linux-kernel - [PATCH v1] backlight: lm3630a: turn off both led strings when display is blank

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Date:   Fri,  5 May 2023 20:57:52 +0200
From:   Maximilian Weigand <mweigand2017@...il.com>
To:     Lee Jones <lee@...nel.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Helge Deller <deller@....de>,
        Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>, dri-devel@...ts.freedesktop.org,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pwm@...r.kernel.org
Cc:     Maximilian Weigand <mweigand@...igand.net>
Subject: [PATCH v1] backlight: lm3630a: turn off both led strings when display is blank

From: Maximilian Weigand <mweigand@...igand.net>

Use display_is_blank() to determine if the led strings should be turned
off in the update_status() functions of both strings.

Signed-off-by: Maximilian Weigand <mweigand@...igand.net>
---
 drivers/video/backlight/lm3630a_bl.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
index d8c42acecb5d..5498b57329f9 100644
--- a/drivers/video/backlight/lm3630a_bl.c
+++ b/drivers/video/backlight/lm3630a_bl.c
@@ -202,7 +202,9 @@ static int lm3630a_bank_a_update_status(struct backlight_device *bl)
 	usleep_range(1000, 2000);
 	/* minimum brightness is 0x04 */
 	ret = lm3630a_write(pchip, REG_BRT_A, bl->props.brightness);
-	if (bl->props.brightness < 0x4)
+
+	if (backlight_is_blank(bl) || (bl->props.brightness < 0x4))
+		/* turn the string off  */
 		ret |= lm3630a_update(pchip, REG_CTRL, LM3630A_LEDA_ENABLE, 0);
 	else
 		ret |= lm3630a_update(pchip, REG_CTRL,
@@ -277,7 +279,9 @@ static int lm3630a_bank_b_update_status(struct backlight_device *bl)
 	usleep_range(1000, 2000);
 	/* minimum brightness is 0x04 */
 	ret = lm3630a_write(pchip, REG_BRT_B, bl->props.brightness);
-	if (bl->props.brightness < 0x4)
+
+	if (backlight_is_blank(bl) || (bl->props.brightness < 0x4))
+		/* turn the string off  */
 		ret |= lm3630a_update(pchip, REG_CTRL, LM3630A_LEDB_ENABLE, 0);
 	else
 		ret |= lm3630a_update(pchip, REG_CTRL,

base-commit: 457391b0380335d5e9a5babdec90ac53928b23b4
--
2.39.2