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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.c167
1 files changed, 167 insertions, 0 deletions
diff --git a/drivers/leds/leds-syscon.c b/drivers/leds/leds-syscon.c
new file mode 100644
index 000000000..6896e2d9b
--- /dev/null
+++ b/drivers/leds/leds-syscon.c
@@ -0,0 +1,167 @@
+/*
+ * Generic Syscon LEDs Driver
+ *
+ * Copyright (c) 2014, Linaro Limited
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#include <linux/io.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 __init syscon_leds_spawn(struct device_node *np,
+ struct device *dev,
+ struct regmap *map)
+{
+ struct device_node *child;
+ int ret;
+
+ for_each_available_child_of_node(np, child) {
+ struct syscon_led *sled;
+ const char *state;
+
+ /* Only check for register-bit-leds */
+ if (of_property_match_string(child, "compatible",
+ "register-bit-led") < 0)
+ continue;
+
+ sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL);
+ if (!sled)
+ return -ENOMEM;
+
+ sled->map = map;
+
+ if (of_property_read_u32(child, "offset", &sled->offset))
+ return -EINVAL;
+ if (of_property_read_u32(child, "mask", &sled->mask))
+ return -EINVAL;
+ sled->cdev.name =
+ of_get_property(child, "label", NULL) ? : child->name;
+ sled->cdev.default_trigger =
+ of_get_property(child, "linux,default-trigger", NULL);
+
+ state = of_get_property(child, "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;
+
+ ret = led_classdev_register(dev, &sled->cdev);
+ if (ret < 0)
+ return ret;
+
+ dev_info(dev, "registered LED %s\n", sled->cdev.name);
+ }
+ return 0;
+}
+
+static int __init syscon_leds_init(void)
+{
+ struct device_node *np;
+
+ for_each_of_allnodes(np) {
+ struct platform_device *pdev;
+ struct regmap *map;
+ int ret;
+
+ if (!of_device_is_compatible(np, "syscon"))
+ continue;
+
+ map = syscon_node_to_regmap(np);
+ if (IS_ERR(map)) {
+ pr_err("error getting regmap for syscon LEDs\n");
+ continue;
+ }
+
+ /*
+ * If the map is there, the device should be there, we allocate
+ * memory on the syscon device's behalf here.
+ */
+ pdev = of_find_device_by_node(np);
+ if (!pdev)
+ return -ENODEV;
+ ret = syscon_leds_spawn(np, &pdev->dev, map);
+ if (ret)
+ dev_err(&pdev->dev, "could not spawn syscon LEDs\n");
+ }
+
+ return 0;
+}
+device_initcall(syscon_leds_init);