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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Generic Syscon LEDs Driver4 *5 * Copyright (c) 2014, Linaro Limited6 * Author: Linus Walleij <linus.walleij@linaro.org>7 */8#include <linux/io.h>9#include <linux/init.h>10#include <linux/of.h>11#include <linux/platform_device.h>12#include <linux/stat.h>13#include <linux/slab.h>14#include <linux/mfd/syscon.h>15#include <linux/regmap.h>16#include <linux/leds.h>17 18/**19 * struct syscon_led - state container for syscon based LEDs20 * @cdev: LED class device for this LED21 * @map: regmap to access the syscon device backing this LED22 * @offset: the offset into the syscon regmap for the LED register23 * @mask: the bit in the register corresponding to the LED24 * @state: current state of the LED25 */26struct syscon_led {27 struct led_classdev cdev;28 struct regmap *map;29 u32 offset;30 u32 mask;31 bool state;32};33 34static void syscon_led_set(struct led_classdev *led_cdev,35 enum led_brightness value)36{37 struct syscon_led *sled =38 container_of(led_cdev, struct syscon_led, cdev);39 u32 val;40 int ret;41 42 if (value == LED_OFF) {43 val = 0;44 sled->state = false;45 } else {46 val = sled->mask;47 sled->state = true;48 }49 50 ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val);51 if (ret < 0)52 dev_err(sled->cdev.dev, "error updating LED status\n");53}54 55static int syscon_led_probe(struct platform_device *pdev)56{57 struct led_init_data init_data = {};58 struct device *dev = &pdev->dev;59 struct device_node *np = dev_of_node(dev);60 struct device *parent;61 struct regmap *map;62 struct syscon_led *sled;63 enum led_default_state state;64 u32 value;65 int ret;66 67 parent = dev->parent;68 if (!parent) {69 dev_err(dev, "no parent for syscon LED\n");70 return -ENODEV;71 }72 map = syscon_node_to_regmap(dev_of_node(parent));73 if (IS_ERR(map)) {74 dev_err(dev, "no regmap for syscon LED parent\n");75 return PTR_ERR(map);76 }77 78 sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL);79 if (!sled)80 return -ENOMEM;81 82 sled->map = map;83 84 if (of_property_read_u32(np, "reg", &sled->offset) &&85 of_property_read_u32(np, "offset", &sled->offset))86 return -EINVAL;87 if (of_property_read_u32(np, "mask", &sled->mask))88 return -EINVAL;89 90 init_data.fwnode = of_fwnode_handle(np);91 92 state = led_init_default_state_get(init_data.fwnode);93 switch (state) {94 case LEDS_DEFSTATE_ON:95 ret = regmap_update_bits(map, sled->offset, sled->mask, sled->mask);96 if (ret < 0)97 return ret;98 sled->state = true;99 break;100 case LEDS_DEFSTATE_KEEP:101 ret = regmap_read(map, sled->offset, &value);102 if (ret < 0)103 return ret;104 sled->state = !!(value & sled->mask);105 break;106 default:107 ret = regmap_update_bits(map, sled->offset, sled->mask, 0);108 if (ret < 0)109 return ret;110 sled->state = false;111 }112 sled->cdev.brightness_set = syscon_led_set;113 114 ret = devm_led_classdev_register_ext(dev, &sled->cdev, &init_data);115 if (ret < 0)116 return ret;117 118 platform_set_drvdata(pdev, sled);119 dev_info(dev, "registered LED %s\n", sled->cdev.name);120 121 return 0;122}123 124static const struct of_device_id of_syscon_leds_match[] = {125 { .compatible = "register-bit-led", },126 {},127};128 129static struct platform_driver syscon_led_driver = {130 .probe = syscon_led_probe,131 .driver = {132 .name = "leds-syscon",133 .of_match_table = of_syscon_leds_match,134 .suppress_bind_attrs = true,135 },136};137builtin_platform_driver(syscon_led_driver);138