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/*
* 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/module.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 device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
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(parent->of_node);
if (!map) {
dev_err(dev, "no regmap for syscon LED parent\n");
return -ENODEV;
}
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;
sled->cdev.name =
of_get_property(np, "label", NULL) ? : np->name;
sled->cdev.default_trigger =
of_get_property(np, "linux,default-trigger", NULL);
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;
ret = led_classdev_register(dev, &sled->cdev);
if (ret < 0)
return ret;
platform_set_drvdata(pdev, sled);
dev_info(dev, "registered LED %s\n", sled->cdev.name);
return 0;
}
static int syscon_led_remove(struct platform_device *pdev)
{
struct syscon_led *sled = platform_get_drvdata(pdev);
led_classdev_unregister(&sled->cdev);
/* Turn it off */
regmap_update_bits(sled->map, sled->offset, sled->mask, 0);
return 0;
}
static const struct of_device_id of_syscon_leds_match[] = {
{ .compatible = "register-bit-led", },
{},
};
MODULE_DEVICE_TABLE(of, of_syscon_leds_match);
static struct platform_driver syscon_led_driver = {
.probe = syscon_led_probe,
.remove = syscon_led_remove,
.driver = {
.name = "leds-syscon",
.of_match_table = of_syscon_leds_match,
},
};
module_platform_driver(syscon_led_driver);
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