linux-kernel - [PATCH 2/2] leds: syscon: Implement support for value property

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Date:   Wed,  6 Jul 2022 13:28:28 +0200
From:   Pali Rohár <pali@...nel.org>
To:     Pavel Machek <pavel@....cz>, Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Marek Behún <kabel@...nel.org>
Cc:     linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] leds: syscon: Implement support for value property

This new value property specify when is LED enabled. By default its value
is from the mask and therefore LED is enabled when bit is set. This change
allows to define inverted logic (0 - enable LED, 1 - disable LED) by
setting value property to zero.

Signed-off-by: Pali Rohár <pali@...nel.org>
---
 drivers/leds/leds-syscon.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/leds/leds-syscon.c b/drivers/leds/leds-syscon.c
index 7eddb8ecb44e..337a0bada967 100644
--- a/drivers/leds/leds-syscon.c
+++ b/drivers/leds/leds-syscon.c
@@ -29,6 +29,7 @@ struct syscon_led {
 	struct regmap *map;
 	u32 offset;
 	u32 mask;
+	u32 value;
 	bool state;
 };
 
@@ -41,10 +42,10 @@ static void syscon_led_set(struct led_classdev *led_cdev,
 	int ret;
 
 	if (value == LED_OFF) {
-		val = 0;
+		val = ~sled->value;
 		sled->state = false;
 	} else {
-		val = sled->mask;
+		val = sled->value;
 		sled->state = true;
 	}
 
@@ -85,6 +86,8 @@ static int syscon_led_probe(struct platform_device *pdev)
 		return -EINVAL;
 	if (of_property_read_u32(np, "mask", &sled->mask))
 		return -EINVAL;
+	if (of_property_read_u32(np, "value", &sled->value))
+		sled->value = sled->mask;
 
 	state = of_get_property(np, "default-state", NULL);
 	if (state) {
@@ -94,18 +97,19 @@ static int syscon_led_probe(struct platform_device *pdev)
 			ret = regmap_read(map, sled->offset, &val);
 			if (ret < 0)
 				return ret;
-			sled->state = !!(val & sled->mask);
+			sled->state = (val & sled->mask) == sled->value;
 		} else if (!strcmp(state, "on")) {
 			sled->state = true;
 			ret = regmap_update_bits(map, sled->offset,
 						 sled->mask,
-						 sled->mask);
+						 sled->value);
 			if (ret < 0)
 				return ret;
 		} else {
 			sled->state = false;
 			ret = regmap_update_bits(map, sled->offset,
-						 sled->mask, 0);
+						 sled->mask,
+						 ~sled->value);
 			if (ret < 0)
 				return ret;
 		}
-- 
2.20.1