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From: ChiaEn Wu <chiaen_wu@richtek.com>
To: <pavel@ucw.cz>, <lee@kernel.org>, <matthias.bgg@gmail.com>,
	<angelogioacchino.delregno@collabora.com>
CC: <linux-kernel@vger.kernel.org>, <linux-leds@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>, <linux-mediatek@lists.infradead.org>,
	<peterwu.pub@gmail.com>, <cy_huang@richtek.com>, ChiaEn Wu
	<chiaen_wu@richtek.com>
Subject: [PATCH] leds: mt6360: Fix the second LED can not enable torch mode by V4L2
Date: Tue, 9 Apr 2024 18:21:54 +0800
Message-ID: <28FE6F1712799128001.chiaen_wu@richtek.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain

V4L2 will disable strobe mode of the LED device when enable torch mode,
but this logic will conflict with the "priv->fled_torch_used"
in "mt6360_strobe_set()". So after enabling torch mode of the first
LED, the second LED will not be able to enable torch mode correctly.

Therefore, at the beginning of "mt6360_strobe_set()", check whether the
state of the upcoming change and the current LED device state are the
same, so as to avoid the above problem.

Signed-off-by: ChiaEn Wu <chiaen_wu@richtek.com>
---
 drivers/leds/flash/leds-mt6360.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/flash/leds-mt6360.c b/drivers/leds/flash/leds-mt6360.c
index a90de82f4568..1b75b4d36834 100644
--- a/drivers/leds/flash/leds-mt6360.c
+++ b/drivers/leds/flash/leds-mt6360.c
@@ -241,10 +241,20 @@ static int mt6360_strobe_set(struct led_classdev_flash *fl_cdev, bool state)
 	u32 enable_mask = MT6360_STROBEN_MASK | MT6360_FLCSEN_MASK(led->led_no);
 	u32 val = state ? MT6360_FLCSEN_MASK(led->led_no) : 0;
 	u32 prev = priv->fled_strobe_used, curr;
-	int ret;
+	int ret = 0;
 
 	mutex_lock(&priv->lock);
 
+	/*
+	 * If the state of the upcoming change is the same as the current LED
+	 * device state, then skip the subsequent code to avoid conflict
+	 * with the flow of turning on LED torch mode in V4L2.
+	 */
+	if (state == !!(BIT(led->led_no) & prev)) {
+		dev_info(lcdev->dev, "No change in strobe state [0x%x]\n", prev);
+		goto unlock;
+	}
+
 	/*
 	 * Only one set of flash control logic, use the flag to avoid torch is
 	 * currently used
-- 
2.42.0