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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | // 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 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 (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; 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 = devm_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 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); |