a joycon can't actually be set to hw blink independently
+ * of each other, since they all use the same one subcommand, so this function
+ * actually resets the cycle of all the leds */
+static int joycon_player_led_blink_set(struct led_classdev *led,
+				     unsigned long *delay_on,
+				     unsigned long *delay_off)
+{
+	led->blink_delay_on = *delay_on = JC_LED_BLINK_DELAY_ON;
+	led->blink_delay_off = *delay_off = JC_LED_BLINK_DELAY_OFF;
+
+	return joycon_update_player_leds(led->dev->parent);
+}
+
 static int joycon_home_led_brightness_set(struct led_classdev *led,
 					  enum led_brightness brightness)
 {
@@ -2268,6 +2298,7 @@ static int joycon_leds_create(struct joycon_ctlr *ctlr)
 		led->max_brightness = 1;
 		led->brightness_set_blocking =
 					joycon_player_led_brightness_set;
+		led->blink_set = joycon_player_led_blink_set;
 		led->flags = LED_CORE_SUSPENDRESUME | LED_HW_PLUGGABLE;
 
 		led_val |= joycon_player_led_patterns[player_led_pattern][i] << i;
-- 
2.48.1