Linus Walleij | 535f09c | 2014-05-22 00:34:16 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Generic Syscon LEDs Driver |
| 3 | * |
| 4 | * Copyright (c) 2014, Linaro Limited |
| 5 | * Author: Linus Walleij <linus.walleij@linaro.org> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License as |
| 9 | * published by the Free Software Foundation; either version 2 of |
| 10 | * the License, or (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, |
| 20 | * MA 02111-1307 USA |
Linus Walleij | 535f09c | 2014-05-22 00:34:16 +0200 | [diff] [blame] | 21 | */ |
| 22 | #include <linux/io.h> |
| 23 | #include <linux/of_device.h> |
| 24 | #include <linux/of_address.h> |
| 25 | #include <linux/platform_device.h> |
| 26 | #include <linux/stat.h> |
| 27 | #include <linux/slab.h> |
| 28 | #include <linux/mfd/syscon.h> |
| 29 | #include <linux/regmap.h> |
| 30 | #include <linux/leds.h> |
| 31 | |
| 32 | /** |
| 33 | * struct syscon_led - state container for syscon based LEDs |
| 34 | * @cdev: LED class device for this LED |
| 35 | * @map: regmap to access the syscon device backing this LED |
| 36 | * @offset: the offset into the syscon regmap for the LED register |
| 37 | * @mask: the bit in the register corresponding to the LED |
| 38 | * @state: current state of the LED |
| 39 | */ |
| 40 | struct syscon_led { |
| 41 | struct led_classdev cdev; |
| 42 | struct regmap *map; |
| 43 | u32 offset; |
| 44 | u32 mask; |
| 45 | bool state; |
| 46 | }; |
| 47 | |
| 48 | static void syscon_led_set(struct led_classdev *led_cdev, |
| 49 | enum led_brightness value) |
| 50 | { |
| 51 | struct syscon_led *sled = |
| 52 | container_of(led_cdev, struct syscon_led, cdev); |
| 53 | u32 val; |
| 54 | int ret; |
| 55 | |
| 56 | if (value == LED_OFF) { |
| 57 | val = 0; |
| 58 | sled->state = false; |
| 59 | } else { |
| 60 | val = sled->mask; |
| 61 | sled->state = true; |
| 62 | } |
| 63 | |
| 64 | ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val); |
| 65 | if (ret < 0) |
| 66 | dev_err(sled->cdev.dev, "error updating LED status\n"); |
| 67 | } |
| 68 | |
Linus Walleij | 3f6e42c | 2014-10-24 03:57:19 -0700 | [diff] [blame] | 69 | static int __init syscon_leds_spawn(struct device_node *np, |
| 70 | struct device *dev, |
| 71 | struct regmap *map) |
Linus Walleij | 535f09c | 2014-05-22 00:34:16 +0200 | [diff] [blame] | 72 | { |
Linus Walleij | 535f09c | 2014-05-22 00:34:16 +0200 | [diff] [blame] | 73 | struct device_node *child; |
Linus Walleij | 535f09c | 2014-05-22 00:34:16 +0200 | [diff] [blame] | 74 | int ret; |
| 75 | |
Linus Walleij | 535f09c | 2014-05-22 00:34:16 +0200 | [diff] [blame] | 76 | for_each_available_child_of_node(np, child) { |
| 77 | struct syscon_led *sled; |
| 78 | const char *state; |
| 79 | |
| 80 | /* Only check for register-bit-leds */ |
| 81 | if (of_property_match_string(child, "compatible", |
| 82 | "register-bit-led") < 0) |
| 83 | continue; |
| 84 | |
| 85 | sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL); |
| 86 | if (!sled) |
| 87 | return -ENOMEM; |
| 88 | |
| 89 | sled->map = map; |
| 90 | |
| 91 | if (of_property_read_u32(child, "offset", &sled->offset)) |
| 92 | return -EINVAL; |
| 93 | if (of_property_read_u32(child, "mask", &sled->mask)) |
| 94 | return -EINVAL; |
| 95 | sled->cdev.name = |
| 96 | of_get_property(child, "label", NULL) ? : child->name; |
| 97 | sled->cdev.default_trigger = |
| 98 | of_get_property(child, "linux,default-trigger", NULL); |
| 99 | |
| 100 | state = of_get_property(child, "default-state", NULL); |
| 101 | if (state) { |
| 102 | if (!strcmp(state, "keep")) { |
| 103 | u32 val; |
| 104 | |
| 105 | ret = regmap_read(map, sled->offset, &val); |
| 106 | if (ret < 0) |
| 107 | return ret; |
| 108 | sled->state = !!(val & sled->mask); |
| 109 | } else if (!strcmp(state, "on")) { |
| 110 | sled->state = true; |
| 111 | ret = regmap_update_bits(map, sled->offset, |
| 112 | sled->mask, |
| 113 | sled->mask); |
| 114 | if (ret < 0) |
| 115 | return ret; |
| 116 | } else { |
| 117 | sled->state = false; |
| 118 | ret = regmap_update_bits(map, sled->offset, |
| 119 | sled->mask, 0); |
| 120 | if (ret < 0) |
| 121 | return ret; |
| 122 | } |
Linus Walleij | 535f09c | 2014-05-22 00:34:16 +0200 | [diff] [blame] | 123 | } |
| 124 | sled->cdev.brightness_set = syscon_led_set; |
| 125 | |
| 126 | ret = led_classdev_register(dev, &sled->cdev); |
| 127 | if (ret < 0) |
| 128 | return ret; |
| 129 | |
| 130 | dev_info(dev, "registered LED %s\n", sled->cdev.name); |
| 131 | } |
Linus Walleij | 3f6e42c | 2014-10-24 03:57:19 -0700 | [diff] [blame] | 132 | return 0; |
| 133 | } |
Linus Walleij | 535f09c | 2014-05-22 00:34:16 +0200 | [diff] [blame] | 134 | |
Linus Walleij | 3f6e42c | 2014-10-24 03:57:19 -0700 | [diff] [blame] | 135 | static int __init syscon_leds_init(void) |
| 136 | { |
| 137 | struct device_node *np; |
| 138 | |
| 139 | for_each_of_allnodes(np) { |
| 140 | struct platform_device *pdev; |
| 141 | struct regmap *map; |
| 142 | int ret; |
| 143 | |
| 144 | if (!of_device_is_compatible(np, "syscon")) |
| 145 | continue; |
| 146 | |
| 147 | map = syscon_node_to_regmap(np); |
| 148 | if (IS_ERR(map)) { |
| 149 | pr_err("error getting regmap for syscon LEDs\n"); |
| 150 | continue; |
| 151 | } |
| 152 | |
| 153 | /* |
| 154 | * If the map is there, the device should be there, we allocate |
| 155 | * memory on the syscon device's behalf here. |
| 156 | */ |
| 157 | pdev = of_find_device_by_node(np); |
| 158 | if (!pdev) |
| 159 | return -ENODEV; |
| 160 | ret = syscon_leds_spawn(np, &pdev->dev, map); |
| 161 | if (ret) |
| 162 | dev_err(&pdev->dev, "could not spawn syscon LEDs\n"); |
| 163 | } |
| 164 | |
| 165 | return 0; |
Linus Walleij | 535f09c | 2014-05-22 00:34:16 +0200 | [diff] [blame] | 166 | } |
| 167 | device_initcall(syscon_leds_init); |