1 files changed, 140 insertions, 0 deletions
diff --git a/drivers/leds/leds-syscon.c b/drivers/leds/leds-syscon.c
new file mode 100644
index 000000000..7eddb8ecb
--- /dev/null
+++ b/drivers/leds/leds-syscon.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Generic Syscon LEDs Driver
+ *
+ * Copyright (c) 2014, Linaro Limited
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ */
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/leds.h>
+
+/**
+ * struct syscon_led - state container for syscon based LEDs
+ * @cdev: LED class device for this LED
+ * @map: regmap to access the syscon device backing this LED
+ * @offset: the offset into the syscon regmap for the LED register
+ * @mask: the bit in the register corresponding to the LED
+ * @state: current state of the LED
+ */
+struct syscon_led {
+	struct led_classdev cdev;
+	struct regmap *map;
+	u32 offset;
+	u32 mask;
+	bool state;
+};
+
+static void syscon_led_set(struct led_classdev *led_cdev,
+	enum led_brightness value)
+{
+	struct syscon_led *sled =
+		container_of(led_cdev, struct syscon_led, cdev);
+	u32 val;
+	int ret;
+
+	if (value == LED_OFF) {
+		val = 0;
+		sled->state = false;
+	} else {
+		val = sled->mask;
+		sled->state = true;
+	}
+
+	ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val);
+	if (ret < 0)
+		dev_err(sled->cdev.dev, "error updating LED status\n");
+}
+
+static int syscon_led_probe(struct platform_device *pdev)
+{
+	struct led_init_data init_data = {};
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev_of_node(dev);
+	struct device *parent;
+	struct regmap *map;
+	struct syscon_led *sled;
+	const char *state;
+	int ret;
+
+	parent = dev->parent;
+	if (!parent) {
+		dev_err(dev, "no parent for syscon LED\n");
+		return -ENODEV;
+	}
+	map = syscon_node_to_regmap(dev_of_node(parent));
+	if (IS_ERR(map)) {
+		dev_err(dev, "no regmap for syscon LED parent\n");
+		return PTR_ERR(map);
+	}
+
+	sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL);
+	if (!sled)
+		return -ENOMEM;
+
+	sled->map = map;
+
+	if (of_property_read_u32(np, "offset", &sled->offset))
+		return -EINVAL;
+	if (of_property_read_u32(np, "mask", &sled->mask))
+		return -EINVAL;
+
+	state = of_get_property(np, "default-state", NULL);
+	if (state) {
+		if (!strcmp(state, "keep")) {
+			u32 val;
+
+			ret = regmap_read(map, sled->offset, &val);
+			if (ret < 0)
+				return ret;
+			sled->state = !!(val & sled->mask);
+		} else if (!strcmp(state, "on")) {
+			sled->state = true;
+			ret = regmap_update_bits(map, sled->offset,
+						 sled->mask,
+						 sled->mask);
+			if (ret < 0)
+				return ret;
+		} else {
+			sled->state = false;
+			ret = regmap_update_bits(map, sled->offset,
+						 sled->mask, 0);
+			if (ret < 0)
+				return ret;
+		}
+	}
+	sled->cdev.brightness_set = syscon_led_set;
+
+	init_data.fwnode = of_fwnode_handle(np);
+
+	ret = devm_led_classdev_register_ext(dev, &sled->cdev, &init_data);
+	if (ret < 0)
+		return ret;
+
+	platform_set_drvdata(pdev, sled);
+	dev_info(dev, "registered LED %s\n", sled->cdev.name);
+
+	return 0;
+}
+
+static const struct of_device_id of_syscon_leds_match[] = {
+	{ .compatible = "register-bit-led", },
+	{},
+};
+
+static struct platform_driver syscon_led_driver = {
+	.probe		= syscon_led_probe,
+	.driver		= {
+		.name	= "leds-syscon",
+		.of_match_table = of_syscon_leds_match,
+		.suppress_bind_attrs = true,
+	},
+};
+builtin_platform_driver(syscon_led_driver);