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path: root/drivers/leds/leds-syscon.c
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Diffstat (limited to 'drivers/leds/leds-syscon.c')
-rw-r--r--drivers/leds/leds-syscon.c136
1 files changed, 136 insertions, 0 deletions
diff --git a/drivers/leds/leds-syscon.c b/drivers/leds/leds-syscon.c
new file mode 100644
index 0000000000..360a376fa7
--- /dev/null
+++ b/drivers/leds/leds-syscon.c
@@ -0,0 +1,136 @@
+// 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.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;
+ enum led_default_state state;
+ u32 value;
+ 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;
+
+ init_data.fwnode = of_fwnode_handle(np);
+
+ state = led_init_default_state_get(init_data.fwnode);
+ switch (state) {
+ case LEDS_DEFSTATE_ON:
+ ret = regmap_update_bits(map, sled->offset, sled->mask, sled->mask);
+ if (ret < 0)
+ return ret;
+ sled->state = true;
+ break;
+ case LEDS_DEFSTATE_KEEP:
+ ret = regmap_read(map, sled->offset, &value);
+ if (ret < 0)
+ return ret;
+ sled->state = !!(value & sled->mask);
+ break;
+ default:
+ ret = regmap_update_bits(map, sled->offset, sled->mask, 0);
+ if (ret < 0)
+ return ret;
+ sled->state = false;
+ }
+ sled->cdev.brightness_set = syscon_led_set;
+
+ 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);